x86_64 VM's without a GUI? Or, "serial line" QEMU?

[twork]

I'm struggling with some Gentoo VM's on QEMU/KVM, using Virtual Machine Manager (virt-manager). I've made some mistake with the kernel build, so the VM panics and croaks when it's time to mount root.

Worse, I'm doing this through a network that's slow and sloppy, so interacting with a VM through a graphical view of the emulated BIOS screen is a pain. Keystrokes take forever to come back, or they don't come back, or sometimes the screen just dies and I have to reconnect. So trying to track down my mistake is a slow, frustrating process.

I miss the olden days, of interacting with Unix hardware through a serial line. Is there some way to emulate that interface in this environment? Must we always pretend that we're sitting at a PC? Rather, I know it can be done, but I can't find the recipe. Hint?

[russK]

Years ago I gave up on virt-manager, the abstractions seemed to limit the specific features that were available in the underlying implementation.

Assuming you have two boxes, one for a remote host and guest, and another for your local client ? Is it possible to connect a serial cable between the boxes?

qemu supports the -serial <dev> option. With a serial cable you could connect to another box over ttyS0.

[twork]

I do have other computers, but I don't have a way to attach a serial line between them, partly because they're miles away.

I was hoping for a way to do something like what you suggest, but with the serial connection being virtualized. I'm sure I've done something like that in the past, but can't remember how. I also don't recall which virtualization system I was using at the time.

I'm not married to virt-manager; if libvirt or some other tool exposes the VM's serial lines in a more accessible way I'll gladly switch.

So, "VM 1" connects to "VM 2" each via ttyS0, but all the traffic going within the single physical machine.

[szatox]

You can use -nogui switch in quemu or use virt-manager with SPICE (don't connect to it if you don't need it). Enabling compression on your ssh session also makes miracles with X11 over a slow ethernet

[twork]

Oooh, right. I'd been compressing my VNC sessions, and that helps a little, sometimes, but hadn't tried it on SSH directly. Doing that now, will see how much good it does. Thanks.