Hi Guido,
I think in your case you are shutting down before the node has communicated
to the leader that it wants to leave. I wait to get the MemberExited
message before shutting down the node. Maybe I should wait for the
MemberRemoved? Either way the ultimate aim is to not have the unreachable
logic kick in and have to wait x seconds (I use 10 seconds) for the node to
be auto downed by the leader. And the reason why I don't want to wait is
according to the docs the leader wouldn't be able to add nodes whilst any
node in the cluster is considered unreachable, which is a problem if I'm
doing a rolling restart of all the nodes.
Regards,
Ben
On Thursday, March 17, 2016 at 4:51:30 PM UTC-4, Guido Medina wrote:
>
> As for cluster.leave(cluster.selfAddress) my micro-services use the
> following to leave:
>
> Runtime.getRuntime().addShutdownHook(new Thread() {
> @Override
> public void run() {
> final Cluster cluster = Cluster.get(system);
> cluster.leave(cluster.selfAddress());
> system.terminate();
> Configurator.shutdown((LoggerContext) LogManager.getContext());
> }
> });
>
> But honestly I have never seen that work, the other nodes just report it
> as unreachable until it times out and it is completely removed,
> maybe the shutdown happens so fast that it is useless in my case.
>
> HTH,
>
> Guido.
>
> On Thursday, March 17, 2016 at 8:33:29 PM UTC, Guido Medina wrote:
>>
>> Hi Benjamin,
>>
>> I also rely on cluster events and AFAIK you can expect (and trust)
>> *MemberUp* and *MemberRemoved*, these IMHO are the only two consistent
>> states you can trust.
>> In other words, I register some actors only when their nodes reach
>> *MemberUp* and unregister only when their nodes reach *MemberRemoved*
>> Any other state in between I would treat them as information only.
>>
>> So far I haven't got any issue with my mini-shard implementation relying
>> on these only 2 statuses, the draw back is that it will only have to wait
>> for a longer time to react.
>>
>> HTH,
>>
>> Guido.
>>
>> On Thursday, March 17, 2016 at 6:07:48 PM UTC, Benjamin Black wrote:
>>>
>>> Hello,
>>>
>>> I'm adding logic to our service so that when a node is being restarted
>>> it gracefully leaves the cluster using cluster.leave(cluster
>>> .selfAddress). In the cluster specification doc it states:
>>>
>>> If a node is unreachable then gossip convergence is not possible and
>>> therefore any leader actions are also not possible (for instance,
>>> allowing a node to become a part of the cluster). To be able to move
>>> forward the state of theunreachable nodes must be changed. It must
>>> become reachable again or marked as down
>>>
>>> Is this totally true? If a node is unreachable and is the
>>> leaving/exiting/removed state will this stop the leader from adding a new
>>> node? I ask because I have an actor that subscribes to cluster events and I
>>> can see a node is being added whilst another node is considered unreachable
>>> and in the exiting status:
>>>
>>> 14:02:46.843 INFO Exited member Member(address = akka.tcp://
>>> geyser@172.16.120.160:7000, status = Exiting)
>>> 14:02:51.842 INFO Unreachable member Member(address = akka.tcp://
>>> geyser@172.16.120.160:7000, status = Exiting)
>>> 14:02:53.843 INFO Removing member Member(address = akka.tcp://
>>> geyser@172.16.120.160:7000, status = Removed)
>>> 14:02:57.843 INFO Exited member Member(address = akka.tcp://
>>> geyser@172.16.119.46:7000, status = Exiting)
>>> 14:03:02.760 INFO Unreachable member Member(address = akka.tcp://
>>> geyser@172.16.119.46:7000, status = Exiting)
>>> 14:03:04.843 INFO Adding member Member(address = akka.tcp://
>>> geyser@172.16.120.160:7000, status = Up)
>>>
>>> Thanks,
>>> Ben
>>>
>>>
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