ES Snapshots giving error

[Vivek_Samaga (VivSam)]

Am able to successfully register snapshot with the below request.

PUT /_snapshot/my_backup
{
    "type": "fs",
    "settings": {
        "location": "/elk_bak/esback",
        "compress": true
    }
}

But now am facing the issue Indices don't have primary shards error when i run

PUT /_snapshot/my_backup/snapshot_1?wait_for_completion=true

  {
    "index": "logstash-2017.07.02",
    "shard_id": 0,
    "reason": "primary shard is not allocated",
    "status": "INTERNAL_SERVER_ERROR"
  },
  {
    "index": "logstash-2017.07.02",
    "shard_id": 1,
    "reason": "primary shard is not allocated",
    "status": "INTERNAL_SERVER_ERROR"
  },

[thiago (Thiago Souza)]

Your cluster health is probably in a red state because a couple of primary shards of index logstash-2017.07.02 are not available (depending on the problem, part of that index might be gone for good).

You can check what's going on with the Cluster Allocation Explain API