Hi, 

The way I see it, the main corner cases  with rolling restarts are 
1) First seed node, when restarted, cannot join the old cluster (cannot 
reach any of the other seed nodes)
2) The rolling restart doesn't properly check that a nodes has re-joined 
the cluster, before restarting the next nodes. This can lead to a situation 
where all seed nodes are down, resulting in #1 plus a split brain where the 
old cluster is not aware of the new cluster. 

#2 - can be solved using proper health checks (or waiting long enough 
before restarting next node)
#1 - is there a way to prevent the first nodes from forming it's own 
cluster?

Cheers,
Eugene


On Tuesday, June 23, 2015 at 2:48:48 AM UTC-4, Patrik Nordwall wrote:
>
> On Fri, Jun 19, 2015 at 1:59 PM, Brice Figureau <[email protected] 
> <javascript:>> wrote:
>
>> Hi,
>>
>> What would be the correct procedure to perform an automated rolling
>> upgrade of an akka cluster (running a dozen of singleton and sharding)?
>>
>> Is it enough to:
>> 1) "leave" one node
>> 2) wait a bit
>> 3) restart the node JVM
>> 4) do the same on another node
>>
>
> That sounds good to me. 
>
> For step 2 and 3 you can subscribe to MemberRemoved and restart the jvm 
> when you see MemberRemoved with the selfAddress. In 2.4-M1 there is a 
> convenience method for this: Cluster(system).registerOnMemberRemoved
>  
>
>>
>> And should the seed nodes be treated differently?
>>
>
> Make sure that the list of seed nodes of the restarted node contains some 
> of the running nodes, so that it joins the existing cluster.
>
> Cheers,
> Patrik
>  
>
>> --
>> Brice Figureau
>> My Blog: http://www.masterzen.fr/
>>
>> --
>> >>>>>>>>>>      Read the docs: http://akka.io/docs/
>> >>>>>>>>>>      Check the FAQ: 
>> http://doc.akka.io/docs/akka/current/additional/faq.html
>> >>>>>>>>>>      Search the archives: 
>> https://groups.google.com/group/akka-user
>> ---
>> You received this message because you are subscribed to the Google Groups 
>> "Akka User List" group.
>> To unsubscribe from this group and stop receiving emails from it, send an 
>> email to [email protected] <javascript:>.
>> To post to this group, send email to [email protected] 
>> <javascript:>.
>> Visit this group at http://groups.google.com/group/akka-user.
>> For more options, visit https://groups.google.com/d/optout.
>>
>
>
>
> -- 
>
> Patrik Nordwall
> Typesafe <http://typesafe.com/> -  Reactive apps on the JVM
> Twitter: @patriknw
>
>

-- 
>>>>>>>>>>      Read the docs: http://akka.io/docs/
>>>>>>>>>>      Check the FAQ: 
>>>>>>>>>> http://doc.akka.io/docs/akka/current/additional/faq.html
>>>>>>>>>>      Search the archives: https://groups.google.com/group/akka-user
--- 
You received this message because you are subscribed to the Google Groups "Akka 
User List" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to [email protected].
To post to this group, send email to [email protected].
Visit this group at https://groups.google.com/group/akka-user.
For more options, visit https://groups.google.com/d/optout.

Reply via email to