Unsupported security types: 19

[dswd]

On some hosts (e.g. 129.187.143.7) noVNC shows this error and fails.

[dswd]

It seems that this only affects KVM in newer versions. KVM seems to change the authentication method from the default "vnc" to the unsupported "vencrypt+x509+plain" upon the first client connect.
There seems to be no way to circumvent this.

[dswd]

I am pretty sure this is something that proxmox manually patched into qemu: https://git.proxmox.com/?p=pve-qemu-kvm.git;a=blob;f=debian/patches/pve-auth.patch (ARGH!)

[dswd]

Ok, now we have the following choices:

1. Use a patched version of qemu on Proxmox hosts that has a switch which restores the original behaviour. I do not like this as it means that we have to maintain and periodically recompile a third-party binary.
2. Abandon Proxmox alltogether. Plans already exist to support general debian-based systems instead of just Proxmox. In this case this means that Proxmox will not be supported any more. This is most likely the cleanest solution but it requires to migrate all existing hosts away from Proxmox and also find a way to use LXC in the same way we use OpenVZ now.
3. Find a javascript VNC client that implements VeNCrypt or add support to NoVNC. We have to investigate this solution some more to be able to estimate the required effort.

For now this problem is hidden by the fact that the new qemu binary that changes the functionality also has a major version change so that the hostmanager marks KVM as unsupported. #828 should help to detect upgrades.

[dswd]

This looks like a temporary workaround: https://review.openstack.org/#/c/77266/