General Process Troubleshooting

Network connections, port state, PID and program name

netstat -tulpn

Find the working directory of a running process

ls -l /proc/<PID>/cwd
pwdx <PID>

Watch a component's PID to catch crash-restarts (PID changes = it crashed and came back)

watch pgrep <component>

Find which process opened a given TCP port

fuser 7000/tcp

Check if a port is a known/registered service

cat /etc/services

Find which web server is answering on a URL

curl -I <website>

Last cluster/CVM shutdown date and time

last -x | grep shutdown | head -1