100 Days of DevOps and Cloud (AWS), Day 14: Restoring a Broken httpd, and the One EC2 Command With No Undo

Some commands you can walk back. Terminating an EC2 instance is not one of them. Day 14 paired a recoverable problem, a web server knocked over by a rogue process, with an unrecoverable one, deleting a server on purpose, and the contrast is the whole lesson. One Linux task, one AWS task. Track down the process blocking Apache and restore the service, then terminate an EC2 instance and confirm it is gone. The tasks come from the KodeKloud Engineer platform. httpd: diagnose in order, then restore When httpd will not start, resist the urge to guess. Work in order. Start with what the service itself reports: # What does httpd think is wrong systemctl status httpd systemctl start httpd The status output usually names the problem, and a failed bind on the port is the classic one. Before assuming a rogue process, check that httpd's own config is sane, because a wrong port or hostname produces the same "won't start" symptom: # Check the configured listen port and server name grep -i listen /etc/httpd/conf/httpd.conf vi /etc/httpd/conf/httpd.conf # Fix the ServerName directive if it is wrong: ServerName hostname:<port> If the config is fine and the port is genuinely taken, then you go hunting for the process holding it: # Find the PID on the conflicting port sudo su - yum install -y net-tools netstat -tulpn # Clear it, then bring httpd back kill -9 <PID> systemctl enable httpd systemctl start httpd systemctl status httpd kill -9 is SIGKILL, the instant, no-cleanup kill. It is the right tool when a process is wedged and ignoring a polite request, but as a default habit, it is worth trying a plain kill first. The order that matters here is diagnostic: config before process, gentle signal before forceful one. Rushing to kill -9 at the first sign of trouble is how you mask the real cause instead of fixing it. Terminating EC2: the command with no undo Day 9 was about protecting an instance from termination. Day 14 is the other side of that lever, actually terminating one, on purp