Your elasticsearch don’t want to accept connexions or queries anymore after a restart or a “Java heap” memory problem ?

# curl -XGET 'http://localhost:9200/_cluster/health?pretty=true'
{
"cluster_name" : "elasticsearch",
"status" : "red",
[...]
}

You will need to check if one the of indexes is “red” status by requesting the indices list. The command is:

# curl 'localhost:9200/_cat/indices?v'
health status index                pri rep docs.count docs.deleted store.size pri.store.size
red    open   my_index-2014.07.21   3   1   10107061            0      1.7gb          1.7gb
yellow open   my_index-2014.07.22   3   1    6728769            0      1.1gb          1.1gb

What is not said in Elasticsearch documentation is that you will need to delete the datas of the index that is in “red” status to be able to restart elasticsearch. I didn’t find any tool to repair indexes… So datas are losts. You was putting them in the cloud, they gone to space…
That experience made me want to move to another noSQL database… To Be Continued 🙂