linuxexpert-practice-labs/labs/lfca/2-1-system-administration

LFCA 2.1: System administration

A sudo user, a web server as a service, a new disk mounted at boot, and a cron job.

Before you start

Work as root (sudo -i). The lab adds a 1 GiB spare disk, /dev/loop40, standing in for a second virtual disk; it comes back at every boot. It notes whether nginx is installed, and reset puts that back.

Tasks

1. Create a user, add them to the wheel group (RHEL family) or sudo group (Ubuntu), log in as them, and run sudo -l to see what they may do. Then delete the user. Not graded.
2. Install nginx, enable and start it with systemctl enable --now, check systemctl status, fetch the page with curl localhost, and read its log with journalctl -u nginx.
3. Partition /dev/loop40 (one partition is enough), make an ext4 filesystem on the partition, mount it at /data, add it to /etc/fstab, and reboot to prove it comes back.
4. Add a root crontab entry that writes the date to /root/cron-date.txt every two minutes. Check the file once the job has run, then remove the entry, leaving the file.

Hints

• useradd -m -G wheel NAME (or -G sudo), passwd NAME, su - NAME, sudo -l, userdel -r NAME.
• dnf install nginx / apt install nginx, systemctl enable --now nginx, curl -s localhost | head.
• fdisk /dev/loop40 (or parted), then lsblk /dev/loop40; mkfs.ext4 /dev/loop40p1, blkid, a UUID= line in /etc/fstab, systemctl daemon-reload, mount -a, findmnt /data.
• crontab -e with */2 * * * * date >> /root/cron-date.txt; crontab -l.