Downgrade from 7.14 to 7.13.4

[JSieminski (John)]

I see a lot of people asking about downgrades and it seems to be not supported. I was in the process of updating my nodes from 7.7 to 7.13.4 and I wasn't putting the actual version of elastic when doing my update. As a result I now have one node running with 7.14. I now also have shards on the 7.14 node.

Is it possible to move off those shards (everything I have read says you can't move shard from a high version of elastic to lower version of elastic) and then perform some type of downgrade/install of 7.13.4?

Any help would be great. Thanks.

elk002-a 7.13.4 dfilrt -
elk007 7.7.0 m -
elk003 7.13.4 m -
elk004-b 7.13.4 dfilrt -
elk002 7.13.4 m -
elk005 7.13.4 m -
elk006 7.14.0 m -
elk007-b 7.7.0 dilrt -
elk008 7.7.0 m *
elk004-a 7.13.4 dfilrt -
elk006-b 7.14.0 dfilrt -
elk001-c 7.13.4 dfilrt -
elk002-b 7.13.4 dfilrt -
elk001 7.13.4 m -
elk005-b 7.13.4 dfilrt -
elk006-a 7.14.0 dfilrt -
elk001-b 7.13.4 dfilrt -
elk008-c 7.7.0 dilrt -
elk004-c 7.13.4 dfilrt -
elk002-c 7.13.4 dfilrt -
elk005-a 7.13.4 dfilrt -
elk008-b 7.7.0 dilrt -
elk007-a 7.7.0 dilrt -
elk003-b 7.13.4 dfilrt -
elk003-a 7.13.4 dfilrt -
elk004 7.13.4 m -
elk008-a 7.7.0 dilrt -
elk006-c 7.14.0 dfilrt -
elk003-c 7.13.4 dfilrt -
elk001-a 7.13.4 dfilrt -
elk005-c 7.13.4 dfilrt -
elk007-c 7.7.0 dilrt -

[BenB196]

From my understanding there is no easy way to downgrade.

It can in theory be done, if you have a snapshots of the indices from 7.7 or 7.13.4 that you restore, after removing the 7.14 node (but I've never done this and am not 100% sure this will work).

Also, looking at one of the changes in 7.14 Extend version barrier to all upgrades I think you'll need to upgrade all nodes to 7.14, if you do proceed with the upgrade.

Someone more familiar with the workings of Elasticsearch may be able to offer more help here, but I think I covered the basics of possible solutions.

[warkolm (Mark Walkom)]

You need to have snapshots from the lower version to downgrade, you cannot just downgrade the Elasticsearch package due to the way Lucene interacts with the underlying data.