Uninstall X-Pack

Hi,

I have installed X-Pack on a 5.1.2 cluster with a basic license, and then decided I want to remove it again. Following the instructions at https://www.elastic.co/guide/en/x-pack/current/installing-xpack.html#xpack-uninstalling, nodes are unable to join the cluster after restart due to https://github.com/elastic/elasticsearch/pull/15401, ie.

IllegalArgumentException[No custom metadata prototype registered for type [licenses], node likely missing plugins]

How do I properly and cleanly uninstall X-Pack?

Thanks in advance,
-K

How many nodes does this cluster consist of? Please note that x-pack needs to be installed on all nodes, and the same goes for removal of the same.

Thanks. Going through a full cluster restart (disable allocation, shutdown nodes, offline remove plugin, startup nodes, enable allocation) did it.

This warning is due to x-pack being installed in some nodes in the cluster. Uninstalling x-pack in every node of the cluster should allow nodes to join and get rid of this exception.