最后
== 就答题情况而言，第一问100%都可以回答正确，第二问大概只有50%正确率，第三问能回答正确的就不多了，第四问再正确就非常非常少了。其实此题并没有太多刁钻匪夷所思的用法，都是一些可能会遇到的场景，而大多数人但凡有1年到2年的工作经验都应该完全正确才对。 只能说有一些人太急躁太轻视了，希望大家通过此文了解js一些特性。
并祝愿大家在新的一年找工作面试中胆大心细，发挥出最好的水平，找到一份理想的工作。 开源分享：docs.qq.com/doc/DSmRnRG…
systemctl enable httpd
创建Apache状态URL(节点都要做)
vim /etc/httpd/conf.d/status.conf
<location /server-status>
setHandler server-status
Order deny,allow
deny from all
Allow from 127.0.0.1
创建Apache资源
pcs resource create Website ocf💓apache
configfile=/etc/httpd/conf/httpd.conf
statusurl=“http://localhost/server-status” \ op monitor interval=1min
删除Apache资源
pcs resource delete Website
查看状态
[root@rs1 ~]# pcs status
Cluster name: cluster1
Stack: corosync
Current DC: rs1 (version 1.1.20-5.el7-3c4c782f70) - partition with quorum
Last updated: Fri May 8 10:27:09 2020
Last change: Fri May 8 10:26:53 2020 by root via cibadmin on rs1
2 nodes configured
2 resources configured
Online: [ rs1 rs2 ]
Full list of resources:
VIP (ocf::heartbeat:IPaddr2): Started rs2
Website (ocf::heartbeat:apache): Starting rs1
Daemon Status:
corosync: active/disabled
pacemaker: active/disabled
pcsd: active/enabled
无共享存储的web群集就搭建好了，我们可以通过VIP来访问web群集，一台服务器宕机，我们可以利用pcs工具对VIP进行迁移，访问另一台服务器，实现了HA
确保资源在同一节点
1.添加约束确保资源在同一节点
[root@rs1 ~]# pcs constraint
Location Constraints:
Ordering Constraints:
Colocation Constraints:
Ticket Constraints:
[root@rs1 ~]# pcs constraint colocation add Website with VirtualIP INFINITY
[root@rs1 ~]# pcs status
Cluster name: cluster1
Stack: corosync
Current DC: rs1 (version 1.1.20-5.el7-3c4c782f70) - partition with quorum
Last updated: Fri May 8 10:51:57 2020
Last change: Fri May 8 10:51:52 2020 by root via cibadmin on rs1
2 nodes configured
2 resources configured
Online: [ rs1 rs2 ]
Full list of resources:
VirtualIP (ocf::heartbeat:IPaddr2): Started rs1
Website (ocf::heartbeat:apache): Starting rs1
Daemon Status:
corosync: active/disabled
pacemaker: active/disabled
pcsd: active/enabled
2.IP飘逸
[root@rs1 ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: ens32: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 00:0c:29:46:eb:23 brd ff:ff:ff:ff:ff:ff
inet 192.168.43.10/24 brd 192.168.43.255 scope global noprefixroute ens32
valid_lft forever preferred_lft forever
inet6 fe80::a0b8:9a41:6d1b:7285/64 scope link noprefixroute
valid_lft forever preferred_lft forever
[root@rs1 conf.d]# pcs cluster standby rs1
[root@rs2 ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: ens32: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 00:0c:29:01:55:ac brd ff:ff:ff:ff:ff:ff
inet 192.168.43.20/24 brd 192.168.43.255 scope global noprefixroute ens32
valid_lft forever preferred_lft forever
inet 192.168.43.100/24 brd 192.168.43.255 scope global secondary ens32
valid_lft forever preferred_lft forever
inet6 fe80::a0b8:9a41:6d1b:7285/64 scope link tentative noprefixroute dadfailed
valid_lft forever preferred_lft forever
inet6 fe80::1777:3e7e:f136:6cf/64 scope link noprefixroute
valid_lft forever preferred_lft forever
[root@rs1 ~]# pcs status
Cluster name: cluster1
Stack: corosync
Current DC: rs1 (version 1.1.20-5.el7-3c4c782f70) - partition with quorum
Last updated: Sat May 9 02:08:53 2020
Last change: Sat May 9 02:08:47 2020 by root via cibadmin on rs1
2 nodes configured
1 resource configured
Node rs1: standby
Online: [ rs2 ]
Full list of resources:
VirtualIP (ocf::heartbeat:IPaddr2): Started rs2
Daemon Status:
corosync: active/disabled
pacemaker: active/disabled
pcsd: active/enabled
恢复：
[root@rs1 ~]# pcs cluster unstandby rs1
[root@rs1 ~]# pcs status
Cluster name: cluster1
Stack: corosync
Current DC: rs1 (version 1.1.20-5.el7-3c4c782f70) - partition with quorum
Last updated: Sat May 9 02:11:31 2020
Last change: Sat May 9 02:11:23 2020 by root via cibadmin on rs1
2 nodes configured
1 resource configured
Online: [ rs1 rs2 ]
Full list of resources:
VirtualIP (ocf::heartbeat:IPaddr2): Started rs2
Daemon Status:
corosync: active/disabled
pacemaker: active/disabled
pcsd: active/enabled
3.先后顺序
[root@rs1 conf.d]# pcs constraint order VirtualIP then Website
Adding VirtualIP Website (kind: Mandatory) (Options: first-action=start then-action=start)
[root@rs1 conf.d]# pcs constraint
Location Constraints:
Ordering Constraints:
start VirtualIP then start Website (kind:Mandatory)
Colocation Constraints:
Ticket Constraints:
4.优先级
[root@rs1 conf.d]# pcs constraint location Website prefers rs1=50
[root@rs1 conf.d]# pcs constraint location Website prefers rs2=100
最后
其实前端开发的知识点就那么多，面试问来问去还是那么点东西。所以面试没有其他的诀窍，只看你对这些知识点准备的充分程度。so，出去面试时先看看自己复习到了哪个阶段就好。
这里再分享一个复习的路线：（以下体系的复习资料是我从各路大佬收集整理好的）
《前端开发四大模块核心知识笔记》
最后，说个题外话，我在一线互联网企业工作十余年里，指导过不少同行后辈。帮助很多人得到了学习和成长。
开源分享：【大厂前端面试题解析+核心总结学习笔记+真实项目实战+最新讲解视频】
我意识到有很多经验和知识值得分享给大家，也可以通过我们的能力和经验解答大家在IT学习中的很多困惑，所以在工作繁忙的情况下还是坚持各种整理和分享。
