How to run Docker containers inside GNS3 with user namespaces enabled?

[smart2128]

Hi.
every time I try to instantiate a Docker appliance in GNS3, I receive the following error:

Error while creating node from template: Docker has returned an error: 400 privileged mode is incompatible with user namespaces. You must run the container in the host namespace when running privileged mode

Is there a way to properly handle this issue?

Thank you in advance,

[grossmj]

What Docker image have you tried to use? Do you have this issue with any image?

[smart2128]

Yes, I experience the same behavior with any images. I tried several images, (Alpine Linux, DNS, Open vSwitch, etc.).
Thank you for your answer.

[grossmj]

Fixed, this should work in our next release.

[smart2128]

Hi Jeremy,
sorry for re-opening this issue.
I just installed v2.2.50, but, when I try to instantiate a Docker container in GNS3, I still get the same error

Error while creating node from template: Docker has returned an error: 400 privileged mode is incompatible with user namespaces. You must run the container in the host namespace when running privileged mode

Please, let me know if you need more details.

Regards,
Vincenzo

[grossmj]

Have you done anything to enable "user namespaces"?

[smart2128]

I don't remember any customizations by my side, but, reading the Archlinux Docker's wiki page, there's a "User namespace isolation" section that contains a reference to a vulnerability published and patched in February 2019. I'm trying to figure out if it had been enabled by me or by Arch. I'll keep you posted. Thank you, Vincenzo

[smart2128]

I removed userns-remap and now it works as expected.
Forgive me for wasting your time.

[grossmj]

Forgive me for wasting your time.

No worries, I actually have tested with userns-remap and indeed the previous fix didn't work because the param UsernsMode was in the wrong spot. I fixed that and now everything should work even when userns-remap is enabled.