# Find difference between two clusters **URL:** \ **Category:** Elasticsearch\ **Created:** [January 31, 2020, 3:58pm UTC](https://discuss.elastic.co/t/find-difference-between-two-clusters/217417 "2020-01-31T15:58:04Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![brhardwick](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/brhardwick/32/47000_2.png) [@brhardwick](https://discuss.elastic.co/u/brhardwick)\ **Post date:** [January 31, 2020, 3:58pm UTC](https://discuss.elastic.co/t/find-difference-between-two-clusters/217417/1 "2020-01-31T15:58:05Z")
We have a use case that requires us to replace clusters regularly. My current approach is a Blue/Green-type deployment like the following: Cluster A is running, bring up Cluster B and wait for it to be live. Cluster A and B both have the same repository in S3, so snapshot Cluster A, then restore that snapshot in Cluster B. Update the DNS to point from Cluster A to Cluster B Delete Cluster A. This works, but the problem is that data can be populating Cluster A while Cluster B's snapshot is being restored, so that when the DNS is updated, we lose that data. My question is, is there a query that i can run on each index that will find all the missing documents in Cluster B? Is there another way to make sure the clusters are identical? P.S. I know that we can update the cluster by updating each node and migrating the shards away, but lets assume that this approach is off the table for now. ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [February 28, 2020, 3:58pm UTC](https://discuss.elastic.co/t/find-difference-between-two-clusters/217417/2 "2020-02-28T15:58:09Z")
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