Hi Matthieu, this is a known bug in 0.6.1 release. We have fixed it in trunk.
If you are building from trunk, change ClusterConfigInit#init()
admin.addResource(DEFAULT_CLUSTER_NAME,
RESOURCE,
PARTITIONS,
"LEADER_REPLICA",
IdealStateModeProperty.AUTO_REBALANCE.toString());
to
admin.addResource(DEFAULT_CLUSTER_NAME, RESOURCE, PARTITIONS,
"LEADER_REPLICA",
RebalanceMode.FULL_AUTO.toString());
It should work. We are planing to make 0.6.2 release with a few fixes including
this one.
Thanks,
Jason
From: Matthieu Morel <[email protected]<mailto:[email protected]>>
Reply-To:
"[email protected]<mailto:[email protected]>"
<[email protected]<mailto:[email protected]>>
Date: Monday, October 14, 2013 12:09 PM
To: "[email protected]<mailto:[email protected]>"
<[email protected]<mailto:[email protected]>>
Subject: Getting auto_rebalance right
Hi,
I'm trying to use the auto-rebalance mode in Helix.
The use case is the following (standard leader-standby scenario, a bit like the
rsync example in the helix codebase):
- the dataspace is partitioned
- for a given partition, we have
- a leader that is responsible for writing and serving data, logging operations
into a journal
- a replica that fetches updates from a journal and applies them locally but it
does not serve data
Upon failure, the replica becomes leader, applies pending updates and can write
and serve data. Ideally we also get a new replica assigned.
We'd like to use the auto_rebalance mode in Helix so that partitions are
automatically assigned and re-assigned, and so that leaders are automatically
elected.
Unfortunately, I can't really get the balancing right. I might be doing
something wrong, so I uploaded an example here :
https://github.com/matthieumorel/helix-balancing
In this application I would like to get exactly 1 leader and 1 replica for each
of the partitions
In this example we don't reach that result, and when removing a node, we even
get to a situation where there is no leader for a given partition.
Do I have wrong expectations? Is there something wrong with the code, is it
something with helix?
Thanks!
Matthieu
