快速查看zookeeper相关信息（Server status 、Client connections、Watches 、Monitoring ）之4-字符命令

如果读者还没有zookeeper集群环境，可以参考笔者之前的博客，如下：

在获取zookeeper相关信息时，以下4-字符命令比较方便。

Category	Command	Description
Server status	ruok	P straintets. imok if the server is running and not in an error
	conf	Prints the server configuration (from zoo.cfg).
	envi	Prints the server environment, including ZooKeeper version, Java version, and other system properties.
	srvr	Prints server statistics, including latency statistics, the number of znodes, and the server mode (standalone, leader, or follower).
	stat	Prints server statistics and connected clients.
	srst	Resets server statistics.
	isro	Shows whether the server is in read-only (ro) mode (due to a network partition) or read/write mode (rw).
Client connections	dump	Lists all the sessions and ephemeral znodes for the ensemble. You must connect to the leader (see srvr) for this command.
	cons	Lists connection statistics for all the server’s clients.
	crst	Resets connection statistics.
Watches	wchs	Lists summary information for the server’s watches.
	wchc	Lists all the server’s watches by connection. Caution: may impact server performance for a large number of watches.
	wchp	Lists all the server’s watches by znode path. Caution: may impact server performance for a large number of watches.
Monitoring	mntr	Lists server statistics in Java properties format, suitable as a source for monitoring systems such as Ganglia and Nagios.

使用方法如下：

例如：查看sever是否正常：ruok

echo ruok | nc localhost 2181

如果正常则打印出 imok