CusterGroup topology unexpectedly empty

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Raymond Wilson Raymond Wilson
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CusterGroup topology unexpectedly empty

I've been researching a problem where we see a ClusterGroup topology becoming unexpectedly empty. I have not found anything that is similar to my case outlined below: 

We have some code using the C# client on Ignite 2.8.0 like this:

var _group = _ignite?.GetCluster()?.ForAttribute(_roleAttribute, "True");

There are nodes in the grid (deployed on AWS EKS) that have a local attribute with the  _roleAttribute name set to the value "True", yet this command sometimes decides that there are no matching nodes. Once it does so, it does not seem to change requiring a restart of the grid.

In this instance, the _ignite reference may be a long lived reference to the object returned by Ignition.GetIgnite("GridName") and cached for future reference. Is this a safe practice, or can the underlying Ingite object change leaving a long lived Ignite reference containing stale state information about the grid?

Thanks,
Raymond.

--

Raymond Wilson
Solution Architect, Civil Construction Software Systems (CCSS)
11 Birmingham Drive | Christchurch, New Zealand
<a href="tel:+64-21-2013317" style="background-color:transparent;color:rgb(54,53,69)" target="_blank">+64-21-2013317 Mobile
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akurbanov akurbanov
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Re: CusterGroup topology unexpectedly empty

Using ignite reference is completely fine.

What is the exact exception being thrown in this case? I would expect to see
this if the node is out of topology, what does the logs tell? Do other nodes
see this one in the topology?

Please check if there are NODE_FAILED events for the node on other topology
members, where the exception is observed.

Best regards,
Anton



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ilya.kasnacheev ilya.kasnacheev
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Re: CusterGroup topology unexpectedly empty

In reply to this post by Raymond Wilson
Hello!

Please note that ClusterGroups usually do not recompute. This means, if you had two nodes with _roleAttribute "True", and they all went away, the group is now empty, even as two new nodes has joined with the same attribute.

You need to re-create ClusterGroup in order to refresh it.


Regards,
--
Ilya Kasnacheev


ср, 1 июл. 2020 г. в 11:26, Raymond Wilson <[hidden email]>:
I've been researching a problem where we see a ClusterGroup topology becoming unexpectedly empty. I have not found anything that is similar to my case outlined below: 

We have some code using the C# client on Ignite 2.8.0 like this:

var _group = _ignite?.GetCluster()?.ForAttribute(_roleAttribute, "True");

There are nodes in the grid (deployed on AWS EKS) that have a local attribute with the  _roleAttribute name set to the value "True", yet this command sometimes decides that there are no matching nodes. Once it does so, it does not seem to change requiring a restart of the grid.

In this instance, the _ignite reference may be a long lived reference to the object returned by Ignition.GetIgnite("GridName") and cached for future reference. Is this a safe practice, or can the underlying Ingite object change leaving a long lived Ignite reference containing stale state information about the grid?

Thanks,
Raymond.

--

Raymond Wilson
Solution Architect, Civil Construction Software Systems (CCSS)
11 Birmingham Drive | Christchurch, New Zealand
<a href="tel:+64-21-2013317" style="background-color:transparent;color:rgb(54,53,69)" target="_blank">+64-21-2013317 Mobile
[hidden email]