Elasticsearch Indices in Red

Hi

I had initially set up elasticsearch to run in background as service. But while restarting the superviosr, it stopped working. I still am not able to run it in background now. But while restarting it manually.

I noticed the following: when i ran this command: curl 'localhost:9200/_cat/indices?v'

health status index pri rep docs.count docs.deleted store.size pri.store.size
red open logstash-2015.06.14 5 1
red open logstash-2015.08.04 5 1
red open logstash-2015.07.31 5 1

On running the health command for cluster:

curl 'localhost:9200//_cluster/health?pretty'
{
"cluster_name" : "elasticsearch",
"status" : "yellow",
"timed_out" : false,
"number_of_nodes" : 2,
"number_of_data_nodes" : 1,
"active_primary_shards" : 456,
"active_shards" : 456,
"relocating_shards" : 0,
"initializing_shards" : 0,
"unassigned_shards" : 456
}

Please, can somebody explain to me "red" status of indices and also how to keep on running elasticsearch in the background.

Thanks alot
Aditya

Status is red because of

"unassigned_shards" : 456