# Logstash crashing unexpectedly
**URL:** https://discuss.elastic.co/t/logstash-crashing-unexpectedly/53188
**Category:** Logstash
**Created:** [June 17, 2016, 8:26pm UTC](https://discuss.elastic.co/t/logstash-crashing-unexpectedly/53188 "2016-06-17T20:26:18Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@tcouto](https://discuss.elastic.co/u/tcouto)
#### Post date: [June 17, 2016, 8:26pm UTC](https://discuss.elastic.co/t/logstash-crashing-unexpectedly/53188/1 "2016-06-17T20:26:18Z")
Hello, logstash keeps failing and spitting out this error:
```
NoMethodError: undefined method `join' for "_grokparsefailure":String
receive at /opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-output-gelf-1.0.0/lib/logstash/outputs/gelf.rb:178
handle at /opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-1.5.4-java/lib/logstash/outputs/base.rb:88
output_func at (eval):47
outputworker at /opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-1.5.4-java/lib/logstash/pipeline.rb:244
start_outputs at /opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-1.5.4-java/lib/logstash/pipeline.rb:166
```
Here's a gist of my logstash configs: [https://gist.github.com/anonymous/0f05229b611b0a9d68592602d78ea32b](https://gist.github.com/anonymous/0f05229b611b0a9d68592602d78ea32b)
We're sending logs from our production app servers to a central VM in our production environment, and from there we forward them to a graylog server in our local environment.
We have logstash 1.4.2\_modified on the app servers and logstash 1.5.4 on the central 'logshipper' VM.
Logstash on the central 'logshipper' VM crashes when I add a new input file to the app servers' logstash config and do some grokking and mutating. If I leave this out, logstash doesn't crash.
---
### Author:  [@magnusbaeck](https://discuss.elastic.co/u/magnusbaeck)
#### Post date: [June 20, 2016, 5:43am UTC](https://discuss.elastic.co/t/logstash-crashing-unexpectedly/53188/2 "2016-06-20T05:43:06Z")
That's odd. The `tags` field should never be a string. That this is allowed might be a bug that's been fixed in more recent versions of Logstash. I'd try upgrading the LS 1.5.4 instance.
---
### Author:  [@tcouto](https://discuss.elastic.co/u/tcouto)
#### Post date: [June 22, 2016, 5:25pm UTC](https://discuss.elastic.co/t/logstash-crashing-unexpectedly/53188/3 "2016-06-22T17:25:38Z")
Thanks Magnus. I've upgraded the 4 servers on 1.4.2\_modified to 1.5.4, and I'm getting the same error. It usually happens within a few minutes.
Maybe I should also mention that the 'logshipper' is running on centos 5.7 and the 4 app servers are running on centos 5.10.
---
### Author:  [@magnusbaeck](https://discuss.elastic.co/u/magnusbaeck)
#### Post date: [June 22, 2016, 6:11pm UTC](https://discuss.elastic.co/t/logstash-crashing-unexpectedly/53188/4 "2016-06-22T18:11:55Z")
While it's great that you've upgraded the ancient 1.4.2 instances, the problem is most likely introduced on the 1.5.4 which is why I suggested that you upgrade that one.
---
### Author:  [@tcouto](https://discuss.elastic.co/u/tcouto)
#### Post date: [June 22, 2016, 6:24pm UTC](https://discuss.elastic.co/t/logstash-crashing-unexpectedly/53188/5 "2016-06-22T18:24:32Z")
Oh, whoops. I thought you suggested upgrading to 1.5.4
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [July 6, 2017, 4:51am UTC](https://discuss.elastic.co/t/logstash-crashing-unexpectedly/53188/6 "2017-07-06T04:51:06Z")