Exercise: Choose a version and check for updates

Choose a version and check for updates

• List module streams and enable one.
• See the effect of a stream on the offered version, and reset it.
• Review pending updates and decide about a reboot.

Start the exercise

On workstation, start the exercise. It resets the nginx module on servera, so no stream is enabled.

[student@workstation ~]$ lab start sa-modules

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.

List the streams

On servera as root (sudo -i), list the streams of the nginx module, and show which version of the nginx package dnf offers before any stream is enabled.

[student@workstation ~]$ ssh student@servera
[student@servera ~]$ sudo -i
[root@servera ~]# dnf module list nginx
Name  Stream Profiles   Summary
nginx 1.22   common [d] nginx webserver
nginx 1.24   common [d] nginx webserver
nginx 1.26   common [d] nginx webserver

Hint: [d]efault, [e]nabled, [x]disabled, [i]nstalled
[root@servera ~]# dnf list available nginx
Available Packages
nginx.x86_64               2:1.20.1-28.el9_8.6.rocky.0.1               appstream

Your list of streams and versions will depend on your repositories.

Enable a stream

Enable nginx:1.24. What does dnf offer now? Look at the file that records the choice.

[root@servera ~]# dnf module enable -y nginx:1.24
...output omitted...
Complete!
[root@servera ~]# dnf list available nginx
Available Packages
nginx.x86_64   1:1.24.0-7.module+el9.8.0+40319+5de55ea3.5.rocky.0.1    appstream
[root@servera ~]# cat /etc/dnf/modules.d/nginx.module
[nginx]
name=nginx
stream=1.24
profiles=
state=enabled

The offered version changed from 1.20 to 1.24.

Try to switch directly

Try to enable nginx:1.26 without resetting. What does dnf say? Then do it the right way.

[root@servera ~]# dnf module enable -y nginx:1.26
Error: It is not possible to switch enabled streams of a module unless explicitly enabled via configuration option module_stream_switch.
It is recommended to rather remove all installed content from the module, and reset the module using 'dnf module reset <module_name>' command. After you reset the module, you can install the other stream.
[root@servera ~]# dnf module reset -y nginx
...output omitted...
Complete!
[root@servera ~]# dnf module enable -y nginx:1.26
...output omitted...
[root@servera ~]# dnf list available nginx
Available Packages
nginx.x86_64        2:1.26.3-9.module+el9.8.0+40317+f33384ab.4         appstream

Leave no stream enabled

Reset the module, and confirm the choice is gone.

[root@servera ~]# dnf module reset -y nginx
...output omitted...
[root@servera ~]# dnf module list --enabled | tail -3
[root@servera ~]# cat /etc/dnf/modules.d/nginx.module
[nginx]
name=nginx
stream=
profiles=
state=

Review the updates

List the available updates (first lines only), count the security advisories, and ask whether a reboot is advised.

[root@servera ~]# dnf check-update | head -3
kernel.x86_64                          5.14.0-687.54.1.el9_8              baseos
kernel-core.x86_64                     5.14.0-687.54.1.el9_8              baseos
kernel-modules.x86_64                  5.14.0-687.54.1.el9_8              baseos
[root@servera ~]# dnf updateinfo summary
No security updates needed, but 4 updates available
[root@servera ~]# dnf needs-restarting -r
No core libraries or services have been updated since boot-up.
Reboot should not be necessary.
[root@servera ~]# uname -r
5.14.0-687.53.1.el9_8.x86_64
[root@servera ~]# exit
[student@servera ~]$ exit

A kernel update is waiting, but it has not been installed yet; once it is, uname -r will still show the old version until a reboot. Do not apply the updates in this exercise.

Grade and finish

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