Centos安装consul

一、consul单机安装

1、安装

1.下载并解压consul

 cd /opt/

 mkdir consul

 chmod 777 consul

 cd consul

 wget https://releases.hashicorp.com/consul/1.3.0/consul_1.3.0_linux_amd64.zip

 unzip consul_1.3.0_linux_amd64.zip

 cp consul /usr/local/bin/

2. 检查是否安装成功
 consul

 consul version

#前台启动
consul agent -dev -ui -node=consul-dev -client=192.168.1.210


3.浏览器输入:http://IP:8500/出现ConsulWeb界面就表示成功了

2、设置开机自启动

一、路径/usr/lib/systemd/system/，新建一个service命名为，consul.service

[Unit]
Description=consul
After=network.target

[Service]
ExecStart=/usr/local/consul/start.sh
KillSignal=SIGTERM
    
[Install]
WantedBy=multi-user.target

二、编辑/usr/local/consul/start.sh

#!/bin/bash
consul agent -dev -ui -node=consul-dev -client=192.168.1.210

三、执行命令

systemctl start consul
systemctl enable consul 
systemctl status consul

二、consul集群安装

1、准备

三台机器：

vm-a 192.168.1.211 centos7
vm-b 192.168.1.212 centos7
vm-c 192.168.1.213 centos7

Consul官网（https://www.consul.io/downloads.html）

unzip consul_1.3.0_linux_amd64.zip
mv cosul /usr/local/bin

2、集群启动

consul agent -server -bootstrap-expect=3 -data-dir=/tmp/consul -node=192.168.1.211 -bind=192.168.1.211 -client=0.0.0.0 -datacenter=dc1 -ui
consul agent -server -bootstrap-expect=3 -data-dir=/tmp/consul -node=192.168.1.212 -bind=192.168.1.212 -client=0.0.0.0 -datacenter=dc1 -ui
consul agent -server -bootstrap-expect=3 -data-dir=/tmp/consul -node=192.168.1.213 -bind=192.168.1.213 -client=0.0.0.0 -datacenter=dc1 -ui

此时三台机器都会打印：

    2019/03/20 10:57:36 [INFO] agent: Started HTTP server on 127.0.0.1:8500 (tcp)
    2019/03/20 10:57:36 [INFO] agent: started state syncer
    2019/03/20 10:57:44 [ERR] agent: failed to sync remote state: No cluster leader

此时三台机器还未join，不能算是一个集群，三台机器上的consul均不能正常工作，因为leader未选出。

三台机器组成consul集群

consul集群:当一个consul agent启动后，它不知道任何其他节点,要学习到集群中的其他节点，agent必须加入一个已经存在的集群(cluster)。要加入这样的集群，它只需要知道这个集群中的一个节点即可。它加入后，将会和这个member gossip（交谈）并迅速发现集群中的其他节点。一个consul agent可以加入任何类型的其他agent，而不只是那些运行于server mode的agent。

分别登录第2台和第3台虚拟机上执行如下命令，让consul加入集群：
192.168.1.212加入192.168.1.211

[root@localhost consul-cluster]# consul join 192.168.1.211
Successfully joined cluster by contacting 1 nodes.
[root@localhost consul-cluster]#

192.168.1.212加入192.168.1.213

[root@localhost consul-cluster]# consul join 192.168.1.211
Successfully joined cluster by contacting 1 nodes.
[root@localhost consul-cluster]#

很快三台机器都会打印：

   2019/03/20 10:59:12 [INFO] raft: Added peer d89335fd-cfb8-1fc0-3902-b847e125fa2c,      starting replication
    2019/03/20 10:59:12 [INFO] consul: cluster leadership acquired
    2019/03/20 10:59:12 [INFO] consul: New leader elected: 192.168.1.211

证明此时leader已经选出，集群可以正常工作。访问：http://92.168.1.211:8500/

集群状态查看

[root@localhost ~]# consul operator raft list-peers
Node           Address             Status  Type    Build  Protocol  DC   Segment
192.168.1.211  192.168.1.211:8301  alive   server  1.3.0  2         dc1  <all>
192.168.1.212  192.168.1.212:8301  alive   server  1.3.0  2         dc1  <all>
192.168.1.213  192.168.1.213:8301  alive   server  1.3.0  2         dc1  <all>

查看members状态：

[root@localhost ~]# consul members
Node           ID                                    Address             State     Voter  RaftProtocol
192.168.1.211  9caa4a7b-5d40-a754-a6d2-e993ebd54e1e  192.168.1.211:8300  follower  true   3
192.168.1.212  6227c834-9e91-d756-5335-5e7587496235  192.168.1.212:8300  leader    true   3
192.168.1.213  98ba9fdc-f94f-7df2-f7db-70f234937526  192.168.1.213:8300  follower  true   3

备注：集群重启或kill consul时 需要删除/tmp/consul下所有文件

cd /tmp/consul
rm -rf *