Not so much mutual pingability, but mutual tcp-ability. But seriously, why not run ZK in one cluster and put an observer in the other cluster? Or do that bi-directionally?
Or put two machines in each cluster and a tie-breaker somewhere outside like Amazon's EC2? You haven't provided any real motivation for your original architecture. What are you really trying to do? For instance, you say a "distributed systems works in both centers" and needs "fail-over". What do you really mean? Do you want both data centers to continue to operate in the even of partition? In that case you need two separate ZK clusters, possibly with some cross-datacenter ephemeral files. Do you want one data center to stop work if it loses contact with the other? In that case, put a single ZK cluster in one data-center. Do you want to ignore most partition issues, but make sure that exactly one data-center is considered master at all times and that at least one is considered master as much as possible? In that case, use the external tie-breaker architecture. On Fri, Aug 26, 2011 at 1:39 PM, Aleksey Yakovlev < [email protected]> wrote: > Camille: > > Sorry to say, I can't ping one cluster from another... > You are saying, that all the servers mutual pingability is necessary and > sufficient for ZK to operate, right? > > Thanks > AY > > On Fri, Aug 26, 2011 at 12:05 PM, Fournier, Camille F. < > [email protected]> wrote: > > > As long as the two clusters can ping each other, just set up a single ZK > > cluster spread across the two, 3 or 5 nodes (total, not per cluster). > Note > > that if these two clusters are used for business continuity purposes > (spread > > across 2 data centers), you still risk the outage of the zookeeper if you > > lose one of the data centers (the one containing the majority of the ZK > > nodes). > > > > There's no reason to set up 2 ZK quorums and merge them. > > > > C > > > > -----Original Message----- > > From: Aleksey Yakovlev [mailto:[email protected]] > > Sent: Friday, August 26, 2011 10:09 AM > > To: [email protected] > > Subject: Re: Zookeeper on two clusters? > > > > Mahadev: > > > > I need these two clusters to communicate somehow, because our distributed > > system works on both of them - so we need some coordination, for example, > > to > > recover after failures. I could create my own servers/protocols for that, > > but why - the ZooKeeper does just that, right? > > > > The number 5 isn't important here, configuration and communication is > > > > Thanks > > AY > > > > On Fri, Aug 26, 2011 at 1:55 AM, Mahadev Konar <[email protected] > > >wrote: > > > > > Aleksey, > > > I am a little confused. Whats the motivation behind merging the > > > quorums? Why do you want 5 on each cluster? > > > > > > thanks > > > mahadev > > > > > > On Tue, Aug 23, 2011 at 10:24 AM, Aleksey Yakovlev > > > <[email protected]> wrote: > > > > Hi, > > > > > > > > We have two clusters but I can't just ssh from one cluster to another > - > > I > > > > have to enter a password, use some authentication, go through a load > > > > balancer etc > > > > It would be very useful for us to use the Zookeeper as a common > storage > > > > place for small configuration data, accessible from both these > > clusters. > > > > > > > > So, I'm thinking about starting like 5 servers on each cluster and > > merge > > > > them into a single quorum - anybody did that? > > > > If yes, how to configure this double-side quorum? > > > > > > > > (I'm completely new to the Zookeeper) > > > > > > > > Thanks > > > > AY > > > > > > > > > >
