1 安装前准备

使用了腾讯云的一台centos云主机， k8s需要containerd

yum install docker-ce

该命令将会安装docker-ce, docker-ce-cli和containerd

2 安装 kubeadm、kubelet 和 kubectl

直接使用yum安装，找不着，因此需要添加配置/etc/yum.repos.d/kubernetes.repo

[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
       https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg

yum install -y kubelet kubeadm kubectl 
systemctl enable kubelet 
systemctl start kubelet 
setenforce 0

在kubeadm init前，查看systemctl status kubelet状态，是不成功的，因为它需要在kubeadm init生成的配置文件。接下来执行

kubeadm init --image-repository=registry.aliyuncs.com/google_containers

发现报错

Unfortunately, an error has occurred:
        timed out waiting for the condition

This error is likely caused by:
        - The kubelet is not running
        - The kubelet is unhealthy due to a misconfiguration of the node in some way (required cgroups disabled)

If you are on a systemd-powered system, you can try to troubleshoot the error with the following commands:
        - 'systemctl status kubelet'
        - 'journalctl -xeu kubelet'

根据提示查看原因

kuberuntime_sandbox.go:72] "Failed to create sandbox for pod" err="rpc error: code = DeadlineExceeded desc = failed to get sandbox image \"registry.k8s.io/pause:3.9\": failed to pull image \"registry.k8s.io/pause:3.9\": failed to pull and unpack image \"registry.k8s.io/pause:3.9\

解决办法是修改/etc/containerd/config.toml里面内容，但是打开，基本是空内容，这个时候可以查看containerd config dump ，并将其内容写入config.toml进行覆盖。然后修改sandbox_image

sandbox_image = "registry.aliyuncs.com/google_containers/pause:3.9"

sandbox_image = "registry.aliyuncs.com/google_containers/pause:3.9"

修改完记得要重启 systemctl restart containerd 接下来执行

kubeadm reset
kubeadm init --image-repository=registry.aliyuncs.com/google_containers

发现启动成功，然后按信息提示进行配置。

Your Kubernetes control-plane has initialized successfully!

To start using your cluster, you need to run the following as a regular user:

  mkdir -p $HOME/.kube
  sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
  sudo chown $(id -u):$(id -g) $HOME/.kube/config

Alternatively, if you are the root user, you can run:

  export KUBECONFIG=/etc/kubernetes/admin.conf

You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
  https://kubernetes.io/docs/concepts/cluster-administration/addons/

Then you can join any number of worker nodes by running the following on each as root:

kubeadm join 10.0.16.12:6443 --token 7y60uv.xrauoinoozq8blec \
        --discovery-token-ca-cert-hash sha256:21e20ee465f0eb9f407e702fbd12fba3e5c63ebab6bd0c8509f0a9d605a24b83

安装完网络插件后，运行命令

kubectl get  nodes

3 定义一个Pod和Service

apiVersion: v1
kind: Pod
metadata:
  name: redis
  labels:
    app: redis
spec:
  containers:
  - name: redis
    image: redis:latest
    ports:
    - containerPort: 6379

---

apiVersion: v1
kind: Service
metadata:
  name: redis-service
spec:
  type: NodePort
  ports:
  - port: 6379
    targetPort: 6379
  selector:
    app: redis

kubectl apply -f redis.yaml

之所以是pending状态，是因为当前node是有taint的

Taints:             node-role.kubernetes.io/control-plane:NoSchedule

需要在yaml中添加相应属性，才可以, 加入了 tolerations, operator: "Exists", effect: "NoSchedule".

key：污点的键，如果指定，Pod只能容忍具有该键的污点。
operator：操作符，可以是Exists（表示容忍任何键的污点）或Equal（需要指定value字段，表示容忍具有特定键和值的污点）。
effect：污点的效果，可以是NoSchedule（默认值，Pod不会调度到带有匹配污点的节点上）、PreferNoSchedule（节点上没有其他Pod时，Pod可以被调度到该节点上）或NoExecute（Pod不会被调度到带有匹配污点的节点上，如果已经被调度，则会被驱逐）。

apiVersion: v1
kind: Pod
metadata:
  name: redis
  labels:
    app: redis
spec:
  containers:
  - name: redis
    image: redis:latest
    ports:
    - containerPort: 6379
  tolerations:
  - operator: "Exists"
    effect: "NoSchedule"

---

apiVersion: v1
kind: Service
metadata:
  name: redis-service
spec:
  type: NodePort
  ports:
  - port: 6379
    targetPort: 6379
  selector:
    app: redis

此时

4 直接访问api-server

上述均是通过kubectl间接访问api-server，那么如何直接访问api-server呢？

cat ~/.kube/config ，找到client-certificate-data与client-key-data以及访问地址 server: https://10.0.16.12:6443
数据转化echo '<base64_encoded_data' | base64 --decode > client.crt
curl -k --cert ~/.kube/client.crt --key ~/.kube/client.key https://127.0.0.1:6443/api/v1/pods

小白k8s

1 安装前准备

2 安装 kubeadm、kubelet 和 kubectl

3 定义一个Pod和Service

4 直接访问api-server