Q: Your team receives PagerDuty alerts that CPU utilization is consistently hitting 100% on a database server. How do you find what's causing it?

First, I'd SSH into the server and run top or htop. I'd check the load average to see the trend (1, 5, 15 minutes).

• High %us (user): The application or DB process is working hard. I'd find the PID, then use strace -p or perf top or check DB-specific tools (like SHOW PROCESSLIST in MySQL) to see what queries are running.
• High %sy (system): The kernel is doing heavy work (e.g., millions of context switches or network interrupts).
• High %wa (iowait): The CPU is idling waiting for I/O. This means it's a disk bottleneck, not a CPU bottleneck. I'd switch to iotop or iostat -x 1 to find the process thrashing the disk.

In top, I'd look at the CPU states:

• High %st (steal): If it's a VM, the noisy neighbor syndrome. The hypervisor is allocating cycles elsewhere. I would migrate the VM or resize the instance.