zoo.cfg

# The number of milliseconds of each tick
tickTime=2000
# The number of ticks that the initial
# synchronization phase can take
initLimit=10
# The number of ticks that can pass between
# sending a request and getting an acknowledgement
syncLimit=5
# 存储快照位置和事务日志，一般分开存储
# do not use /tmp for storage, /tmp here is just
# example sakes.
dataDir=/tmp/zookeeper
# the port at which the clients will connect
clientPort=2181
# the maximum number of client connections.
# increase this if you need to handle more clients
#maxClientCnxns=60
#
# Be sure to read the maintenance section of the
# administrator guide before turning on autopurge.
#
# http://zookeeper.apache.org/doc/current/zookeeperAdmin.html#sc_maintenance
#
# The number of snapshots to retain in dataDir
#autopurge.snapRetainCount=3
# Purge task interval in hours
# Set to "0" to disable auto purge feature
#autopurge.purgeInterval=1

基本命令

# 查看结点
[zk: 127.0.0.1:2181(CONNECTED) 0] ls /
[zookeeper]
# 创建一个结点
[zk: 127.0.0.1:2181(CONNECTED) 1] create /test "content"
[zookeeper, test]
# 获取结点内容
[zk: 127.0.0.1:2181(CONNECTED) 2] get /test
test
cZxid = 0x4
ctime = Tue Feb 18 11:28:15 CST 2020
mZxid = 0x4
mtime = Tue Feb 18 11:28:15 CST 2020
pZxid = 0x4
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 4
numChildren = 0
# 删除结点
[zk: 127.0.0.1:2181(CONNECTED) 3] delete /test

集群配置

如果是三台 zookeeper 组成的集群

1、配置三个 zoo.cfg

**
指定不同的 clientPort 端口号，指定每台机器不同的 dataDir 位置

# zoo1.cfg
tickTime=2000
initLimit=10
syncLimit=5
dataDir=/home/eric/zookeeper-3.4.14/data/data_1
clientPort=2181
server.1=localhost:2887:3887
server.2=localhost:2888:3888
server.3=localhost:2889:3889

# zoo2.cfg
tickTime=2000
initLimit=10
syncLimit=5
dataDir=/home/eric/zookeeper-3.4.14/data/data_2
clientPort=2182
server.1=localhost:2887:3887
server.2=localhost:2888:3888
server.3=localhost:2889:3889

# zoo3.cfg
tickTime=2000
initLimit=10
syncLimit=5
dataDir=/home/eric/zookeeper-3.4.14/data/data_3
clientPort=2183
server.1=localhost:2887:3887
server.2=localhost:2888:3888
server.3=localhost:2889:3889

2、建立 myid 文件

分别在不同的 dataDir 下建立 myid 文件，并指定不同的值

$ echo "1" > data_1/myid
$ echo "2" > data_2/myid
$ echo "3" > data_3/myid

3、分别启动每个服务

由于是 3 台机器组成的集群，起始只要有两台启动成功了，客户端就可以进行连接了

$ zkServer.sh start ~/zookeeper-3.4.14/conf/zoo1.cfg
$ zkServer.sh start ~/zookeeper-3.4.14/conf/zoo2.cfg
$ zkServer.sh start ~/zookeeper-3.4.14/conf/zoo3.cfg

由于是依次启动 zoo1.cfg，zoo2.cfg，zoo3.cfg 所以 leader 就是 zoo2 这台服务器了

**

4、添加 observer

observer 配置

**

# zoo-observer.cfg
tickTime=2000
initLimit=10
syncLimit=5
dataDir=/home/eric/zookeeper-3.4.14/data/data_ob
clientPort=2184
peerType=observer
server.1=localhost:2887:3887
server.2=localhost:2888:3888
server.3=localhost:2889:3889
server.4=localhost:2890:3890:observer

# 写入标识符到 myid
echo 4 > /home/eric/zookeeper-3.4.14/data/data_ob/myid

follower 配置（修改）

# zoo1.cfg 添加
server.4=localhost:2890:3890:observer

# zoo2.cfg 添加
server.4=localhost:2890:3890:observer

# zoo3.cfg 添加
server.4=localhost:2890:3890:observer

启动 observer

$ zkServer.sh status ~/zookeeper-3.4.14/conf/zoo-observer.cfg
ZooKeeper JMX enabled by default
Using config: /home/eric/zookeeper-3.4.14/conf/zoo-observer.cfg
Mode: observer