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This article mainly introduces how to install and configure zookeeper cluster, which has a certain reference value. Interested friends can refer to it. I hope you can learn a lot after reading this article.

1. Decompress zookeeper

2. Create a zoo.cfg file under $ZOOKEEPER_HOME/conf (see configuration file: zoo_sample.cfg), which is as follows:

# CS communication heartbeat time, the interval at which a heartbeat is maintained between Zookeeper servers or between clients and servers, that is, a heartbeat is sent at each tickTime time. The tickTime=2000# LF initialization communication time limit of tickTime in milliseconds, the maximum number of heartbeats (number of tickTime) that can be tolerated during the initial connection between the follower server (F) and the leader server (L) in the cluster, and the maximum number of heartbeats that can be tolerated between requests and responses between the follower server and the leader server in the cluster (the number of tickTime). SyncLimit=5# data file directory, the directory where Zookeeper saves the data, and by default, Zookeeper saves log files for writing data in this directory. DataDir=/root/app/zookeeper/data# client connection port, the port on which the client connects to the Zookeeper server. Zookeeper will listen on this port and accept access requests from the client. ClientPort=2181# server name and address: cluster information (server number, server address, LF communication port, election port) # this configuration item is written in a special format. The rules are as follows: # server.N=YYY:A:B server.1=hadoop.master:2888:3888server.2=hadoop.slave:2888:3888# port # 2181: connection for client # 2888:follower and leader communication # 3888:leader election port

3. Create a myid file according to zoo.cfg under the path configured by dataDir, and enter the N content of server.N (for example, if the current machine is server.1, enter 1 in myid)

4. Copy the configured zookeepr to other nodes

Scp-r $ZOOKEEPER_HOME root@hostname:/home

5. Remember to modify myid after copying

6. Start the script on each node:

$ZOOKEEPER_HOME/bin/zkServer.sh start

7. Check command

7.1If Error contacting service appears in # zkServer.sh status//. It is probably not running. Error, because only one node has been started, unable to start cluster mode 7.2,# echo ruok | nc localhost 2181max / return imok if the command is successful (iTunm ok)

8. Zk client

$ZOOKEEPER_HOME/bin/zkCli.sh-server hostname:2181// starts a zk client / / finally you need to remember a help command to master the usage of other commands (you need to know the znode similar to the file system before operation, simple description: all nodes in zk are znode nodes, and znode nodes can not only serve as directories but also store data.) CREATE create znodeSET to set up znode data GET query znodeRMR delete znode... Wait, check by yourself.

9. Java client

Related codes:

Import org.apache.zookeeper.CreateMode;import org.apache.zookeeper.WatchedEvent;import org.apache.zookeeper.Watcher;import org.apache.zookeeper.ZooDefs.Ids;import org.apache.zookeeper.ZooKeeper;public class ZKClient {/ / connection address private final static String CONN = "192.168.1.200 zk 2181"; / / client and zk timeout (unit:ms) private final static int SESSION_TIMEOUT = 5000 Public static void main (String [] args) throws Exception {/ / 1, persistent node: when the created node is successful, the node will persist on the zk / / 2. Temporary node: once an intentional or unintentional client timeout or shutdown occurs during the creation of the node, the node is deleted ZooKeeper zk = new ZooKeeper (CONN, SESSION_TIMEOUT) New Watcher () {@ Override public void process (WatchedEvent event) {/ / receive zk notification of each time System.out.println ("-") System.out.println ("Path:" + event.getPath ()); System.out.println ("type:" + event.getType ()); System.out.println ("state" + event.getState ()); System.out.println ("wrapper:" + event.getWrapper ()) System.out.println ("- -");}}); String path = "/ hello"; byte [] data = "testhello!" .getBytes (); zk.create (path,data, Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT); zk.close ();}}

Thank you for reading this article carefully. I hope the article "how to install and configure zookeeper Cluster" shared by the editor will be helpful to everyone. At the same time, I also hope you will support us and pay attention to the industry information channel. More related knowledge is waiting for you to learn!

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