docker-compose zookeeper build a clustered environment CodingCode

docker-compose zookeeper build a clustered environment

 

Use docker-compose zookeeper build a clustered environment

zookeeper is a clustered environment, micro-service architecture for managing the following configuration management functions.

This article is a fundamental step how to build a docker zookeeper cluster environment.
We used to build docker-compose the following zookeeper cluster environment:

1. Cluster consists of three node: zookeeper1, zookeeper2, zookeeper3

1. Download zookeeper docker image

$ docker pull zookeeper

2. Edit docker-compose.yaml file

version: '2'
networks:
  byfn:

services:
  zookeeper1:
    image: zookeeper
    container_name: zookeeper1
    environment:
        - ZOO_MY_ID=1
        - ZOO_SERVERS=server.1=zookeeper1:2888:3888 server.2=zookeeper2:2888:3888 server.3=zookeeper3:2888:3888
    ports:
      - 2181
    networks:
      - byfn

  zookeeper2:
    image: zookeeper
    container_name: zookeeper2
    environment:
        - ZOO_MY_ID=2
        - ZOO_SERVERS=server.1=zookeeper1:2888:3888 server.2=zookeeper2:2888:3888 server.3=zookeeper3:2888:3888
    ports:
      - 2181
    networks:
      - byfn

  zookeeper3:
    image: zookeeper
    container_name: zookeeper3
    environment:
        - ZOO_MY_ID=3
        - ZOO_SERVERS=server.1=zookeeper1:2888:3888 server.2=zookeeper2:2888:3888 server.3=zookeeper3:2888:3888
    ports:
      - 2181
    networks:
      - byfn

Detailed configuration, refer to the document: https://hub.docker.com/_/zookeeper/
here very clearly describes how to modify the configuration, data storage, and adjust the log level and output settings.

3. Start Service

$ docker-compose up

4. Verify the status of a cluster

$ docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED STATUS PORTS NAMES c1f7646bf0e6 zookeeper "/docker-entrypoin..." 23 minutes ago Up 23 minutes 2888/tcp, 3888/tcp, 0.0.0.0:32794->2181/tcp zookeeper2 7e05f06c258d zookeeper "/docker-entrypoin..." 23 minutes ago Up 23 minutes 2888/tcp, 3888/tcp, 0.0.0.0:32793->2181/tcp zookeeper3 d293438c1813 zookeeper "/docker-entrypoin..." 23 minutes ago Up 23 minutes 2888/tcp, 3888/tcp, 0.0.0.0:32792->2181/tcp zookeeper1 $ docker exec -t zookeeper1 zkServer.sh status ZooKeeper JMX enabled by default Using config: /conf/zoo.cfg Mode: follower $ docker exec -t zookeeper2 zkServer.sh status ZooKeeper JMX enabled by default Using config: /conf/zoo.cfg Mode: follower $ docker exec -t zookeeper3 zkServer.sh status ZooKeeper JMX enabled by default Using config: /conf/zoo.cfg Mode: leader 

Here we see three zookeeper nodes, zookeeper3 is a leader, zookeeper1 and zookeeper2 are follower.

Other status check command:

$ nc localhost 32794 <<< ruok
imok

$ echo srvr | nc localhost 32794 Zookeeper version: 3.4.13-2d71af4dbe22557fda74f9a9b4309b15a7487f03, built on 06/29/2018 04:05 GMT Latency min/avg/max: 0/7/116 Received: 40 Sent: 39 Connections: 1 Outstanding: 0 Zxid: 0x10000000e Mode: follower Node count: 5 

4. Using cluster

4.1 Basic Operations

[zk: localhost:2181(CONNECTED) 4] create /foo "Hello foo" Created /foo [zk: localhost:2181(CONNECTED) 5] get /foo Hello foo cZxid = 0x100000013 ctime = Fri Jan 04 02:29:47 GMT 2019 mZxid = 0x100000013 mtime = Fri Jan 04 02:29:47 GMT 2019 pZxid = 0x100000013 cversion = 0 dataVersion = 0 aclVersion = 0 ephemeralOwner = 0x0 dataLength = 9 numChildren = 0 [zk: localhost:2181(CONNECTED) 6] ls /foo [] 

4.2 Creating a path create

[zk: localhost:2181(CONNECTED) 7] create /foo1/foo1 "Hello foo1" Node does not exist: /foo1/foo1 

Creation failed because the zookeeper does not support recursion created, you must first create a level of parent directory node.
When you create a parent directory, you can let the value is empty. (In fact, a directory also can bring value, the two do not conflict.)

[zk: localhost:2181(CONNECTED) 14] create /foo1 "" # 或者：create /foo1 "" Created /foo1 [zk: localhost:2181(CONNECTED) 15] create /foo1/foo1 "Hello foo1" Created /foo1/foo1 

4.3 ls View element node

[zk: localhost:2181(CONNECTED) 21] ls /foo1 [foo1] 

Because / foo1 is a directory, he had a child node below / foo1 / foo1

[zk: localhost:2181(CONNECTED) 21] ls /foo1/foo1 [] 

Because / foo1 / foo1 is a meta-node, the node has no child below him.

Note, ls command can list a directory, you can not list all the subdirectories recursively.

4.4 Gets the value get

get /foo1/foo1

4.5 modify the value set

set /foo1/foo1 'newvalue'

4.6 delete nodes delete

delete /foo1/foo1

Note that you can only delete empty child node; so if you want to delete a node, you must first of all child nodes are removed.
If you want to delete a non-empty directory, you can also use rmr command.

Author: CodingCode
link: https: //www.jianshu.com/p/8d31ede99206
Source: Jane books
are copyrighted by the author. Commercial reprint please contact the author authorized, non-commercial reprint please indicate the source.