This is the third day of my participation in the August Text Challenge.More challenges in August
1. Zookeeper environment construction
The following uses the Linux operating system as an example to describe how to install ZooKeeper.
1) Stand-alone environment
1. Install JDK
There are a lot of information online, you can find it yourself.
2. Download ZooKeeper
Address: zookeeper.apache.org/releases.ht…
3. Decompress the package
Tar ZXVF – apache – they are – 3.6.1 track – bin. Tar. Gz
4. Go to the apache-zookeeper-3.6.1-bin directory and change the zoo_sample. CFG file name CD apache-zookeeper-3.6.1-bin
cd conf
mv zoo_sample.cfg zoo.cfg
5. The ZooKeeper service is started
cd ..
bin/zkServer.sh start
If the following information is displayed, the startup is successful
Viewing the Startup Status
bin/zkServer.sh status
Shut down the server
bin/zkServer.sh stop
Check the server status again
2) Cluster environment
A real cluster needs to be deployed on different servers, but in our test, it consumes too much memory to start multiple virtual machines, so we usually build a pseudo cluster, that is, all the services are built on one VIRTUAL machine and distinguished by ports.
The preparatory work
1. Install JDK
2. Download ZooKeeper
3. Decompress zooKeeper, copy the zoo_sample. CFG file from the conf file to zoo1. CFG, zoo2. CFG, and zoo3. CFG
4. Create a data directory in the decompressed ZooKeeper directory and create three subdirectories data1, data2, and data3 respectively
5. Set the dataDir (zoo.cfg) clientPort of each ZooKeeper to 2181, 2182, and 2183
Configure the cluster
1. Create a myID file in the data directory of each ZooKeeper with the contents 1, 2, and 3 respectively. This file records the ID of each server
2. In zookeeper zoo. CFG, configure the client access port clientPort and cluster server IP address list.
Server. 1 = 127.0.0.1:2881-3881
Server. 2 = 127.0.0.1:2882-3882
Server. 3 = 127.0.0.1:2883-3883
Server. server ID= SERVER IP address: communication port between servers: port for voting between servers To start a cluster
Start three ZK instances in turn, with a leader and two followers
2. Basic use of ZooKeeper
The data structure
The result of the ZooKeeper data model is similar to the Unix file system and can be viewed as a tree as a whole, with each node called a ZNode and each ZNode uniquely identified by its path
ZNode Node type
1. Persistent directory node (Persisitent) : After the client disconnects from ZooKeeper, Persisitent still exists
Persisitent_Sequential: When a client disconnects from ZooKeeper, the node still exists, and ZooKeeper numbers the node sequentially
3. Ephemeral node: This node was removed after the client was disconnected from ZooKeeper
Ephemeral_Sequential node: After the client disconnects from ZooKeeper, the node is deleted and zooKeeper numbers the node sequentially
Command execution
Use zkClient to access the ZooKeeper client cli and enter help to view the ZooKeeper client commands
The preceding figure lists all zooKeeper client command lines. The following describes some common command lines
1. View the current node data and the number of updates
ls -w /
Create node -s with sequence -e temporary
create zktest data
3. Get the node value
get /zktest
4. Set the node value
set /zktest data1
5. View the node status
stat /
6. Delete the node
delete /zktest
7. Delete nodes recursively
rmr /zktest