Re: [gentoo-user] {OT} Allow work from home?

[J. Roeleveld]

On Tuesday, January 19, 2016 01:46:45 AM lee wrote:
> "J. Roeleveld" <joost@××××××××.org> writes:
> > On Monday, January 18, 2016 02:02:27 AM lee wrote:
> >> "J. Roeleveld" <joost@××××××××.org> writes:
> >> > On 17 January 2016 18:35:20 CET, Mick <michaelkintzios@×××××.com>
> >> > wrote:
> >> >
> >> > [...]
> >> >
> >> >>I use the icaclient provided by Citrix to access my virtual desktop at
> >> >>work,
> >> >>but have never tried to set up something similar at home.  What
> >> >>opensource
> >> >>software would I need for this?  Is there a wiki somewhere to follow?
> >> >>
> >> > I'd love to do this myself as well.
> >> >
> >> > Citrix sells the full package as 'XenDesktop'. To do it yourself you
> >> > need
> >> > a VMserver (Xen or similar) and a remote desktop tool that hooks into
> >> > the
> >> > VM display. (Spice or VNC)
> >> >
> >> > Then you need some way of authenticating users and providing access to
> >> > the
> >> > client software. [...]
> >>
> >> You would have a full VM for each user?
> >
> > Yes
> >
> >> That would be a huge waste of resources,
> >
> > Diskspace and CPU can easily be overcommitted.
>
> Overcommitting disk space sounds like a very bad idea.  Overcommitting
> memory is not possible with xen.

Overcommitting diskspace isn't such a bad idea, considering most installs 
never utilize all the available diskspace.
Overcommitting memory is, i think, on the roadmap for Xen. (Disclaimer: At 
least, I seem to remember reading that somewhere)

> >> plus having to take care of a lot of VMs,
> >
> > Automated.
>
> Like how?

How do you manage a large amount of physical machines?
Just change physical to VMs and do it the same.
With VMs you have more options for automation.

> >> plus having to buy  a lot of Windoze licenses
> >
> > Volume licensing takes care of that.
>
> expensive

Depends on the requirements. It's cheaper then a few hundred seperate windows 
licenses.

> >> and taking about a week to install the updates
> >> after installing a VM.
> >
> > Never heard of VM templates?
>
> It still takes a week to put the updates onto the template.

Last time I had to fully reinstall a windows machine it took me a day to do 
all the updates. Microsoft even has server software that will keep them 
locally and push them to the clients.

> >> Add to that that the xen host goes down at
> >> random time intervals (because the sending queue of the network card
> >> times out for reasons that cannot be determined) which can be as long as
> >> a day, a week or even up to three weeks, and you are likely to become a
> >> rather unhappy administrator.
> >
> > Sorry, but I consider that a bug in your hardware. If it's really that
> > unstable, replace it.
> > I've been running Xen enabled servers for nearly 15 years. Never had
> > issues
> > like that. If it were truly that unstable, it wouldn't be gaining
> > popularity.
> The hardware has already been replaced, and the problem persists.  Other
> machines of identical hardware that don't run xen don't show any issues.

I still say the hardware is buggy. With replacing, I meant replace it with 
different hardware, not a different version of the same buggy stuff.

> >> Try kvm instead, and you'll find that
> >> it's impossible to migrate the VMs from xen to to kvm when you want to
> >> use virtio drivers because you can't install them on an existing Windoze
> >> VM.
> >
> > Not a problem with the virtualisation technology. It is an issue with
> > driver management inside MS Windows.
> > There are ways to migrate VMs succesfully, I just don't see the point in
> > wasting time for that.
>
> It's time consuming when you have to reinstall the VMs to migrate them
> to kvm.  And when you don't have the installers of all the software
> that's on some of the VMs and can't get them, you either have to run
> them without virtio drivers or you can't migrate them.

There are Howtos on the internet describing how to migrate VMs from 1 
technology to another. Shouldn't be too hard.
And keeping the installers at hand is, in my opinion, a requirement of sane 
system management.
I have installers for all the versions of software I deal with.

> > The biggest reason why I don't use KVM is the lack of full snapshot
> > functionality. Snapshotting disks is nice, but you end up with an unclean-
> > shutdown situation and anything that's not yet committed to disk is gone.
>
> I'm not sure what you mean.  When you take a snapshot while the VM is not
> shut down, what difference does it make whether you use xen or kvm?

A "snapshot" for KVM is ONLY the disks.
With Xen, VMWare and Virtualbox, I can also make a snapshot/copy of what's in 
memory. It's that which makes the difference.

> >> Then there's the question how well vnc or spice connections work over a
> >> VPN that goes over the internet.
> >
> > VNC works quite well, as long as you use a minimal desktop. (like
> > blackbox). Don't expect KDE or Gnome to be usable.
> > I haven't tried Spice yet, but I've read that it performs better.
>
> It's not like you had a choice when you have Windoze VMs.

Windows has RDP, which is a lot better than VNC. Especially when dealing with 
low-bandwidth connections.

> >> It's not like the employees could get
> >> reliable internet connections with sufficient bandwidth, not to mention
> >> that the company would have to get one in the first place, which isn't
> >> much easier to get, if any.
> >
> > That depends on where you are.
>
> In this country, you have to be really lucky to find a place where you
> can get a decent internet connection.

Then in your country, working from home might not be the best option.

> > The company could host the servers in a decent datacentre, which should
> > take care of the bandwidth issues.
>
> And give all their data out of hands?  And how much does that cost?

I'm talking about putting your own hardware there, not letting the datacentre 
company access to the servers.

> > For the employees, if they want to work from home, it's up to them to
> > ensure they have a reliable connection.
>
> It is as much problem of the company when they want the employees to
> work at home.  And the employees don't have a choice, they can only get
> a connection they can get.

If the company insists people work from home, they need to ensure the 
employees have the option for a usable connection. Most companies I deal with 
leave working from home as an option to the employees.

> >> It might work in theory.  How would it be feasible in practise?
> >
> > Plenty of companies do it this way. If you don't want to pay for software
> > like XenDesktop, you need to do all the work setting it up yourself.
>
> VNC is somewhat slow over a 1Gbit LAN.  Did they find some way to
> overcome this problem?

Depends on the settings.

> This sounds like it is for people with unlimited resources.
>
> BTW, access a VM through VNC, and you don't even have any way to make
> the mouse pointer in the VNC window actually follow the mouse pointer
> you're using, which makes it rather annoying to do anything in the VM
> you're looking at.  If you found a solution for that, I'd be curious as
> to how you solved this problem.

There is, it's even documented.
I'm assuming you are talking about the VNC-console Xen provides?

Configure the mouse to be a tablet in the VM config and the issue disappears.

--
Joost