ETCD集群安装配置及简单应用

环境配置

CentOS Linux release 7.3.1611 (Core) 

etcd-v3.2.6

192.168.108.128 节点1

192.168.108.129 节点2

192.168.108.130 节点3

ETCD下载

https://github.com/coreos/etcd/releases/download/v3.2.6/etcd-v3.2.6-linux-amd64.tar.gz

ETCD安装配置

• 解压安装：

$ tar -zxvf  etcd-v3.2.6-linux-amd64.tar.gz -C /opt/

$ cd /opt

$ mv etcd-v3.2.6-linux-amd64  etcd-v3.2.6

$ mkdir /etc/etcd           # 创建etcd配置文件目录

• 创建etcd配置文件：

$ vi /etc/etcd/conf.yml

节点1，添加如下内容：

name: etcd-1
data-dir: /opt/etcd-v3.2.6/data
listen-client-urls: http://192.168.108.128:2379,http://127.0.0.1:2379
advertise-client-urls: http://192.168.108.128:2379,http://127.0.0.1:2379
listen-peer-urls: http://192.168.108.128:2380
initial-advertise-peer-urls: http://192.168.108.128:2380
initial-cluster: etcd-1=http://192.168.108.128:2380,etcd-2=http://192.168.108.129:2380,etcd-3=http://192.168.108.130:2380
initial-cluster-token: etcd-cluster-token
initial-cluster-state: new

节点2，添加如下内容：

name: etcd-2
data-dir: /opt/etcd-v3.2.6/data
listen-client-urls: http://192.168.108.129:2379,http://127.0.0.1:2379
advertise-client-urls: http://192.168.108.129:2379,http://127.0.0.1:2379
listen-peer-urls: http://192.168.108.129:2380
initial-advertise-peer-urls: http://192.168.108.129:2380
initial-cluster: etcd-1=http://192.168.108.128:2380,etcd-2=http://192.168.108.129:2380,etcd-3=http://192.168.108.130:2380
initial-cluster-token: etcd-cluster-token
initial-cluster-state: new

节点3，添加如下内容：

name: etcd-3
data-dir: /opt/etcd-v3.2.6/data
listen-client-urls: http://192.168.108.130:2379,http://127.0.0.1:2379
advertise-client-urls: http://192.168.108.130:2379,http://127.0.0.1:2379
listen-peer-urls: http://192.168.108.130:2380
initial-advertise-peer-urls: http://192.168.108.130:2380
initial-cluster: etcd-1=http://192.168.108.128:2380,etcd-2=http://192.168.108.129:2380,etcd-3=http://192.168.108.130:2380
initial-cluster-token: etcd-cluster-token
initial-cluster-state: new

• 更新etcd系统默认配置：

当前使用的是etcd v3版本，系统默认的是v2，通过下面命令修改配置。

$ vi /etc/profile

在末尾追加

export ETCDCTL_API=3

$ source /etc/profile

ETCD命令

$ cd  /opt/etcd-v3.2.6

• 创建etcd配置文件：

$ ./etcdctl version

etcdctl version: 3.2.6
API version: 3.2

• 启动命令：

$ ./etcd --config-file=/etc/etcd/conf.yml

• 查看集群成员信息：

$ ./etcdctl member list

2618ce5cd761aa8e: name=etcd-3 peerURLs=http://192.168.108.130:2380 clientURLs=http://127.0.0.1:2379,http://192.168.108.130:2379 isLeader=false
9c359d48a2f34938: name=etcd-1 peerURLs=http://192.168.108.128:2380 clientURLs=http://127.0.0.1:2379,http://192.168.108.128:2379 isLeader=false
f3c45714407d68f3: name=etcd-2 peerURLs=http://192.168.108.129:2380 clientURLs=http://127.0.0.1:2379,http://192.168.108.129:2379 isLeader=true

• 查看集群状态（Leader节点）：

$ ./etcdctl cluster-health

member 2618ce5cd761aa8e is healthy: got healthy result from http://127.0.0.1:2379
member 9c359d48a2f34938 is healthy: got healthy result from http://127.0.0.1:2379
member f3c45714407d68f3 is healthy: got healthy result from http://127.0.0.1:2379
cluster is healthy

ECTD读写操作

基于HTTP协议的API使用起来比较简单，这里主要通过etcdctl和curl两种方式来做简单介绍。

下面通过给message key设置Hello值示例：

$ ./etcdctl set /message Hello

Hello

$ curl -X PUT http://127.0.0.1:2379/v2/keys/message -d value="Hello"
{"action":"set","node":{"key":"/message","value":"Hello","modifiedIndex":4,"createdIndex":4}}

读取message的值：

$ ./etcdctl  get /message
Hello

$ curl http://127.0.0.1:2379/v2/keys/message
{"action":"get","node":{"key":"/message","value":"Hello","modifiedIndex":9,"createdIndex":9}}

删除message key：

$ ./etcdctl  rm  /message

$ curl -X DELETE http://127.0.0.1:2379/v2/keys/message
{"action":"delete","node":{"key":"/message","modifiedIndex":10,"createdIndex":9},"prevNode":{"key":"/message","value":"Hello","modifiedIndex":9,"createdIndex":9}}

说明：因为是集群，所以message在其中一个节点创建后，在集群中的任何节点都可以查询到。

配置ETCD为启动服务

编辑/usr/lib/systemd/system/etcd.service，添加下面内容：

[Unit]
Description=Etcd Server
After=network.target
After=network-online.target
Wants=network-online.target

[Service]
Type=notify
WorkingDirectory=/opt/etcd-v3.2.6/
# User=etcd
ExecStart=/opt/etcd-v3.2.6/etcd --config-file=/etc/etcd/conf.yml
Restart=on-failure
LimitNOFILE=65536

[Install]
WantedBy=multi-user.target

更新启动：

systemctl daemon-reload
systemctl enable etcd
systemctl start etcd
systemctl restart etcd

systemctl status etcd.service -l

参考文档

https://coreos.com/etcd/docs/latest/getting-started-with-etcd.html