Thanks Mark, The real driver for me wanting to promote a different leader is when I create a new Collection via the Collections API across a multi-server SolrCloud, the leader of each shard is always the same host, so you're right that I'm tackling the wrong problem with this request, although it would fix it for me.
If I create the cores manually via the cores API, one-by-one, I am able to get what I expect, but when running this Collections API call on a 3 SOLR 4.1 instance, 3 shard setup, 1 server becomes the leader of all 3 shards, meaning it will get all the writes for everything (correct me if I am wrong). If so, this will not scale well with all writes to one node (or correct me if I am wrong)? curl -v 'http://<HOST>:8983/solr/admin/collections?action=CREATE&name=test&numShards=3&replicationFactor=1&maxShardsPerNode=2' Currently on my 3 instance SOLR 4.1 setup, the above call creates the following: - ServerA is the leader of all 3 shards (the problem I want to address). - ServerB + ServerC are automagically replicas of the 3 leader shards on ServerA. So again, my issue is one server gets all the writes. Does anyone else encounter this? If so, I should spawn a separate thread on my specific issue. Cheers, Tim -----Original Message----- From: Mark Miller [mailto:markrmil...@gmail.com] Sent: Tuesday, February 19, 2013 8:44 PM To: solr-user@lucene.apache.org Subject: Re: Is it possible to manually select a shard leader in a running SolrCloud? You can't easily do it the way it's implemented in ZooKeeper. We would probably internally have to do the same thing - elect a new leader and drop him until the one we wanted came up. The main thing doing it internally would gain is that you could skip the elected guy from becoming the actual leader and just move on to the next candidate. Still some tricky corner cases to deal with and such as well. I think for most things you would use this to solve, there is probably an alternate thing that should be addressed. - Mark On Mon, Feb 18, 2013 at 4:15 PM, Vaillancourt, Tim <tvaillanco...@ea.com> wrote: > Hey all, > > I feel having to unload the leader core to force an election is "hacky", and > as far as I know would still leave which node becomes the Leader to chance, > ie I cannot guarantee "NodeX" becomes Leader 100% in all cases. > > Also, this imposes additional load temporarily. > > Is there a way to force the winner of the Election, and if not, is there a > known feature-request for this? > > Cheers, > > Tim Vaillancourt > > -----Original Message----- > From: Joseph Dale [mailto:joey.d...@gmail.com] > Sent: Sunday, February 03, 2013 7:42 AM > To: solr-user@lucene.apache.org > Subject: Re: Is it possible to manually select a shard leader in a running > SolrCloud? > > With solrclound all cores are collections. The collections API it just a > wrapper to call the core api a million times with one command. > > to /solr/admin/cores?action=CREATE&name=core1&collection=core1&shard=1 > > Basically your "creating" the shard again, after leader props have gone out. > Solr will check ZK and find a core meeting that description, then simply get > a copy of the index from the leader of that shard. > > > On Feb 3, 2013, at 10:37 AM, Brett Hoerner <br...@bretthoerner.com> wrote: > >> What is the inverse I'd use to re-create/load a core on another >> machine but make sure it's also "known" to SolrCloud/as a shard? >> >> >> On Sat, Feb 2, 2013 at 4:01 PM, Joseph Dale <joey.d...@gmail.com> wrote: >> >>> >>> To be more clear lets say bob it the leader of core 1. On bob do a >>> /admin/cores?action=unload&name=core1. This removes the core/shard >>> from bob, giving the other servers a chance to grab leader props. >>> >>> -Joey >>> >>> On Feb 2, 2013, at 11:27 AM, Brett Hoerner <br...@bretthoerner.com> wrote: >>> >>>> Hi, >>>> >>>> I have a 5 server cluster running 1 collection with 20 shards, >>> replication >>>> factor of 2. >>>> >>>> Earlier this week I had to do a rolling restart across the cluster, >>>> this worked great and the cluster stayed up the whole time. The >>>> problem is >>> that >>>> the last node I restarted is now the leader of 0 shards, and is >>>> just holding replicas. >>>> >>>> I've noticed this node has abnormally high load average, while the >>>> other nodes (who have the same number of shards, but more leaders >>>> on >>>> average) >>> are >>>> fine. >>>> >>>> First, I'm wondering if that loud could be related to being a 5x >>>> replica and 0x leader? >>>> >>>> Second, I was wondering if I could somehow flag single shards to >>> re-elect a >>>> leader (or force a leader) so that I could more evenly distribute >>>> how >>> many >>>> leader shards each physical server has running? >>>> >>>> Thanks. >>> >>> > > -- - Mark
