Example how you can recovery your elastic from red status to green but lose your data

gistfile1.txt

POST _cluster/reroute?retry_failed
{
  "commands" : [
    {
      "allocate_empty_primary": {
        "index" : "Index-YYYY-MM-DD-HH",
        "shard" : 66,
        "node": "some-node",
        "accept_data_loss": true
      }
    }
  ]
}