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消息型中间件之RabbitMQ集群

  在上一篇博客中我们简单的介绍了下rabbitmq简介,安装配置相关指令的说明以及rabbitmqctl的相关子命令的说明;回顾请参考https://www.cnblogs.com/qiuhom-1874/p/13561245.html;今天我 们来聊一聊rabbitmq的集群;之所以要用集群是因为在一个分布式应用环境中,rabbitmq的作用是连接各组件,一旦rabbitmq服务挂掉,可能影响整个线上业务,为了避免这样的问题出现,我们就必须想办法对rabbitmq做高可用,能够让集群中的每个rabbitmq节点把自身接收到的消息通过网络同步到其他节点,这样一来使得每个节点都有整个rabbitmq集群的所有消息,即便其中一台rabbitmq宕机不影响消息丢失的情况;rabbitmq集群它的主要作用就是各节点互相同步消息,从而实现了数据的冗余;除了rabbitmq的数据冗余,我们还需要考虑,一旦后端有多台rabbitmq我们就需要通过对后端多台rabbitmq-server做负载均衡,使得每个节点能够分担一部分流量,同时对客户端访问提供一个统一的访问接口;客户端就可以基于负载均衡的地址来请求rabbitmq,通过负载均衡调度,把客户端的请求分摊到后端多个rabbitmq上;如果某一台rabbitmq宕机了,根据负载均衡的健康状态监测,自动将请求不调度到宕机的rabbitmq-server上,从而也实现了对rabbitmq高可用;

  在实现rabbitmq集群前我们需要做以下准备

  1、更改各节点的主机名同hosts文件解析的主机名相同,必须保证各节点主机名称不一样,并且可以通过hosts文件解析出来;

  2、时间同步,时间同步对于一个集群来讲是最基本的要求;

  3、各节点的cookie信息必须保持一致;

  实验环境说明

节点名 主机名 ip地址
node01 node01 192.168.0.41
node2 node2 192.168.0.42
负载均衡 node3 192.168.0.43

 

 

 

 

 

   

  1、配置各节点的主机名称

[root@node01 ~]# hostnamectl set-hostname node01 [root@node01 ~]# cat /etc/hosts 127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4 ::1         localhost localhost.localdomain localhost6 localhost6.localdomain6 192.168.0.41 node01 192.168.0.42 node2 192.168.0.43 node3 [root@node01 ~]# scp /etc/hosts node2:/etc/ hosts                                                                                100%  218   116.4KB/s   00:00     [root@node01 ~]# scp /etc/hosts node3:/etc/ hosts                                                                                100%  218   119.2KB/s   00:00     [root@node01 ~]#  

  提示:对于rabbitmq集群来讲就只有node01和node2,这两个节点互相同步消息;而负载均衡是为了做流量负载而设定的,本质上不属于rabbitmq集群;所以对于负载均衡的主机名是什么都可以;

  验证:链接个节点验证主机名是否正确,以及hosts文件

[root@node2 ~]# hostname node2 [root@node2 ~]# cat /etc/hosts 127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4 ::1         localhost localhost.localdomain localhost6 localhost6.localdomain6 192.168.0.41 node01 192.168.0.42 node2 192.168.0.43 node3 [root@node2 ~]#  

  在各节点安装rabbitmq-server

yum install rabbitmq-server -y 

  启动各节点rabbitmq-server

消息型中间件之RabbitMQ集群

消息型中间件之RabbitMQ集群

  提示:node01上启动了rabbitmq-management插件,所以15672处于监听;而node2没有启动rabbitmq-management插件,15672端口并没有处于监听状体;对于一个rabbitmq集群,25672这个端口就是专用于集群个节点通信;

  现在基本环境已经准备好,现在我们就可以来配置集群了,rabbitmq集群的配置非常简单,默认情况启动一个rabbitmq,它就是一个集群,所以25672处于监听状态嘛,只不过集群中就只有一个自身节点;

  验证:各节点集群状态信息,节点名是否同主机hostname名称相同

消息型中间件之RabbitMQ集群

 消息型中间件之RabbitMQ集群

  提示:从上面的信息可以看到两个节点的集群名称都是同host主机名相同;

  停止node2上的应用,把node2加入node01集群

消息型中间件之RabbitMQ集群

  提示:这里提示我们无法连接到rabbit@node01,出现以上错误的主要原因有两个,第一个是主机名称解析不正确;第二是cookie不一致;

  复制cookie信息

[root@node2 ~]# scp /var/lib/rabbitmq/.erlang.cookie node01:/var/lib/rabbitmq/ The authenticity of host 'node01 (192.168.0.41)' can't be established. ECDSA key fingerprint is SHA256:EG9nua4JJuUeofheXlgQeL9hX5H53JynOqf2vf53mII. ECDSA key fingerprint is MD5:57:83:e6:46:2c:4b:bb:33:13:56:17:f7:fd:76:71:cc. Are you sure you want to continue connecting (yes/no)? yes Warning: Permanently added 'node01,192.168.0.41' (ECDSA) to the list of known hosts. .erlang.cookie                                                                       100%   20    10.6KB/s   00:00     [root@node2 ~]#  

  验证:md5sum验证各节点cookie是否一致

[root@node2 ~]# md5sum /var/lib/rabbitmq/.erlang.cookie  1d4f9e4d6c92cf0c749cc4ace68317f6  /var/lib/rabbitmq/.erlang.cookie [root@node2 ~]# ssh node01 Last login: Wed Aug 26 19:41:30 2020 from 192.168.0.232 [root@node01 ~]# md5sum /var/lib/rabbitmq/.erlang.cookie  1d4f9e4d6c92cf0c749cc4ace68317f6  /var/lib/rabbitmq/.erlang.cookie [root@node01 ~]#  

  提示:现在两个节点的cookie信息一致了,再次把node2加入到node01上看看是否能够加入?

[root@node2 ~]# rabbitmqctl join_cluster rabbit@node01 Clustering node rabbit@node2 with rabbit@node01 ... Error: unable to connect to nodes [rabbit@node01]: nodedown  DIAGNOSTICS ===========  attempted to contact: [rabbit@node01]  rabbit@node01:   * connected to epmd (port 4369) on node01   * epmd reports node 'rabbit' running on port 25672   * TCP connection succeeded but Erlang distribution failed   * suggestion: hostname mismatch?   * suggestion: is the cookie set correctly?  current node details: - node name: rabbitmqctl2523@node2 - home dir: /var/lib/rabbitmq - cookie hash: HU+eTWySzwx0nMSs5oMX9g==  [root@node2 ~]# 

  提示:还是提示我们加不进去,这里的原因是我们更新了node01的cookie信息,没有重启rabbitmq-server,所以它默认还是以前的cookie;

  重启node01上的rabbitmq-server

[root@node01 ~]# systemctl restart rabbitmq-server.service  [root@node01 ~]# ss -tnl State       Recv-Q Send-Q              Local Address:Port                             Peer Address:Port               LISTEN      0      128                     127.0.0.1:631                                         *:*                   LISTEN      0      128                             *:15672                                       *:*                   LISTEN      0      100                     127.0.0.1:25                                          *:*                   LISTEN      0      100                     127.0.0.1:64667                                       *:*                   LISTEN      0      128                             *:8000                                        *:*                   LISTEN      0      128                             *:8001                                        *:*                   LISTEN      0      128                             *:25672                                       *:*                   LISTEN      0      5                       127.0.0.1:8010                                        *:*                   LISTEN      0      128                             *:111                                         *:*                   LISTEN      0      128                             *:80                                          *:*                   LISTEN      0      128                             *:4369                                        *:*                   LISTEN      0      5                   192.168.122.1:53                                          *:*                   LISTEN      0      128                             *:22                                          *:*                   LISTEN      0      128                           ::1:631                                        :::*                   LISTEN      0      100                           ::1:25                                         :::*                   LISTEN      0      128                            :::5672                                       :::*                   LISTEN      0      128                            :::111                                        :::*                   LISTEN      0      128                            :::80                                         :::*                   LISTEN      0      128                            :::4369                                       :::*                   LISTEN      0      128                            :::22                                         :::*                   [root@node01 ~]#  

  提示:如果是把node01的cookie复制给node2,我们需要重启node2,总之拿到新cookie节点都要重启,保证在用cookie的信息一致就可以了;

  再次把node2加入到node01

[root@node2 ~]# rabbitmqctl join_cluster rabbit@node01 Clustering node rabbit@node2 with rabbit@node01 ... ...done. [root@node2 ~]#  

  提示:加入对应节点集群没有报错就表示加入集群成功;

  验证:查看各节点的集群状态信息

消息型中间件之RabbitMQ集群

消息型中间件之RabbitMQ集群

  提示:在两个节点上我们都可以看到两个节点;到此node2就加入到node01这个集群中了;但是两个节点的集群状态信息不一样,原因是node2上没有启动应用,启动应用以后,它俩的状态信息就会是一样;

  启动node2上的应用

消息型中间件之RabbitMQ集群

消息型中间件之RabbitMQ集群

  提示:此时两个节点的状态信息就一样了;到此rabbitmq集群就搭建好了;

  验证:在浏览器登录node1的15672,看看web管理界面是否有节点信息?

消息型中间件之RabbitMQ集群

  提示:node2之所以没有统计信息是因为node2上没有启动rabbitmq-management插件;启用插件就可以统计到数据;

  rabbitmqctl集群相关子命令

  join_cluster <clusternode> [–ram]:加入指定节点集群;

  cluster_status:查看集群状态

  change_cluster_node_type disc | ram:更改节点存储类型,disc表示磁盘,ram表示内存;一个集群中必须有一个节点为disc类型;

[root@node2 ~]# rabbitmqctl cluster_status Cluster status of node rabbit@node2 ... [{nodes,[{disc,[rabbit@node01,rabbit@node2]}]},  {running_nodes,[rabbit@node01,rabbit@node2]},  {cluster_name,<<"rabbit@node01">>},  {partitions,[]}] ...done. [root@node2 ~]# rabbitmqctl change_cluster_node_type ram Turning rabbit@node2 into a ram node ... Error: mnesia_unexpectedly_running [root@node2 ~]# 

  提示:这里提示我们mnesia_unexpectedly_running,所以我们更改不了节点类型;解决办法是停止node2上的应用,然后在更改类型,在启动应用即可;

[root@node2 ~]# rabbitmqctl stop_app Stopping node rabbit@node2 ... ...done. [root@node2 ~]# rabbitmqctl cluster_status Cluster status of node rabbit@node2 ... [{nodes,[{disc,[rabbit@node01,rabbit@node2]}]}] ...done. [root@node2 ~]# rabbitmqctl change_cluster_node_type ram Turning rabbit@node2 into a ram node ... ...done. [root@node2 ~]# rabbitmqctl start_app Starting node rabbit@node2 ... ...done. [root@node2 ~]# rabbitmqctl cluster_status               Cluster status of node rabbit@node2 ... [{nodes,[{disc,[rabbit@node01]},{ram,[rabbit@node2]}]},  {running_nodes,[rabbit@node01,rabbit@node2]},  {cluster_name,<<"rabbit@node01">>},  {partitions,[]}] ...done. [root@node2 ~]#  

  提示:可以看到node2就变成了ram类型了;

[root@node01 ~]#  rabbitmqctl change_cluster_node_type ram Turning rabbit@node01 into a ram node ... Error: mnesia_unexpectedly_running [root@node01 ~]# rabbitmqctl stop_app Stopping node rabbit@node01 ... ...done. [root@node01 ~]# rabbitmqctl cluster_status Cluster status of node rabbit@node01 ... [{nodes,[{disc,[rabbit@node01]},{ram,[rabbit@node2]}]}] ...done. [root@node01 ~]#  rabbitmqctl change_cluster_node_type ram Turning rabbit@node01 into a ram node ... Error: {resetting_only_disc_node,"You cannot reset a node when it is the only disc node in a cluster. Please convert another node of the cluster to a disc node first."} [root@node01 ~]#  

  提示:这里需要注意一个集群中至少保持一个节点是disc类型;所以node2更改成ram类型,node01就必须是disc类型;

  forget_cluster_node [–offline]:离开集群;

[root@node01 ~]# rabbitmqctl cluster_status Cluster status of node rabbit@node01 ... [{nodes,[{disc,[rabbit@node01]},{ram,[rabbit@node2]}]},  {running_nodes,[rabbit@node2,rabbit@node01]},  {cluster_name,<<"rabbit@node01">>},  {partitions,[]}] ...done. [root@node01 ~]# rabbitmqctl forget_cluster_node rabbit@node2 Removing node rabbit@node2 from cluster ... Error: {failed_to_remove_node,rabbit@node2,                               {active,"Mnesia is running",rabbit@node2}} [root@node01 ~]#  

  提示:我们在node01上移除node2,提示我们node2节点处于活跃状态不能移除;这也告诉我们这个子命令只能移除不在线的节点;

  下线node2上的应用

[root@node2 ~]# rabbitmqctl stop_app Stopping node rabbit@node2 ... ...done. [root@node2 ~]# 

  再次移除node2

[root@node01 ~]# rabbitmqctl cluster_status Cluster status of node rabbit@node01 ... [{nodes,[{disc,[rabbit@node01]},{ram,[rabbit@node2]}]},  {running_nodes,[rabbit@node01]},  {cluster_name,<<"rabbit@node01">>},  {partitions,[]}] ...done. [root@node01 ~]# rabbitmqctl forget_cluster_node rabbit@node2           Removing node rabbit@node2 from cluster ... ...done. [root@node01 ~]# rabbitmqctl cluster_status                   Cluster status of node rabbit@node01 ... [{nodes,[{disc,[rabbit@node01]}]},  {running_nodes,[rabbit@node01]},  {cluster_name,<<"rabbit@node01">>},  {partitions,[]}] ...done. [root@node01 ~]# 

  update_cluster_nodes clusternode:更新集群节点信息;

  把node2加入node01这个集群

[root@node2 ~]# rabbitmqctl stop_app Stopping node rabbit@node2 ... ...done. [root@node2 ~]# rabbitmqctl join_cluster rabbit@node01 Clustering node rabbit@node2 with rabbit@node01 ... ...done. [root@node2 ~]# rabbitmqctl cluster_status Cluster status of node rabbit@node2 ... [{nodes,[{disc,[rabbit@node01,rabbit@node2]}]}] ...done. [root@node2 ~]# rabbitmqctl start_app Starting node rabbit@node2 ... ...done. [root@node2 ~]# rabbitmqctl cluster_status Cluster status of node rabbit@node2 ... [{nodes,[{disc,[rabbit@node01,rabbit@node2]}]},  {running_nodes,[rabbit@node01,rabbit@node2]},  {cluster_name,<<"rabbit@node01">>},  {partitions,[]}] ...done. [root@node2 ~]#  

  停掉node2上的应用

[root@node2 ~]# rabbitmqctl stop_app Stopping node rabbit@node2 ... ...done. [root@node2 ~]# rabbitmqctl cluster_status Cluster status of node rabbit@node2 ... [{nodes,[{disc,[rabbit@node01,rabbit@node2]}]}] ...done. [root@node2 ~]#  

  提示:如果此时有新节点加入集群,如果在把node01上的应用停掉,node2再次启动应用就会提示错误;如下

  把node3加入node01

[root@node3 ~]# rabbitmqctl cluster_status             Cluster status of node rabbit@node3 ... [{nodes,[{disc,[rabbit@node3]}]},  {running_nodes,[rabbit@node3]},  {cluster_name,<<"rabbit@node3">>},  {partitions,[]}] ...done. [root@node3 ~]# rabbitmqctl stop_app Stopping node rabbit@node3 ... ...done. [root@node3 ~]# rabbitmqctl join_cluster rabbit@node01 Clustering node rabbit@node3 with rabbit@node01 ... ...done. [root@node3 ~]# rabbitmqctl start_app Starting node rabbit@node3 ... ...done. [root@node3 ~]# rabbitmqctl cluster_status Cluster status of node rabbit@node3 ... [{nodes,[{disc,[rabbit@node01,rabbit@node2,rabbit@node3]}]},  {running_nodes,[rabbit@node01,rabbit@node3]},  {cluster_name,<<"rabbit@node01">>},  {partitions,[]}] ...done. [root@node3 ~]#  

  停掉node01上的应用

[root@node01 ~]# rabbitmqctl cluster_status Cluster status of node rabbit@node01 ... [{nodes,[{disc,[rabbit@node01,rabbit@node2,rabbit@node3]}]},  {running_nodes,[rabbit@node3,rabbit@node01]},  {cluster_name,<<"rabbit@node01">>},  {partitions,[]}] ...done. [root@node01 ~]# rabbitmqctl stop_app Stopping node rabbit@node01 ... ...done. [root@node01 ~]# rabbitmqctl cluster_status Cluster status of node rabbit@node01 ... [{nodes,[{disc,[rabbit@node01,rabbit@node2,rabbit@node3]}]}] ...done. [root@node01 ~]#  

  启动node2上的应用

[root@node2 ~]# rabbitmqctl cluster_status Cluster status of node rabbit@node2 ... [{nodes,[{disc,[rabbit@node01,rabbit@node2]}]}] ...done. [root@node2 ~]# rabbitmqctl start_app      Starting node rabbit@node2 ...    BOOT FAILED ===========  Error description:    {could_not_start,rabbit,        {bad_return,            {{rabbit,start,[normal,[]]},             {'EXIT',                 {rabbit,failure_during_boot,                     {error,                         {timeout_waiting_for_tables,                             [rabbit_user,rabbit_user_permission,rabbit_vhost,                              rabbit_durable_route,rabbit_durable_exchange,                              rabbit_runtime_parameters,                              rabbit_durable_queue]}}}}}}}  Log files (may contain more information):    /var/log/rabbitmq/rabbit@node2.log    /var/log/rabbitmq/rabbit@node2-sasl.log  Error: {rabbit,failure_during_boot,            {could_not_start,rabbit,                {bad_return,                    {{rabbit,start,[normal,[]]},                     {'EXIT',                         {rabbit,failure_during_boot,                             {error,                                 {timeout_waiting_for_tables,                                     [rabbit_user,rabbit_user_permission,                                      rabbit_vhost,rabbit_durable_route,                                      rabbit_durable_exchange,                                      rabbit_runtime_parameters,                                      rabbit_durable_queue]}}}}}}}} [root@node2 ~]#  

  提示:此时node2就启动不起来了,这时我们就需要用到update_cluster_nodes子命令向node3更新集群信息,然后再次在node2上启动应用就不会报错了;

  向node3询问更新集群节点信息,并启动node2上的应用

[root@node2 ~]# rabbitmqctl update_cluster_nodes rabbit@node3 Updating cluster nodes for rabbit@node2 from rabbit@node3 ... ...done. [root@node2 ~]# rabbitmqctl cluster_status                    Cluster status of node rabbit@node2 ... [{nodes,[{disc,[rabbit@node01,rabbit@node2,rabbit@node3]}]}] ...done. [root@node2 ~]# rabbitmqctl start_app Starting node rabbit@node2 ... ...done. [root@node2 ~]# rabbitmqctl cluster_status Cluster status of node rabbit@node2 ... [{nodes,[{disc,[rabbit@node01,rabbit@node2,rabbit@node3]}]},  {running_nodes,[rabbit@node3,rabbit@node2]},  {cluster_name,<<"rabbit@node01">>},  {partitions,[]}] ...done. [root@node2 ~]#  

  提示:可以看到更新了集群节点信息后,在node2上查看集群状态信息就可以看到node3了;此时在启动node2上的应用就没有任何问题;

  sync_queue queue:同步指定队列;

  cancel_sync_queue queue:取消指定队列同步

  set_cluster_name name:设置集群名称

[root@node2 ~]# rabbitmqctl cluster_status Cluster status of node rabbit@node2 ... [{nodes,[{disc,[rabbit@node01,rabbit@node2,rabbit@node3]}]},  {running_nodes,[rabbit@node01,rabbit@node3,rabbit@node2]},  {cluster_name,<<"rabbit@node01">>},  {partitions,[]}] ...done. [root@node2 ~]# rabbitmqctl set_cluster_name rabbit@rabbit_node02 Setting cluster name to rabbit@rabbit_node02 ... ...done. [root@node2 ~]# rabbitmqctl cluster_status                        Cluster status of node rabbit@node2 ... [{nodes,[{disc,[rabbit@node01,rabbit@node2,rabbit@node3]}]},  {running_nodes,[rabbit@node01,rabbit@node3,rabbit@node2]},  {cluster_name,<<"rabbit@rabbit_node02">>},  {partitions,[]}] ...done. [root@node2 ~]#  

  提示:在集群任意一个节点更改名称都会同步到其他节点;也就是说集群状态信息在每个节点都是保持一致的;

  基于haproxy负载均衡rabbitmq集群

  1、安装haproxy

[root@node3 ~]# yum install -y haproxy Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile  * base: mirrors.aliyun.com  * extras: mirrors.aliyun.com  * updates: mirrors.aliyun.com Resolving Dependencies --> Running transaction check ---> Package haproxy.x86_64 0:1.5.18-9.el7 will be installed --> Finished Dependency Resolution  Dependencies Resolved  ====================================================================================================  Package                Arch                  Version                     Repository           Size ==================================================================================================== Installing:  haproxy                x86_64                1.5.18-9.el7                base                834 k  Transaction Summary ==================================================================================================== Install  1 Package  Total download size: 834 k Installed size: 2.6 M Downloading packages: haproxy-1.5.18-9.el7.x86_64.rpm                                              | 834 kB  00:00:00      Running transaction check Running transaction test Transaction test succeeded Running transaction   Installing : haproxy-1.5.18-9.el7.x86_64                                                      1/1    Verifying  : haproxy-1.5.18-9.el7.x86_64                                                      1/1   Installed:   haproxy.x86_64 0:1.5.18-9.el7                                                                       Complete! [root@node3 ~]#  

  提示:haproxy可以重新找个主机部署,也可以在集群中的某台节点上部署;建议重新找个主机部署,这样可避免端口冲突;

  配置haproxy

消息型中间件之RabbitMQ集群

  提示:以上就是haproxy负载均衡rabbitmq集群的示例,我们通过使用haproxy的tcp模式去代理rabbitmq,并且使用轮询的算法把请求调度到后端server上;

  验证:启动haproxy,看看对应的端口是否处于监听状态,状态页面是否能够正常检测到后端server是否在线?

消息型中间件之RabbitMQ集群

  提示:此时负载均衡就搭建好了,后续使用这个集群,我们就可以把这个负载均衡上监听的地址给用户访问即可;这里要考虑一点haproxy是新的单点;

  在浏览器打开haproxy的状态页看看后端server是否在线?

消息型中间件之RabbitMQ集群

  提示:可以看到后端3台rabbitmq-server都是正常在线;

  停止node3上的rabbitmq,看看haproxy是否能够及时发现node3不再线,并把它标记为down?

消息型中间件之RabbitMQ集群

消息型中间件之RabbitMQ集群

  提示:我们根据haproxy对后端server做健康状态检查来实现rabbitmq集群的故障转移,所以对于rabbitmq集群来讲,它只复制消息的同步,实现数据冗余,真正高可用还是要靠前端的调度器实现;对于nginx负载均衡rabbitmq可以参考ngixn对tcp协议的代理来写配置;有关nginx负载均衡tcp应用相关话题,可以参考本人博客https://www.cnblogs.com/qiuhom-1874/p/12468946.html我这里就不过多阐述;

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