本篇文章较长，介绍了docker的概念、安装、命令、镜像、容器卷以及常用软件的安装
1、简介
1.1 是什么
出现的原因：环境配置相当麻烦，换一台机器，就要重来一次，费力费时。很多人想到，能不能从根本上解决问题，软件可以带环境安装？也就是说，安装的时候，把原始环境一模一样地复制过来。开发人员利用 Docker 可以消除协作编码时“在我的机器上可正常工作”的问题。
镜像文件，保证了环境迁移的一致
一次镜像，处处运行，
一句话：解决了运行环境和配置问题的软件容器，方便做持续继承并有助于整体发布的容器虚拟化技术
1.2 docker与虚拟机的比较
传统虚拟机技术
虚拟机就是带环境安装的一种解决方案
它可以在一种操作系统里面运行另一种操作系统，比如在Windows10系统里面运行Linux系统CentOS7。应用程序对此毫无感知，因为虚拟机看上去跟真实系统一模一样，而对于底层系统来说，虚拟机就是一个普通文件，不需要了就删掉，对其他部分毫无影响。这类虚拟机完美的运行了另一套系统，能够使应用程序，操作系统和硬件三者之间的逻辑不变。
虚拟机的缺点：
- 资源占用多
- 冗余步骤多
- 启动慢
容器化技术
由于前面虚拟机存在某些缺点，Linux发展出了另外一种虚拟化技术：Linux容器（Linux Containers，缩写为LXC）
Linux容器是与系统其他部分隔离开的一系列进程，从另一个镜像运行，并由该镜像提供支持进程所需的全部文件。容器提供的镜像包含了应用的所有依赖项，因而在从开发到测试再到生产的整个过程中，它都具有可移植性和一致性。
**Linux 容器不是模拟一个完整的操作系统而是对进程进行隔离。**有了容器，就可以将软件运行所需的所有资源打包到一个隔离的容器中。**容器与虚拟机不同，不需要捆绑一整套操作系统，**只需要软件工作所需的库资源和设置。系统因此而变得高效轻量并保证部署在任何环境中的软件都能始终如一地运行。
对比
2 docker安装
安装步骤
-
确定你是CentOS7及以上的版本
-
卸载旧版本
-
安装gcc相关：
yum -y install gccyum -y install gcc-c++ -
安装需要的软件包：
yum install -y yum-utils -
设置stable镜像仓库：:star:一定要装国内镜像，这里使用阿里云的镜像：
yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -
更新yum软件包索引（非必要，但是最好更新）
yum makecache fast -
安装DOCKER CE
yum -y install docker-ce docker-ce-cli containerd.io docker-compose-plugin -
启动docker
systemctl start docker查看版本
-
hello-world
本地是没有这个镜像的，需要从远程仓库中拉取hello-world镜像
阿里云镜像加速（必须）
是什么
promotion.aliyun.com/ntms/act/ku…
获取加速器地址连接
-
登录阿里云，进入控制台中的容器镜像服务
-
获取加速地址
-
之后按照图片中的操作文档执行即可
永远的helloworld
docker run hello-world做了什么
Docker为什么比虚拟机快
docker利用的是宿主机的内核，而不需要加载操作系统OS的内核。虚拟机需要加载虚拟机OS的内核，很重。
3 docker常用命令
3.1 帮助启动类命令
和防火墙很类似
重点要学会帮助命令
3.2 镜像命令
docker images
列出本地主机上的镜像
-
-a ：列出本地所有的镜像
-
-q ：只显示镜像ID
查询镜像
docker search
查询某个镜像的名字，回去docker的hub中去查，我们配置了阿里云的加速，所有速度会快一些，比如查找redis镜像
这里默认列出所有的，按照点赞数从高到低。我们一般不需要看那么多，所有可以限制显示的条数，使用命令docker redis --limit 5，只列出前5个镜像
拉取镜像
拉取镜像，docker pull xxx:TAG
其中TAG标签指定版本号，如果不指定，默认使用最新版即latest
下载成功查看容器卷
查看镜像、容器、数据卷所占的空间
docker system df，类似系统的查看磁盘使用情况df -h
删除镜像
docker rmi，后面指定镜像名称或者id
参数
- -f ：强制删除，如果当前镜像有容器正在运行，默认无法删除，需要强制删除
删除多个镜像
docker rmi -f 镜像名1:TAG 镜像名2:TAG
删除全部镜像
docker rmi -f ${docker images -qa}
虚悬镜像
3.3 容器命令-1
1 在docker使用一个ubuntu镜像
就是在docker上拉取一个ubuntu镜像，也就是使用docker模拟出另外一个Linux系统。
2 运行一个容器
docker run [OPTIONS] IMAGE [COMMAND] [ARG...]
OPTIONS说明：
2.0 COMMAND
一般使用/bin/bash即可，如果需要输入命令进行交互的话，一般都会带上这个COMMAND命令
2.1 交互模式
-i：以交互模式（interactive）运行容器，通常和-t一起使用
-t：为容器重新分配一个伪输入终端，伪终端（tty），通常与 -i 同时使用
启动交互式容器
可以看到在docker中运行了一个Linux系统（ubuntu），在容器中执行/bin/bash命令
退出 exit
2.2 指定端口映射
-p：指定端口映射，将宿主机的端口映射到docker内部的端口，比如：-p 8080 : 80
2.3 指定容器的名字
--name=容器名字：指定容器的新名字，如果不指定，系统随机分配
3 列出在运行的容器
docker ps
参数说明：
-a:列出当前所有正在运行的容器+历史上运行过的-l:显示最近创建的容器。-n：显示最近n个创建的容器。-q:静默模式，只显示容器编号。
4 退出容器
4.1 exit
run 进去容器，exit退出，容器停止
4.2 ctrl+p+q
run进去容器，ctrl+p+q退出，容器不停止
5 启动已经停止的容器
docker start 容器ID或容器名
6 重启容器
docker restart 容器ID或容器名
7 停止容器
docker stop 容器ID或容器名
8 强制停止容器
docker kill 容器ID或容器名
9 删除已经停止的容器
docker rm 容器ID或容器名
注意：不能删除正在运行的容器，
删除多个容器，就写多个容器id即可
3.4 容器命令2-后台启动和容器内部细节
1 启动守护式容器（后台服务器）
在大部分的场景下，我们希望docker的服务是在后台运行的，我们可以通过-d指定容器的后台运行模式
docker run -d 镜像名
以启动ubuntu为例，执行docker run -d ubuntu，启动之后
你会发现，后台启动之后，再进行ps，并没有这个容器。这是docker机制的问题，就是容器运行的命令如果不是那些一直挂起的命令，就是会自动退出的，因为后台启动之后，没有对应的前台进程，这样容器会立即自杀因为他觉得自己没事可做了。也即是docker容器后台运行，就必须有一个前台进程。
所以解决方案就是，你以前台模式启动，然后ctrl + p + q退出即可
注意，这是由于ubuntu是后台启动之后没有对应的前台应用，所以会自杀。对于一些后台启动之后有前台进程的，就不会自杀，比如下面说到的redis
2 以redis前台启动和后台启动为例
前台启动：
这样的话，终端不能关闭（不再赘述）
后台启动
直接docker run -d redis:6.0.8启动即可
docker 启动redis的方便性
想一下原来安装redis需要make啥之类的，这里只需要直接根据镜像run一个容器即可，非常方便，如果启动多个redis进行集群，那么docker是很nb的
3 查看容器日志
docker logs 容器id
编码开发微服务
上线部署容器化
时时刻刻要监控
devops
4 查看容器内运行的进程
docker top 容器id
5 查看容器内部细节
docker inspect 容器id
复习一下docker中容器的概念，也就是说可以把容器看做一个简易版的Linux环境
3.5 容器命令3-重新进入docker容器
1 exec
docker exec 容器id
可选参数：
以ubuntu容器为例：重新进入ubuntu容器实例
2 attach
docker attach 容器id
这里进入ubuntu不用加上 /bin/bash参数
3 exec 和 attach的区别
attach 直接进入容器启动命令的终端，不会启动新的进程 用exit退出，会导致容器的停止
exec 是在容器中打开新的终端，并且可以启动新的进程 用exit退出，不会导致容器的停止。
推荐:star: ：使用exec命令，因为这样exit退出之后，不会导致容器的停止
4 以redis为例
5 docker云原生优势所在
拥抱云原生哇:happy:
3.6 容器命令4-导入导出
1 将容器内的文件拷贝到主机上
docker cp 容器id:容器内路径 目的主机路径
这个主要用途是可以将容器内的重要文件进行一个备份
2 导入导出容器
export导出容器的内容留作为一个tar归档文件[对应import命令]import从tar包中的内容创建一个新的文件系统再导入为镜像[对应export]
命令：export 容器id > 文件名.tar
cat 文件名.tar | docker import - 镜像用户/镜像名:镜像号版本
3.7 容器命令小总结
基本命令
| 操作 | 命令 |
|---|---|
| 运行一个容器 | docker run [OPTIONS] IMAGE[:TAG] [COMMAND] [ARG...] |
| 参数说明：COMMAND | 使用什么类型的命令行操作，一般使用/bin/bash即可 |
| 交互模式 | -i(以交互模式运行容器），一般和-t（分配一个伪终端）配合使用 |
| 指定端口映射 | -p 宿主机端口：docker内部端口 |
| 指定容器的名字 | --name=容器名字 |
| 列出在运行的容器 | docker ps，-a所有容器，-l最近创建的容器 |
| 退出容器 | exit，退出后容器停止；ctrl+p+q，退出后容器不停止 |
| 启动已经停止的容器 | docker start 容器ID或容器名 |
| 重启容器 | docker restart 容器ID或容器名 |
| 停止容器 | docker stop 容器ID或容器名 |
| 强制停止容器 | docker kill 容器ID或容器名 |
| 删除已经停止的容器 | docker rm 容器ID或容器名，不能删除正在运行的容器，可以加-f强制删除 |
| 删除多个容器 | docker rm 多个容器id |
后台启动
| 操作 | 命令 |
|---|---|
| 启动守护式容器（后台服务器） | docker run -d 镜像名 |
| 查看容器日志 | docker logs 容器id |
| 查看容器内运行的进程 | docker top 容器id |
| 查看容器内部细节 | docker inspect 容器id |
重新进入容器
| 操作 | 命令 |
|---|---|
| exec | docker exec 容器id |
| attach | docker attach 容器id |
| exec 和 attach的区别 | attach 直接进入容器启动命令的终端，不会启动新的进程 用exit退出，会导致容器的停止 |
| exec 和 attach的区别 | exec 是在容器中打开新的终端，并且可以启动新的进程 用exit退出，不会导致容器的停止。 |
导入和导出
| 操作 | 命令 | |
|---|---|---|
| 将容器内的文件拷贝到主机上 | docker cp 容器id:容器内路径 目的主机路径 | |
| 导出 | export 容器id > 文件名.tar | |
| 导出说明 | 导出容器的内容留作为一个tar归档文件[对应import命令] | |
| 导入 | `cat 文件名.tar | docker import - 镜像用户/镜像名:镜像号版本` |
| 导入说明 | import 从tar包中的内容创建一个新的文件系统再导入为镜像[对应export] |
4、Docker镜像
4.1 镜像
是什么
是一种轻量级、可执行的独立软件包，它包含运行某个软件所需的所有内容，我们把应用程序和配置依赖打包好形成一个可交付的运行环境**(包括代码、运行时需要的库、环境变量和配置文件等)**，这个打包好的运行环境就是image镜像文件。
只有通过这个镜像文件才能生成Docker容器实例(类似Java中new出来一个对象)。
分层的镜像
以我们的pull为例，在下载的过程中我们可以看到docker的镜像好像是在一层一层的在下载
UnionFS（联合文件系统）
UnionFS（联合文件系统）：Union文件系统（UnionFS）是一种分层、轻量级并且高性能的文件系统，它支持对文件系统的修改作为一次提交来一层层的叠加，同时可以将不同目录挂载到同一个虚拟文件系统下(unite several directories into a single virtual filesystem)。Union 文件系统是 Docker 镜像的基础。镜像可以通过分层来进行继承，基于基础镜像（没有父镜像），可以制作各种具体的应用镜像。
特性：一次同时加载多个文件系统，但从外面看起来，只能看到一个文件系统，联合加载会把各层文件系统叠加起来，这样最终的文件系统会包含所有底层的文件和目录
就是外面只能看到最外层的，就像一个花卷，你吃肯定先吃最外层的
Docker镜像加载原理
docker的镜像实际上由一层一层的文件系统组成，这种层级的文件系统UnionFS。
bootfs(boot file system)主要包含bootloader（根加载）和kernel（Linux内核）, bootloader主要是引导加载kernel, Linux刚启动时会加载bootfs文件系统，在Docker镜像的最底层是引导文件系统bootfs（所以说可以把容器看做一个简易版的Linux环境）。这一层与我们典型的Linux/Unix系统是一样的，包含boot加载器和内核。当boot加载完成之后整个内核就都在内存中了，此时内存的使用权已由bootfs转交给内核，此时系统也会卸载bootfs。
rootfs (root file system) ，在bootfs之上。包含的就是典型 Linux 系统中的 /dev, /proc, /bin, /etc 等标准目录和文件。rootfs就是各种不同的操作系统发行版，比如Ubuntu，Centos等等。
平时我们安装进虚拟机的CentOS都是好几个G，为什么docker这里才200M？？
对于一个精简的OS，rootfs可以很小，只需要包括最基本的命令、工具和程序库就可以了，因为底层直接用Host的kernel，自己只需要提供 rootfs 就行了。由此可见对于不同的linux发行版, bootfs基本是一致的, rootfs会有差别, 因此不同的发行版可以公用bootfs。
重点理解
Docker镜像都是只读的，容器层是可写的，
为什么docker使用这种分层结构呢
镜像分层最大的一个好处就是共享资源，方便复制迁移，就是为了复用。
比如说有多个镜像都从相同的 base 镜像构建而来，那么 Docker Host 只需在磁盘上保存一份 base 镜像； 同时内存中也只需加载一份 base 镜像，就可以为所有容器服务了。而且镜像的每一层都可以被共享。
4.2 只读与可写
Docker镜像层都是只读的，容器层是可写的
当容器启动时，一个新的可写层被加载到镜像的顶部。 这一层通常被称作“容器层”，“容器层”之下的都叫“镜像层”。
当容器启动时，一个新的可写层被加载到镜像的顶部。这一层通常被称作“容器层”，“容器层”之下的都叫“镜像层”。
容器对外暴露的肯定最外层，即镜像层，所以说，有了下面的结论：
所有对容器的改动 - 无论添加、删除、还是修改文件都只会发生在容器层中。只有容器层是可写的，容器层下面的所有镜像层都是只读的
4.3 commit命令
就是使用修改后的容器实例反向生成一个镜像文件
docker commit命令
docker commit -m="提交的描述信息" -a="作者" 容器ID 要创建的目标镜像名:[标签名]
案例演示
我们下载一个ubuntu镜像，他的容器时默认不带有vim的：
我们执行命令安装vim，然后利用vim新建一个a.txt文件并添加一些文本进去
安装完成之后，退出容器，执行commit命令
docker commit -m="提交的描述信息" -a="作者" 容器ID 要创建的目标镜像名:[标签名]
可以看到，新的镜像已经生成，大小为180MB，比原生的73MB大了不少
回想一下分层的镜像，这里新提交的这个镜像就是在原先基础镜像的基础上加了一层vim软件。
那么以这个新的镜像运行容器，那么容器中就会带有vim软件，并且在根目录下含有a.txt文件和添加的文本
小总结
Docker中的镜像分层，支持通过扩展现有镜像，创建新的镜像。类似Java继承于一个Base基础类，自己再按需扩展。 新镜像是从 base 镜像一层一层叠加生成的。每安装一个软件，就在现有镜像的基础上增加一层
5、本地镜像发布到阿里云
5.1 流程图
5.2 镜像的生成方法
两种方法：
1、上一章说的commit命令
2、使用DockerFile 在高级篇中讲
5.3 本地镜像推送到阿里云
1、本地镜像的素材原型
2、进入阿里云开发者平台
控制台中进入容器镜像服务
3、创建仓库镜像
-
进入控制台的容器镜像服务
-
选择个人实例
-
新建命名空间
-
新建仓库
-
管理界面获得脚本
4、将本地镜像推送到阿里云
参考管理页面的推送命名，直接复制，将里面的东西改成自己的即可
1、首先登录到阿里云
2、根据本地镜像生成推送镜像，并进行推送
推送完成即可
这里面的镜像大小，是压缩之后的大小
5.4 阿里云上的镜像下载到本地
我们推送到阿里云，就是为了方便下载到本地，下面演示一下下载到本地
先将本地中的镜像删除
删除之后，去拉取，可以看到结果
我们直接运行这个镜像
发现在根目录下有我们之前的a.txt文件，且有vim可以使用
6、本地镜像发布到私有库
6.1 是什么
1 官方Docker Hub地址：hub.docker.com/，中国大陆访问太慢了且…
2 Dockerhub、阿里云这样的公共镜像仓库可能不太方便，涉及机密的公司不可能提供镜像给公网，所以需要创建一个本地私人仓库供给团队使用，基于公司内部项目构建镜像。
Docker Registry是官方提供的工具，可以用于构建私有镜像仓库，就相当于把dockerHub或者阿里云镜像仓库自己搭建一套私有的。（类似于maven私服）
6.2 将本地镜像推送到私有库
1、下载镜像Docker Registry
2、运行私有库Registry，相当于本地有个私有Docker Hub
docker run -d -p 5000:5000 -v /zzyyuse/myregistry/:/tmp/registry --privileged=true registry
默认情况，仓库被创建在容器的/var/lib/registry目录下，建议自行用容器卷映射，方便于宿主机联调
3、案例演示创建一个新镜像，ubuntu安装ifconfig命令
使用原始的ubuntu镜像运行一个容器，在容器中安装net-tools，然后再commit出我们自己的新镜像
4、curl验证私服库上有什么镜像
curl -XGET http://192.168.111.162:5000/v2/_catalog
可以看到，目前私服库没有任何镜像上传过。。。。。。
5、将新镜像修改符合私服规范的Tag
按照公式： docker tag 镜像:Tag Host:Port/Repository:Tag
使用命令 docker tag 将zzyyubuntu:1.2 这个镜像修改为192.168.111.162:5000/zzyyubuntu:1.2
命令为：
docker tag zzyyubuntu:1.2 192.168.111.162:5000/zzyyubuntu:1.2
6、修改配置文件使之支持http
这个配置文件就是当初配置阿里云加速时添加的配置文件，是一个JSON格式的内容，我们需要加上红框中的那一行（记得两行之间添加逗号）
7、push推送到私服库
docker push 192.168.111.162:5000/zzyyubuntu:1.2
8、curl验证私服库上有什么镜像
9、pull到本地并运行
docker pull 192.168.111.162:5000/zzyyubuntu:1.2
7、Docker容器数据卷
7.1 坑
坑：容器卷记得加入 --privileged=true
why:
Docker挂载主机目录访问如果出现cannot open directory .: Permission denied 解决办法：在挂载目录后多加一个--privileged=true参数即可
如果是CentOS7安全模块会比之前系统版本加强，不安全的会先禁止，所以目录挂载的情况被默认为不安全的行为， 在SELinux里面挂载目录被禁止掉了额，如果要开启，我们一般使用--privileged=true命令，扩大容器的权限解决挂载目录没有权限的问题，也即 使用该参数，container内的root拥有真正的root权限，否则，container内的root只是外部的一个普通用户权限。
7.2 概念
卷就是目录或文件，存在于一个或多个容器中，由docker挂载到容器，但不属于联合文件系统，因此能够绕过Union File System提供一些用于持续存储或共享数据的特性：
- 卷的设计目的就是数据的持久化
- 完全独立于容器的生存周期，因此Docker不会在容器删除时删除其挂载的数据卷
总之：
- 一句话：有点类似我们Redis里面的rdb和aof文件
- 将docker容器内的数据保存进宿主机的磁盘中
- 运行一个带有容器卷存储功能的容器实例
- 操作是双向的，如果主机修改文件，容器中也会改变
docker run -it --privileged=true -v /宿主机绝对路径目录:/容器内目录 镜像名
7.3 能干嘛
将运用与运行的环境打包镜像，run后形成容器实例运行 ，但是我们对数据的要求希望是持久化的
Docker容器产生的数据，如果不备份，那么当容器实例删除后，容器内的数据自然也就没有了。 为了能保存数据在docker中我们使用卷。
特点： 1：数据卷可在容器之间共享或重用数据 2：卷中的更改可以直接实时生效，爽 3：数据卷中的更改不会包含在镜像的更新中 4：数据卷的生命周期一直持续到没有容器使用它为止
反正就是如果突然容器挂了，但是重要的数据都备份到了宿主机
7.4 容器卷案例
1、命令：
docker run -it --privileged=true -v /宿主机绝对路径目录:/容器内目录 镜像名
2、查看数据卷是否挂载成功：
docker inspect 容器ID
3、容器和宿主机之间数据共享
- docker修改，主机同步获得
- 主机修改，docker同步获得
- docker容器stop，主机修改，docker容器重启看数据是否同步。
7.5 读写规则和映射添加说明
读写（默认）
docker run -it --privileged=true -v /宿主机绝对路径目录:/容器内目录:rw 镜像名
默认同上案例，默认就是rw
只读
docker run -it --privileged=true -v /宿主机绝对路径目录:/容器内目录:ro 镜像名
容器实例内部被限制，只能读取不能写
ro = read only
此时如果宿主机写入内容，可以同步给容器内，容器可以读取到
7.6 卷的继承和共享
1、容器1完成和宿主机的映射
docker run -it --privileged=true -v /mydocker/u:/tmp --name u1 ubuntu
容器中：
宿主机中：
2、容器2继承容器1的卷规则：
docker run -it --privileged=true --volumes-from 父类 --name u2 ubuntu
可以看到，u2里面有u1创建的文件，之后u2创建一个文件，我们看一下宿主机和u1中的情况
宿主机：
u1：
3、如果u1挂掉，u2会怎么样？
先说结论：完全没有影响，就相当于u2只是继承了u1的容器卷挂载规则，u1和u2是独立的两个容器，u1死了和u2没啥关系
如果u1再活过来，那么u1还能获取他死的时候，u2进行的文件操作。就相当于一个宿主机上挂了两个容器，两个容器中谁死了都没有关系。
8、常用软件
8.1、总体概述
对比：
步骤：
- 搜索镜像 （镜像详细介绍，看dockerHub官网）
- 拉取镜像
- 查看镜像
- 启动镜像：服务端口的映射
- 停止容器
- 移除容器
8.2 安装Tomcat
8.3 安装mysql
简单版
关于如何使用这个镜像，就去官网看就可以了，一定要学会看官网：
mysql - Official Image | Docker Hub
一套下来，直接成功，非常完美
在本地使用Navicat连接成功
更改默认字符集
在客户端查看字符集可能显示的是utf-8，但是在docker容器中查字符集是latin1，这是因为客户端自动帮你改了显示
在下面实战版中通过配置文件更改字符集
实战版
新建容器
上面简单版没有挂载数据卷，玩意容器被删了，数据库中的数据将会丢失，这是无法接受的，所以我们需要挂载容器卷
执行命令：
docker run -d -p 3306:3306 --privileged=true -v /zzyyuse/mysql/log:/var/log/mysql -v /zzyyuse/mysql/data:/var/lib/mysql -v /zzyyuse/mysql/conf:/etc/mysql/conf.d -e MYSQL_ROOT_PASSWORD=123456 --name mysql mysql:5.7
命令分析：
docker run
-d #后台启动
-p 3306:3306 #端口映射
--privileged=true #挂载数据卷
-v /zzyyuse/mysql/log:/var/log/mysql #挂载数据卷
-v /zzyyuse/mysql/data:/var/lib/mysql #挂载数据卷
-v /zzyyuse/mysql/conf:/etc/mysql/conf.d #挂载数据卷
-e MYSQL_ROOT_PASSWORD=123456 #设置root用户密码
--name mysql #容器名称
mysql:5.7
新建my.cnf
通过容器卷同步给mysql容器实例
[client]
default_character_set=utf8
[mysqld]
collation_server = utf8_general_ci
character_set_server = utf8
重启mysql容器实例
手欠删了mysql容器实例
删了之后，我们再运行一个新的，挂载好容器数据卷，就可以将数据恢复到新建的mysql容器实例中
8.4 安装redis
执行命令：docker run -d -p 6380:6379 --name myr3 --privileged=true -v /app/redis/redis.conf:/etc/redis/redis.conf -v /app/redis/data:/data redis:6.0.8 redis-server /etc/redis/redis.conf
命令分析：
docker run
-d #后台运行容器
-p 6379:6379 #端口映射
--name myr3 #容器名称
--privileged=true #挂载数据卷
-v /app/redis/redis.conf:/etc/redis/redis.conf #挂载数据卷
-v /app/redis/data:/data #挂载数据卷
redis:6.0.8 #镜像名称
redis-server /etc/redis/redis.conf #指定操作命令为redis-serve并指定读取宿主机同步过去的配置文件
配置文件
默认配置文件需要更改的地方：
**
将一个redis.conf文件模板拷贝进/app/redis目录下
# Redis configuration file example.
#
# Note that in order to read the configuration file, Redis must be
# started with the file path as first argument:
#
# ./redis-server /path/to/redis.conf
# Note on units: when memory size is needed, it is possible to specify
# it in the usual form of 1k 5GB 4M and so forth:
#
# 1k => 1000 bytes
# 1kb => 1024 bytes
# 1m => 1000000 bytes
# 1mb => 1024*1024 bytes
# 1g => 1000000000 bytes
# 1gb => 1024*1024*1024 bytes
#
# units are case insensitive so 1GB 1Gb 1gB are all the same.
################################## INCLUDES ###################################
# Include one or more other config files here. This is useful if you
# have a standard template that goes to all Redis servers but also need
# to customize a few per-server settings. Include files can include
# other files, so use this wisely.
#
# Notice option "include" won't be rewritten by command "CONFIG REWRITE"
# from admin or Redis Sentinel. Since Redis always uses the last processed
# line as value of a configuration directive, you'd better put includes
# at the beginning of this file to avoid overwriting config change at runtime.
#
# If instead you are interested in using includes to override configuration
# options, it is better to use include as the last line.
#
# include /path/to/local.conf
# include /path/to/other.conf
################################## MODULES #####################################
# Load modules at startup. If the server is not able to load modules
# it will abort. It is possible to use multiple loadmodule directives.
#
# loadmodule /path/to/my_module.so
# loadmodule /path/to/other_module.so
################################## NETWORK #####################################
# By default, if no "bind" configuration directive is specified, Redis listens
# for connections from all the network interfaces available on the server.
# It is possible to listen to just one or multiple selected interfaces using
# the "bind" configuration directive, followed by one or more IP addresses.
#
# Examples:
#
# bind 192.168.1.100 10.0.0.1
# bind 127.0.0.1 ::1
#
# ~~~ WARNING ~~~ If the computer running Redis is directly exposed to the
# internet, binding to all the interfaces is dangerous and will expose the
# instance to everybody on the internet. So by default we uncomment the
# following bind directive, that will force Redis to listen only into
# the IPv4 loopback interface address (this means Redis will be able to
# accept connections only from clients running into the same computer it
# is running).
#
# IF YOU ARE SURE YOU WANT YOUR INSTANCE TO LISTEN TO ALL THE INTERFACES
# JUST COMMENT THE FOLLOWING LINE.
# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#bind 127.0.0.1
# Protected mode is a layer of security protection, in order to avoid that
# Redis instances left open on the internet are accessed and exploited.
#
# When protected mode is on and if:
#
# 1) The server is not binding explicitly to a set of addresses using the
# "bind" directive.
# 2) No password is configured.
#
# The server only accepts connections from clients connecting from the
# IPv4 and IPv6 loopback addresses 127.0.0.1 and ::1, and from Unix domain
# sockets.
#
# By default protected mode is enabled. You should disable it only if
# you are sure you want clients from other hosts to connect to Redis
# even if no authentication is configured, nor a specific set of interfaces
# are explicitly listed using the "bind" directive.
protected-mode no
# Accept connections on the specified port, default is 6379 (IANA #815344).
# If port 0 is specified Redis will not listen on a TCP socket.
port 6379
# TCP listen() backlog.
#
# In high requests-per-second environments you need an high backlog in order
# to avoid slow clients connections issues. Note that the Linux kernel
# will silently truncate it to the value of /proc/sys/net/core/somaxconn so
# make sure to raise both the value of somaxconn and tcp_max_syn_backlog
# in order to get the desired effect.
tcp-backlog 511
# Unix socket.
#
# Specify the path for the Unix socket that will be used to listen for
# incoming connections. There is no default, so Redis will not listen
# on a unix socket when not specified.
#
# unixsocket /tmp/redis.sock
# unixsocketperm 700
# Close the connection after a client is idle for N seconds (0 to disable)
timeout 0
# TCP keepalive.
#
# If non-zero, use SO_KEEPALIVE to send TCP ACKs to clients in absence
# of communication. This is useful for two reasons:
#
# 1) Detect dead peers.
# 2) Take the connection alive from the point of view of network
# equipment in the middle.
#
# On Linux, the specified value (in seconds) is the period used to send ACKs.
# Note that to close the connection the double of the time is needed.
# On other kernels the period depends on the kernel configuration.
#
# A reasonable value for this option is 300 seconds, which is the new
# Redis default starting with Redis 3.2.1.
tcp-keepalive 300
################################# GENERAL #####################################
# By default Redis does not run as a daemon. Use 'yes' if you need it.
# Note that Redis will write a pid file in /var/run/redis.pid when daemonized.
daemonize no
# If you run Redis from upstart or systemd, Redis can interact with your
# supervision tree. Options:
# supervised no - no supervision interaction
# supervised upstart - signal upstart by putting Redis into SIGSTOP mode
# supervised systemd - signal systemd by writing READY=1 to $NOTIFY_SOCKET
# supervised auto - detect upstart or systemd method based on
# UPSTART_JOB or NOTIFY_SOCKET environment variables
# Note: these supervision methods only signal "process is ready."
# They do not enable continuous liveness pings back to your supervisor.
supervised no
# If a pid file is specified, Redis writes it where specified at startup
# and removes it at exit.
#
# When the server runs non daemonized, no pid file is created if none is
# specified in the configuration. When the server is daemonized, the pid file
# is used even if not specified, defaulting to "/var/run/redis.pid".
#
# Creating a pid file is best effort: if Redis is not able to create it
# nothing bad happens, the server will start and run normally.
pidfile /var/run/redis_6379.pid
# Specify the server verbosity level.
# This can be one of:
# debug (a lot of information, useful for development/testing)
# verbose (many rarely useful info, but not a mess like the debug level)
# notice (moderately verbose, what you want in production probably)
# warning (only very important / critical messages are logged)
loglevel notice
# Specify the log file name. Also the empty string can be used to force
# Redis to log on the standard output. Note that if you use standard
# output for logging but daemonize, logs will be sent to /dev/null
logfile ""
# To enable logging to the system logger, just set 'syslog-enabled' to yes,
# and optionally update the other syslog parameters to suit your needs.
# syslog-enabled no
# Specify the syslog identity.
# syslog-ident redis
# Specify the syslog facility. Must be USER or between LOCAL0-LOCAL7.
# syslog-facility local0
# Set the number of databases. The default database is DB 0, you can select
# a different one on a per-connection basis using SELECT <dbid> where
# dbid is a number between 0 and 'databases'-1
databases 16
# By default Redis shows an ASCII art logo only when started to log to the
# standard output and if the standard output is a TTY. Basically this means
# that normally a logo is displayed only in interactive sessions.
#
# However it is possible to force the pre-4.0 behavior and always show a
# ASCII art logo in startup logs by setting the following option to yes.
always-show-logo yes
################################ SNAPSHOTTING ################################
#
# Save the DB on disk:
#
# save <seconds> <changes>
#
# Will save the DB if both the given number of seconds and the given
# number of write operations against the DB occurred.
#
# In the example below the behaviour will be to save:
# after 900 sec (15 min) if at least 1 key changed
# after 300 sec (5 min) if at least 10 keys changed
# after 60 sec if at least 10000 keys changed
#
# Note: you can disable saving completely by commenting out all "save" lines.
#
# It is also possible to remove all the previously configured save
# points by adding a save directive with a single empty string argument
# like in the following example:
#
# save ""
save 900 1
save 300 10
save 60 10000
# By default Redis will stop accepting writes if RDB snapshots are enabled
# (at least one save point) and the latest background save failed.
# This will make the user aware (in a hard way) that data is not persisting
# on disk properly, otherwise chances are that no one will notice and some
# disaster will happen.
#
# If the background saving process will start working again Redis will
# automatically allow writes again.
#
# However if you have setup your proper monitoring of the Redis server
# and persistence, you may want to disable this feature so that Redis will
# continue to work as usual even if there are problems with disk,
# permissions, and so forth.
stop-writes-on-bgsave-error yes
# Compress string objects using LZF when dump .rdb databases?
# For default that's set to 'yes' as it's almost always a win.
# If you want to save some CPU in the saving child set it to 'no' but
# the dataset will likely be bigger if you have compressible values or keys.
rdbcompression yes
# Since version 5 of RDB a CRC64 checksum is placed at the end of the file.
# This makes the format more resistant to corruption but there is a performance
# hit to pay (around 10%) when saving and loading RDB files, so you can disable it
# for maximum performances.
#
# RDB files created with checksum disabled have a checksum of zero that will
# tell the loading code to skip the check.
rdbchecksum yes
# The filename where to dump the DB
dbfilename dump.rdb
# The working directory.
#
# The DB will be written inside this directory, with the filename specified
# above using the 'dbfilename' configuration directive.
#
# The Append Only File will also be created inside this directory.
#
# Note that you must specify a directory here, not a file name.
dir ./
################################# REPLICATION #################################
# Master-Replica replication. Use replicaof to make a Redis instance a copy of
# another Redis server. A few things to understand ASAP about Redis replication.
#
# +------------------+ +---------------+
# | Master | ---> | Replica |
# | (receive writes) | | (exact copy) |
# +------------------+ +---------------+
#
# 1) Redis replication is asynchronous, but you can configure a master to
# stop accepting writes if it appears to be not connected with at least
# a given number of replicas.
# 2) Redis replicas are able to perform a partial resynchronization with the
# master if the replication link is lost for a relatively small amount of
# time. You may want to configure the replication backlog size (see the next
# sections of this file) with a sensible value depending on your needs.
# 3) Replication is automatic and does not need user intervention. After a
# network partition replicas automatically try to reconnect to masters
# and resynchronize with them.
#
# replicaof <masterip> <masterport>
# If the master is password protected (using the "requirepass" configuration
# directive below) it is possible to tell the replica to authenticate before
# starting the replication synchronization process, otherwise the master will
# refuse the replica request.
#
# masterauth <master-password>
# When a replica loses its connection with the master, or when the replication
# is still in progress, the replica can act in two different ways:
#
# 1) if replica-serve-stale-data is set to 'yes' (the default) the replica will
# still reply to client requests, possibly with out of date data, or the
# data set may just be empty if this is the first synchronization.
#
# 2) if replica-serve-stale-data is set to 'no' the replica will reply with
# an error "SYNC with master in progress" to all the kind of commands
# but to INFO, replicaOF, AUTH, PING, SHUTDOWN, REPLCONF, ROLE, CONFIG,
# SUBSCRIBE, UNSUBSCRIBE, PSUBSCRIBE, PUNSUBSCRIBE, PUBLISH, PUBSUB,
# COMMAND, POST, HOST: and LATENCY.
#
replica-serve-stale-data yes
# You can configure a replica instance to accept writes or not. Writing against
# a replica instance may be useful to store some ephemeral data (because data
# written on a replica will be easily deleted after resync with the master) but
# may also cause problems if clients are writing to it because of a
# misconfiguration.
#
# Since Redis 2.6 by default replicas are read-only.
#
# Note: read only replicas are not designed to be exposed to untrusted clients
# on the internet. It's just a protection layer against misuse of the instance.
# Still a read only replica exports by default all the administrative commands
# such as CONFIG, DEBUG, and so forth. To a limited extent you can improve
# security of read only replicas using 'rename-command' to shadow all the
# administrative / dangerous commands.
replica-read-only yes
# Replication SYNC strategy: disk or socket.
#
# -------------------------------------------------------
# WARNING: DISKLESS REPLICATION IS EXPERIMENTAL CURRENTLY
# -------------------------------------------------------
#
# New replicas and reconnecting replicas that are not able to continue the replication
# process just receiving differences, need to do what is called a "full
# synchronization". An RDB file is transmitted from the master to the replicas.
# The transmission can happen in two different ways:
#
# 1) Disk-backed: The Redis master creates a new process that writes the RDB
# file on disk. Later the file is transferred by the parent
# process to the replicas incrementally.
# 2) Diskless: The Redis master creates a new process that directly writes the
# RDB file to replica sockets, without touching the disk at all.
#
# With disk-backed replication, while the RDB file is generated, more replicas
# can be queued and served with the RDB file as soon as the current child producing
# the RDB file finishes its work. With diskless replication instead once
# the transfer starts, new replicas arriving will be queued and a new transfer
# will start when the current one terminates.
#
# When diskless replication is used, the master waits a configurable amount of
# time (in seconds) before starting the transfer in the hope that multiple replicas
# will arrive and the transfer can be parallelized.
#
# With slow disks and fast (large bandwidth) networks, diskless replication
# works better.
repl-diskless-sync no
# When diskless replication is enabled, it is possible to configure the delay
# the server waits in order to spawn the child that transfers the RDB via socket
# to the replicas.
#
# This is important since once the transfer starts, it is not possible to serve
# new replicas arriving, that will be queued for the next RDB transfer, so the server
# waits a delay in order to let more replicas arrive.
#
# The delay is specified in seconds, and by default is 5 seconds. To disable
# it entirely just set it to 0 seconds and the transfer will start ASAP.
repl-diskless-sync-delay 5
# Replicas send PINGs to server in a predefined interval. It's possible to change
# this interval with the repl_ping_replica_period option. The default value is 10
# seconds.
#
# repl-ping-replica-period 10
# The following option sets the replication timeout for:
#
# 1) Bulk transfer I/O during SYNC, from the point of view of replica.
# 2) Master timeout from the point of view of replicas (data, pings).
# 3) Replica timeout from the point of view of masters (REPLCONF ACK pings).
#
# It is important to make sure that this value is greater than the value
# specified for repl-ping-replica-period otherwise a timeout will be detected
# every time there is low traffic between the master and the replica.
#
# repl-timeout 60
# Disable TCP_NODELAY on the replica socket after SYNC?
#
# If you select "yes" Redis will use a smaller number of TCP packets and
# less bandwidth to send data to replicas. But this can add a delay for
# the data to appear on the replica side, up to 40 milliseconds with
# Linux kernels using a default configuration.
#
# If you select "no" the delay for data to appear on the replica side will
# be reduced but more bandwidth will be used for replication.
#
# By default we optimize for low latency, but in very high traffic conditions
# or when the master and replicas are many hops away, turning this to "yes" may
# be a good idea.
repl-disable-tcp-nodelay no
# Set the replication backlog size. The backlog is a buffer that accumulates
# replica data when replicas are disconnected for some time, so that when a replica
# wants to reconnect again, often a full resync is not needed, but a partial
# resync is enough, just passing the portion of data the replica missed while
# disconnected.
#
# The bigger the replication backlog, the longer the time the replica can be
# disconnected and later be able to perform a partial resynchronization.
#
# The backlog is only allocated once there is at least a replica connected.
#
# repl-backlog-size 1mb
# After a master has no longer connected replicas for some time, the backlog
# will be freed. The following option configures the amount of seconds that
# need to elapse, starting from the time the last replica disconnected, for
# the backlog buffer to be freed.
#
# Note that replicas never free the backlog for timeout, since they may be
# promoted to masters later, and should be able to correctly "partially
# resynchronize" with the replicas: hence they should always accumulate backlog.
#
# A value of 0 means to never release the backlog.
#
# repl-backlog-ttl 3600
# The replica priority is an integer number published by Redis in the INFO output.
# It is used by Redis Sentinel in order to select a replica to promote into a
# master if the master is no longer working correctly.
#
# A replica with a low priority number is considered better for promotion, so
# for instance if there are three replicas with priority 10, 100, 25 Sentinel will
# pick the one with priority 10, that is the lowest.
#
# However a special priority of 0 marks the replica as not able to perform the
# role of master, so a replica with priority of 0 will never be selected by
# Redis Sentinel for promotion.
#
# By default the priority is 100.
replica-priority 100
# It is possible for a master to stop accepting writes if there are less than
# N replicas connected, having a lag less or equal than M seconds.
#
# The N replicas need to be in "online" state.
#
# The lag in seconds, that must be <= the specified value, is calculated from
# the last ping received from the replica, that is usually sent every second.
#
# This option does not GUARANTEE that N replicas will accept the write, but
# will limit the window of exposure for lost writes in case not enough replicas
# are available, to the specified number of seconds.
#
# For example to require at least 3 replicas with a lag <= 10 seconds use:
#
# min-replicas-to-write 3
# min-replicas-max-lag 10
#
# Setting one or the other to 0 disables the feature.
#
# By default min-replicas-to-write is set to 0 (feature disabled) and
# min-replicas-max-lag is set to 10.
# A Redis master is able to list the address and port of the attached
# replicas in different ways. For example the "INFO replication" section
# offers this information, which is used, among other tools, by
# Redis Sentinel in order to discover replica instances.
# Another place where this info is available is in the output of the
# "ROLE" command of a master.
#
# The listed IP and address normally reported by a replica is obtained
# in the following way:
#
# IP: The address is auto detected by checking the peer address
# of the socket used by the replica to connect with the master.
#
# Port: The port is communicated by the replica during the replication
# handshake, and is normally the port that the replica is using to
# listen for connections.
#
# However when port forwarding or Network Address Translation (NAT) is
# used, the replica may be actually reachable via different IP and port
# pairs. The following two options can be used by a replica in order to
# report to its master a specific set of IP and port, so that both INFO
# and ROLE will report those values.
#
# There is no need to use both the options if you need to override just
# the port or the IP address.
#
# replica-announce-ip 5.5.5.5
# replica-announce-port 1234
################################## SECURITY ###################################
# Require clients to issue AUTH <PASSWORD> before processing any other
# commands. This might be useful in environments in which you do not trust
# others with access to the host running redis-server.
#
# This should stay commented out for backward compatibility and because most
# people do not need auth (e.g. they run their own servers).
#
# Warning: since Redis is pretty fast an outside user can try up to
# 150k passwords per second against a good box. This means that you should
# use a very strong password otherwise it will be very easy to break.
#
# requirepass foobared
# Command renaming.
#
# It is possible to change the name of dangerous commands in a shared
# environment. For instance the CONFIG command may be renamed into something
# hard to guess so that it will still be available for internal-use tools
# but not available for general clients.
#
# Example:
#
# rename-command CONFIG b840fc02d524045429941cc15f59e41cb7be6c52
#
# It is also possible to completely kill a command by renaming it into
# an empty string:
#
# rename-command CONFIG ""
#
# Please note that changing the name of commands that are logged into the
# AOF file or transmitted to replicas may cause problems.
################################### CLIENTS ####################################
# Set the max number of connected clients at the same time. By default
# this limit is set to 10000 clients, however if the Redis server is not
# able to configure the process file limit to allow for the specified limit
# the max number of allowed clients is set to the current file limit
# minus 32 (as Redis reserves a few file descriptors for internal uses).
#
# Once the limit is reached Redis will close all the new connections sending
# an error 'max number of clients reached'.
#
# maxclients 10000
############################## MEMORY MANAGEMENT ################################
# Set a memory usage limit to the specified amount of bytes.
# When the memory limit is reached Redis will try to remove keys
# according to the eviction policy selected (see maxmemory-policy).
#
# If Redis can't remove keys according to the policy, or if the policy is
# set to 'noeviction', Redis will start to reply with errors to commands
# that would use more memory, like SET, LPUSH, and so on, and will continue
# to reply to read-only commands like GET.
#
# This option is usually useful when using Redis as an LRU or LFU cache, or to
# set a hard memory limit for an instance (using the 'noeviction' policy).
#
# WARNING: If you have replicas attached to an instance with maxmemory on,
# the size of the output buffers needed to feed the replicas are subtracted
# from the used memory count, so that network problems / resyncs will
# not trigger a loop where keys are evicted, and in turn the output
# buffer of replicas is full with DELs of keys evicted triggering the deletion
# of more keys, and so forth until the database is completely emptied.
#
# In short... if you have replicas attached it is suggested that you set a lower
# limit for maxmemory so that there is some free RAM on the system for replica
# output buffers (but this is not needed if the policy is 'noeviction').
#
# maxmemory <bytes>
# MAXMEMORY POLICY: how Redis will select what to remove when maxmemory
# is reached. You can select among five behaviors:
#
# volatile-lru -> Evict using approximated LRU among the keys with an expire set.
# allkeys-lru -> Evict any key using approximated LRU.
# volatile-lfu -> Evict using approximated LFU among the keys with an expire set.
# allkeys-lfu -> Evict any key using approximated LFU.
# volatile-random -> Remove a random key among the ones with an expire set.
# allkeys-random -> Remove a random key, any key.
# volatile-ttl -> Remove the key with the nearest expire time (minor TTL)
# noeviction -> Don't evict anything, just return an error on write operations.
#
# LRU means Least Recently Used
# LFU means Least Frequently Used
#
# Both LRU, LFU and volatile-ttl are implemented using approximated
# randomized algorithms.
#
# Note: with any of the above policies, Redis will return an error on write
# operations, when there are no suitable keys for eviction.
#
# At the date of writing these commands are: set setnx setex append
# incr decr rpush lpush rpushx lpushx linsert lset rpoplpush sadd
# sinter sinterstore sunion sunionstore sdiff sdiffstore zadd zincrby
# zunionstore zinterstore hset hsetnx hmset hincrby incrby decrby
# getset mset msetnx exec sort
#
# The default is:
#
# maxmemory-policy noeviction
# LRU, LFU and minimal TTL algorithms are not precise algorithms but approximated
# algorithms (in order to save memory), so you can tune it for speed or
# accuracy. For default Redis will check five keys and pick the one that was
# used less recently, you can change the sample size using the following
# configuration directive.
#
# The default of 5 produces good enough results. 10 Approximates very closely
# true LRU but costs more CPU. 3 is faster but not very accurate.
#
# maxmemory-samples 5
# Starting from Redis 5, by default a replica will ignore its maxmemory setting
# (unless it is promoted to master after a failover or manually). It means
# that the eviction of keys will be just handled by the master, sending the
# DEL commands to the replica as keys evict in the master side.
#
# This behavior ensures that masters and replicas stay consistent, and is usually
# what you want, however if your replica is writable, or you want the replica to have
# a different memory setting, and you are sure all the writes performed to the
# replica are idempotent, then you may change this default (but be sure to understand
# what you are doing).
#
# Note that since the replica by default does not evict, it may end using more
# memory than the one set via maxmemory (there are certain buffers that may
# be larger on the replica, or data structures may sometimes take more memory and so
# forth). So make sure you monitor your replicas and make sure they have enough
# memory to never hit a real out-of-memory condition before the master hits
# the configured maxmemory setting.
#
# replica-ignore-maxmemory yes
############################# LAZY FREEING ####################################
# Redis has two primitives to delete keys. One is called DEL and is a blocking
# deletion of the object. It means that the server stops processing new commands
# in order to reclaim all the memory associated with an object in a synchronous
# way. If the key deleted is associated with a small object, the time needed
# in order to execute the DEL command is very small and comparable to most other
# O(1) or O(log_N) commands in Redis. However if the key is associated with an
# aggregated value containing millions of elements, the server can block for
# a long time (even seconds) in order to complete the operation.
#
# For the above reasons Redis also offers non blocking deletion primitives
# such as UNLINK (non blocking DEL) and the ASYNC option of FLUSHALL and
# FLUSHDB commands, in order to reclaim memory in background. Those commands
# are executed in constant time. Another thread will incrementally free the
# object in the background as fast as possible.
#
# DEL, UNLINK and ASYNC option of FLUSHALL and FLUSHDB are user-controlled.
# It's up to the design of the application to understand when it is a good
# idea to use one or the other. However the Redis server sometimes has to
# delete keys or flush the whole database as a side effect of other operations.
# Specifically Redis deletes objects independently of a user call in the
# following scenarios:
#
# 1) On eviction, because of the maxmemory and maxmemory policy configurations,
# in order to make room for new data, without going over the specified
# memory limit.
# 2) Because of expire: when a key with an associated time to live (see the
# EXPIRE command) must be deleted from memory.
# 3) Because of a side effect of a command that stores data on a key that may
# already exist. For example the RENAME command may delete the old key
# content when it is replaced with another one. Similarly SUNIONSTORE
# or SORT with STORE option may delete existing keys. The SET command
# itself removes any old content of the specified key in order to replace
# it with the specified string.
# 4) During replication, when a replica performs a full resynchronization with
# its master, the content of the whole database is removed in order to
# load the RDB file just transferred.
#
# In all the above cases the default is to delete objects in a blocking way,
# like if DEL was called. However you can configure each case specifically
# in order to instead release memory in a non-blocking way like if UNLINK
# was called, using the following configuration directives:
lazyfree-lazy-eviction no
lazyfree-lazy-expire no
lazyfree-lazy-server-del no
replica-lazy-flush no
############################## APPEND ONLY MODE ###############################
# By default Redis asynchronously dumps the dataset on disk. This mode is
# good enough in many applications, but an issue with the Redis process or
# a power outage may result into a few minutes of writes lost (depending on
# the configured save points).
#
# The Append Only File is an alternative persistence mode that provides
# much better durability. For instance using the default data fsync policy
# (see later in the config file) Redis can lose just one second of writes in a
# dramatic event like a server power outage, or a single write if something
# wrong with the Redis process itself happens, but the operating system is
# still running correctly.
#
# AOF and RDB persistence can be enabled at the same time without problems.
# If the AOF is enabled on startup Redis will load the AOF, that is the file
# with the better durability guarantees.
#
# Please check http://redis.io/topics/persistence for more information.
appendonly no
# The name of the append only file (default: "appendonly.aof")
appendfilename "appendonly.aof"
# The fsync() call tells the Operating System to actually write data on disk
# instead of waiting for more data in the output buffer. Some OS will really flush
# data on disk, some other OS will just try to do it ASAP.
#
# Redis supports three different modes:
#
# no: don't fsync, just let the OS flush the data when it wants. Faster.
# always: fsync after every write to the append only log. Slow, Safest.
# everysec: fsync only one time every second. Compromise.
#
# The default is "everysec", as that's usually the right compromise between
# speed and data safety. It's up to you to understand if you can relax this to
# "no" that will let the operating system flush the output buffer when
# it wants, for better performances (but if you can live with the idea of
# some data loss consider the default persistence mode that's snapshotting),
# or on the contrary, use "always" that's very slow but a bit safer than
# everysec.
#
# More details please check the following article:
# http://antirez.com/post/redis-persistence-demystified.html
#
# If unsure, use "everysec".
# appendfsync always
appendfsync everysec
# appendfsync no
# When the AOF fsync policy is set to always or everysec, and a background
# saving process (a background save or AOF log background rewriting) is
# performing a lot of I/O against the disk, in some Linux configurations
# Redis may block too long on the fsync() call. Note that there is no fix for
# this currently, as even performing fsync in a different thread will block
# our synchronous write(2) call.
#
# In order to mitigate this problem it's possible to use the following option
# that will prevent fsync() from being called in the main process while a
# BGSAVE or BGREWRITEAOF is in progress.
#
# This means that while another child is saving, the durability of Redis is
# the same as "appendfsync none". In practical terms, this means that it is
# possible to lose up to 30 seconds of log in the worst scenario (with the
# default Linux settings).
#
# If you have latency problems turn this to "yes". Otherwise leave it as
# "no" that is the safest pick from the point of view of durability.
no-appendfsync-on-rewrite no
# Automatic rewrite of the append only file.
# Redis is able to automatically rewrite the log file implicitly calling
# BGREWRITEAOF when the AOF log size grows by the specified percentage.
#
# This is how it works: Redis remembers the size of the AOF file after the
# latest rewrite (if no rewrite has happened since the restart, the size of
# the AOF at startup is used).
#
# This base size is compared to the current size. If the current size is
# bigger than the specified percentage, the rewrite is triggered. Also
# you need to specify a minimal size for the AOF file to be rewritten, this
# is useful to avoid rewriting the AOF file even if the percentage increase
# is reached but it is still pretty small.
#
# Specify a percentage of zero in order to disable the automatic AOF
# rewrite feature.
auto-aof-rewrite-percentage 100
auto-aof-rewrite-min-size 64mb
# An AOF file may be found to be truncated at the end during the Redis
# startup process, when the AOF data gets loaded back into memory.
# This may happen when the system where Redis is running
# crashes, especially when an ext4 filesystem is mounted without the
# data=ordered option (however this can't happen when Redis itself
# crashes or aborts but the operating system still works correctly).
#
# Redis can either exit with an error when this happens, or load as much
# data as possible (the default now) and start if the AOF file is found
# to be truncated at the end. The following option controls this behavior.
#
# If aof-load-truncated is set to yes, a truncated AOF file is loaded and
# the Redis server starts emitting a log to inform the user of the event.
# Otherwise if the option is set to no, the server aborts with an error
# and refuses to start. When the option is set to no, the user requires
# to fix the AOF file using the "redis-check-aof" utility before to restart
# the server.
#
# Note that if the AOF file will be found to be corrupted in the middle
# the server will still exit with an error. This option only applies when
# Redis will try to read more data from the AOF file but not enough bytes
# will be found.
aof-load-truncated yes
# When rewriting the AOF file, Redis is able to use an RDB preamble in the
# AOF file for faster rewrites and recoveries. When this option is turned
# on the rewritten AOF file is composed of two different stanzas:
#
# [RDB file][AOF tail]
#
# When loading Redis recognizes that the AOF file starts with the "REDIS"
# string and loads the prefixed RDB file, and continues loading the AOF
# tail.
aof-use-rdb-preamble yes
################################ LUA SCRIPTING ###############################
# Max execution time of a Lua script in milliseconds.
#
# If the maximum execution time is reached Redis will log that a script is
# still in execution after the maximum allowed time and will start to
# reply to queries with an error.
#
# When a long running script exceeds the maximum execution time only the
# SCRIPT KILL and SHUTDOWN NOSAVE commands are available. The first can be
# used to stop a script that did not yet called write commands. The second
# is the only way to shut down the server in the case a write command was
# already issued by the script but the user doesn't want to wait for the natural
# termination of the script.
#
# Set it to 0 or a negative value for unlimited execution without warnings.
lua-time-limit 5000
################################ REDIS CLUSTER ###############################
# Normal Redis instances can't be part of a Redis Cluster; only nodes that are
# started as cluster nodes can. In order to start a Redis instance as a
# cluster node enable the cluster support uncommenting the following:
#
# cluster-enabled yes
# Every cluster node has a cluster configuration file. This file is not
# intended to be edited by hand. It is created and updated by Redis nodes.
# Every Redis Cluster node requires a different cluster configuration file.
# Make sure that instances running in the same system do not have
# overlapping cluster configuration file names.
#
# cluster-config-file nodes-6379.conf
# Cluster node timeout is the amount of milliseconds a node must be unreachable
# for it to be considered in failure state.
# Most other internal time limits are multiple of the node timeout.
#
# cluster-node-timeout 15000
# A replica of a failing master will avoid to start a failover if its data
# looks too old.
#
# There is no simple way for a replica to actually have an exact measure of
# its "data age", so the following two checks are performed:
#
# 1) If there are multiple replicas able to failover, they exchange messages
# in order to try to give an advantage to the replica with the best
# replication offset (more data from the master processed).
# Replicas will try to get their rank by offset, and apply to the start
# of the failover a delay proportional to their rank.
#
# 2) Every single replica computes the time of the last interaction with
# its master. This can be the last ping or command received (if the master
# is still in the "connected" state), or the time that elapsed since the
# disconnection with the master (if the replication link is currently down).
# If the last interaction is too old, the replica will not try to failover
# at all.
#
# The point "2" can be tuned by user. Specifically a replica will not perform
# the failover if, since the last interaction with the master, the time
# elapsed is greater than:
#
# (node-timeout * replica-validity-factor) + repl-ping-replica-period
#
# So for example if node-timeout is 30 seconds, and the replica-validity-factor
# is 10, and assuming a default repl-ping-replica-period of 10 seconds, the
# replica will not try to failover if it was not able to talk with the master
# for longer than 310 seconds.
#
# A large replica-validity-factor may allow replicas with too old data to failover
# a master, while a too small value may prevent the cluster from being able to
# elect a replica at all.
#
# For maximum availability, it is possible to set the replica-validity-factor
# to a value of 0, which means, that replicas will always try to failover the
# master regardless of the last time they interacted with the master.
# (However they'll always try to apply a delay proportional to their
# offset rank).
#
# Zero is the only value able to guarantee that when all the partitions heal
# the cluster will always be able to continue.
#
# cluster-replica-validity-factor 10
# Cluster replicas are able to migrate to orphaned masters, that are masters
# that are left without working replicas. This improves the cluster ability
# to resist to failures as otherwise an orphaned master can't be failed over
# in case of failure if it has no working replicas.
#
# Replicas migrate to orphaned masters only if there are still at least a
# given number of other working replicas for their old master. This number
# is the "migration barrier". A migration barrier of 1 means that a replica
# will migrate only if there is at least 1 other working replica for its master
# and so forth. It usually reflects the number of replicas you want for every
# master in your cluster.
#
# Default is 1 (replicas migrate only if their masters remain with at least
# one replica). To disable migration just set it to a very large value.
# A value of 0 can be set but is useful only for debugging and dangerous
# in production.
#
# cluster-migration-barrier 1
# By default Redis Cluster nodes stop accepting queries if they detect there
# is at least an hash slot uncovered (no available node is serving it).
# This way if the cluster is partially down (for example a range of hash slots
# are no longer covered) all the cluster becomes, eventually, unavailable.
# It automatically returns available as soon as all the slots are covered again.
#
# However sometimes you want the subset of the cluster which is working,
# to continue to accept queries for the part of the key space that is still
# covered. In order to do so, just set the cluster-require-full-coverage
# option to no.
#
# cluster-require-full-coverage yes
# This option, when set to yes, prevents replicas from trying to failover its
# master during master failures. However the master can still perform a
# manual failover, if forced to do so.
#
# This is useful in different scenarios, especially in the case of multiple
# data center operations, where we want one side to never be promoted if not
# in the case of a total DC failure.
#
# cluster-replica-no-failover no
# In order to setup your cluster make sure to read the documentation
# available at http://redis.io web site.
########################## CLUSTER DOCKER/NAT support ########################
# In certain deployments, Redis Cluster nodes address discovery fails, because
# addresses are NAT-ted or because ports are forwarded (the typical case is
# Docker and other containers).
#
# In order to make Redis Cluster working in such environments, a static
# configuration where each node knows its public address is needed. The
# following two options are used for this scope, and are:
#
# * cluster-announce-ip
# * cluster-announce-port
# * cluster-announce-bus-port
#
# Each instruct the node about its address, client port, and cluster message
# bus port. The information is then published in the header of the bus packets
# so that other nodes will be able to correctly map the address of the node
# publishing the information.
#
# If the above options are not used, the normal Redis Cluster auto-detection
# will be used instead.
#
# Note that when remapped, the bus port may not be at the fixed offset of
# clients port + 10000, so you can specify any port and bus-port depending
# on how they get remapped. If the bus-port is not set, a fixed offset of
# 10000 will be used as usually.
#
# Example:
#
# cluster-announce-ip 10.1.1.5
# cluster-announce-port 6379
# cluster-announce-bus-port 6380
################################## SLOW LOG ###################################
# The Redis Slow Log is a system to log queries that exceeded a specified
# execution time. The execution time does not include the I/O operations
# like talking with the client, sending the reply and so forth,
# but just the time needed to actually execute the command (this is the only
# stage of command execution where the thread is blocked and can not serve
# other requests in the meantime).
#
# You can configure the slow log with two parameters: one tells Redis
# what is the execution time, in microseconds, to exceed in order for the
# command to get logged, and the other parameter is the length of the
# slow log. When a new command is logged the oldest one is removed from the
# queue of logged commands.
# The following time is expressed in microseconds, so 1000000 is equivalent
# to one second. Note that a negative number disables the slow log, while
# a value of zero forces the logging of every command.
slowlog-log-slower-than 10000
# There is no limit to this length. Just be aware that it will consume memory.
# You can reclaim memory used by the slow log with SLOWLOG RESET.
slowlog-max-len 128
################################ LATENCY MONITOR ##############################
# The Redis latency monitoring subsystem samples different operations
# at runtime in order to collect data related to possible sources of
# latency of a Redis instance.
#
# Via the LATENCY command this information is available to the user that can
# print graphs and obtain reports.
#
# The system only logs operations that were performed in a time equal or
# greater than the amount of milliseconds specified via the
# latency-monitor-threshold configuration directive. When its value is set
# to zero, the latency monitor is turned off.
#
# By default latency monitoring is disabled since it is mostly not needed
# if you don't have latency issues, and collecting data has a performance
# impact, that while very small, can be measured under big load. Latency
# monitoring can easily be enabled at runtime using the command
# "CONFIG SET latency-monitor-threshold <milliseconds>" if needed.
latency-monitor-threshold 0
############################# EVENT NOTIFICATION ##############################
# Redis can notify Pub/Sub clients about events happening in the key space.
# This feature is documented at http://redis.io/topics/notifications
#
# For instance if keyspace events notification is enabled, and a client
# performs a DEL operation on key "foo" stored in the Database 0, two
# messages will be published via Pub/Sub:
#
# PUBLISH __keyspace@0__:foo del
# PUBLISH __keyevent@0__:del foo
#
# It is possible to select the events that Redis will notify among a set
# of classes. Every class is identified by a single character:
#
# K Keyspace events, published with __keyspace@<db>__ prefix.
# E Keyevent events, published with __keyevent@<db>__ prefix.
# g Generic commands (non-type specific) like DEL, EXPIRE, RENAME, ...
# $ String commands
# l List commands
# s Set commands
# h Hash commands
# z Sorted set commands
# x Expired events (events generated every time a key expires)
# e Evicted events (events generated when a key is evicted for maxmemory)
# A Alias for g$lshzxe, so that the "AKE" string means all the events.
#
# The "notify-keyspace-events" takes as argument a string that is composed
# of zero or multiple characters. The empty string means that notifications
# are disabled.
#
# Example: to enable list and generic events, from the point of view of the
# event name, use:
#
# notify-keyspace-events Elg
#
# Example 2: to get the stream of the expired keys subscribing to channel
# name __keyevent@0__:expired use:
#
notify-keyspace-events Ex
#
# By default all notifications are disabled because most users don't need
# this feature and the feature has some overhead. Note that if you don't
# specify at least one of K or E, no events will be delivered.
#notify-keyspace-events ""
############################### ADVANCED CONFIG ###############################
# Hashes are encoded using a memory efficient data structure when they have a
# small number of entries, and the biggest entry does not exceed a given
# threshold. These thresholds can be configured using the following directives.
hash-max-ziplist-entries 512
hash-max-ziplist-value 64
# Lists are also encoded in a special way to save a lot of space.
# The number of entries allowed per internal list node can be specified
# as a fixed maximum size or a maximum number of elements.
# For a fixed maximum size, use -5 through -1, meaning:
# -5: max size: 64 Kb <-- not recommended for normal workloads
# -4: max size: 32 Kb <-- not recommended
# -3: max size: 16 Kb <-- probably not recommended
# -2: max size: 8 Kb <-- good
# -1: max size: 4 Kb <-- good
# Positive numbers mean store up to _exactly_ that number of elements
# per list node.
# The highest performing option is usually -2 (8 Kb size) or -1 (4 Kb size),
# but if your use case is unique, adjust the settings as necessary.
list-max-ziplist-size -2
# Lists may also be compressed.
# Compress depth is the number of quicklist ziplist nodes from *each* side of
# the list to *exclude* from compression. The head and tail of the list
# are always uncompressed for fast push/pop operations. Settings are:
# 0: disable all list compression
# 1: depth 1 means "don't start compressing until after 1 node into the list,
# going from either the head or tail"
# So: [head]->node->node->...->node->[tail]
# [head], [tail] will always be uncompressed; inner nodes will compress.
# 2: [head]->[next]->node->node->...->node->[prev]->[tail]
# 2 here means: don't compress head or head->next or tail->prev or tail,
# but compress all nodes between them.
# 3: [head]->[next]->[next]->node->node->...->node->[prev]->[prev]->[tail]
# etc.
list-compress-depth 0
# Sets have a special encoding in just one case: when a set is composed
# of just strings that happen to be integers in radix 10 in the range
# of 64 bit signed integers.
# The following configuration setting sets the limit in the size of the
# set in order to use this special memory saving encoding.
set-max-intset-entries 512
# Similarly to hashes and lists, sorted sets are also specially encoded in
# order to save a lot of space. This encoding is only used when the length and
# elements of a sorted set are below the following limits:
zset-max-ziplist-entries 128
zset-max-ziplist-value 64
# HyperLogLog sparse representation bytes limit. The limit includes the
# 16 bytes header. When an HyperLogLog using the sparse representation crosses
# this limit, it is converted into the dense representation.
#
# A value greater than 16000 is totally useless, since at that point the
# dense representation is more memory efficient.
#
# The suggested value is ~ 3000 in order to have the benefits of
# the space efficient encoding without slowing down too much PFADD,
# which is O(N) with the sparse encoding. The value can be raised to
# ~ 10000 when CPU is not a concern, but space is, and the data set is
# composed of many HyperLogLogs with cardinality in the 0 - 15000 range.
hll-sparse-max-bytes 3000
# Streams macro node max size / items. The stream data structure is a radix
# tree of big nodes that encode multiple items inside. Using this configuration
# it is possible to configure how big a single node can be in bytes, and the
# maximum number of items it may contain before switching to a new node when
# appending new stream entries. If any of the following settings are set to
# zero, the limit is ignored, so for instance it is possible to set just a
# max entires limit by setting max-bytes to 0 and max-entries to the desired
# value.
stream-node-max-bytes 4096
stream-node-max-entries 100
# Active rehashing uses 1 millisecond every 100 milliseconds of CPU time in
# order to help rehashing the main Redis hash table (the one mapping top-level
# keys to values). The hash table implementation Redis uses (see dict.c)
# performs a lazy rehashing: the more operation you run into a hash table
# that is rehashing, the more rehashing "steps" are performed, so if the
# server is idle the rehashing is never complete and some more memory is used
# by the hash table.
#
# The default is to use this millisecond 10 times every second in order to
# actively rehash the main dictionaries, freeing memory when possible.
#
# If unsure:
# use "activerehashing no" if you have hard latency requirements and it is
# not a good thing in your environment that Redis can reply from time to time
# to queries with 2 milliseconds delay.
#
# use "activerehashing yes" if you don't have such hard requirements but
# want to free memory asap when possible.
activerehashing yes
# The client output buffer limits can be used to force disconnection of clients
# that are not reading data from the server fast enough for some reason (a
# common reason is that a Pub/Sub client can't consume messages as fast as the
# publisher can produce them).
#
# The limit can be set differently for the three different classes of clients:
#
# normal -> normal clients including MONITOR clients
# replica -> replica clients
# pubsub -> clients subscribed to at least one pubsub channel or pattern
#
# The syntax of every client-output-buffer-limit directive is the following:
#
# client-output-buffer-limit <class> <hard limit> <soft limit> <soft seconds>
#
# A client is immediately disconnected once the hard limit is reached, or if
# the soft limit is reached and remains reached for the specified number of
# seconds (continuously).
# So for instance if the hard limit is 32 megabytes and the soft limit is
# 16 megabytes / 10 seconds, the client will get disconnected immediately
# if the size of the output buffers reach 32 megabytes, but will also get
# disconnected if the client reaches 16 megabytes and continuously overcomes
# the limit for 10 seconds.
#
# By default normal clients are not limited because they don't receive data
# without asking (in a push way), but just after a request, so only
# asynchronous clients may create a scenario where data is requested faster
# than it can read.
#
# Instead there is a default limit for pubsub and replica clients, since
# subscribers and replicas receive data in a push fashion.
#
# Both the hard or the soft limit can be disabled by setting them to zero.
client-output-buffer-limit normal 0 0 0
client-output-buffer-limit replica 256mb 64mb 60
client-output-buffer-limit pubsub 32mb 8mb 60
# Client query buffers accumulate new commands. They are limited to a fixed
# amount by default in order to avoid that a protocol desynchronization (for
# instance due to a bug in the client) will lead to unbound memory usage in
# the query buffer. However you can configure it here if you have very special
# needs, such us huge multi/exec requests or alike.
#
# client-query-buffer-limit 1gb
# In the Redis protocol, bulk requests, that are, elements representing single
# strings, are normally limited ot 512 mb. However you can change this limit
# here.
#
# proto-max-bulk-len 512mb
# Redis calls an internal function to perform many background tasks, like
# closing connections of clients in timeout, purging expired keys that are
# never requested, and so forth.
#
# Not all tasks are performed with the same frequency, but Redis checks for
# tasks to perform according to the specified "hz" value.
#
# By default "hz" is set to 10. Raising the value will use more CPU when
# Redis is idle, but at the same time will make Redis more responsive when
# there are many keys expiring at the same time, and timeouts may be
# handled with more precision.
#
# The range is between 1 and 500, however a value over 100 is usually not
# a good idea. Most users should use the default of 10 and raise this up to
# 100 only in environments where very low latency is required.
hz 10
# Normally it is useful to have an HZ value which is proportional to the
# number of clients connected. This is useful in order, for instance, to
# avoid too many clients are processed for each background task invocation
# in order to avoid latency spikes.
#
# Since the default HZ value by default is conservatively set to 10, Redis
# offers, and enables by default, the ability to use an adaptive HZ value
# which will temporary raise when there are many connected clients.
#
# When dynamic HZ is enabled, the actual configured HZ will be used as
# as a baseline, but multiples of the configured HZ value will be actually
# used as needed once more clients are connected. In this way an idle
# instance will use very little CPU time while a busy instance will be
# more responsive.
dynamic-hz yes
# When a child rewrites the AOF file, if the following option is enabled
# the file will be fsync-ed every 32 MB of data generated. This is useful
# in order to commit the file to the disk more incrementally and avoid
# big latency spikes.
aof-rewrite-incremental-fsync yes
# When redis saves RDB file, if the following option is enabled
# the file will be fsync-ed every 32 MB of data generated. This is useful
# in order to commit the file to the disk more incrementally and avoid
# big latency spikes.
rdb-save-incremental-fsync yes
# Redis LFU eviction (see maxmemory setting) can be tuned. However it is a good
# idea to start with the default settings and only change them after investigating
# how to improve the performances and how the keys LFU change over time, which
# is possible to inspect via the OBJECT FREQ command.
#
# There are two tunable parameters in the Redis LFU implementation: the
# counter logarithm factor and the counter decay time. It is important to
# understand what the two parameters mean before changing them.
#
# The LFU counter is just 8 bits per key, it's maximum value is 255, so Redis
# uses a probabilistic increment with logarithmic behavior. Given the value
# of the old counter, when a key is accessed, the counter is incremented in
# this way:
#
# 1. A random number R between 0 and 1 is extracted.
# 2. A probability P is calculated as 1/(old_value*lfu_log_factor+1).
# 3. The counter is incremented only if R < P.
#
# The default lfu-log-factor is 10. This is a table of how the frequency
# counter changes with a different number of accesses with different
# logarithmic factors:
#
# +--------+------------+------------+------------+------------+------------+
# | factor | 100 hits | 1000 hits | 100K hits | 1M hits | 10M hits |
# +--------+------------+------------+------------+------------+------------+
# | 0 | 104 | 255 | 255 | 255 | 255 |
# +--------+------------+------------+------------+------------+------------+
# | 1 | 18 | 49 | 255 | 255 | 255 |
# +--------+------------+------------+------------+------------+------------+
# | 10 | 10 | 18 | 142 | 255 | 255 |
# +--------+------------+------------+------------+------------+------------+
# | 100 | 8 | 11 | 49 | 143 | 255 |
# +--------+------------+------------+------------+------------+------------+
#
# NOTE: The above table was obtained by running the following commands:
#
# redis-benchmark -n 1000000 incr foo
# redis-cli object freq foo
#
# NOTE 2: The counter initial value is 5 in order to give new objects a chance
# to accumulate hits.
#
# The counter decay time is the time, in minutes, that must elapse in order
# for the key counter to be divided by two (or decremented if it has a value
# less <= 10).
#
# The default value for the lfu-decay-time is 1. A Special value of 0 means to
# decay the counter every time it happens to be scanned.
#
# lfu-log-factor 10
# lfu-decay-time 1
########################### ACTIVE DEFRAGMENTATION #######################
#
# WARNING THIS FEATURE IS EXPERIMENTAL. However it was stress tested
# even in production and manually tested by multiple engineers for some
# time.
#
# What is active defragmentation?
# -------------------------------
#
# Active (online) defragmentation allows a Redis server to compact the
# spaces left between small allocations and deallocations of data in memory,
# thus allowing to reclaim back memory.
#
# Fragmentation is a natural process that happens with every allocator (but
# less so with Jemalloc, fortunately) and certain workloads. Normally a server
# restart is needed in order to lower the fragmentation, or at least to flush
# away all the data and create it again. However thanks to this feature
# implemented by Oran Agra for Redis 4.0 this process can happen at runtime
# in an "hot" way, while the server is running.
#
# Basically when the fragmentation is over a certain level (see the
# configuration options below) Redis will start to create new copies of the
# values in contiguous memory regions by exploiting certain specific Jemalloc
# features (in order to understand if an allocation is causing fragmentation
# and to allocate it in a better place), and at the same time, will release the
# old copies of the data. This process, repeated incrementally for all the keys
# will cause the fragmentation to drop back to normal values.
#
# Important things to understand:
#
# 1. This feature is disabled by default, and only works if you compiled Redis
# to use the copy of Jemalloc we ship with the source code of Redis.
# This is the default with Linux builds.
#
# 2. You never need to enable this feature if you don't have fragmentation
# issues.
#
# 3. Once you experience fragmentation, you can enable this feature when
# needed with the command "CONFIG SET activedefrag yes".
#
# The configuration parameters are able to fine tune the behavior of the
# defragmentation process. If you are not sure about what they mean it is
# a good idea to leave the defaults untouched.
# Enabled active defragmentation
# activedefrag yes
# Minimum amount of fragmentation waste to start active defrag
# active-defrag-ignore-bytes 100mb
# Minimum percentage of fragmentation to start active defrag
# active-defrag-threshold-lower 10
# Maximum percentage of fragmentation at which we use maximum effort
# active-defrag-threshold-upper 100
# Minimal effort for defrag in CPU percentage
# active-defrag-cycle-min 5
# Maximal effort for defrag in CPU percentage
# active-defrag-cycle-max 75
# Maximum number of set/hash/zset/list fields that will be processed from
# the main dictionary scan
# active-defrag-max-scan-fields 1000
