What is eating the CPU?
Every running program is a process with a number (PID), an owner and a share of CPU and memory. When a server is slow, you find the greedy process and stop it.
Inspect and stop processes
ps ps aux top ps aux | grep node pgrep -f crunch kill 1777 ps aux | grep -c crunch sleep 100 & jobs kill 1188 sudo kill 1188
Always try a plain kill first: it lets the program save work and clean up. Use kill -9 only if it ignores you.