On Fri, Apr 18, 2014 at 3:02 AM, roger peppe <rogpe...@gmail.com> wrote:
> I've just landed some changes on juju tip that enable "highly available" > juju environments. In a HA environment, there are several state servers - > if one dies, one of the others should take over. > > To make a HA environment, run the "ensure-availability" command. For > example to make a HA environment with three state servers, run: > > $ juju ensure-availability -n 3 > > This will add new servers as necessary. It will also maintain the > current state server set if some servers have gone down. > > A new field in the status output, state-server-member-status, present > only for state server machines, indicates the current status of each > state server. > > When the status of a majority of state server machines is "has-vote", > the environment should be resilient to any one of them going down. > > If a state server machine goes down and you run ensure-availability again, > it should detect that the machine has gone down and create a new machine > to replace it. When the new machine is available, the original (down) > machine's status will become "no-vote". > > If you run ensure-availability again, it will see that the machine has > no vote and is down, and will remove its state server status. At that > point the machine can actually be removed (you'll need the --force flag). > > Anyone that's interested, please try it out. It would be great if people > could see whether it works for them - there are bound to be some teething > problems! > > There is one major caveat: upgrading an existing environment > to HA is not supported currently (Andrew Wilkins has a branch in review > that > should fix this). > Upgrade support landed on the weekend. If would be great it some intrepid users would test this out. (I have tested it, of course.) > Please note that the transition times when mongo is failing over can be > quite long (on the order of minutes), so you'll need to be patient. > > Many thanks to everyone that's pitched in to help get this done. > > cheers, > rog. > > -- > Juju-dev mailing list > Juju-dev@lists.ubuntu.com > Modify settings or unsubscribe at: > https://lists.ubuntu.com/mailman/listinfo/juju-dev > >
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