Chapter 19: Network file systems and autofs

Exercise: NFS and autofs review

Serve two directories from serverb, mount one permanently on servera, write a file across the network, and give servera an on-demand, read-only view of the other with an autofs wildcard map.

NFS and autofs review

Export directories, start the server and open the firewall.
Mount an export permanently with fstab and _netdev.
Serve a read-only wildcard autofs map.

Before you start: reset the servers and complete this chapter's lessons. serverb is the server and servera the client; lab start and lab grade run on workstation.

On both servers install nfs-utils if needed. On serverb, create /srv/projects (owned by student) and /srv/archive/2025/notes.txt.
Export /srv/projects read-write and /srv/archive read-only to your lab network.
Start and enable nfs-server and open the nfs firewall service permanently.
On servera, mount serverb:/srv/projects on /mnt/projects through fstab with _netdev.
As student on servera, write written from servera into /mnt/projects/from-client.txt.
On servera, install and enable autofs and serve /remote/archive/KEY from serverb:/srv/archive/KEY read-only with one wildcard line.
On workstation, fill in answers.txt.

Start the exercise

[student@workstation ~]$ lab start sa-nfs-review

The server

[student@workstation ~]$ ssh student@serverb
[student@serverb ~]$ sudo -i
[root@serverb ~]# dnf install -y nfs-utils > /dev/null
[root@serverb ~]# mkdir -p /srv/projects /srv/archive/2025
[root@serverb ~]# chown student:student /srv/projects
[root@serverb ~]# echo "old notes" > /srv/archive/2025/notes.txt
[root@serverb ~]# cat > /etc/exports <<'EOT'
/srv/projects  172.25.250.0/24(rw,sync)
/srv/archive   172.25.250.0/24(ro,sync)
EOT
[root@serverb ~]# systemctl enable --now nfs-server
[root@serverb ~]# firewall-cmd --permanent --add-service=nfs; firewall-cmd --reload
success
success
[root@serverb ~]# exportfs -v | cut -c1-55
/srv/projects 	172.25.250.0/24(sync,wdelay,hide,no_subtree_check,
/srv/archive  	172.25.250.0/24(sync,wdelay,hide,no_subtree_check,

On the lab, replace the network with the one your servers use (ip -br addr); the lab's own network may differ from the printed one.

The permanent mount and a write

[student@workstation ~]$ ssh student@servera
[student@servera ~]$ sudo -i
[root@servera ~]# dnf install -y nfs-utils > /dev/null
[root@servera ~]# mkdir -p /mnt/projects
[root@servera ~]# echo 'serverb:/srv/projects  /mnt/projects  nfs  defaults,_netdev  0 0' >> /etc/fstab
[root@servera ~]# systemctl daemon-reload; mount -a
[root@servera ~]# findmnt /mnt/projects -o TARGET,SOURCE,FSTYPE
TARGET        SOURCE                FSTYPE
/mnt/projects serverb:/srv/projects nfs4
[root@servera ~]# su - student -c 'echo "written from servera" > /mnt/projects/from-client.txt'
[root@servera ~]# ls -l /mnt/projects
-rw-r--r--. 1 student student 21 Oct  3 19:20 from-client.txt

autofs

[root@servera ~]# dnf install -y autofs > /dev/null
[root@servera ~]# echo '/remote/archive  /etc/auto.archive' > /etc/auto.master.d/archive.autofs
[root@servera ~]# echo '*  -ro,sync  serverb:/srv/archive/&' > /etc/auto.archive
[root@servera ~]# systemctl enable --now autofs
[root@servera ~]# cat /remote/archive/2025/notes.txt
old notes
[root@servera ~]# touch /remote/archive/2025/x
touch: cannot touch '/remote/archive/2025/x': Read-only file system

Grade

On workstation, fill in answers.txt and grade:

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