LINUX集群学习二——pacemaker+corosync+pcs实验
环境：centos 6.9
Pacemaker: 1.1.15
Corosync:1.47
Pcs: 0.9.155
准备工作：
- 配置SSH双机互信;
- 配置主机名解析/etc/hosts文件；
- 关闭防火墙：service iptables stop
- 关闭selunux：setenforce 0
- 关闭networkmanager: chkconfig NetworkManager off 、service NetworkManager stop
一、 软件安装
使用yum源可以直接安装corosync pacemaker以及pcs软件：
yum install corosync pacemaker pcs -y
二、 开启pcsd服务，两台都要开启
Service pcsd start
[root@node1 ~]# service pcsd start
Starting pcsd: [ OK ]
[root@node1 ~]#
[root@node1 ~]#
[root@node1 ~]# ssh node2 "service pcsd start"
Starting pcsd: [ OK ]
[root@node1 ~]#
三、 设置hacluster账号的密码，两台都要设置
为hacluster设置一个密码，用于pcs与pcsd通信
[root@node1 ~]# grep "hacluster" /etc/passwd
hacluster:x:496:493:heartbeat user:/var/lib/heartbeat/cores/hacluster:/sbin/nologin
[root@node2 ~]# passwd hacluster
Changing password for user hacluster.
New password:
Retype new password:
passwd: all authentication tokens updated successfully.
[root@node2 ~]#
四、 配置corosync，生成/etc/cluster/cluster.conf文件，在指定的节点上给pcs与pcsd完成认证。
[root@node1 ~]# pcs cluster auth node1 node2
Username: hacluster //输入上面设置的帐户及密码
Password:
node1: Authorized
Error: Unable to communicate with node2
[root@node1 ~]# service iptables stop
iptables: Setting chains to policy ACCEPT: filter [ OK ]
iptables: Flushing firewall rules: [ OK ]
iptables: Unloading modules: [ OK ]
[root@node1 ~]#
[root@node1 ~]#
[root@node1 ~]# getenforce
Disabled
[root@node1 ~]# pcs cluster auth node1 node2
Username: hacluster
Password:
node1: Authorized
node2: Authorized
tcp 0 0 :::2224 :::* LISTEN 2303/ruby
备注：务必要关闭防火墙，或者配置iptables放行tcp 2224端口。
pcs cluster setup --name mycluster node1 node2 设置集群相关的参数
只有两台服务器pcsd服务、networkmanager关闭等基础条件准备好后才能够成功配置集群的参数，并且生成cluster.conf文件
[root@node1 corosync]# pcs cluster setup --name webcluster node1 node2 --force
Destroying cluster on nodes: node1, node2...
node1: Stopping Cluster (pacemaker)...
node2: Stopping Cluster (pacemaker)...
node1: Successfully destroyed cluster
node2: Successfully destroyed cluster
Sending cluster config files to the nodes...
node1: Updated cluster.conf...
node2: Updated cluster.conf...
Synchronizing pcsd certificates on nodes node1, node2...
node1: Success
node2: Success
Restarting pcsd on the nodes in order to reload the certificates...
node1: Success
node2: Success
[root@node1 corosync]# cat /etc/cluster/cluster.conf //生成的配置文件
<cluster config_version="9" name="webcluster">
<fence_daemon/>
<clusternodes>
<clusternode name="node1" nodeid="1">
<fence>
<method name="pcmk-method">
<device name="pcmk-redirect" port="node1"/>
</method>
</fence>
</clusternode>
<clusternode name="node2" nodeid="2">
<fence>
<method name="pcmk-method">
<device name="pcmk-redirect" port="node2"/>
</method>
</fence>
</clusternode>
</clusternodes>
<cman broadcast="no" expected_votes="1" transport="udp" two_node="1"/>
<fencedevices>
<fencedevice agent="fence_pcmk" name="pcmk-redirect"/>
</fencedevices>
<rm>
<failoverdomains/>
<resources/>
</rm>
五、 启动集群服务
pcs cluster start --all //注意关闭NetworkManager服务
可以使用pcs --debug cluster start --all 打开调试模式，检查其中的错误，提示需要关闭NetworkManager服务
六、 查看集群节点状态：
Pcs status
Pcs status corosync
Pcs status cluster
[root@node1 corosync]# pcs status
Cluster name: webcluster
WARNING: no stonith devices and stonith-enabled is not false
Stack: cman
Current DC: node1 (version 1.1.15-5.el6-e174ec8) - partition with quorum
Last updated: Mon Apr 30 10:06:42 2018 Last change: Mon Apr 30 09:26:32 2018 by root via crmd on node2
2 nodes and 0 resources configured
Online: [ node1 node2 ]
No resources
Daemon Status:
cman: active/disabled
corosync: active/disabled
pacemaker: active/disabled
pcsd: active/disabled
[root@node1 corosync]# pcs status corosync
Nodeid Name
1 node1
2 node2
检查一下是有配置错误，可以看到都是和stonith相关
Crm_verify –L –V
使用下面的命令关闭这些错误：
pcs property set stonith-enabled=false #关掉这些错误
七、 配置服务
-
配置VIP服务
pcs resource create vip ocf:heartbeat:IPaddr2 ip=192.168.110.150 cidr_netmask=24 op monitor interval=30s
pcs status 查看资源是否启动，注意这里测试发现掩码需要配置为与网卡同掩码，否则资源启动不了 - 配置httpd服务
这里有两种方式，使用ocf:heartbeat:apache或者使用lsb:httpd方式，前者需要手工在两台服务器上将httpd服务启动，而后者服务由pacemaker集群启动。
pcs resource create web lsb:httpd op monitor interval=20s
pcs status 可以看到资源已经启动。
同时，可以在对应的节点上面直接service httpd status查看服务是否启动，以及ip addr 查看VIP是否获取到。
八、 资源约束配置
- 配置资源的启动顺序：order，要求vip先启动，web后启动。
pcs constraint order vip then web - 配置位置约束，希望资源优先在node1节点上运行，设置vip/web对node1节点的优先级为150，对node2节点的优先级为50：
pcs constraint location web prefers node1=150
pcs constraint location vip prefers node1=150
pcs constraint location web prefers node2=50
pcs constraint location vip prefers node2=50
[root@node1 ~]# pcs constraint
Location Constraints:
Resource: vip
Enabled on: node1 (score:100)
Enabled on: node2 (score:50)
Resource: web
Enabled on: node1 (score:100)
Enabled on: node2 (score:50)
注意：如果多个资源分布在不同的设备上，而这些资源又必须共同在同一个设备上才能够正常的对外提供服务，那么这个集群将不能正常工作。
可以看到只有web以及vip对node1的优先级都调整为150后，集群才能够正常对外提供服务，否则会出现两个资源分布在不同的设备而导致不能对外提供服务
- 配置资源组，只有两者对节点的位置优先级调整为一样后，资源组同时切换：
pcs resource group add mygroup vip web
[root@node2 ~]# pcs status groups
mygroup: vip web
[root@node1 ~]# pcs resource
Resource Group: httpgroup
vip (ocf::heartbeat:IPaddr2): Started node1
web (lsb:httpd): Started node1
[root@node1 ~]# crm_simulate -sL
Current cluster status:
Online: [ node1 node2 ]
Resource Group: httpgroup
vip (ocf::heartbeat:IPaddr2): Started node1
web (lsb:httpd): Started node1
Allocation scores:
group_color: httpgroup allocation score on node1: 0
group_color: httpgroup allocation score on node2: 0
group_color: vip allocation score on node1: 100
group_color: vip allocation score on node2: 50
group_color: web allocation score on node1: 100
group_color: web allocation score on node2: 50
native_color: web allocation score on node1: 200
native_color: web allocation score on node2: 100
native_color: vip allocation score on node1: 400
native_color: vip allocation score on node2: 150
也可以将整个资源组作为整体调整优先级，如下：
pcs constraint location httpgroup prefers node2=100
pcs constraint location httpgroup prefers node1=200
[root@node1 ~]# pcs constraint
Location Constraints:
Resource: httpgroup
Enabled on: node1 (score:200)
Enabled on: node2 (score:100)
Resource: vip
Enabled on: node1 (score:100)
Enabled on: node2 (score:50)
Resource: web
Enabled on: node1 (score:100)
Enabled on: node2 (score:50)
Ordering Constraints:
start vip then start web (kind:Mandatory)
- 配置排列约束，让vip与web 资源运行在一起，分数为100
[root@node1 ~]# pcs constraint colocation add vip with web 100
[root@node1 ~]# pcs constraint show
Location Constraints:
Resource: httpgroup
Enabled on: node1 (score:200)
Enabled on: node2 (score:100)
Resource: vip
Enabled on: node1 (score:100)
Enabled on: node2 (score:50)
Resource: web
Enabled on: node1 (score:100)
Enabled on: node2 (score:50)
Ordering Constraints:
start vip then start web (kind:Mandatory)
Colocation Constraints:
vip with web (score:100)
Ticket Constraints:
九、 将资源切换到node2上面
pcs constraint location web prefers node1=100 //将web资源对node1的位置优先级调整为100，可以看到资源从node2转换到node1，注意可以调整httpgroup，也可以同时调整web以及vip对node2的优先级。
May 1 09:43:02 node1 crmd[2965]: notice: State transition S_IDLE -> S_POLICY_ENGINE | input=I_PE_CALC cause=C_FSA_INTERNAL origin=abort_transition_graph
May 1 09:43:02 node1 pengine[2964]: warning: Processing failed op monitor for web on node2: not running (7)
May 1 09:43:02 node1 pengine[2964]: notice: Move web#011(Started node2 -> node1)
May 1 09:43:02 node1 pengine[2964]: notice: Calculated transition 4, saving inputs in /var/lib/pacemaker/pengine/pe-input-57.bz2
May 1 09:43:02 node1 crmd[2965]: notice: Initiating stop operation web_stop_0 on node2 | action 6
May 1 09:43:02 node1 crmd[2965]: notice: Initiating start operation web_start_0 locally on node1 | action 7
May 1 09:43:03 node1 lrmd[2962]: notice: web_start_0:3682:stderr [ httpd: Could not reliably determine the server‘s fully qualified domain name, using node1.yang.com for ServerName ]
May 1 09:43:03 node1 crmd[2965]: notice: Result of start operation for web on node1: 0 (ok) | call=12 key=web_start_0 confirmed=true cib-update=42
May 1 09:43:03 node1 crmd[2965]: notice: Initiating monitor operation web_monitor_20000 locally on node1 | action 8
May 1 09:43:03 node1 crmd[2965]: notice: Transition 4 (Complete=4, Pending=0, Fired=0, Skipped=0, Incomplete=0, Source=/var/lib/pacemaker/pengine/pe-input-57.bz2): Complete
May 1 09:43:03 node1 crmd[2965]: notice: State transition S_TRANSITION_ENGINE -> S_IDLE | input=I_TE_SUCCESS cause=C_FSA_INTERNAL origin=notify_crmd
十、 遗留问题：
节点配置web资源后，始终有一个报错未能解决，如下：
[root@node1 ~]# pcs status
Cluster name: mycluster
Stack: cman
Current DC: node1 (version 1.1.15-5.el6-e174ec8) - partition with quorum
Last updated: Tue May 1 11:13:00 2018 Last change: Tue May 1 11:04:20 2018 by root via cibadmin on node1
2 nodes and 2 resources configured
Online: [ node1 node2 ]
Full list of resources:
Resource Group: httpgroup
vip (ocf::heartbeat:IPaddr2): Started node1
web (lsb:httpd): Started node1
Failed Actions: //看着像和监控有关，但一直未能弄明白原因
* web_monitor_20000 on node2 ‘not running‘ (7): call=11, status=complete, exitreason=‘none‘,
last-rc-change=‘Tue May 1 09:41:09 2018‘, queued=0ms, exec=16msDaemon Status:
cman: active/disabled
corosync: active/disabled
pacemaker: active/disabled
pcsd: active/disabled
命令：
pcs cluster 设备集群的pcsd认证、集群参数、启动集群节点、删除节点等功能。
pcs cluster stop node1 // 关闭集群中的node1
[root@node2 ~]# pcs status
Cluster name: mycluster
Stack: cman
Current DC: node2 (version 1.1.15-5.el6-e174ec8) - partition with quorum
Last updated: Sat Apr 28 02:23:00 2018 Last change: Sat Apr 28 02:16:12 2018 by root via cibadmin on node2
2 nodes and 2 resources configured
Online: [ node2 ]
OFFLINE: [ node1 ]
Full list of resources:
Resource Group: mygroup
vip (ocf::heartbeat:IPaddr2): Started node2
web (lsb:httpd): Started node2
Daemon Status:
cman: active/disabled
corosync: active/disabled
pacemaker: active/disabled
pcsd: active/disabled
此时由于node1上的集群功能已经关闭，无法在node2上直接开启，需要在node1上开启：
[root@node1 ~]# pcs status
Error: cluster is not currently running on this node
[root@node1 ~]#
[root@node1 ~]#
[root@node1 ~]# pcs cluster start node1
node1: Starting Cluster...
pcs resource ：资源相关的命令，包括资源创建、资源删除、资源使能、描述等。
Pcs constraint：资源约束相关的配置命令
Pcs status ：资源状态查看相关的命令。