# Cannot connect to the Elasticsearch cluster currently configured for Kibana after the upgrade to 6.4

**URL:** <https://discuss.elastic.co/t/cannot-connect-to-the-elasticsearch-cluster-currently-configured-for-kibana-after-the-upgrade-to-6-4/148459>\
**Category:** Kibana\
**Created:** [September 13, 2018, 1:25pm UTC](https://discuss.elastic.co/t/cannot-connect-to-the-elasticsearch-cluster-currently-configured-for-kibana-after-the-upgrade-to-6-4/148459 "2018-09-13T13:25:33Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![RFeidi](https://avatars.discourse-cdn.com/v4/letter/r/51bf81/32.png) [@RFeidi](https://discuss.elastic.co/u/RFeidi)\
**Post date:** [September 13, 2018, 1:25pm UTC](https://discuss.elastic.co/t/cannot-connect-to-the-elasticsearch-cluster-currently-configured-for-kibana-after-the-upgrade-to-6-4/148459/1 "2018-09-13T13:25:33Z")

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Hi Elastic Team,  
I did an upgrade of the Elastic cluster from the 6.3.2 to the 6.4, and then I cannot connect to the Elasticsearch cluster currently configured for Kibana.  
When I check the kibana logs , message error is below " Port 5601 is already in use. Another instance of kibana may be running"  
lsod -i :5601  
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME  
node 1223 kibana 11u IPv4 27239 0t0 TCP hostname.domain

and Elasticsearch service failed, error is the Elastic logs "ElasticsearchUncaughtExceptionHandler] [SIEM] fatal error in thread [Thread-6], exiting  
java.lang.OutOfMemoryError: Java heap space"

OS: CentOS7  
Elasticsearch version : 6.4  
Kibana version : 6.4  
java -version  
openjdk version "1.8.0\_171"  
OpenJDK Runtime Environment (build 1.8.0\_171-b10)  
OpenJDK 64-Bit Server VM (build 25.171-b10, mixed mode)

Thanks

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**Author:** ![jbudz](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/jbudz/32/45922_2.png) [@jbudz](https://discuss.elastic.co/u/jbudz)\
**Post date:** [September 13, 2018, 2:45pm UTC](https://discuss.elastic.co/t/cannot-connect-to-the-elasticsearch-cluster-currently-configured-for-kibana-after-the-upgrade-to-6-4/148459/2 "2018-09-13T14:45:44Z")

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For kibana, can you share a little about your upgrade process? If the server's already running it may be as simple as restarting it so it can reload the new files.

For es, I'm guessing when the elasticsearch cluster is coming back online, shards are being moved causing a spike in memory usage. Does the server have available memory and are java.options configured to use less memory (should be ~half) of the available memory?

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**Author:** ![RFeidi](https://avatars.discourse-cdn.com/v4/letter/r/51bf81/32.png) [@RFeidi](https://discuss.elastic.co/u/RFeidi)\
**Post date:** [September 13, 2018, 4:15pm UTC](https://discuss.elastic.co/t/cannot-connect-to-the-elasticsearch-cluster-currently-configured-for-kibana-after-the-upgrade-to-6-4/148459/3 "2018-09-13T16:15:50Z")

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For Kibana, it was an sample install of rpm package with rpm -e of the 6.3.2 version. Restart is done , kibana go online for few minutes and then stop.  
At that moment , Elasticsearch service fails .  
For ES: cluster go back and down , it is not stable.  
java -XshowSettings:all  
VM settings:  
Max. Heap Size (Estimated): 13.92G  
Ergonomics Machine Class: server  
Using VM: OpenJDK 64-Bit Server VM  
please advice.  
Thanks

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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:** [October 11, 2018, 4:15pm UTC](https://discuss.elastic.co/t/cannot-connect-to-the-elasticsearch-cluster-currently-configured-for-kibana-after-the-upgrade-to-6-4/148459/4 "2018-10-11T16:15:57Z")

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