# Checking cluster node availability **URL:** \ **Category:** Elasticsearch\ **Created:** [June 25, 2015, 2:24pm UTC](https://discuss.elastic.co/t/checking-cluster-node-availability/24342 "2015-06-25T14:24:51Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Arcimboldo](https://avatars.discourse-cdn.com/v4/letter/a/c77e96/32.png) [@Arcimboldo](https://discuss.elastic.co/u/Arcimboldo)\ **Post date:** [June 25, 2015, 2:24pm UTC](https://discuss.elastic.co/t/checking-cluster-node-availability/24342/1 "2015-06-25T14:24:51Z")
Hi, we cannot use one of the proper Java clients because we're currently stuck with Java 6. For our circuit-breaking node selector, we want to find out if a crashed or otherwise unavailable node has become available again in as inexpensive a fashion as possible. Do other nodes in an Elasticsearch cluster have an idea of a node's current availability? I haven't found that kind of information where I expected it most - in cluster health or node stats/state... Thanks and best regards Heiko ---
**Author:** ![magnusbaeck](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/magnusbaeck/32/44943_2.png) [@magnusbaeck](https://discuss.elastic.co/u/magnusbaeck)\ **Post date:** [June 25, 2015, 5:26pm UTC](https://discuss.elastic.co/t/checking-cluster-node-availability/24342/2 "2015-06-25T17:26:19Z")
If the node is listed in e.g. the result of e.g. a `/_nodes` or `/_cluster/state` request it's part of the cluster and is healthy as far as the cluster knows. Or am I misunderstanding your question? ---
**Author:** ![Arcimboldo](https://avatars.discourse-cdn.com/v4/letter/a/c77e96/32.png) [@Arcimboldo](https://discuss.elastic.co/u/Arcimboldo)\ **Post date:** [June 26, 2015, 8:59am UTC](https://discuss.elastic.co/t/checking-cluster-node-availability/24342/3 "2015-06-26T08:59:15Z")
I think we're talking of the same thing. Do you know how up-to-date cluster knowledge is? In other words, if another cluster node lists the node to be checked in, for example, the "\_nodes" result how long ago did it usually try to communicate with that node? Right now, I've implemented a kind of "ping" where I issue a "\_nodes//network" request and am happy if it answers at all, not caring for the exact result - the point was to use a request that is inexpensive and does not need any preparation on our side but generates the usual [java.net](http://java.net) exceptions like SocketTimeoutException if the problem remains. What we're interested in is just whether the node is reachable again, so to really check cluster health could be too strict a condition. However, of course what we don't take into account with this approach, I could imagine, is network partitioning, or split-brain - the node could be reachable but still not be part of the cluster. Our check should just be a necessary condition to decide whether to give the node another try with a "real" request - it need not be sufficient in the mathematical sense of the word. Still, would you rather recommend your approach to us, it being "more sufficient" than ours? ThanksHeiko ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [July 6, 2017, 12:05am UTC](https://discuss.elastic.co/t/checking-cluster-node-availability/24342/4 "2017-07-06T00:05:15Z")