title: What causes an Elasticsearch index to drop its linked indices?
body: <p>What can cause an index to drop its linked indices? We have several Index Lifecycle Policies in place for our cluster, but one of them (filebeat ILM policy) descended to 0 (from more then 10) linked indices, thus causing data loss, logs are no longer visible in Kibana.</p>
  <p><a href="https://i.stack.imgur.com/SXBXX.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/SXBXX.png" alt="enter image description here" /></a></p>
  <p>Re-indexing does not help, since the indices in question are not present when running a listing operation:</p>
  <p><code>GET /_cat/indices/%2A?v=&amp;s=index:desc</code></p>
  <p>Is there a way to retrieve the indices? How can this be prevented in the future? What is the root cause for this situation? We are running Elasticsearch on k8s cluster.</p>
  <p>This is the policy in question:</p>
  <pre><code>{
    &quot;filebeat&quot; : {
      &quot;version&quot; : 2787,
      &quot;modified_date&quot; : &quot;2021-06-30T13:19:52.560Z&quot;,
      &quot;policy&quot; : {
        &quot;phases&quot; : {
          &quot;hot&quot; : {
            &quot;min_age&quot; : &quot;0ms&quot;,
            &quot;actions&quot; : {
              &quot;rollover&quot; : {
                &quot;max_size&quot; : &quot;50gb&quot;,
                &quot;max_age&quot; : &quot;1d&quot;
              }
            }
          },
          &quot;delete&quot; : {
            &quot;min_age&quot; : &quot;30d&quot;,
            &quot;actions&quot; : {
              &quot;delete&quot; : { }
            }
          }
        }
      }
    }
  }
  </code></pre>