linuxexpert-practice-labs/labs/lfcs/3-6-automounters/README.md

LFCS 3.6: Filesystem automounters

Mounting NFS shares and home directories on demand with autofs, idle timeouts, and systemd's own automounting.

Before you start

The lab adds a second machine, nfs1 (10.99.0.2), running an NFS server that exports to the lab network 10.99.0.0/24:

• nfs1:/srv/share, with a file hello.txt in it;
• nfs1:/export/home, holding home directories for alice and bob (/export/home/alice and /export/home/bob, each with a welcome.txt).

nfs1 shares this VM's files, so you can see the exported directories here too, but mount them from nfs1. The lab creates users alice and bob (password Lab-Pass-1) with the same UIDs as on the server, and installs the NFS client tools. It also adds a 256 MiB spare disk, /dev/loop40, that already holds an ext4 filesystem and comes back at every boot before filesystems are mounted.

Tasks

1. Automount nfs1:/srv/share at /mnt/share with autofs, using a direct map.
2. Automount every user's home directory from nfs1:/export/home under /home/remote with one wildcard line, and make /home/remote/alice alice's home directory.
3. Make autofs unmount idle shares after 30 seconds, for both maps.
4. Without autofs, make the filesystem on /dev/loop40 mount at /data only when it's first used, set up in /etc/fstab.

Hints

• /etc/auto.master.d/*.autofs (or /etc/auto.master) and map files; systemctl reload autofs; findmnt -t autofs,nfs4; automount -m.
• * and & in an indirect map; usermod -d; su - alice, pwd. The homes are private and root is squashed on the share, so look inside them as their owner.
• --timeout= in the master map.
• x-systemd.automount (and x-systemd.idle-timeout) in /etc/fstab; systemctl daemon-reload; systemctl list-units --type=automount.