Simple script to force reallocation of unassigned primary shard

reroute_primary.sh

HOST={{ some_master_hostname/ip address }}
PORT=9200
TO_NODE="{{ destination_node }}"

curl "http://$HOST:$PORT/_cat/shards" | grep UNAS | awk '{print $1" "$2}' | while read var_index var_shard; do 
  curl -XPOST "http://$HOST:$PORT/_cluster/reroute?pretty" -H 'Content-Type: application/json' -d "
    {
      \"commands\" : [
        {
          \"allocate_stale_primary\":
            { 
              \"index\" : \"$var_index\",
              \"shard\" : \"$var_shard\", 
              \"node\" : \"$TO_NODE\",
              \"accept_data_loss\": true
            }
        }
      ]
    }";
    sleep 5; 
done