[ZOOKEEPER-1727] Doc request: The right way to expand a cluster

• Type: Wish
• Status: Resolved
• Priority: Minor
• Resolution: Duplicate
• Affects Version/s: 3.5.0
• Fix Version/s: 3.5.0
• Assignee: Alexander Shraer
• Reporter: Justin SB
• Created: 13/Jul/13 01:31
• Updated: 13/Jul/13 19:58
• Resolved: 13/Jul/13 19:43

Description

When expanding a cluster from 2->3, if ZK server #3 isn't up yet, then it seems that the reconfig request times out with a connection-loss error. The configuration is updated though. So we could wait, reconnect, and then refetch the config to make sure we did join the quorum, though that seems a little bit hacky!

What is correct way to do this (and cluster growth in general)? Should we bring up new ZK servers before issuing the reconfig command? What is the right way to bring up new ZK servers (connect as a client, request the config, save the config to the zk.conf.dynamic file, add our new server line to the new zk.conf.dynamic file, start the new server, call reconfig as a client to the existing cluster)?

Is this documented anywhere? (Just the steps to do it "the right way" would be great, no need for actual code)

Issue Links

• Is contained by: ZOOKEEPER-1660 Add documentation for dynamic reconfiguration