On Jun 19, 2013, at 2:20 AM, Per Steffensen <[email protected]> wrote:
> On 6/18/13 2:15 PM, Mark Miller wrote: >> I don't know what the best method to use now is, but the slightly longer >> term plan is to: >> >> * Have a new mode where you cannot preconfigure cores, only use the >> collection's API. >> * ZK becomes the cluster state truth. >> * The Overseer takes actions to ensure cores live/die in different places >> based on the truth in ZK. > Not that we have to decide on this now, but I guess in "my scenario" I do not > see why the Overseer should be involved. The replica is already assigned to > run on the "replaced" machine with a specific IP/hostname (actually a > specific Solr node-name), so I guess that the Solr node itself on this > new/replaced machine should just go look in ZK when it starts up and realize > that it ought to run this and that replica and start loading them itself. I > recognize that the Overseer should/could be involved in relocating replica > for different reasons - loadbalancing, rack-awareness etc. But in cases where > a replica is already assigned to a certain node-name according to ZK state, > but the node is not preconfigured (in solr.xml) to run this replica, the node > itself should just realize that it ought to run it anyway and load it. But it > probably have to be thought through well. Just my immediate thoughts. Specific node names have since been essentially deprecated - auto assigned generic node names are what we have transitioned to. You should easily be able to host a shard with a machine that has a different address without confusion. By and large, the Overseer will be able too assume responsibility for assignments (though I'm sure how much it will do will be configurable) at a high level. It will be able to do things like look at maxShardsPerNode and replicationFactor and periodically follow rules to make adjustments. The Overseer being in charge is more a conceptual idea though, not the implementation. When a core starts up and checks with ZK and sees the collection it belongs to no longer exists or something, it likely to just not load rather than wait for an Overseer to spot and it remove it later. - Mark --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
