Hi Henry, Thanks for the info. I will spend some more time to understand the issues before starting with the implementation. I will let you know if I have any questions (which I am sure I will).
Just to clarify, "by solved issue" you mean from design perspective and not from implementation right? Regards, -Vishal On Mon, May 3, 2010 at 1:16 PM, Henry Robinson <he...@cloudera.com> wrote: > Hi Vishal - > > Great that you're interested in contributing! This would be a really neat > feature to get into ZK. > > The documentation that exists is essentially all on the JIRA. I had a patch > that 'worked' but was nowhere near commit-ready. I'm trying to dig it up, > but it appears it may have gone to the great bit-bucket in the sky. Trunk > has moved sufficiently that a new patch would be required anyhow. > > There were two main difficulties with this issue. The first is changing the > voting protocol to cope with changes in views. Since proposals are > pipelined, the leader needs to keep track of what the view was that should > vote for a proposal. IIRC, the other subtlety is making sure that when a > view change is proposed, a quorum of votes is received from both the > outgoing view and the incoming one. Otherwise it's possible to transition > to > a 'dead' view in which no progress can be made. > > The second is to figure out the metadata management - how do we 'find' > ZooKeeper servers if the ensemble may have moved onto a completely separate > set of machines? That is, if the original ensemble was on A, B, C and the > current ensemble is D, E, F - where do we look to find where the ensemble > is > located? > > The first is a solved issue, the second is more a matter of taste than > designing distributed protocols. > > Really happy to help with this issue - I'd love to see it get resurrected. > > cheers, > Henry > > On 3 May 2010 07:25, Vishal K <vishalm...@gmail.com> wrote: > > > Hi Henry, > > > > I just commented on the Jira. I would be happy to contribute. > > Please advise on the current status and next steps. Thanks. > > > > Regards, > > -Vishal > > > > > > -- > Henry Robinson > Software Engineer > Cloudera > 415-994-6679 >
