I have CI system. It consists of
- Jenkins Master server (version 2.60.2) running on Ubuntu 16.04
- Jenkins slaves Swarm Slave (version 3.4.1) running on Ubuntu 16.04
- Selenium hub (version 3.4.0) running on Ubuntu 16.04
- 4 Selenium nodes for Safari Browser (version 3.4.0) Running on Mac OS Siera 10.12.5 . With Safari 10.
Im testing Java Script project that uses Mocha+Karma to run tests.
Most of the time everything is working as it should. But sometimes i have error like this one.
{"message":"[get(\"http://my-jenkins-slave-hostname:9876/?id=39481\")] Error response status: 13, UnknownError - An unknown server-side error occurred while processing the command. Selenium error: com.google.gson.stream.MalformedJsonException: Use JsonReader.setLenient(true) to accept malformed JSON at line 1 column 8 path $","status":13,"cause":{"value":{"stacktrace":"com.google.gson.JsonSyntaxException: com.google.gson.stream.MalformedJsonException: Use JsonReader.setLenient...It looks like some nodes of selenium sometimes fail randomly. All nodes are exact replicas of same image (Im using Mac Stadium to manage Mac OS nodes)
Ive tried to configure Karma to give more details in logs, ive tried to increase timeouts, but no luck. Error message stays the same. How can i troubleshoot such problem? Any ideas?