Install_linux_azcmagent.sh missing Ubuntu 26.04 support despite agent 1.67 changelog

Question

Install_linux_azcmagent.sh missing Ubuntu 26.04 support despite agent 1.67 changelog

Fredrik Björck 20

Install_linux_azcmagent.sh missing Ubuntu 26.04 support despite agent 1.67 changelog

Summary

The public Azure Connected Machine agent Linux install script (downloaded via https://aka.ms/azcmagent) still rejects Ubuntu 26.04 as an unsupported distribution, even though the agent release notes state that version 1.67 (August 2026) added:

Added support for Ubuntu 26.04 (x86-64) — Feature, Linux

There appears to be a gap between the agent package (which supports 26.04 per the changelog) and the public install script (which does not).

Environment

OS: Ubuntu 26.04 (x86-64)
Install method: Install_linux_azcmagent.sh downloaded fresh via curl -sL https://aka.ms/azcmagent -o Install_linux_azcmagent.sh (confirmed not a caching issue — re-downloaded on 2026-08-24, four days after the release notes page was last updated on 2026-08-20)
Deployment: Ansible / AWX automation

Error observed


Using 'curl' for downloads

Total usable memory: 7407760 kB

Platform type:  x86_64:Linux

Retrieving distro info from /etc/os-release...

No HIS endpoint provided, using default gbl.his.arc.azure.com

Install_linux_azcmagent.sh: unsupported Linux distribution: Ubuntu:26.04. For supported OSs, see https://learn.microsoft.com/en-us/azure/azure-arc/servers/prerequisites#supported-operating-systems

Exit code 133 (unsupported Linux distribution).

Root cause (confirmed via script inspection)

The Ubuntu case block in the downloaded script only matches major/minor version combinations up to 24.04, with no branch for 26:


elif [ "${distro_major_version}" -eq 22 ] && [ "${distro_minor_version}" -eq 04 ]; then

    echo "Configuring for Ubuntu 22.04..."

    deb_distro=ubuntu/22.04

elif [ "${distro_major_version}" -eq 24 ] && [ "${distro_minor_version}" -eq 04 ]; then

    echo "Configuring for Ubuntu 24.04..."

    deb_distro=ubuntu/24.04

else

    exit_failure 133 "$0: unsupported Linux distribution: ${distro}:${distro_major_version}.${distro_minor_version}. For supported OSs, see https://learn.microsoft.com/en-us/azure/azure-arc/servers/prerequisites#supported-operating-systems"

fi

There is no elif branch for distro_major_version -eq 26, so any Ubuntu 26.04 host hits the catch-all unsupported Linux distribution error regardless of the agent package's actual capabilities.

Request

Please update Install_linux_azcmagent.sh (served from aka.ms/azcmagent) to add an Ubuntu 26.04 branch, consistent with the 1.67 release notes, e.g.:


elif [ "${distro_major_version}" -eq 26 ] && [ "${distro_minor_version}" -eq 04 ]; then

    echo "Configuring for Ubuntu 26.04..."

    deb_distro=ubuntu/26.04

It would also help to confirm whether the ubuntu/26.04/prod path exists in the packages.microsoft.com repository, since that's needed regardless of the script fix.

Impact

This blocks Azure Arc onboarding for any Ubuntu 26.04 host using the standard/documented installation method, despite the underlying agent supporting the OS since 1.67.

Happy to provide further logs or test on our environment if useful.

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Answer 1

Hello @Fredrik Björck

Your analysis looks correct, and I can reproduce the inconsistency in Microsoft's currently published guidance.

There are actually three separate pieces that need to agree before I would consider Ubuntu 26.04 fully supported for Azure Arc onboarding:

Azure Connected Machine agent binary/package
Microsoft Linux package repository
Install_linux_azcmagent.sh + Azure Arc supported-OS matrix

You've identified a gap between those components.

The current Azure Arc prerequisites documentation states explicitly that if an OS version isn't listed, it isn't supported. At present, the Ubuntu entries shown are:

Ubuntu 18.04

Ubuntu 20.04

Ubuntu 22.04

Ubuntu 24.04

Ubuntu 26.04 isn't currently listed.

At the same time, your freshly downloaded Install_linux_azcmagent.sh confirms that the installation path hasn't yet been updated either. The script stops after the Ubuntu 24.04 condition and returns:

unsupported Linux distribution: Ubuntu:26.04

Exit code 133

So I agree that this isn't an Ansible/AWX issue or a stale local copy of the installer. Your inspection demonstrates that the current public installation script itself doesn't recognize 26.04.

Microsoft documents Install_linux_azcmagent.sh as the supported installation bundle that identifies whether the Linux distribution is supported and configures the appropriate Microsoft package repository before installing the Connected Machine agent.

I therefore wouldn't recommend adding this manually to the production script:

elif [ "${distro_major_version}" -eq 26 ] &&
     [ "${distro_minor_version}" -eq 04 ]; then
    deb_distro=ubuntu/26.04

That would only bypass the script's OS validation. It wouldn't establish that the complete Azure Arc stack and associated extensions/services are supported on Ubuntu 26.04.

Likewise, pointing 26.04 at the Ubuntu 24.04 Microsoft repository would be an unsupported assumption unless Microsoft specifically documents that configuration.

The package-based installation documentation currently gives Ubuntu 24.04 as the Ubuntu repository example and installs azcmagent from Microsoft's configured package repository.

So I think your request to Microsoft is valid.

This appears to require confirmation from the Azure Arc/Connected Machine Agent product team on two points:

Whether Ubuntu 26.04 x86-64 is now officially supported by Azure Arc-enabled Servers, not just by the 1.67 agent binary.
Whether the ubuntu/26.04/prod repository and Install_linux_azcmagent.sh deployment path are now intended to be available.

If version 1.67 officially added Ubuntu 26.04 support as stated in the release notes you're seeing, then the supported OS matrix, Microsoft package repository, and aka.ms/azcmagent installation script should align.

Until Microsoft confirms that rollout, I would keep the AWX deployment on Ubuntu 24.04 rather than bypassing the installer's distribution check.

Sharing these references with you:

Azure Arc Connected Machine agent prerequisites

Connect Linux machines to Azure Arc using a deployment script

Package-based Linux installation

Given that you've already provided the exact failing condition, fresh-download date, exit code, and missing script branch, I think this should be escalated to the Azure Arc product team rather than treated as an installation troubleshooting issue.

Help make this community better for everyone: if this answer resolved your issue, please accept it or leave an upvote. If not, share more details in a comment so we can continue the discussion and find the right solution.

Fredrik Björck 20 Reputation points

2026-08-25T07:01:36.66+00:00

Hi,

Thank you so much for this thorough and well-structured response — really appreciate you taking the time to reproduce the issue, break down the three separate components (agent package, package repository, install script), and lay out exactly what needs to align before Ubuntu 26.04 can be considered fully supported. That's a much clearer picture than I had.

I agree with your recommendation not to manually patch the script or assume the 24.04 repo would work — better to wait for official confirmation from the product team.

One note: I tried to escalate this further via a support ticket in the Azure Portal, but unfortunately we don't have a support plan that allows creating a ticket for this. So I'm not able to push this to the product team directly through that channel. If you have any other suggestions for how to get this in front of the right team (e.g. a GitHub repo for the install script, or another feedback channel), I'd be glad to hear them — otherwise I'll leave this thread as the reference point for now.

Thanks again for the detailed write-up.

Best regards, Fredrik
Allan Solomon Mejia 8,085 Reputation points

2026-08-25T15:18:40.9133333+00:00

Hi @Fredrik Björck

Thank you for confirming. Since you don't have an Azure support plan, I suggest reporting this via the Feedback option rather than filing an issue in an unrelated GitHub repository.

Azure Feedback Community Portal.

Microsoft currently lists Install_linux_azcmagent.sh as the supported Linux installation bundle, together with the code that determines which distributions are supported and which are not.

Please also provide the exact date you downloaded the script, the Ubuntu 26.04 version, the exit code, and the distribution branch you found missing or incorrect. This information should let the documentation or product team reproduce the problem and assign it to the right person.

The Azure Arc Jumpstart scenarios are available in the public microsoft/azure_arc GitHub repository, but you should not use that repository as the main place to report a production Connected Machine agent installer issue unless Microsoft specifically tells you to.

For now, I agree the Q&A thread should stay as a reference too, especially since you've already documented the reproducible behavior.

Please don't forget to "Accept the Answer" if this information helped you. This will help us and others in the community.
Fredrik Rinnestam 0 Reputation points

2026-08-26T14:55:53.3133333+00:00

I'm in the same situation. I did modify the install script to include 26.04 which worked. But after a few hours I was surprised to find that the microsoft-prod.list had been modified. Instead of the specified gpg key, url and path to the functional 26.04 repository, the repo file had been changed to use the ubuntu 18.04 repo. This breaks stuff btw.

Curious to see wtf had happened I enabled auditing on the repo file after changing it back:
<snip>

type=CWD msg=audit(1787745172.998:337): cwd="/var/lib/waagent/Microsoft.Azure.AzureDefenderForServers.MDE.Linux-1.0.16.4"
<snip>

So even if you manage to install it, issues remain.
Allan Solomon Mejia 8,085 Reputation points

2026-08-26T15:38:01.66+00:00

Hi @Fredrik Björck

Please let me know if you need any further assistance. Otherwise, if the information provided helped you, please click “Accept Answer” to help others who may encounter the same problem.

Thank you!