Re: [gentoo-user] virtualbox in headless configuration broken after update: delayed echo [ RESOLVED, kinda ]

["J. Roeleveld" <joost@antarean.org>]

On Tuesday, June 16, 2020 11:08:23 PM CEST n952162 wrote:
> On 06/16/20 22:36, J. Roeleveld wrote:
> > On 16 June 2020 21:07:56 CEST, n952162 <n952162@web.de> wrote:
> >> On 06/10/20 15:19, n952162 wrote:
> >>> I updated my system and now characters typed into vbox over ssh are
> >>> not echo-ed until *after* a CR is entered.
> >>> 
> >>> I diffed the stty output, to see if I could spot anything:
> >>> 
> >>> 10~>cat /tmp/sttydiff
> >>> 2,3c2,3
> >>> <  rows 37
> >>> <  columns 100
> >>> ---
> >>> 
> >>>>    rows 44
> >>>>    columns 88
> >>> 
> >>> 21d20
> >>> <  discard = ^O
> >>> 23c22,23
> >>> < min = 1
> >>> ---
> >>> 
> >>>> discard = ^O
> >>>> 
> >>>>    min = 1
> >>> 
> >>> 30c30
> >>> < hupcl
> >>> ---
> >>> 
> >>>> -hupcl
> >>> 
> >>> 36c36
> >>> < brkint
> >>> ---
> >>> 
> >>>> -brkint
> >>> 
> >>> 48,49c48,49
> >>> < imaxbel
> >>> < iutf8
> >>> ---
> >>> 
> >>>> -imaxbel
> >>>> -iutf8
> >>> 
> >>> Also, the font seems to be screwed up, because the last line of the
> >>> window only shows the top half of the line.
> >>> 
> >>> Anybody else encounter this or know what's wrong?
> >>> 
> >>> Vbox seems to work okay when run locally, on the machine it's
> >>> installed on.
> >> 
> >> I think this is resolved, kinda.
> >> I just discovered that if I turn off the vbox menu bar, the command
> >> entry line works properly again, both in X-less console mode and in X.
> >> 
> >>      Settings -> User Interface -> Enable menu bar (disable this)
> >> 
> >> I've always had that menu bar, and need it, so something got
> >> changed/broken, and I still have a problem, but at least now I don't
> >> have to enter commands in blindly.
> > 
> > Are these Virtualbox VMs critical?
> > If yes, I would suggest migrating them to a more reliable virtualisation
> > technology.
> > 
> > I do not consider Virtualbox suitable for anything but a desktop based VM
> > method for a quick test or simulation.
> > 
> > Gor anything serious, I would suggest Xen, KVM or VMWare.
> > 
> > --
> > Joost
> 
> Well, no, they're really not critical, but your comment surprises me. 
> I've been using vbox for years, on various assignments, and never
> encountered anything else.  Can you say a word or two to that, or
> provide a URL?  Which free vm is "the best"?

I never bothered bookmarking URLs about this, but can elaborate on my 
reasoning and experience.

Virtualbox is a nice product and I do use it when it is convenient. It is 
perfect for quickly starting a VM to test something. It integrates nicely with 
the desktop to be able to quickly copy/paste data across and also easy to 
connect to the filesystem on the host.

This also mentions the reason why it is NOT suitable for actual production 
use. It is a virtualisation tool for a desktop.

If you want your VMs to run as fast and stable as possible, you want the host 
to be as minimal as possible. This means:
- it runs headless (no GUI, just text) and the host has only 1 task: Run VMs.
- it doesn't contain anything else (only exception is stuff for monitoring)

Virtualbox does not (afaik) support block-devices for VMs. It only supports 
file-based disks. This is fine as it allows you to "quickly" move these to 
different storage. But it adds another layer between the hardware and VM 
(filesystem on the host) which adds it's own write-caching and potential 
corruption (I have had this on several occasions).

The virtualisation systems I mentioned in my previous email (Xen, KVM, VMWare) 
all support block-devices and sit as close to hardware as is possible. In the 
case of VMWare, I am talking about the server product, not the desktop 
product. The VMWare desktop product has the same problems as VirtualBox.

As for which free one is best, I am reluctant to answer specifically as both 
Xen and KVM are good.

Personally, I use Xen. I have been using it since one of the 2.x versions and 
KVM didn't exist back then.
Xen has the hypervisor in a small "kernel" and the host runs as a VM with full 
privileges. You can add additional privileges VMs to provide storage, further 
seperating tasks between VMs.
Citrix also provides a free version of their Xen-product which can be managed 
remotely, but their remote-tool is windows-only last time I checked. I run Xen 
on top of Gentoo and manage everything from the CLI.

KVM runs inside a Linux kernel and this instance automatically is the host. (I 
don't know enough to properly compare the 2, there are plenty of resources 
about comparisons online, most are biased to one or the other)

Both Xen and KVM can be managed with other tools like virt-manager. I don't as 
I don't like the way those tools want to manage the whole environment.

As for use of these systems, when only looking at companies where I have 
experience with:

- VMWare is often used for virtualising servers
- Xen (Citrix) is often used to provide Virtual Desktop to users
- KVM is used by most VPS providers
- Virtualbox is used for training sessions

I have not come across MS HyperV outside of small businesses that need some 
local VMs. These companies tend to put all their infrastructure with one of 
the big cloud-VM providers (Like AWS, Azure, Googles,...)

--
Joost