I have no idea why after Jenkins is updated to version 1.591 (Ubuntu Server 12.04), the originally correctly set up reverse proxy now becomes broken. My current setting is exactly the same as said in Jenkins wiki:
ProxyPass /jenkins http://localhost:8081/jenkins nocanon
ProxyPassReverse /jenkins http://localhost:8081/jenkins
ProxyPreserveHost On
ProxyRequests Off
AllowEncodedSlashes NoDecode
<Proxy http://localhost:8081/jenkins*>
Order deny,allow
Allow from all
</Proxy>
also --prefix=/jenkins
has been added into /etc/default/jenkins
file
Is that a bug in Jenkins?
It turns out everything works fine even though the annoying message persistently appears. I think it is a minor bug of the version.