docker-compose創建zookeeper集群

1、獲取zookeeper的鏡像

docker pull zookeeper

當出現如下結果時, 表示鏡像已經下載完成了: 

>>> docker pull zookeeper
Using default tag: latest
latest: Pulling from library/zookeeper
e110a4a17941: Pull complete
a696cba1f6e8: Pull complete
bc427bd93e95: Pull complete
c72391ae24f6: Pull complete
40ab409b6b34: Pull complete
d4bb8183b85d: Pull complete
0600755f1470: Pull complete
Digest: sha256:12458234bb9f01336df718b7470cabaf5c357052cbcb91f8e80be07635994464
Status: Downloaded newer image for zookeeper:latest

 

2、單機運行zookeeper

啟動zookeeper容器：

>>> docker run --name my_zookeeper -d zookeeper:latest

 

查看zookeeper容器運行的日志：

docker logs -f my_zookeeper

 

3、搭建zookeeper集群

因為一個一個地啟動Zookeeper太麻煩了, 所以為了方便起見, 我直接使用 docker-compose 來啟動Zookeeper集群.
首先創建一個名為 docker-compose.yml 的文件, 其內容如下:

version: '2'
services:
    zoo1:
        image: zookeeper
        restart: always
        container_name: zoo1
        ports:
            - "2181:2181"
        environment:
            ZOO_MY_ID: 1
            ZOO_SERVERS: server.1=zoo1:2888:3888 server.2=zoo2:2888:3888 server.3=zoo3:2888:3888
    zoo2:
        image: zookeeper
        restart: always
        container_name: zoo2
        ports:
            - "2182:2181"
        environment:
            ZOO_MY_ID: 2
            ZOO_SERVERS: server.1=zoo1:2888:3888 server.2=zoo2:2888:3888 server.3=zoo3:2888:3888
    zoo3:
        image: zookeeper
        restart: always
        container_name: zoo3
        ports:
            - "2183:2181"
        environment:
            ZOO_MY_ID: 3
            ZOO_SERVERS: server.1=zoo1:2888:3888 server.2=zoo2:2888:3888 server.3=zoo3:2888:3888

這個配置文件會告訴 Docker 分別運行三個 zookeeper 鏡像, 並分別將本地的 2181, 2182, 2183 端口綁定到對應的容器的2181端口上.ZOO_MY_ID 和 ZOO_SERVERS 是搭建 ZK 集群需要設置的兩個環境變量, 其中 ZOO_MY_ID 表示 ZK 服務的 id, 它是1-255 之間的整數, 必須在集群中唯一. ZOO_SERVERS 是ZK 集群的主機列表.

接着我們在 docker-compose.yml 當前目錄下運行:

COMPOSE_PROJECT_NAME=zk_test docker-compose up

即可啟動 ZK 集群了.
執行上述命令成功后, 接着在另一個終端中運行 docker-compose ps 命令可以查看啟動的 ZK 容器:

>>> COMPOSE_PROJECT_NAME=zk_test docker-compose ps
Name              Command               State           Ports
----------------------------------------------------------------------
zoo1   /docker-entrypoint.sh zkSe ...   Up      0.0.0.0:2181->2181/tcp
zoo2   /docker-entrypoint.sh zkSe ...   Up      0.0.0.0:2182->2181/tcp
zoo3   /docker-entrypoint.sh zkSe ...   Up      0.0.0.0:2183->2181/tcp