# Elasticsearch Java Transport Client - Max Connections

**URL:** <https://discuss.elastic.co/t/elasticsearch-java-transport-client-max-connections/26889>\
**Category:** Elasticsearch\
**Created:** [August 5, 2015, 12:49pm UTC](https://discuss.elastic.co/t/elasticsearch-java-transport-client-max-connections/26889 "2015-08-05T12:49:06Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![Kiran\_Sriharsha](https://avatars.discourse-cdn.com/v4/letter/k/e36b37/32.png) [@Kiran\_Sriharsha](https://discuss.elastic.co/u/Kiran_Sriharsha)\
**Post date:** [August 5, 2015, 12:49pm UTC](https://discuss.elastic.co/t/elasticsearch-java-transport-client-max-connections/26889/1 "2015-08-05T12:49:06Z")

</div>

Hi

I am using a 3 amazon machines for elasticsearch indexing. I have a multiple tomcat instances in different machines that would connect to this elasticsearch cluster. After 3 or 4 tomcat instances are up, weirdly few of the previously working java api calls are getting NoNodeAvailable exception.

Is there any limit on number of clients an ES can accept?  
I am running all services in default configuration.

Thanks in advance  
Sri Harsha

---

<div class="post-metadata">

**Author:** ![warkolm](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/warkolm/32/39224_2.png) [@warkolm](https://discuss.elastic.co/u/warkolm)\
**Post date:** [August 7, 2015, 2:07am UTC](https://discuss.elastic.co/t/elasticsearch-java-transport-client-max-connections/26889/2 "2015-08-07T02:07:57Z")

</div>

Are you running ES in Tomcat?

---

<div class="post-metadata">

**Author:** ![Kiran\_Sriharsha](https://avatars.discourse-cdn.com/v4/letter/k/e36b37/32.png) [@Kiran\_Sriharsha](https://discuss.elastic.co/u/Kiran_Sriharsha)\
**Post date:** [August 9, 2015, 10:34am UTC](https://discuss.elastic.co/t/elasticsearch-java-transport-client-max-connections/26889/3 "2015-08-09T10:34:52Z")

</div>

ES in Tomcat?

ES There are 3 machines allocated for Elasticsearch.  
To connect to that ES cluster, we have war files in tomcat using ES Java API.

Thanks  
Sri Harsha

---

<div class="post-metadata">

**Author:** ![warkolm](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/warkolm/32/39224_2.png) [@warkolm](https://discuss.elastic.co/u/warkolm)\
**Post date:** [August 9, 2015, 10:21pm UTC](https://discuss.elastic.co/t/elasticsearch-java-transport-client-max-connections/26889/4 "2015-08-09T22:21:18Z")

</div>

Right.

What do your ES logs look like? Are you monitoring ES and the threadpools?

---

<div class="post-metadata">

**Author:** ![Kiran\_Sriharsha](https://avatars.discourse-cdn.com/v4/letter/k/e36b37/32.png) [@Kiran\_Sriharsha](https://discuss.elastic.co/u/Kiran_Sriharsha)\
**Post date:** [August 10, 2015, 3:31am UTC](https://discuss.elastic.co/t/elasticsearch-java-transport-client-max-connections/26889/5 "2015-08-10T03:31:58Z")

</div>

I see only NoNodeAvailableException only in both ES and ES-Client logs.

We have made few experiments and identified that AWS LB was creating few issues that was closing connections. A question related to which is posted in [ES in AWS](https://discuss.elastic.co/t/es-in-aws/27086)

Thanks  
Sri Harsha

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [July 5, 2017, 11:56pm UTC](https://discuss.elastic.co/t/elasticsearch-java-transport-client-max-connections/26889/6 "2017-07-05T23:56:40Z")

</div>