Thanks in a large part to this lovely post, we now cover these and other top ILM configuration errors on our Troubleshooting ILM blog.
Direct summarized resolutions:
index.lifecycle.rollover_alias [x] does not point to index [y]You’ll need to check your index settings
index.lifecycle.rollover_alias. Either the index is pointing to the wrong alias or the alias does not exist. You can check the latter by running Get Aliases. Here’s an example Elastic Discuss issue. You may consider Data Streams which handle this for you.
alias [x] has more than one write index [y,z]When you run Get Aliases, you’ll notice that two indices are marked as
is_write_index:truewhen only one should be per alias. You’ll want to toggleis_write_index:falseon one of the indices via the Aliases API.