Exercise: Make the storage permanent

Mount the two file systems and the swap area at boot, using UUIDs and sensible options, test the entries before rebooting, and prove them with a reboot.

Make the storage permanent

Write fstab entries by UUID for xfs, ext4 and swap.
Test with findmnt --verify, mount -a and swapon -a.
Verify the entries after a reboot.

Start the exercise

On workstation, start the exercise. It partitions /dev/sdb of servera and creates the xfs file system, the ext4 file system and the swap area of the previous exercise.

[student@workstation ~]$ lab start sa-fstab-storage

Later tasks assume that you are logged in to the server they name: ssh student@servera from workstation, then sudo -i for a root shell.

Unmount and collect the UUIDs

On servera as root, unmount /data and /logs if they are still mounted from the previous exercise, create the mount points /srv/data and /srv/archive, and read the UUIDs of the three partitions.

[student@workstation ~]$ ssh student@servera
[student@servera ~]$ sudo -i
[root@servera ~]# umount /data /logs 2> /dev/null; swapoff -a
[root@servera ~]# mkdir -p /srv/data /srv/archive
[root@servera ~]# blkid -s UUID -o value /dev/sdb1 /dev/sdb2 /dev/sdb3
c64946eb-fc27-4485-8020-db4119b686eb
cd0b3883-1d6d-4271-a89e-2f48a2dac5b7
89858a47-2255-4fa3-a2a9-64711ac2d782

If the file systems do not exist (you reset the servers), recreate them as in the previous exercise first.

Back up fstab and add the lines

Back up /etc/fstab, then add: sdb1 on /srv/data as xfs with defaults; sdb2 on /srv/archive as ext4 with defaults,noexec; and sdb3 as swap. Use the UUIDs.

[root@servera ~]# cp /etc/fstab /root/fstab.bak
[root@servera ~]# cat >> /etc/fstab <<EOT
UUID=$(blkid -s UUID -o value /dev/sdb1)  /srv/data     xfs   defaults          0 0
UUID=$(blkid -s UUID -o value /dev/sdb2)  /srv/archive  ext4  defaults,noexec   0 0
UUID=$(blkid -s UUID -o value /dev/sdb3)  none          swap  defaults          0 0
EOT
[root@servera ~]# tail -4 /etc/fstab
LABEL=UEFI    /boot/efi vfat  defaults  0 0
UUID=c64946eb-fc27-4485-8020-db4119b686eb  /srv/data     xfs   defaults          0 0
UUID=cd0b3883-1d6d-4271-a89e-2f48a2dac5b7  /srv/archive  ext4  defaults,noexec   0 0
UUID=89858a47-2255-4fa3-a2a9-64711ac2d782  none          swap  defaults          0 0

The shell filled in the UUIDs from blkid, avoiding copy mistakes.

Test before rebooting

Reload systemd, verify the file, mount everything, enable the swap, and show the result. What does rc=0 from mount -a tell you?

[root@servera ~]# systemctl daemon-reload
[root@servera ~]# findmnt --verify | tail -3
0 parse errors, 0 errors, 1 warning
/
   [W] recommended root FS passno is 1 (current is 0)
[root@servera ~]# mount -a; echo "rc=$?"
rc=0
[root@servera ~]# swapon -a; swapon --show
NAME      TYPE      SIZE USED PRIO
/dev/sdb3 partition 512M   0B   -2
[root@servera ~]# findmnt -o TARGET,SOURCE,FSTYPE,OPTIONS /srv/data /srv/archive
TARGET       SOURCE    FSTYPE OPTIONS
/srv/data    /dev/sdb1 xfs    rw,relatime,seclabel,attr2,inode64,logbufs=8,logbsize=32k,noquota
/srv/archive /dev/sdb2 ext4   rw,noexec,relatime,seclabel

rc=0 and no output: every entry mounted without error. noexec shows in the options of the archive.

Prove noexec

Copy /bin/true to /srv/archive and to /srv/data and try to run both.

[root@servera ~]# cp /bin/true /srv/archive/t; cp /bin/true /srv/data/t
[root@servera ~]# /srv/data/t && echo "data: ran"
data: ran
[root@servera ~]# /srv/archive/t
-bash: /srv/archive/t: Permission denied

The file is executable and root runs it on /srv/data, but noexec stops programs on /srv/archive.

Reboot and check

Reboot, log in again, and show the mounts, the swap and the block device tree.

[root@servera ~]# systemctl reboot
[student@workstation ~]$ ssh student@servera
[student@servera ~]$ df -hT /srv/data /srv/archive
Filesystem     Type  Size  Used Avail Use% Mounted on
/dev/sdb1      xfs   960M   39M  922M   5% /srv/data
/dev/sdb2      ext4  974M   24K  907M   1% /srv/archive
[student@servera ~]$ swapon --show
NAME      TYPE      SIZE USED PRIO
/dev/sdb3 partition 512M   0B   -2
[student@servera ~]$ lsblk -f /dev/sdb
NAME   FSTYPE FSVER LABEL UUID                                 FSAVAIL FSUSE% MOUNTPOINTS
sdb
├─sdb1 xfs                c64946eb-fc27-4485-8020-db4119b686eb    921M     4% /srv/data
├─sdb2 ext4   1.0   logs  cd0b3883-1d6d-4271-a89e-2f48a2dac5b7  906.2M     0% /srv/archive
└─sdb3 swap   1           89858a47-2255-4fa3-a2a9-64711ac2d782                [SWAP]

Everything came back without any manual mount: that is a permanent configuration. Keep it for the next exercise.

Grade and finish

Check your work with lab grade sa-fstab-storage, then put the exercise away with lab finish sa-fstab-storage.