title: Why Druid segments become unavailable after data ingestion
body: <p>Druid cluster shows unavailable for certain segments of data of data source after data ingestion.
  Ex: <strong>72.4% available (2352 segments, 647 segments unavailable)</strong>
  We have a clustered deployment 3 nodes :
  master node (coordinator amd overlord)
  Data node (historical and middlemanager)
  Query node (broker and router)
  Any specific reason why it is happening so.</p>