Hi, there,
We have a ES cluster with version 6.3.2. We have three separate Master nodes and two hot data nodes. We want to roll upgrade to latest version 6.5.1. We followed below instruction:
https://www.elastic.co/guide/en/elasticsearch/reference/current/rolling-upgrades.html
The purpose of rolling upgrade is to keep the ES up and running during the upgrade time. Here is what I did and the problem I got:
First, I brought down master node one by one. Whenever I brought down one master node, I will check the kibana and the data ingestion work, both are fine when I did the rolling upgrade master nodes.
Second, when I brought down the first hot data node, I can't access Kibana, it complains internal errors. Four minutes later, after I finished hot data node upgrades, immediately I can access Kibana.
Third, I brought down second hot data node, and this time both the kibana and data ingestion work fine.
However, after I finished the rolling upgrade, I checked the index that keeps running for the whole time of the upgrade, I found there is a gap on all the charts. the time matches with the first hot data node down time. So now I am not sure if the rolling upgrade can keep the index ingestion.
Please advise.
Thanks!