Is there a system projection with cluster operational events?

EventStoreDB
#1

I’am playing with competing right now, I like it a lot already. Just wonder if there is a way to be notified of a cluster loosing a node or a new one added, maybe through some system projections, like $stats-[ip] or something similar?

Why I’am asking… I have a use case when I fan out long running tasks to three nodes using competing. Now in order to check if these tasks are running I have to make some ping services to check if they are alive, and if not restart them on other nodes (using competing). If ES would have some event about node lost or added that would help to act more reactively.

#2

You should really pull latest I made a lot of fixes including to cluster recoveries on competing.

To be clear you want an event for node lost connection/gained connection from competing itself?

Cheers,

Greg

#3

GET /gossip on one of the nodes - this should have everything you need. However, it will monitor this internally and redispatch messages which were with nodes that die automatically (as I recall from the discussions, havent looked through that part yet).

James

#4

It does unless you explicitly park a message. This is controlled by the retry timeout

#5

I think he wants the connections in a group correct me if I’m wrong… You can ping this now on http get /subscriptions/(stream)/(group name) but it requires a polling btw. Also you probably want to try enabling extra statistics here (get additional timing information on the connections)

#6

You see I want to use competing to start long running tasks, these tasks are services of remote devices, and these can live for long time. So I use competing to distribute services along all nodes and start them. Each service consumes tasks from it’s own stream. When a node goes down it’s services goes down too. I think it would be great if this information about lost node would come out as an event on some stream. In that case I could redistribute services over again easily. The GET /gossip is an option, yes. Don’t know about information /subscriptions/stream/group yet, I should look more at it.

2014 m. spalis 31 d., penktadienis 18:20:26 UTC+2, Greg Young rašė:

#7

Gossip tell you about the cluster of event store nodes. You are looking for the other

#8

yep, subscriptions/stream provides connectionCount field, cool. I’ll use that I think.

2014 m. spalis 31 d., penktadienis 21:03:44 UTC+2, Greg Young rašė:

#9

Enable extra statistics :slight_smile: likely something you want to monitor…