Troubleshoot issues with package upgrades on the Azure Linux Container Host

The Azure Linux Container Host for AKS has dnf-automatic enabled by default, a systemd service that runs daily and automatically installs any recently published updated packages. This ensures that packages in the Azure Linux Container Host should automatically update when a fix is published. Note, that for some settings of Node OS Upgrade Channel, dnf-automatic will be disabled by default.

Symptoms

However, sometimes the packages in the Azure Linux Container Host fail to receive automatic upgrades, which can lead to the following symptoms:

• Error messages while referencing or using an updated package.
• Packages not functioning as expected.
• Outdated versions of packages are displayed when checking the Azure Linux Container Host package list. You can verify if the packages on your image are synchronized with the recently published packaged by visiting the repository on packages.microsoft.com or checking the release notes in the Azure Linux GitHub repository.

Cause

Some packages, such as the Linux Kernel, require a reboot for the updates to take effect. To facilitate automatic reboots, the Azure Linux VM runs the check-restart service, which creates the /var/run/reboot-required file when a package update requires a reboot.

Solution

To ensure that Kubernetes acts on the request for a reboot, we recommend setting up the kured daemonset. Kured monitors your nodes for the /var/run/reboot-required file and, when it's found, drains the work off the node and reboots it.

Next steps

If the preceding steps do not resolve the issue, open a support ticket.