# Frequent disconnects between nodes

**URL:** https://discuss.elastic.co/t/frequent-disconnects-between-nodes/13205
**Category:** Elasticsearch
**Created:** [August 13, 2013, 9:11pm UTC](https://discuss.elastic.co/t/frequent-disconnects-between-nodes/13205 "2013-08-13T21:11:09Z")
**Posts on this page:** 14
**Page:** 1

<div class="post-metadata">

### Author: ![Runar\_Myklebust](https://avatars.discourse-cdn.com/v4/letter/r/a6a055/32.png) [@Runar\_Myklebust](https://discuss.elastic.co/u/Runar_Myklebust)
#### Post date: [August 13, 2013, 9:11pm UTC](https://discuss.elastic.co/t/frequent-disconnects-between-nodes/13205/1 "2013-08-13T21:11:09Z")

</div>

Hi.

We have a setup with embedded ES (0.20.6) with 7 nodes. At a regular basis,  
one or more nodes looses connection to the master, and thus (since the  
minimum\_master\_nodes setting is 1) creates a split-brain scenario - The  
split-brain issue is ok for now, but the frequency of disconnects is not.

There are "no indications" that the network is causing this, but one could  
of course never be sure, although is a bit of an hassle to get the service  
provider to accept this anyway without any more evidence.

The cluster uses unicast to communicate, and in an attemt to avoid these  
regular node fallout we have set the discovery.zen.fd.ping\_timout = 240s  
but it doesnt seem to make things any better. Also, the nodes failing are  
just as often located within the same network as nodes on a different  
subnet.

Here is a view of the log from the node falling out of the cluster:

> <https://gist.github.com/runarmyklebust/6225706>

Im a bit stuck on how to proceed to find the reason for these disconnects  
all the time (that is, surely a couple of nodes will fail within a day or  
two). Any pointers would be appreciated.

## greetings

Runar Myklebust

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### Author: ![Runar\_Myklebust](https://avatars.discourse-cdn.com/v4/letter/r/a6a055/32.png) [@Runar\_Myklebust](https://discuss.elastic.co/u/Runar_Myklebust)
#### Post date: [August 14, 2013, 9:44am UTC](https://discuss.elastic.co/t/frequent-disconnects-between-nodes/13205/2 "2013-08-14T09:44:55Z")

</div>

Another thing to point out;

I see some mentions of 'transport.ping\_timeout' for client setting. How  
does this compare / when does this come into account vs the  
'discovery.zen.fd.ping\_timeout' ? Is tuning this "transport.ping\_timeout"  
worth a shot?

For out embedded client, we are not setting any specific options at all for  
now, we initialize the client like this:

public void start()  
{  
this.client = this.node.client();  
}

The node is initalized with a lot of settings though, through:

this.node = NodeBuilder.nodeBuilder().settings( settings ).build();

Will it be sufficient to add the "transport.ping\_timeout" to the node  
settings?

On Tue, Aug 13, 2013 at 11:11 PM, Runar Myklebust [runar.a.m@gmail.com](mailto:runar.a.m@gmail.com)wrote:

> Hi.
> 
> We have a setup with embedded ES (0.20.6) with 7 nodes. At a regular  
> basis, one or more nodes looses connection to the master, and thus (since  
> the minimum\_master\_nodes setting is 1) creates a split-brain scenario - The  
> split-brain issue is ok for now, but the frequency of disconnects is not.
> 
> There are "no indications" that the network is causing this, but one could  
> of course never be sure, although is a bit of an hassle to get the service  
> provider to accept this anyway without any more evidence.
> 
> The cluster uses unicast to communicate, and in an attemt to avoid these  
> regular node fallout we have set the discovery.zen.fd.ping\_timout = 240s  
> but it doesnt seem to make things any better. Also, the nodes failing are  
> just as often located within the same network as nodes on a different  
> subnet.
> 
> Here is a view of the log from the node falling out of the cluster:
> 
> [Log from node falling out of cluster · GitHub](https://gist.github.com/runarmyklebust/6225706)
> 
> Im a bit stuck on how to proceed to find the reason for these disconnects  
> all the time (that is, surely a couple of nodes will fail within a day or  
> two). Any pointers would be appreciated.
> 
> ## greetings
> 
> Runar Myklebust

## -- mvh

Runar Myklebust

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<div class="post-metadata">

### Author: ![jprante](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/jprante/32/44941_2.png) [@jprante](https://discuss.elastic.co/u/jprante)
#### Post date: [August 14, 2013, 12:38pm UTC](https://discuss.elastic.co/t/frequent-disconnects-between-nodes/13205/3 "2013-08-14T12:38:47Z")

</div>

From what I understand, you have a split brain situation. A second master  
wants to rejoin, the state difference is detected, but the rejoin request  
fails. To fix this, my only idea is to isolate the second master and remove  
state and data from that node before rejoining.

Increasing timeouts may be a workaround for the moment. But if your network  
is not reliable, you should diagnose and fix that. Maybe network monitoring  
tools can help you, like tcpdump, ntop, wireshark... only to mention a few.

Jörg

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### Author: ![Runar\_Myklebust](https://avatars.discourse-cdn.com/v4/letter/r/a6a055/32.png) [@Runar\_Myklebust](https://discuss.elastic.co/u/Runar_Myklebust)
#### Post date: [August 14, 2013, 1:13pm UTC](https://discuss.elastic.co/t/frequent-disconnects-between-nodes/13205/4 "2013-08-14T13:13:36Z")

</div>

Hi Jörg, thanks for answering.  
The split-brain is "ok", in the sense that I know that it will happen with  
the current setup if the nodes drops out.  
The reason for the disconnects on the other hand, are more of a concern  
right now. Im a bit stuck on finding out why exactly the disconnects  
happens since I have very limited access to the system, and has to ask for  
assistance on what to check for explicitly.  
At the moment, the log level for discovery and transport has been altered  
to "finest", so that will hopefully reveal some more information.

On Wed, Aug 14, 2013 at 2:38 PM, [joergprante@gmail.com](mailto:joergprante@gmail.com) \<  
[joergprante@gmail.com](mailto:joergprante@gmail.com)\> wrote:

> From what I understand, you have a split brain situation. A second master  
> wants to rejoin, the state difference is detected, but the rejoin request  
> fails. To fix this, my only idea is to isolate the second master and remove  
> state and data from that node before rejoining.
> 
> Increasing timeouts may be a workaround for the moment. But if your  
> network is not reliable, you should diagnose and fix that. Maybe network  
> monitoring tools can help you, like tcpdump, ntop, wireshark... only to  
> mention a few.
> 
> Jörg
> 
> --  
> You received this message because you are subscribed to the Google Groups  
> "elasticsearch" group.  
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## -- mvh

Runar Myklebust

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### Author: ![jprante](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/jprante/32/44941_2.png) [@jprante](https://discuss.elastic.co/u/jprante)
#### Post date: [August 14, 2013, 3:31pm UTC](https://discuss.elastic.co/t/frequent-disconnects-between-nodes/13205/5 "2013-08-14T15:31:22Z")

</div>

Just to add one more thought. Network disconnects may only be a symptom and  
examining the network subsystem may not reveal anything useful.

You said you have limited access and ES is embedded. It could also be that  
ES is drained from necessary resources (CPU, memory, disk) by other  
software or activity of the system, and you see only network disconnects,  
but not the cause of the problem.

Jörg

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### Author: ![Ivan](https://avatars.discourse-cdn.com/v4/letter/i/df788c/32.png) [@Ivan](https://discuss.elastic.co/u/Ivan)
#### Post date: [August 15, 2013, 6:55pm UTC](https://discuss.elastic.co/t/frequent-disconnects-between-nodes/13205/6 "2013-08-15T18:55:43Z")

</div>

There are two levels of timeouts. The first checks if the process is  
running and accepting connections. The second is if the machine itself is  
actually running.

If the process itself is slow, then the first timeout will occur and might  
have little to do with network. As Jörg mentioned, if elasticsearch is  
constrained, it might not be responding in a timely matter. If you are  
limited in the amount of memory you have, you might be experience large  
garbage collections. Upgrading to 0.90.x will improve memory usage and  
reduce the amount/time need for GC.

Cheers,

Ivan

On Wed, Aug 14, 2013 at 8:31 AM, [joergprante@gmail.com](mailto:joergprante@gmail.com) \<  
[joergprante@gmail.com](mailto:joergprante@gmail.com)\> wrote:

> Just to add one more thought. Network disconnects may only be a symptom  
> and examining the network subsystem may not reveal anything useful.
> 
> You said you have limited access and ES is embedded. It could also be that  
> ES is drained from necessary resources (CPU, memory, disk) by other  
> software or activity of the system, and you see only network disconnects,  
> but not the cause of the problem.
> 
> Jörg
> 
> --  
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### Author: ![Runar\_Myklebust](https://avatars.discourse-cdn.com/v4/letter/r/a6a055/32.png) [@Runar\_Myklebust](https://discuss.elastic.co/u/Runar_Myklebust)
#### Post date: [August 16, 2013, 7:17am UTC](https://discuss.elastic.co/t/frequent-disconnects-between-nodes/13205/7 "2013-08-16T07:17:33Z")

</div>

Ok, so the "transport.ping\_timeout" checks if the process is running then?

Now, after a run with tracing, I can see a lot of these in the logs:

2013-08-14 14:47:19,224 DEBUG [org.elasticsearch.transport.netty]  
(elasticsearch[local][transport\_client\_worker][T#2]{New I/O worker #2})  
[local] disconnected from  
[[local][VbxjXeqGRIyNFzvK-1JCIw][inet[/ **NODE24** :8800]]{local=false}],  
channel closed event  
2013-08-14 14:47:24,080 DEBUG [org.elasticsearch.transport.netty]  
(elasticsearch[local][transport\_client\_worker][T#3]{New I/O worker #3})  
[local] disconnected from  
[[local][V7FXnZiLR-GVIyZ2DOwV2w][inet[/ **NODE26** :8800]]{local=false}],  
channel closed event

After a while, the node that the current master gets the "channel closed  
event" from, looses connection with master and starts master election and  
makes all kinds of trouble. As far as I can see, no GC or other slowdowns  
has happened on the NODE24 or NODE26, so this seems to be a network issue,  
right?

On Thu, Aug 15, 2013 at 8:55 PM, Ivan Brusic [ivan@brusic.com](mailto:ivan@brusic.com) wrote:

> There are two levels of timeouts. The first checks if the process is  
> running and accepting connections. The second is if the machine itself is  
> actually running.
> 
> If the process itself is slow, then the first timeout will occur and might  
> have little to do with network. As Jörg mentioned, if elasticsearch is  
> constrained, it might not be responding in a timely matter. If you are  
> limited in the amount of memory you have, you might be experience large  
> garbage collections. Upgrading to 0.90.x will improve memory usage and  
> reduce the amount/time need for GC.
> 
> Cheers,
> 
> Ivan
> 
> On Wed, Aug 14, 2013 at 8:31 AM, [joergprante@gmail.com](mailto:joergprante@gmail.com) \<  
> [joergprante@gmail.com](mailto:joergprante@gmail.com)\> wrote:
> 
> > Just to add one more thought. Network disconnects may only be a symptom  
> > and examining the network subsystem may not reveal anything useful.
> > 
> > You said you have limited access and ES is embedded. It could also be  
> > that ES is drained from necessary resources (CPU, memory, disk) by other  
> > software or activity of the system, and you see only network disconnects,  
> > but not the cause of the problem.
> > 
> > Jörg
> > 
> > --  
> > You received this message because you are subscribed to the Google Groups  
> > "elasticsearch" group.  
> > To unsubscribe from this group and stop receiving emails from it, send an  
> > email to [elasticsearch+unsubscribe@googlegroups.com](mailto:elasticsearch+unsubscribe@googlegroups.com).  
> > For more options, visit [https://groups.google.com/groups/opt\_out](https://groups.google.com/groups/opt_out).
> 
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## -- mvh

Runar Myklebust

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### Author: ![jprante](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/jprante/32/44941_2.png) [@jprante](https://discuss.elastic.co/u/jprante)
#### Post date: [August 16, 2013, 9:13am UTC](https://discuss.elastic.co/t/frequent-disconnects-between-nodes/13205/8 "2013-08-16T09:13:43Z")

</div>

The "channel closed event" notice is a normal event that is happening  
during connection pool activity and just an informational message on  
"DEBUG" log level.

It seems unrelated to the "unable to rejoin cluster" situations you have  
posted.

Do you get failure/error messages in the log?

Jörg

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### Author: ![Runar\_Myklebust](https://avatars.discourse-cdn.com/v4/letter/r/a6a055/32.png) [@Runar\_Myklebust](https://discuss.elastic.co/u/Runar_Myklebust)
#### Post date: [August 16, 2013, 9:32am UTC](https://discuss.elastic.co/t/frequent-disconnects-between-nodes/13205/9 "2013-08-16T09:32:52Z")

</div>

Hmmm..

Here is first traces of that something is visibly going wrong, around 19:10:

Node47:  
2013-08-14 19:09:49,243 DEBUG [org.elasticsearch.transport.netty]  
(elasticsearch[local][transport\_client\_worker][T#3]{New I/O worker #3})  
[local] disconnected from  
[[local][VbxjXeqGRIyNFzvK-1JCIw][inet[/ **NODE24** :8800]]{local=false}],  
channel closed event  
2013-08-14 19:09:54,109 DEBUG [org.elasticsearch.transport.netty]  
(elasticsearch[local][transport\_client\_worker][T#3]{New I/O worker #3})  
[local] disconnected from  
[[local][V7FXnZiLR-GVIyZ2DOwV2w][inet[/ **NODE26** :8800]]{local=false}],  
channel closed event  
2013-08-14 19:10:06,008 DEBUG [org.elasticsearch.transport.netty]  
(elasticsearch[local][transport\_client\_worker][T#4]{New I/O worker #4})  
[local] disconnected from  
[[local][da-T28GDRtWgadrkCvxS-w][inet[/ **NODE25** :8800]]{local=false}],  
channel closed event  
2013-08-14 19:10:34,253 TRACE [org.elasticsearch.discovery.zen.fd]  
(elasticsearch[local][generic][T#19]) [local] [node]  
[[local][VbxjXeqGRIyNFzvK-1JCIw][inet[/ **NODE24** :8800]]{local=false}]  
transport disconnected (with verified connect)  
2013-08-14 19:10:34,259 DEBUG [org.elasticsearch.transport.netty]  
(elasticsearch[local][generic][T#24]) [local] connected to node  
[[local][V7FXnZiLR-GVIyZ2DOwV2w][inet[/ **NODE26** :8800]]{local=false}]  
2013-08-14 19:10:34,259 DEBUG [org.elasticsearch.transport.netty]  
(elasticsearch[local][generic][T#25]) [local] connected to node  
[[local][da-T28GDRtWgadrkCvxS-w][inet[/ **NODE25** :8800]]{local=false}]  
2013-08-14 19:10:34,273 DEBUG [org.elasticsearch.transport.netty]  
(elasticsearch[local][generic][T#26]) [local] connected to node  
[[local][VbxjXeqGRIyNFzvK-1JCIw][inet[/ **NODE24** :8800]]{local=false}]  
2013-08-14 19:10:34,290 DEBUG [org.elasticsearch.transport.netty]  
(elasticsearch[local][generic][T#27]) [local] disconnected from  
[[local][VbxjXeqGRIyNFzvK-1JCIw][inet[/ **NODE24** :8800]]{local=false}]

Node24:  
2013-08-14 19:10:35,167 DEBUG [org.elasticsearch.discovery.zen.fd]  
(elasticsearch[local][transport\_client\_worker][T#4]{New I/O worker #4})  
[local] [master] pinging a master  
[local][Y01TgbUzRg-JIIpQ7NqlZg][inet[/ **NODE47** :8800]]{local=false} but we  
do not exists on it, act as if its master failure  
2013-08-14 19:10:35,170 DEBUG [org.elasticsearch.discovery.zen.fd]  
(elasticsearch[local][transport\_client\_worker][T#4]{New I/O worker #4})  
[local] [master] stopping fault detection against master  
[[local][Y01TgbUzRg-JIIpQ7NqlZg][inet[/ **NODE47** :8800]]{local=false}],  
reason [master failure, do not exists on master, act as master failure]  
2013-08-14 19:10:35,171 INFO [org.elasticsearch.discovery.zen]  
(elasticsearch[local][generic][T#1]) [local] master\_left  
[[local][Y01TgbUzRg-JIIpQ7NqlZg][inet[/ **NODE47** :8800]]{local=false}],  
reason [do not exists on master, act as master failure]  
2013-08-14 19:10:35,174 DEBUG [org.elasticsearch.discovery.zen.fd]  
(elasticsearch[local][clusterService#updateTask][T#1]) [local] [master]  
restarting fault detection against master  
[[local][JrRrD5Y8R8WHn1ZAkjYNBw][inet[/ **NODE45** :8800]]{local=false}],  
reason [possible elected master since master left (reason = do not exists  
on master, act as master failure)]  
2013-08-14 19:10:35,181 DEBUG [org.elasticsearch.transport.netty]  
(elasticsearch[local][generic][T#1]) [local] disconnected from  
[[local][Y01TgbUzRg-JIIpQ7NqlZg][inet[/ **NODE47** :8800]]{local=false}]  
2013-08-14 19:10:36,233 DEBUG [org.elasticsearch.discovery.zen.fd]  
(elasticsearch[local][transport\_client\_worker][T#4]{New I/O worker #4})  
[local] [master] pinging a master  
[local][JrRrD5Y8R8WHn1ZAkjYNBw][inet[/ **NODE45** :8800]]{local=false} that  
is no longer a master  
2013-08-14 19:10:36,235 INFO [org.elasticsearch.discovery.zen]  
(elasticsearch[local][generic][T#5]) [local] master\_left  
[[local][JrRrD5Y8R8WHn1ZAkjYNBw][inet[/ **NODE45** :8800]]{local=false}],  
reason [no longer master]  
2013-08-14 19:10:36,235 DEBUG [org.elasticsearch.discovery.zen.fd]  
(elasticsearch[local][transport\_client\_worker][T#4]{New I/O worker #4})  
[local] [master] stopping fault detection against master  
[[local][JrRrD5Y8R8WHn1ZAkjYNBw][inet[/ **NODE45** :8800]]{local=false}],  
reason [master failure, no longer master]  
2013-08-14 19:10:36,241 DEBUG [org.elasticsearch.discovery.zen.fd]  
(elasticsearch[local][clusterService#updateTask][T#1]) [local] [master]  
restarting fault detection against master  
[[local][V7FXnZiLR-GVIyZ2DOwV2w][inet[/ **NODE26** :8800]]{local=false}],  
reason [possible elected master since master left (reason = no longer  
master)]  
2013-08-14 19:10:36,245 DEBUG [org.elasticsearch.transport.netty]  
(elasticsearch[local][generic][T#5]) [local] disconnected from  
[[local][JrRrD5Y8R8WHn1ZAkjYNBw][inet[/ **NODE45** :8800]]{local=false}]  
2013-08-14 19:10:37,359 DEBUG [org.elasticsearch.discovery.zen.fd]  
(elasticsearch[local][transport\_client\_worker][T#3]{New I/O worker #3})  
[local] [master] pinging a master  
[local][V7FXnZiLR-GVIyZ2DOwV2w][inet[/ **NODE26** :8800]]{local=false} that  
is no longer a master  
2013-08-14 19:10:37,361 INFO [org.elasticsearch.discovery.zen]  
(elasticsearch[local][generic][T#10]) [local] master\_left  
[[local][V7FXnZiLR-GVIyZ2DOwV2w][inet[/ **NODE26** :8800]]{local=false}],  
reason [no longer master]  
2013-08-14 19:10:37,363 DEBUG [org.elasticsearch.discovery.zen.fd]  
(elasticsearch[local][transport\_client\_worker][T#3]{New I/O worker #3})  
[local] [master] stopping fault detection against master  
[[local][V7FXnZiLR-GVIyZ2DOwV2w][inet[/ **NODE26** :8800]]{local=false}],  
reason [master failure, no longer master]  
2013-08-14 19:10:37,393 DEBUG [org.elasticsearch.transport.netty]  
(elasticsearch[local][generic][T#10]) [local] disconnected from  
[[local][V7FXnZiLR-GVIyZ2DOwV2w][inet[/ **NODE26** :8800]]{local=false}]

Node25:  
2013-08-14 19:10:34,309 DEBUG [org.elasticsearch.transport.netty]  
(elasticsearch[local][generic][T#1]) [local] disconnected from  
[[local][VbxjXeqGRIyNFzvK-1JCIw][inet[/ **NODE24** :8800]]{local=false}]  
2013-08-14 19:10:37,387 DEBUG [org.elasticsearch.discovery.zen.fd]  
(elasticsearch[local][clusterService#updateTask][T#1]) [local] [master]  
restarting fault detection against master  
[[local][VbxjXeqGRIyNFzvK-1JCIw][inet[/ **NODE24** :8800]]{local=false}],  
reason [new cluster stare received and we monitor the wrong master  
[[local][Y01TgbUzRg-JIIpQ7NqlZg][inet[/ **NODE47** :8800]]{local=false}]]  
2013-08-14 19:10:37,397 DEBUG [org.elasticsearch.transport.netty]  
(elasticsearch[local][clusterService#updateTask][T#1]) [local] connected to  
node [[local][VbxjXeqGRIyNFzvK-1JCIw][inet[/ **NODE24** :8800]]{local=false}]  
2013-08-14 19:10:37,405 DEBUG [org.elasticsearch.transport.netty]  
(elasticsearch[local][generic][T#10]) [local] disconnected from  
[[local][Y01TgbUzRg-JIIpQ7NqlZg][inet[/ **NODE47** :8800]]{local=false}]  
2013-08-14 19:10:37,410 DEBUG [org.elasticsearch.transport.netty]  
(elasticsearch[local][generic][T#10]) [local] disconnected from  
[[local][V7FXnZiLR-GVIyZ2DOwV2w][inet[/ **NODE26** :8800]]{local=false}]  
2013-08-14 19:10:37,424 DEBUG [org.elasticsearch.transport.netty]  
(elasticsearch[local][generic][T#10]) [local] disconnected from  
[[local][JrRrD5Y8R8WHn1ZAkjYNBw][inet[/ **NODE45** :8800]]{local=false}]

On Fri, Aug 16, 2013 at 11:13 AM, [joergprante@gmail.com](mailto:joergprante@gmail.com) \<  
[joergprante@gmail.com](mailto:joergprante@gmail.com)\> wrote:

> The "channel closed event" notice is a normal event that is happening  
> during connection pool activity and just an informational message on  
> "DEBUG" log level.
> 
> It seems unrelated to the "unable to rejoin cluster" situations you have  
> posted.
> 
> Do you get failure/error messages in the log?
> 
> Jörg
> 
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## -- mvh

Runar Myklebust

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### Author: ![jprante](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/jprante/32/44941_2.png) [@jprante](https://discuss.elastic.co/u/jprante)
#### Post date: [August 16, 2013, 11:12am UTC](https://discuss.elastic.co/t/frequent-disconnects-between-nodes/13205/10 "2013-08-16T11:12:04Z")

</div>

You have a split brain with another master, and you should repair your  
broken node real soon.

Elasticsearch does not accept the node connects because it tries to  
announce being a master.

Jörg

Am 16.08.2013 11:32, schrieb Runar Myklebust:

> 2013-08-14 19:10:37,387 DEBUG [org.elasticsearch.discovery.zen.fd]  
> (elasticsearch[local][clusterService#updateTask][T#1]) [local]  
> [master] restarting fault detection against master  
> [[local][VbxjXeqGRIyNFzvK-1JCIw][inet[/ **NODE24** :8800]]{local=false}], reason  
> [new cluster stare received and we monitor the wrong master  
> [[local][Y01TgbUzRg-JIIpQ7NqlZg][inet[/ **NODE47** :8800]]{local=false}]]

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### Author: ![Runar\_Myklebust](https://avatars.discourse-cdn.com/v4/letter/r/a6a055/32.png) [@Runar\_Myklebust](https://discuss.elastic.co/u/Runar_Myklebust)
#### Post date: [August 16, 2013, 11:24am UTC](https://discuss.elastic.co/t/frequent-disconnects-between-nodes/13205/11 "2013-08-16T11:24:17Z")

</div>

Hi again Jörg.  
The split-brain is "expected", but the reason for the disconnect is still  
unclear. The strange thing is, that I see no traces of zen discovery ping  
attempts. No indications that anything is wrong before the "master failure"  
message.  
And NODE47 is seemingly working normal both before and after the disconnect.

On Fri, Aug 16, 2013 at 1:12 PM, Jörg Prante [joergprante@gmail.com](mailto:joergprante@gmail.com) wrote:

> You have a split brain with another master, and you should repair your  
> broken node real soon.
> 
> Elasticsearch does not accept the node connects because it tries to  
> announce being a master.
> 
> Jörg
> 
> Am 16.08.2013 11:32, schrieb Runar Myklebust:
> 
> 2013-08-14 19:10:37,387 DEBUG [org.elasticsearch.discovery.\*\*zen.fd]
> 
> > (elasticsearch[local][\*\*clusterService#updateTask][T#\*\*1]) [local]  
> > [master] restarting fault detection against master  
> > [[local][VbxjXeqGRIyNFzvK-**1JCIw][inet[/NODE24:8800]]**{local=false}],  
> > reason [new cluster stare received and we monitor the wrong master  
> > [[local][Y01TgbUzRg-**JIIpQ7NqlZg][inet[/NODE47:**  
> > 8800]]{local=false}]]
> 
> --  
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> .

## -- mvh

Runar Myklebust

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### Author: ![jprante](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/jprante/32/44941_2.png) [@jprante](https://discuss.elastic.co/u/jprante)
#### Post date: [August 16, 2013, 1:29pm UTC](https://discuss.elastic.co/t/frequent-disconnects-between-nodes/13205/12 "2013-08-16T13:29:05Z")

</div>

Well that is the reason for the disconnect. Your second master node has  
a defect internal cluster state. This is detected by the other master  
when it tries to reconnect, and the node is disconnected so it can't  
join the cluster again.

Have you cleared the defect node from any data?

Jörg

Am 16.08.2013 13:24, schrieb Runar Myklebust:

> The split-brain is "expected", but the reason for the disconnect is  
> still unclear. The strange thing is, that I see no traces of zen  
> discovery ping attempts. No indications that anything is wrong before  
> the "master failure" message.

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### Author: ![Runar\_Myklebust](https://avatars.discourse-cdn.com/v4/letter/r/a6a055/32.png) [@Runar\_Myklebust](https://discuss.elastic.co/u/Runar_Myklebust)
#### Post date: [August 19, 2013, 7:14am UTC](https://discuss.elastic.co/t/frequent-disconnects-between-nodes/13205/13 "2013-08-19T07:14:25Z")

</div>

As far as I can read of the logs; this is whats happening:

at 19:09:49,243 - a channel closed event is received from NODE24 to NODE47  
(Master) and it is disconnected  
at 19:10:34,273 - a connection to NODE24 is done, then  
at 19:10:34,290 - we get a "disconnected" from NODE24

19:10:35,167 - NODE24 pings master (NODE47) but the master does not have  
NODE24 in its list of nodes, and threats this like a master failure.

This scenario always happens after a while, also when the nodes are  
initialized by deleting index-files etc. Also, this happens only on certain  
nodes, that is: between nodes in different networks.

For the other nodes, the NODE47 still works as a master, also a restart on  
NODE24 will fix the issue. I still dont understand why the disconnect of  
NODE24 from NODE47 happens in the first place. Everything happens within a  
second or two, so any timeout seems unlikely.

On Fri, Aug 16, 2013 at 3:29 PM, Jörg Prante [joergprante@gmail.com](mailto:joergprante@gmail.com) wrote:

> Well that is the reason for the disconnect. Your second master node has a  
> defect internal cluster state. This is detected by the other master when it  
> tries to reconnect, and the node is disconnected so it can't join the  
> cluster again.
> 
> Have you cleared the defect node from any data?
> 
> Jörg
> 
> Am 16.08.2013 13:24, schrieb Runar Myklebust:
> 
> The split-brain is "expected", but the reason for the disconnect is still
> 
> > unclear. The strange thing is, that I see no traces of zen discovery ping  
> > attempts. No indications that anything is wrong before the "master failure"  
> > message.
> 
> --  
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> .

## -- mvh

Runar Myklebust

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### Author: ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)
#### Post date: [July 6, 2017, 2:20am UTC](https://discuss.elastic.co/t/frequent-disconnects-between-nodes/13205/14 "2017-07-06T02:20:39Z")

</div>


