CA Single Sign-On Tech Tip by Albert F, Support Engineer for July 13th, 2015
Starting SPS on Linux with the sps-ctl script, the following output is returned with an empty pid, and there is no SPS Tomcat process running:
# ./sps-ctl start
Successfully Started Apache..
Proxy Engine (pid ) already running. Cannot be started.
There is a "sps.pid" file which location you can verify in your starting script, set by the SPS_PID_FILE variable value.
This is caused when the sps-ctl script is not used to properly stop the SPS, like server reboots or crashes, and this file remains created but the process is not running so this is why we get the message with an empty pid.
Deleting this file "sps.pid" will solve the issue.