[ZOOKEEPER-762] Allow dynamic addition/removal of server nodes in the client API

• Type: Sub-task
• Status: Resolved
• Priority: Minor
• Resolution: Duplicate
• Fix Version/s: 3.5.0
• Component/s: c client, java client
• Assignee: Unassigned
• Reporter: Dave Wright
• Created: 03/May/10 20:54
• Updated: 29/Dec/12 23:47
• Resolved: 29/Dec/12 23:47

Description

Currently the list of zookeeper servers needs to be provided to the client APIs at construction time, and cannot be changed without a complete shutdown/restart of the client API. However, there are scenarios that require the server list to be updated, such as removal or addition of a ZK cluster node, and it would be nice if the list could be updated via a simple API call.

The general approach (in the Java client) would be to "RemoveServer()/AddServer()" functions for Zookeeper that calls down to ClientCnxn, where they are just maintained in a list. Of course if
the server being removed is the one currently connected, we'd need to disconnect, but a simple call to disconnect() seems like it would resolve that and trigger the automatic re-connection logic.
An equivalent change could be made in the C code.

This change would also make dynamic cluster membership in ZOOKEEPER-107 easier to implement.

Issue Links

• blocks: ZOOKEEPER-836 hostlist as string
• is related to: ZOOKEEPER-1355 Add zk.updateServerList(newServerList)