Zookeeper

Apache ZooKeeper 是一个开源的分布式协调服务，主要用于分布式应用程序中管理和协调不同节点之间的通信。它为分布式系统提供了高效的同步、配置管理、命名服务、集群管理等功能。ZooKeeper 通过提供一个类似文件系统的层次结构来存储数据，这些数据称为 znode，支持节点的创建、删除、监听和更新操作，保证了系统的一致性和可靠性。

ZooKeeper 采用了 高可用 和 一致性 的设计，可以通过多个服务器组成集群进行容错。它广泛应用于分布式系统中的服务发现、配置管理、分布式锁、队列管理等场景。

• 官网链接

文档使用以下1台服务器，具体服务分配见描述的进程

IP地址	主机名	描述
192.168.1.131	bigdata01	Zookeeper节点

基础配置

下载软件包

wget https://dlcdn.apache.org/zookeeper/zookeeper-3.9.3/apache-zookeeper-3.9.3-bin.tar.gz

解压软件包

tar -zxvf apache-zookeeper-3.9.3-bin.tar.gz -C /usr/local/software/
ln -s /usr/local/software/apache-zookeeper-3.9.3-bin /usr/local/software/zookeeper

配置环境变量

cat >> ~/.bash_profile <<"EOF"
## ZOOKEEPER_HOME
export ZOOKEEPER_HOME=/usr/local/software/zookeeper
export PATH=$PATH:$ZOOKEEPER_HOME/bin
EOF
source ~/.bash_profile

集群配置

配置zookeeper ID

创建目录

mkdir -p /data/service/zookeeper/{data,logs}

配置zkID

echo 1 > /data/service/zookeeper/data/myid

配置zoo.cfg

参考官方文档

cat > $ZOOKEEPER_HOME/conf/zoo.cfg <<EOF
clientPort=2181
clientPortAddress=0.0.0.0
server.1=bigdata01:2888:3888
admin.enableServer=false
admin.serverAddress=0.0.0.0
admin.serverPort=8181
admin.commandURL=/commands
maxClientCnxns=1024
autopurge.snapRetainCount=3
autopurge.purgeInterval=1
snapCount=100000
tickTime=2000
initLimit=10
syncLimit=5
dataDir=/data/service/zookeeper/data
dataLogDir=/data/service/zookeeper/logs
EOF

配置JVM参数

cat > $ZOOKEEPER_HOME/conf/java.env <<"EOF"
export JAVA_HOME=/usr/local/software/jdk8
export ZK_SERVER_HEAP=2048
export JVMFLAGS="-Dzookeeper.electionPortBindRetry=0"
EOF

启动集群

启动zookeeper

AdminServer: http://bigdata01:8181/commands

Client Address：bigdata01:2181

存在一个QuorumPeerMain进程

zkServer.sh start

查看zookeeper

$ zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /usr/local/software/zookeeper/bin/../conf/zoo.cfg
Client port found: 2181. Client address: localhost. Client SSL: false.
Mode: standalone

关闭zookeeper

zkServer.sh stop

设置服务自启

编辑配置文件

sudo tee /etc/systemd/system/zookeeper.service <<"EOF"
[Unit]
Description=Apache ZooKeeper
Documentation=https://zookeeper.apache.org
After=network.target
[Service]
Type=simple
WorkingDirectory=/usr/local/software/zookeeper
ExecStart=/usr/local/software/zookeeper/bin/zkServer.sh start-foreground
ExecStop=/usr/local/software/zookeeper/bin/zkServer.sh stop
Restart=on-failure
RestartSec=10
TimeoutStartSec=90
TimeoutStopSec=120
StartLimitIntervalSec=600
StartLimitBurst=3
KillMode=control-group
KillSignal=SIGTERM
SuccessExitStatus=143
User=admin
Group=ateng
[Install]
WantedBy=multi-user.target
EOF

启动服务

sudo systemctl daemon-reload
sudo systemctl enable zookeeper.service
sudo systemctl start zookeeper.service
sudo systemctl status zookeeper.service

使用集群

客户端连接集群

zkCli.sh -server bigdata01:2181

创建znode

[zk: bigdata01:2181(CONNECTED) 0] create /ateng "my name is ateng"
Created /ateng
[zk: bigdata01:2181(CONNECTED) 1] ls /
[ateng, zookeeper]
[zk: bigdata01:2181(CONNECTED) 2] quit