After starting the WA Agent on Linux, it never completes the startup process and becomes available for connections from a manager. The defaultlog_agent.log only contains a single line...
07/10/2018 12:55:20.350-0400 2 main.MainThread.CybAgentDriver.runApplication[:243] - CA Workload Automation Agent 11.4, Build 1609, Service Pack 00, Maintenance Level 0 starting
WA Agent 11.3/11.4
The level of available entropy on the server was extremely low. This is common on VMs that are not heavily utilized. Low entropy can cause the agent to hang during startup while trying to initialize encryption routines.
Run the following command to monitor the available entropy on the server...
watch -n 1 cat /proc/sys/kernel/random/entropy_avail
In addition, a kill -3 can be issued against the hung cybAgent.bin process which will cause it to dump thread info to <AGENT_HOME>/nohup.stdout. In that file, look for the following...
MainThread" prio=10 tid=0xf6908c00 nid=0x3153 runnable [0xf740e000]
at java.io.FileInputStream.readBytes(Native Method)
at java.io.FileInputStream.read(Unknown Source)
at sun.security.provider.SeedGenerator$URLSeedGenerator.getSeedBytes(Unknown Source)
If the above is in the nohup.stdout file after the thread info dump, it confirms that the agent is hanging while trying to initialize encryption routines.
Ideally, the available entropy on the server should be at a minimum of 150 to avoid issues with the agent initializing the encryption routines. If the level of available entropy on the server is falling below the minimum, and the above messages are present in the thread info dump, a system admin will need to take steps to generate additional entropy on the server.