Update Zookeeper documentation

zookeeper/content.md

@@ -14,7 +14,7 @@ Apache ZooKeeper is a software project of the Apache Software Foundation, provid
 $ docker run --name some-zookeeper --restart always -d %%IMAGE%%
 ```
 
-This image includes `EXPOSE 2181 2888 3888` (the zookeeper client port, follower port, election port respectively), so standard container linking will make it automatically available to the linked containers. Since the Zookeeper "fails fast" it's better to always restart it.
+This image includes `EXPOSE 2181 2888 3888 8080` (the zookeeper client port, follower port, election port, AdminServer port respectively), so standard container linking will make it automatically available to the linked containers. Since the Zookeeper "fails fast" it's better to always restart it.
 
 ## Connect to Zookeeper from an application in another Docker container
 
@@ -82,17 +82,23 @@ Defaults to `true`. Zookeeper's [`standaloneEnabled`](https://zookeeper.apache.o
 
 > Prior to 3.5.0, one could run ZooKeeper in Standalone mode or in a Distributed mode. These are separate implementation stacks, and switching between them during run time is not possible. By default (for backward compatibility) standaloneEnabled is set to true. The consequence of using this default is that if started with a single server the ensemble will not be allowed to grow, and if started with more than one server it will not be allowed to shrink to contain fewer than two participants.
 
+### `ZOO_ADMINSERVER_ENABLED`
+
+Defaults to `true`. Zookeeper's [`admin.enableServer`](http://zookeeper.apache.org/doc/r3.5.5/zookeeperAdmin.html#sc_adminserver_config)
+
+> New in 3.5.0: The AdminServer is an embedded Jetty server that provides an HTTP interface to the four letter word commands. By default, the server is started on port 8080, and commands are issued by going to the URL "/commands/[command name]", e.g., http://localhost:8080/commands/stat.
+
 ### `ZOO_AUTOPURGE_PURGEINTERVAL`
 
 Defaults to `0`. Zookeeper's [`autoPurge.purgeInterval`](https://zookeeper.apache.org/doc/current/zookeeperAdmin.html#sc_advancedConfiguration)
 
-> New in 3.4.0: The time interval in hours for which the purge task has to be triggered. Set to a positive integer (1 and above) to enable the auto purging. Defaults to 0.
+> The time interval in hours for which the purge task has to be triggered. Set to a positive integer (1 and above) to enable the auto purging. Defaults to 0.
 
 ### `ZOO_AUTOPURGE_SNAPRETAINCOUNT`
 
 Defaults to `3`. Zookeeper's [`autoPurge.snapRetainCount`](https://zookeeper.apache.org/doc/current/zookeeperAdmin.html#sc_advancedConfiguration)
 
-> New in 3.4.0: When enabled, ZooKeeper auto purge feature retains the autopurge.snapRetainCount most recent snapshots and the corresponding transaction logs in the dataDir and dataLogDir respectively and deletes the rest. Defaults to 3. Minimum value is 3.
+> When enabled, ZooKeeper auto purge feature retains the autopurge.snapRetainCount most recent snapshots and the corresponding transaction logs in the dataDir and dataLogDir respectively and deletes the rest. Defaults to 3. Minimum value is 3.
 
 ## Replicated mode