今晚來透過Docker-compose,來建立3個節點的etcd Cluster.
方便後面使用.

網路環境拓樸圖:

Docker-compose安裝

version: "3.6"

services:
  node1:
    image: quay.io/coreos/etcd:v3.4.0
    volumes:
      - node1-data:/etcd-data
    ports:
      - "12379:2379"
    expose:
      - 2379
      - 2380
    networks:
      cluster_net:
        ipv4_address: 172.16.238.100
    environment:
      - ETCDCTL_API=3
    command:
      - /usr/local/bin/etcd
      - --data-dir=/etcd-data
      - --name=node1
      - --initial-advertise-peer-urls=http://172.16.238.100:2380
      - --listen-peer-urls=http://0.0.0.0:2380
      - --advertise-client-urls=http://172.16.238.100:2379
      - --listen-client-urls=http://0.0.0.0:2379
      - --initial-cluster=node1=http://172.16.238.100:2380,node2=http://172.16.238.101:2380,node3=http://172.16.238.102:2380
      - --initial-cluster-state=new
      - --initial-cluster-token=docker-etcd
      - --auto-compaction-retention=1
      - --auto-compaction-mode=periodic

  node2:
    image: quay.io/coreos/etcd:v3.4.0
    volumes:
      - node2-data:/etcd-data
    networks:
      cluster_net:
        ipv4_address: 172.16.238.101
    environment:
      - ETCDCTL_API=3
    ports:
      - "12380:2379"
    expose:
      - 2379
      - 2380
    command:
      - /usr/local/bin/etcd
      - --data-dir=/etcd-data
      - --name=node2
      - --initial-advertise-peer-urls=http://172.16.238.101:2380
      - --listen-peer-urls=http://0.0.0.0:2380
      - --advertise-client-urls=http://172.16.238.101:2379
      - --listen-client-urls=http://0.0.0.0:2379
      - --initial-cluster=node1=http://172.16.238.100:2380,node2=http://172.16.238.101:2380,node3=http://172.16.238.102:2380
      - --initial-cluster-state=new
      - --initial-cluster-token=docker-etcd
      - --auto-compaction-retention=1
      - --auto-compaction-mode=periodic
  node3:
    image: quay.io/coreos/etcd:v3.4.0
    volumes:
      - node3-data:/etcd-data
    networks:
      cluster_net:
        ipv4_address: 172.16.238.102
    environment:
      - ETCDCTL_API=3
    ports:
      - "12381:2379"
    expose:
      - 2379
      - 2380
    command:
      - /usr/local/bin/etcd
      - --data-dir=/etcd-data
      - --name=node3
      - --initial-advertise-peer-urls=http://172.16.238.102:2380
      - --listen-peer-urls=http://0.0.0.0:2380
      - --advertise-client-urls=http://172.16.238.102:2379
      - --listen-client-urls=http://0.0.0.0:2379
      - --initial-cluster=node1=http://172.16.238.100:2380,node2=http://172.16.238.101:2380,node3=http://172.16.238.102:2380
      - --initial-cluster-state=new
      - --initial-cluster-token=docker-etcd
      - --auto-compaction-retention=1
      - --auto-compaction-mode=periodic
volumes:
  node1-data:
  node2-data:
  node3-data:

networks:
  cluster_net:
    driver: bridge
    ipam:
      driver: default
      config:
      -
        subnet: 172.16.238.0/24

參數說明

etcd主要用到兩個Port2379、2380.
2379主要是給外部或者是client端使用的.
2380則是給etcd各節點內部調用的.

要使用etcd V3版本, 需要配置環境變數ETCDCTL_API=3
可以透過etcdctl來查證版本

data-dir這個就用來放置WAL寫入的資料

name顧名思義就是節點名稱, 方便管理
initial-advertise-peer-urls集群之中, 給其他內部節點對該節點調用的URL網址, 如果有多個中間用,隔開.
預設是http://localhost:2380

舉例http://example.com:2380, http://10.0.0.1:2380

listen-peer-urls 用來告訴etcd說, 能接受來自指定scheme:IP:port的傳入請求. scheme包含了http或https.
如果IP指定成0.0.0.0則表示etcd會接聽所有來自這port的傳入請求.
如果有多個中間用,隔開.
預設是http://localhost:2380
舉例http://10.0.0.1:2380

advertise-client-urls給外部/client來調用的URL, 如果有多個中間用,隔開.
預設是http://localhost:2379

listen-client-urls跟listen-peer-urls差別在於, 這個是給外部/client用的.
預設是http://localhost:2379

initial-cluster就集群初始化的啟動配置, 主要配置集群一開始各節點的名稱跟 位子name=initial-advertise-peer-urls, 如果有多個中間用,隔開.

預設是default=http://localhost:2380

initial-cluster-state就兩個值neworexisting
主要就告訴etcd節點, 是全新的叢集還是嘗試去加入其他已經存在的叢集.
預設是new

initial-cluster-token集群的名字(我覺得是這樣)
官網寫Initial cluster token for the etcd cluster during bootstrap.
預設是etcd-cluster

所有init-*開頭的設定, 都只有在啟動集群時才會用到.

auto-compaction-retentionmvcc紀錄將會被保存多久, 0表示關閉自動壓縮.
預設是0

auto-compaction-mode 用來解釋auto-compaction-retention, 選項有periodic跟revision; 如果選擇periodic, 那auto-compaction-retention的值就是保留幾小時以內的; 如果選擇revision就是保留最近幾個版本之內的.
預設是periodic

etcd configation flags