環境配置
CentOS Linux release 7.3.1611 (Core)
etcd-v3.2.6
192.168.108.128 節點1
192.168.108.129 節點2
192.168.108.130 節點3
ETCD下載
https://github.com/coreos/etcd/releases/download/v3.2.6/etcd-v3.2.6-linux-amd64.tar.gz
ETCD安裝配置
- 解壓安裝：
$ 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 # 創建etcd配置文件目錄
- 創建etcd配置文件：
$ vi /etc/etcd/conf.yml
節點1，添加如下內容：
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
節點2，添加如下內容：
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
節點3，添加如下內容：
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系統默認配置：
當前使用的是etcd v3版本，系統默認的是v2，通過下面命令修改配置。
$ vi /etc/profile
在末尾追加
export ETCDCTL_API=3
$ source /etc/profile
ETCD命令
$ cd /opt/etcd-v3.2.6
- 創建etcd配置文件：
$ ./etcdctl version
etcdctl version: 3.2.6
API version: 3.2
- 啟動命令：
$ ./etcd --config-file=/etc/etcd/conf.yml
- 查看集群成員信息：
$ ./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- 查看集群狀態（Leader節點）：
$ ./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讀寫操作
基於HTTP協議的API使用起來比較簡單，這里主要通過etcdctl和curl兩種方式來做簡單介紹。
下面通過給message key設置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}}
讀取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}}
刪除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}}
說明：因為是集群，所以message在其中一個節點創建后，在集群中的任何節點都可以查詢到。
配置ETCD為啟動服務
編輯/usr/lib/systemd/system/etcd.service，添加下面內容：
[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
更新啟動：
systemctl daemon-reload
systemctl enable etcd
systemctl start etcd
systemctl restart etcd
systemctl status etcd.service -l