Ubuntu16.04安装Consul

1.下载安装包

https://www.consul.io/downloads.html
wget https://releases.hashicorp.com/consul/1.5.3/consul_1.5.3_linux_amd64.zip

2.解压

unzip consul_1.5.3_linux_amd64.zip

3.mv

sudo mv consul /usr/local/bin/consul

4.启动

参考：https://blog.csdn.net/u010046908/article/details/61916389

-dev 开发模式启动的时候，数据是存储在内存中，重启之后数据将丢失

consul agent -dev

-server 生成模式启动的时候，如果是server的话需要指定-server，如果是client的话，需要指定-client，比如

consul agent -ui -server -bootstrap-expect 1 -data-dir /tmp/consul -node=consul-server -bind=192.168.1.100 -client=192.168.1.100

-bootstrap-expect 1 通知consul server我们现在准备加入的server节点个数，该参数是为了延迟日志复制的启动直到我们指定数量的server节点成功的加入后启动

-data-dir /tmp/consul 数据持久的路径

-node=consul-server 指定节点在集群中的名称

-bind=192.168.1.100 该地址用来在集群内部的通讯，集群内的所有节点到地址都必须是可达的，默认是0.0.0.0，这意味着Consulo会使用第一个可用的私有IP地址，Consul可以使用TCP和UDP并且可以使用共同的端口，如果存在防火墙，这两者协议必须是允许的

-client 指定节点为client，指定客户端接口的绑定地址，包括：HTTP、DNS、RPC，默认是127.0.0.1，只允许回环接口访问，也就是本机访问，如果要想同一局域网内的其他机器访问，需要修改成自己的内网ip

server节点，指定client等于内网ip，统一局域网的机器可以访问，指定client=0.0.0.0，外网机器可以访问

nohup ./consul agent -ui -server -bootstrap-expect 1 -data-dir /home/dl/projects/consul-1.5.3/consul-data -node=xxx -client=xxx >> ./logs/consul.log 2>&1 &

client节点，不指定client的话，只能本机访问client节点，指定client=0.0.0.0，外网机器可以访问

nohup ./consul agent -ui -data-dir /home/dl/projects/consul-1.5.3/consul-data -node=xxx -bind=xxxx -client=xxx >> ./logs/consul.log 2>&1 &

join

./consul join server的ip

当3台分布式部署的时候，需要如下部署

参考：https://blog.csdn.net/chenchong08/article/details/77885989

nohup ./consul agent -ui -server -bootstrap-expect 3 -data-dir /home/dl/projects/consul-1.5.3/consul-data -node=host1 -client=0.0.0.0 -bind=ip1 >> ./logs/consul.log 2>&1 &
nohup ./consul agent -ui -server -bootstrap-expect 3 -data-dir /home/dl/projects/consul-1.5.3/consul-data -node=host2 -client=0.0.0.0 -bind=ip2 >> ./logs/consul.log 2>&1 &
./consul join host1
nohup ./consul agent -ui -server -bootstrap-expect 3 -data-dir /home/dl/projects/consul-1.5.3/consul-data -node=host3 -client=0.0.0.0 -bind=ip3 >> ./logs/consul.log 2>&1 &
./consul join host2

查看集群状态

./consul operator raft list-peers
Node           ID                                    Address           State     Voter  RaftProtocol
host1  f6ec724d-95ec-00da-97a2-4412d1070889  10.90.1.111:8300  follower  true   3
host2  a79165a3-7ffe-0bcf-9222-c50538d7f394  10.90.1.112:8300  leader    true   3
host3  54fed87b-b76a-432b-9ede-1933bb9d88c5  10.90.1.113:8300  follower  true   3

这时候host2是leader，当host2挂掉的时候，会有短暂不可用，之后leader选出，host1成为新的leader

./consul operator raft list-peers
Error getting peers: Failed to retrieve raft configuration: Unexpected response code: 500 (rpc error getting client: failed to get conn: dial tcp 10.90.1.113:0->10.90.1.112:8300: connect: connection refused)

./consul operator raft list-peers
Node           ID                                    Address           State     Voter  RaftProtocol
host1  f6ec724d-95ec-00da-97a2-4412d1070889  10.90.1.111:8300  leader    true   3
host2  a79165a3-7ffe-0bcf-9222-c50538d7f394  10.90.1.112:8300  follower  true   3
host3  54fed87b-b76a-432b-9ede-1933bb9d88c5  10.90.1.113:8300  follower  true   3

新的leader的日志不断刷说有个follow挂了

2019/12/30 16:42:17 [ERROR] raft: Failed to heartbeat to 10.90.1.111:8300: dial tcp 10.90.1.113:0->10.90.1.111:8300: connect: connection refused
    2019/12/30 16:42:18 [WARN] consul: error getting server health from "host1": rpc error getting client: failed to get conn: dial tcp 10.90.1.113:0->10.90.1.111:8300: connect: connection refused

启动host2的进程，自动加入集群，不用再join，集群状态恢复

5.使用

访问8500端口

5.kv存储

consul支持通过HTTP API和通过CLI API将配置进行存储

put命令

consul kv put app1/config/parameter1 1
Success! Data written to: app1/config/parameter1

put成功之后，就可以在页面中看到该配置

具体数值

put之后可以使用get命令来获取这个配置

consul kv get app1/config/parameter1
1

递归获取

consul kv get -recurse app1
app1/config/parameter1:1
app1/config/parameter2:2
app1/config/parameter3:3

删除

consul kv delete app1/config/parameter2 2

HTTP api

get kv

curl http://xxxx:8500/v1/kv/app1?recurse
[{"LockIndex":0,"Key":"app1/config/parameter1","Flags":0,"Value":"MQ==","CreateIndex":5986,"ModifyIndex":5986},{"LockIndex":0,"Key":"app1/config/parameter2","Flags":0,"Value":"Mg==","CreateIndex":5987,"ModifyIndex":5987}]

get单个

curl http://xxx:8500/v1/kv/app1/config/parameter1
[{"LockIndex":0,"Key":"app1/config/parameter1","Flags":0,"Value":"MQ==","CreateIndex":5986,"ModifyIndex":5986}]

其中kv存储的v的值是经过base64编码过的，需要进行解码

echo 'MQ==' | base64 -d
1

put kv

curl -X PUT -d '1111111' http://xxxx:8500/v1/kv/app1/config/parameter1

delete kv

curl -X DELETE -d http://xxx:8500/v1/kv/app1/config/parameter2

consul配置导入和导出

export命令

./consul kv export app1/config
[
	{
		"key": "app1/config/parameter1",
		"flags": 0,
		"value": "MTExMTExMWZmcmZmZg=="
	},
	{
		"key": "app1/config/parameter2",
		"flags": 0,
		"value": "Mg=="
	},
	{
		"key": "app1/config/parameter3",
		"flags": 0,
		"value": "Mw=="
	}
]

import命令

./consul kv import @test.json
Imported: app1/config/parameter4
Imported: app1/config/parameter5
Imported: app1/config/parameter6

watch

https://www.consul.io/docs/agent/watches.html

当配置更新能自动回调

需要写一个配置文件，比如 consul-watch.json

{
  "watches": [
    {
      "type": "key",
      "key": "app1/conf/parameter1",
      "handler_type": "http",
      "http_handler_config": {
         "path":"http://localhost:8000",
         "method": "GET",
         "header": {"x-foo":["bar", "baz"]},
         "timeout": "10s",
         "tls_skip_verify": false
      }
    }
  ]
}

上面的配置是监听单个key的变化，如果想监听多个

"type": "keyprefix",
"prefix": "app1/",

然后在启动命令中加上配置文件夹的地址，比如

-config-dir /home/lintong/software/consul-1.5.3/consul-conf

然后当配置发生变动的时候，会自动调用这个回调接口

如果修改了配置，比如把GET接口换成POST接口，需要reload这个配置，执行下面命令

consul reload

如果是post的回调接口的话，consul回调的时候会往post请求的request中放入更新的这一条配置，headers和body如下

Host: localhost:8000
User-Agent: Go-http-client/1.1
Content-Length: 124
Content-Type: application/json
X-Consul-Index: 5131
X-Foo: bar
X-Foo: baz
Accept-Encoding: gzip
Connection: close

{"Key":"app1/config/parameter1","CreateIndex":7,"ModifyIndex":5131,"LockIndex":0,"Flags":0,"Value":"IjEyMyI=","Session":""}