# The logstash keep getting 'UNEXPECTED POOL ERROR', even the Elastic Search is in GREEN mode

**URL:** <https://discuss.elastic.co/t/the-logstash-keep-getting-unexpected-pool-error-even-the-elastic-search-is-in-green-mode/130132>\
**Category:** Logstash\
**Created:** [May 1, 2018, 3:36pm UTC](https://discuss.elastic.co/t/the-logstash-keep-getting-unexpected-pool-error-even-the-elastic-search-is-in-green-mode/130132 "2018-05-01T15:36:51Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![michael1412](https://avatars.discourse-cdn.com/v4/letter/m/ecd19e/32.png) [@michael1412](https://discuss.elastic.co/u/michael1412)\
**Post date:** [May 1, 2018, 3:36pm UTC](https://discuss.elastic.co/t/the-logstash-keep-getting-unexpected-pool-error-even-the-elastic-search-is-in-green-mode/130132/1 "2018-05-01T15:36:51Z")

</div>

- Version: Logstash 5.5, AWS Elasticsearch 5.5
- Operating System: Linux CentOS 7(Logstash)
- Sample Error:

**[2018-05-01T12:05:52,235]**[WARN][logstash.outputs.elasticsearch] Marking url as dead. Last error: [LogStash::Outputs::ElasticSearch::HttpClient::Pool::HostUnreachableError] Elasticsearch Unreachable: [[https://XXX.amazonaws.com:443/](https://XXX.amazonaws.com:443/)][Manticore::ClientProtocolException] [XXX.amazonaws.com:443](http://XXX.amazonaws.com:443) failed to respond {:url=\>[https://XXX.amazonaws.com:443/](https://XXX.amazonaws.com:443/), :error\_message=\>"Elasticsearch Unreachable: [[https://XXX.amazonaws.com:443/](https://XXX.amazonaws.com:443/)][Manticore::ClientProtocolException] [XXX.amazonaws.com:443](http://XXX.amazonaws.com:443) failed to respond", :error\_class=\>"LogStash::Outputs::ElasticSearch::HttpClient::Pool::HostUnreachableError"}

**[2018-05-01T12:05:52,235]**[ERROR][logstash.outputs.elasticsearch] Attempted to send a bulk request to elasticsearch' but Elasticsearch appears to be unreachable or down! {:error\_message=\>"Elasticsearch Unreachable: [[https://XXX.amazonaws.com:443/](https://XXX.amazonaws.com:443/)][Manticore::ClientProtocolException] [XXX.amazonaws.com:443](http://XXX.amazonaws.com:443) failed to respond", :class=\>"LogStash::Outputs::ElasticSearch::HttpClient::Pool::HostUnreachableError", :will\_retry\_in\_seconds=\>2}

**[2018-05-01T12:05:54,088]**[WARN][logstash.outputs.elasticsearch] UNEXPECTED POOL ERROR {:e=\>#\<LogStash::Outputs::ElasticSearch::HttpClient::Pool::NoConnectionAvailableError: No Available connections\>}

**[2018-05-01T12:05:55,920]**[INFO][logstash.outputs.elasticsearch] Running health check to see if an Elasticsearch connection is working {:healthcheck\_url=\>[https://XXXX.amazonaws.com:443/](https://XXXX.amazonaws.com:443/), :path=\>"/"}

**[2018-05-01T12:05:55,936]**[WARN][logstash.outputs.elasticsearch] Restored connection to ES instance {:url=\>"[https://XXX.amazonaws.com:443/](https://XXX.amazonaws.com:443/)"}

- Thread\_Pool Settings:  
bulk:"max" : 4, "min":4, "queue\_size": 200

---

<div class="post-metadata">

**Author:** ![yaauie](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/yaauie/32/23363_2.png) [@yaauie](https://discuss.elastic.co/u/yaauie)\
**Post date:** [May 1, 2018, 9:54pm UTC](https://discuss.elastic.co/t/the-logstash-keep-getting-unexpected-pool-error-even-the-elastic-search-is-in-green-mode/130132/2 "2018-05-01T21:54:14Z")

</div>

It looks like the machine on which your Logstash is running is losing its route to your Elasticsearch host(s).

---

<div class="post-metadata">

**Author:** ![michael1412](https://avatars.discourse-cdn.com/v4/letter/m/ecd19e/32.png) [@michael1412](https://discuss.elastic.co/u/michael1412)\
**Post date:** [May 1, 2018, 10:06pm UTC](https://discuss.elastic.co/t/the-logstash-keep-getting-unexpected-pool-error-even-the-elastic-search-is-in-green-mode/130132/3 "2018-05-01T22:06:11Z")

</div>

> [@yaauie](#):
>
> ks like the machine on which your Logstash is running is losing its route to your Elasticsearch host(s).

Thanks for your reply. So you think that may be caused by network glitch?

---

<div class="post-metadata">

**Author:** ![yaauie](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/yaauie/32/23363_2.png) [@yaauie](https://discuss.elastic.co/u/yaauie)\
**Post date:** [May 2, 2018, 6:23am UTC](https://discuss.elastic.co/t/the-logstash-keep-getting-unexpected-pool-error-even-the-elastic-search-is-in-green-mode/130132/4 "2018-05-02T06:23:43Z")

</div>

Whether it is a network glitch, a change in your virtual network configuration, or the hosts you are pointing at being replaced by new nodes with new IPs, there are many possibilities.

---

<div class="post-metadata">

**Author:** ![michael1412](https://avatars.discourse-cdn.com/v4/letter/m/ecd19e/32.png) [@michael1412](https://discuss.elastic.co/u/michael1412)\
**Post date:** [May 2, 2018, 1:59pm UTC](https://discuss.elastic.co/t/the-logstash-keep-getting-unexpected-pool-error-even-the-elastic-search-is-in-green-mode/130132/5 "2018-05-02T13:59:29Z")

</div>

Is there a way that I can narrow down the reasons? What could be best solution to this kind of issue.

---

<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:** [May 30, 2018, 1:59pm UTC](https://discuss.elastic.co/t/the-logstash-keep-getting-unexpected-pool-error-even-the-elastic-search-is-in-green-mode/130132/6 "2018-05-30T13:59:31Z")

</div>

This topic was automatically closed 28 days after the last reply. New replies are no longer allowed.