After Upgrade to 4.3.7: No leader Graylog server node

[gsmith]

Hello,

It could be a couple different issues, hard to tell from just the information you gave.
BUT the Erro you See NO MASTER , you can check here.

Notification condition [NO_MASTER] has been fixed

@RCR I’m new to Graylog but hopefully I can be of some help. Based on looking at the EventProcessorEventFactory.java code the node ID is being retrieved by first retrieving the hostname of the node from the Graylog configuration. Unfortunately, there isn’t sufficient granularity in the code to determine if the hostname retrieval is the part that is failing or if it’s still something related to the node ID lookup using the hostname. So we have to tackle one at a time to see what we find. I don’t …

or here

How to fix disconnecting Graylog node after upgrading from version 3.0 to 3.1