centos7 Etcd集群基本設定

etcd是CoreOS團隊於2013年6月發起的開源專案，它的目標是構建一個高可用的分散式鍵值(key-value)資料庫。etcd內部採用raft協定作為一致性演算法，etcd基於Go語言實現。
etcd作為服務發現系統，有以下的特點
• 簡單：安裝配置簡單，而且提供了HTTP API進行交互，使用也很簡單
• 安全：支持SSL證書驗證
• 快速：根據官方提供的benchmark資料，單實例支援每秒2k+讀操作
• 可靠：採用raft演算法，實現分散式系統資料的可用性和一致性
• etcd項目位址：https://github.com/coreos/etcd/

etcd單機佈署安裝

curl -L https://github.com/coreos/etcd/releases/download/v3.2.1/etcd-v3.2.1-linux-amd64.tar.gz -o etcd-v3.2.1-linux-amd64.tar.gz
tar xzvf etcd-v3.2.1-linux-amd64.tar.gz
mv etcd-v3.2.1-linux-amd64 etcd

vi /etc/profile
加入以下內容

# etcd
export PATH=/root/etcd:$PATH
export ETCDCTL_API=3

執行source /etc/profile
測試

$ etcdctl version
$ etcdctl version
$ ./etcdctl put aaa 1
OK
$ ./etcdctl get aaa
aaa
1

etcd集群配置
192.168.0.204 node1
192.168.0.205 node2
192.168.0.206 node3

每台都要裝的部份

wget https://github.com/etcd-io/etcd/releases/download/v3.3.17/etcd-v3.3.17-linux-amd64.tar.gz
tar -zxvf etcd-v3.3.17-linux-amd64.tar.gz -C /opt/
cd /opt
mv etcd-v3.3.17-linux-amd64 etcd-v3.3.17

設定環境變數
vi /etc/profile
# etcd
export PATH=/opt/etcd-v3.3.17:$PATH
export ETCDCTL_API=3
執行source /etc/profile

mkdir /etc/etcd # 建立etcd配置檔案目錄
cd /etc/etcd

在每個節點上編輯設定檔
vi /etc/etcd/conf.yml

node1

name: etcd-1
data-dir: /opt/etcd-v3.3.17/data
listen-client-urls: http://192.168.0.204:2379,http://127.0.0.1:2379
advertise-client-urls: http://192.168.0.204:2379,http://127.0.0.1:2379
listen-peer-urls: http://192.168.0.204:2380
initial-advertise-peer-urls: http://192.168.0.204:2380
initial-cluster: etcd-1=http://192.168.0.204:2380,etcd-2=http://192.168.0.205:2380,etcd-3=http://192.168.0.206:2380
initial-cluster-token: etcd-cluster-token
initial-cluster-state: new

node2

name: etcd-2
data-dir: /opt/etcd-v3.3.17/data
listen-client-urls: http://192.168.0.205:2379,http://127.0.0.1:2379
advertise-client-urls: http://192.168.0.205:2379,http://127.0.0.1:2379
listen-peer-urls: http://192.168.0.205:2380
initial-advertise-peer-urls: http://192.168.0.205:2380
initial-cluster: etcd-1=http://192.168.0.204:2380,etcd-2=http://192.168.0.205:2380,etcd-3=http://192.168.0.206:2380
initial-cluster-token: etcd-cluster-token
initial-cluster-state: new

node3

name: etcd-3
data-dir: /opt/etcd-v3.3.17/data
listen-client-urls: http://192.168.0.206:2379,http://127.0.0.1:2379
advertise-client-urls: http://192.168.0.206:2379,http://127.0.0.1:2379
listen-peer-urls: http://192.168.0.206:2380
initial-advertise-peer-urls: http://192.168.0.206:2380
initial-cluster: etcd-1=http://192.168.0.204:2380,etcd-2=http://192.168.0.205:2380,etcd-3=http://192.168.0.206:2380
initial-cluster-token: etcd-cluster-token
initial-cluster-state: new

檢視叢集成員資訊

etcdctl member list

message key設定Hello值示例

etcdctl set /message Hello
curl -X PUT http://127.0.0.1:2379/v2/keys/message -d value="Hello"

讀取message的值

etcdctl get /message
curl http://127.0.0.1:2379/v2/keys/message

刪除message key

etcdctl del /message
curl -X DELETE http://127.0.0.1:2379/v2/keys/message

設定啟動服務
/usr/lib/systemd/system/etcd.service

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

[Service]
Type=notify
WorkingDirectory=/opt/etcd-v3.3.17/
# User=etcd
ExecStart=/opt/etcd-v3.3.17/etcd --config-file=/etc/etcd/conf.yml
Restart=on-failure
LimitNOFILE=65536

[Install]
WantedBy=multi-user.target

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

systemctl status etcd.service -l

-------------------------------------------------------

安裝etcd webui

環境要安裝node.js、git

git clone https://github.com/henszey/etcd-browser.git
cd etcd-browser/
vim server.js

編輯server.js，修改內容如下：

var etcdHost = process.env.ETCD_HOST || '192.168.0.204';
var etcdPort = process.env.ETCD_PORT || 2379;
var serverPort = process.env.SERVER_PORT || 8000;

然後啟動

node server.js

訪問ui http://192.168.0.204:8000