Setting a serial device in VM's hardware forces xtermjs console instead of novnc console

[JJi]

Hello everybody.
Apologies if this question has been brought up before. I did a search but couldn't find any answer to this particular problem I'm facing.

So, I have a Proxmox 6.2 up and running, and a VM running Windows.
I have manually setup a serial device (serial0) /dev/ttyS0 to give the VM straight access to my server's physical serial port.

If I try opening up the server's console using the right-click menu, it opens up console window, but not the one expected. It's attempting to access a serial connection of some sort, causing it to fail with "Connection failed (code: 1006)" and a single line of text that reads: "unable to find a serial interface"

The URL that's being opened in the console window is:
https://<server name>:8006/?console=kvm&xtermjs=1&vmid=<ID number>&vmname=<VM name>&node=<Proxmox server name>&cmd=

Other VM's that don't have a serial port set up at all, the console opens up as expected and its URL looks like this:
https://<server name>:8006/?console=kvm&novnc=1&vmid=<ID number>&vmname=<VM name>&node=<Proxmox server name>&resize=off&cmd=

Note the bold+italic text that shows the difference.
I can access the correct console by modifying the URL with &novnc=1 in the address bar to point to the VM that has serial device set, but that's a kind of a dirty "hack".

Steps to reproduce this behavior is as follows:
1. Power off the VM.
2. Modify VM's config file, manually adding a serial device (serial0) that points to /dev/ttySx
3. Power on the VM.
4. Attempt to access the VM console from the right-click menu. It should fail.

Removing the serial device will give you a novnc console.
Does this count as expected behavior or a bug of some sort? This behavior didn't occur in Proxmox VE 5.x.

 

[dcsapak]

what is your 'default' console set in the datacenter options? and what is your pveversion -v ?

 

[JJi]

In the datacenter options, Console Viewer is "Default (xterm.js)". This was left untouched when I upgraded from PVE 5 to 6.

pveversion -v gives the following information:

proxmox-ve: 6.2-1 (running kernel: 5.4.41-1-pve)
pve-manager: 6.2-11 (running version: 6.2-11/22fb4983)
pve-kernel-5.4: 6.2-6
pve-kernel-helper: 6.2-6
pve-kernel-5.3: 6.1-6
pve-kernel-5.4.60-1-pve: 5.4.60-2
pve-kernel-5.4.55-1-pve: 5.4.55-1
pve-kernel-5.4.44-2-pve: 5.4.44-2
pve-kernel-5.4.44-1-pve: 5.4.44-1
pve-kernel-5.4.41-1-pve: 5.4.41-1
pve-kernel-5.4.34-1-pve: 5.4.34-2
pve-kernel-4.15: 5.4-12
pve-kernel-5.3.18-3-pve: 5.3.18-3
pve-kernel-5.3.18-2-pve: 5.3.18-2
pve-kernel-4.15.18-24-pve: 4.15.18-52
pve-kernel-4.15.18-12-pve: 4.15.18-36
ceph-fuse: 14.2.11-pve1
corosync: 3.0.4-pve1
criu: 3.11-3
glusterfs-client: 5.5-3
ifupdown: 0.8.35+pve1
ksm-control-daemon: 1.3-1
libjs-extjs: 6.0.1-10
libknet1: 1.16-pve1
libproxmox-acme-perl: 1.0.5
libpve-access-control: 6.1-2
libpve-apiclient-perl: 3.0-3
libpve-common-perl: 6.2-2
libpve-guest-common-perl: 3.1-3
libpve-http-server-perl: 3.0-6
libpve-storage-perl: 6.2-6
libqb0: 1.0.5-1
libspice-server1: 0.14.2-4~pve6+1
lvm2: 2.03.02-pve4
lxc-pve: 4.0.3-1
lxcfs: 4.0.3-pve3
novnc-pve: 1.1.0-1
proxmox-mini-journalreader: 1.1-1
proxmox-widget-toolkit: 2.2-12
pve-cluster: 6.1-8
pve-container: 3.2-1
pve-docs: 6.2-5
pve-edk2-firmware: 2.20200531-1
pve-firewall: 4.1-2
pve-firmware: 3.1-3
pve-ha-manager: 3.1-1
pve-i18n: 2.2-1
pve-qemu-kvm: 5.1.0-1
pve-xtermjs: 4.7.0-2
qemu-server: 6.2-14
smartmontools: 7.1-pve2
spiceterm: 3.1-1
vncterm: 1.6-2
zfsutils-linux: 0.8.4-pve1

 

[dcsapak]

oh sorry, can you also post the vm config? (qm config ID)

 

[r.jochum]

Dominik, i have the same:

# qm config 101
agent: 1
bootdisk: scsi0
cores: 8
cpu: Skylake-Client
ide2: none,media=cdrom
memory: 30720
name: rk3s01
net0: virtio=<mac>,bridge=vmbr0,firewall=1
numa: 0
ostype: l26
scsi0: local-zfs:vm-101-disk-0,discard=on,size=32G,ssd=1
scsi1: local-zfs:vm-101-disk-1,discard=on,size=600G,ssd=1
scsihw: virtio-scsi-pci
serial0: socket
smbios1: uuid=<some-uuid>
sockets: 1
startup: order=2,up=60
vga: qxl
vmgenid: <some-id>

EDIT: Manualy selecting NoVNC/Spice works for me

 

[JJi]

oh sorry, can you also post the vm config? (qm config ID)

No problem, Here's the output:

balloon: 2048
boot: cd
bootdisk: scsi0
cores: 2
description: Wx Data Acquisition Server
hotplug: usb
keyboard: fi
localtime: 1
memory: 4096
name: <Redacted>
net0: virtio=<Redacted>,bridge=vmbr0
numa: 1
ostype: win10
sata0: none,media=cdrom
scsi0: datastore-xigmanas-zraid10-nfs:104/vm-104-disk-0.qcow2,cache=writethrough,discard=on,size=80G
scsihw: virtio-scsi-pci
serial0: /dev/ttyS0
smbios1: uuid=<Redacted>
sockets: 1
vga: std

 

[dcsapak]

yeah i can see why .. we detect a serial console and use xtermjs by default, maybe we should only do that if the display is also selected as the serial terminal?
a setting per vm? i am not sure.. could you open a bug report here: https://bugzilla.proxmox.com
it's better to discuss this issue there