tty access from a cluster node to its kvm guests.

[PEB]

Hey there.

I'm trying to find a way of accessing to my kvm guests by console. The point is simple : my nodes doesn't have any X server, and I want to be able to connect to the guests even if I have no X server to run the web interface.

I heard about virsh, but it's not compatible with proxmox setup. I heard about VNC, but it requires a X server.

I didn't find any way to do it properly. Is there any qm command or other that I missed ?

Thanks,
PEB

 

[tom]

if you don´t use the VNC console, you need to configure access to your KVM guests via standard network tools, e.g. SSH.

 

[PEB]

Thanks !

Then, what should I do if my guest is broken and not accessible via network ?

 

[tom]

use the VNC console. works on any windows, linux, mac PC. even on via Android APP.

if you have no access to the management interface (no network to the host) you need to fix the host network via CLI - this is not related to the guests.

 

[PEB]

VNC is heavier than a simple tty access. Let's imagine that one of our guests (the mail server as for an example) doesn't have network anymore, and we are in front of our host, with no X server.

There is no way we can use VNC, and there is a need to fix the broken VM, so to access to its TTY. What can I do in this situation to fix the problem quickly ?

 

[tom]

read my post. if you have not network in the guest, use VNC console.

if you really think you need it, install X server on your Proxmox VE host.

 

[PEB]

I read it, but I heard that VNC needs a X server.

If I'm away from my network (which is behind a 1Mb/s box), and there is a problem, the vnc proxy will be too heavy.
I'm trying to find the simplest and lightest way to administrate my guests if I need to. We have a low bandwidth.

Thanks,

 

[mo_]

this sounds like youre running linux guests and you really should be running your linux guests via openvz which is superior in almost every way to KVM as far as linux guests are concerned. and there youd have your "couldnt possibly be any easier" guest access via vzctl enter/exec

 

[tom]

I read it, but I heard that VNC needs a X server.

yes. but just use a desktop system and access via browser. no x server needed on the host.

If I'm away from my network (which is behind a 1Mb/s box), and there is a problem, the vnc proxy will be too heavy.
I'm trying to find the simplest and lightest way to administrate my guests if I need to. We have a low bandwidth.
Thanks,

use SSH or similar to manage your servers. if you lost network, use VNC console. there is no other way.

 

[bert64]

You can configure a serial console for kvm guests, i add the following to the /etc/pve/qemu-server/VMID.conf:
args: -serial unix:/var/run/qemu-server/VMID.serial,server,nowait

And i have a number of corresponding minicom rc files:
root@proxmox:/etc/minicom# cat minirc.119
pu port unix#/var/run/qemu-server/119.serial
pu minit
pu mreset

so i can just do "minicom vmid"...

The caveat here is that you cannot interact with the bios, only with the bootloader and beyond. KVM does have an ncurses based interface which lets you interact with the bios and bootloaders not configured for serial access but i haven't tried using that.

 

[PEB]

yes. but just use a desktop system and access via browser. no x server needed on the host.

[...]

use SSH or similar to manage your servers. if you lost network, use VNC console. there is no other way.

Thanks. But I'm bit surprised by your answer. Xen managed to offer this possibility by the command xm console. At the same time, virsh allows many possibilities on many virtualization tools. But lib-virt is in conflict with pve.

If these tools exist, I guess it's for the same reason I was asking for on this forum : light and powerful tool.

Willing to stay on a VNC shell or the WEB UI managment console (powered by Java, heavy) seems in my opinion equivalent to deny the potential low bandwidth issue, and the need to not encapsulate SSH/X or WEBUI/JAVA.

You're doing a great job, and I will to thank you for this. But this console access is a point of failure. Also is the difficulty to access on the host to the guests disks (but I found how to with kpartx, so no problem on this).

Thanks to bert64, I'll try to work with it, no baudrate defined ?

 

[tom]

you mix some tools here, virsh is not a tool for accessing VM console.
how can you fix a windows host with virsh? e.g. update a driver? seems I miss something here.

take a look on:

• qm ('man qm')
• KVM monitor
• pvesh