Error during SonarQube Scanner execution from Jenkins plugin - jenkins

Question

I get the following error when I try to execute SonarQube Scanner as a part of Jenkins build:
ERROR: SonarQube server [http://<hostname>:9000] can not be reached
INFO: ------------------------------------------------------------------------
INFO: EXECUTION FAILURE
INFO: ------------------------------------------------------------------------
INFO: Total time: 0.242s
INFO: Final Memory: 5M/483M
INFO: ------------------------------------------------------------------------
ERROR: Error during SonarQube Scanner execution
org.sonarsource.scanner.api.internal.ScannerException: Unable to execute SonarQube
at org.sonarsource.scanner.api.internal.IsolatedLauncherFactory$1.run(IsolatedLauncherFactory.java:84)
at
... 8 more
Caused by: java.lang.IllegalStateException: Status returned by
url [http://<hostname>:9000/batch/index] is not valid: [404]
at org.sonarsource.scanner.api.internal.ServerConnection.callUrl(ServerConnection.java:115)
at org.sonarsource.scanner.api.internal.Jars.getBootstrapIndex(Jars.java:96)
... 12 more
ERROR:
I can access the following URL from my Jenkins host: http://:9000/sonar/ . When I try to execute this:
wget http://<hostname>:9000/batch/index
I get the same 404 http error in response. I have no idea from where this URL postfix /batch/index comes from. Web search did not give any clues for this.
My Sonar version is 6.0. My Jenkins Sonar Scanner plugin version is 2.6.1.
Used JVM:
java version "1.8.0_121"
Java(TM) SE Runtime Environment (build 1.8.0_121-b13)
Java HotSpot(TM) 64-Bit Server VM (build 25.121-b13, mixed mode)

Answer 1

What is your the setting for sonar's web context (sonar.web.context) on your sonar server? It would be inside of sonar.properties. By default both the Jenkins plugin and the sonar server configuration set it to root:
'http://<hostname>:9000/'
The first thing I would do is to make sure those are matching in the sonar configuration and the jenkins plugin configuration.
I've seen tutorials that tell you to use /sonar or something similar. In that case, the jenkins plugin would need to be set to /sonar as well, like:
'http://<hostname>:9000/sonar'