zookeeper

zookeeper的功能：
注册中心
协调服务

nacos consul 也能实现注册中心

zk单机部署

root@ubuntu20:~# cd /apps
wget https://mirrors.tuna.tsinghua.edu.cn/apache/zookeeper/zookeeper-3.8.2/apache-zookeeper-3.8.2-bin.tar.gz

注意：3.5.x版本之后，应下载 apache-zookeeper-x.x.x-bin.tar.gz ，而不是 apache-zookeeper-x.x.x.tar.gz
会报Error: Could not find or load main class org.apache.zookeeper.ZooKeeperMain

tar -xf apache-zookeeper-3.8.2-bin.tar.gz
cd apache-zookeeper-3.8.2-bin/
cd conf/
mv zoo_sample.cfg zoo.cfg
vi zoo.cfg

# The number of milliseconds of each ticktickTime=2000# The number of ticks that the initial # synchronization phase can takeinitLimit=10#cs# The number of ticks that can pass between # sending a request and getting an acknowledgementsyncLimit=5# the directory where the snapshot is stored.# do not use /tmp for storage, /tmp here is just # example sakes.dataDir=/data/zookeeper
# the port at which the clients will connectclientPort=2181

…/bin/zkServer.sh start
ss -nlt |grep 2181

./bin/zkCli.sh
[zk: localhost:2181(CONNECTED) 1] create /host1 “192.168.1.100”
Created /host1
[zk: localhost:2181(CONNECTED) 2] get /host1
192.168.1.100

[zk: localhost:2181(CONNECTED) 3] ls /
[host1, zookeeper]

[zk: localhost:2181(CONNECTED) 8] create /luo
Created /luo
[zk: localhost:2181(CONNECTED) 9] create /luo/host1 “8.8.8.8”
Created /luo/host1
[zk: localhost:2181(CONNECTED) 10] create /luo/host2 “8.8.8.8”
Created /luo/host2
[zk: localhost:2181(CONNECTED) 11] ls /luo
[host1, host2]
[zk: localhost:2181(CONNECTED) 27] get /luo/host2 #最后的信息要用get
8.8.8.8

python创建

#!/bin/enc python#coding:utf8#需要安装kazoo  使用 pip3 install kazoo
from  kazoo.client import  KazooClient
zk=KazooClient(hosts='192.168.74.70:2181')
zk.start()#makepath=True   makepath是递归创建
zk.create('/name/t1',b'luohuiwen',makepath=True)#查查看具体数据 相当于get#data=zk.get('/name/t1')## 获取某个节点下所有子节点，相当于ls
data = zk.get_children('/name/')
print(data)#与zk断开  
zk.stop()

连接zookConnection dropped: socket connection error: 句柄无效。
结论：kazoo版本2.9.0问题， 重新安装2.8.0版本就ok了，安装时指定版本号 kazoo==2.8.0

pip show kazoo
pip3 uninstall kazoo
pip3 install kazoo==2.8.0

zk集群部署

安装jdk
apt update
apt install openjdk-11-jdk -y

写入leader ，leader向flower同步

集群中一半写入成功就算成功，

集群中要一半以上的zk工作正常，整个集群可用

2181 客户端访问端口

2888 数据同步端口 lender才有

3888 选举端口

flower会和lender的2888端口镜像同步

root@ubuntu20:/apps/apache-zookeeper-3.8.2-bin#  grep -vE "^$|^#"   conf/zoo.cfg tickTime=2000initLimit=10syncLimit=5dataDir=/data/zookeeper
clientPort=2181maxClientCnxns=120

拷贝配置文件到其他节点
root@ubuntu20:/apps/apache-zookeeper-3.8.2-bin# scp conf/zoo.cfg 192.168.74.71:/apps/apache-zookeeper-3.8.2-bin/
root@ubuntu20:/apps/apache-zookeeper-3.8.2-bin# scp conf/zoo.cfg 192.168.74.72:/apps/apache-zookeeper-3.8.2-bin/

各个节点生成myid文件
mkdir -p /data/zookeeper/ && echo 1 > /data/zookeeper/myid
mkdir -p /data/zookeeper/ && echo 2 > /data/zookeeper/myid
mkdir -p /data/zookeeper/ && echo 3 > /data/zookeeper/myid

/apps/apache-zookeeper-3.8.2-bin/bin/zkServer.sh start

/apps/apache-zookeeper-3.8.2-bin/bin/zkServer.sh status
/apps/apache-zookeeper-3.8.2-bin/bin/zkServer.sh restart

72是leader
在70写入数据72可以查看

ZooInspector查看

在72 leader查看 netstat -antpl
tcp6 0 0 192.168.74.72:2888 192.168.74.70:33952 ESTABLISHED 161320/java
tcp6 0 0 192.168.74.72:2888 192.168.74.71:35050 ESTABLISHED 161320/java

192.168.74.70的33952端口（随机端口） 向192.168.74.72:2888 同步数据

选举过程

投票
对比事务id，事务id最新的成为主，一样的比myid ，myid大的成为leader

监控2181端口

配置开机自启动

cat /etc/rc.local
#!/bin/bash
echo "test rc " > /var/test.log
/apps/apache-zookeeper-3.8.2-bin/bin/zkServer.sh start
chmod +x /etc/rc.local

客户端编译

不支持java11版本

cd /opt && mkdir zk && cd zk
apt install git -y
git clone https://github.com/zzhang5/zooinspector.git
cd zooinspector/
mvn clean package
mvn clean package

跳过测试
mvn clean install package -Dmaven.test.skip=true