Added -level option to HA Monitor. Can also pass -Dcom.cloudbees.jenkins.ha.level=… to a Jenkins process with embedded HA.
The HA Monitor did not work in 4.0; due a failure in the code which detects that a cluster participant is on the same host, it would only ever run the demotion script, never the promotion script. (The fix is actually in the embedded HA, or HA proxy WAR, not in the HA Monitor itself.)
If it is the health check URL we should return ASAP rather than letting the default processing of the standby application handle the request, as this gives the load balancer information as quickly as possible.
The -daemon flag to the HA Monitor did not work on some platforms.