Re: [Xen-users] Installing Xen on Debian Sarge

[Miguel Enrique Cobá Martínez <m.coba.m@xxxxxxxxx>]

Mark Foster wrote:
> Miguel Enrique Cobá Martínez wrote:
>
> > 2. They are all about installing on plain devices, not lvm volumes.
> If you are serious about using Xen for production systems you will want 
> use LVM or something other than simple file-based disks. Sounds like 
> some others are using true SANs or gnbd or drbd? My personal preference 
> is to assign an 8GB logical volume for "/" and another volume for swap, 
> the size depending on how much RAM will be assigned to the DomU. That 
> fits my bill, but in the physical world I much prefer giving separate 
> partitions for /boot, /usr, /var and so on. It's just too much 
> (maintenance) overhead with virtual systems. I also prefer to use RAID 
> 0+1 over SCSI.
Yes I agree, in my future servers I will be using something more robust 
that simple IDE disk. For the moment, as I am starting with Xen, I have 
to use my desktop for all the tests. Unfortunately, until I can show a 
working system and the advantages for use it, they aren't investing much 
money for this :D
> > I will be testing a distributed system I built for work. For this I need
> > a central node and 10 remote nodes. I thought that Xen will be the
> > perfect solution. Just create 11 DomUs with minimal debian in each one,
> > run the test of the system and collect statistics.
> >
> > I have put a lot of time in my current desktop, so I would like to
> > continue using my desktop, but running as Dom0. I would like to use the
> > second hard drive to install the virtual machines.
>
> I would recommend a dedicated system for Xen Dom0, as running it on your 
> desktop is asking for trouble. Running your desktop in Xen as a DomU is 
> also silly.
> Keep your Dom0 as small as possible to minimize your risk when patching 
> (you are patching right?)
Yes they are a lot of trouble. I finally have a Dom0 and three DomU, all 
with sarge, but the dom0 nvidia card is quite hard to configure.
> > After a lot of problems and 3 days of search and testing I finally
> > booted my machine as Dom0. These are the steps I followed:
> >
> > 1. I used the unstable pkgs for xen
>
> OK.
>
> > 2. I downloaded the src from:
> > http://www.cl.cam.ac.uk/Research/SRG/netos/xen/downloads/xen-2.0.7-src.tgz 
> >
> > and compiled using my current kernel config in /boot.
>
> Huh? You used the pkgs AND you installed from src?
Yes, because the packages only install /boot/xen.gz, xend and xendomains 
 and symlinks in /etc/init.d/. You are supposed to build or download 
your dom0 and domU images.
> > 3. I installed the new XenLinux kernel in /boot and configured menu.lst
> > according.
> > 3. I had to build a initrd image so that the boot process could mount
> > the root partition on lvm. I use the script from
> > /usr/share/doc/lvm2/examples/lvm2create_initrd.gz
> > to build the initrd, as mkinitrd has a bug with lvm root partitions.
>
> Ah, good info!
>
> > 4. I updated grub to use the initrd and all worked ok.
> >
> > After that, I had my system running Xen but without graphical setup.
> > This is  not a problem, as I probably could configured correctly with
> > patience.
> > I am now ready for creating domains for the real work and I can say that
> > I have managed to install Xen successfully.
> > In spite of that, I have the feeling that the solution isn't optimal or
> > the best.
> >
> > So, the questions:
> >
> > - I'm doing this the proper way? 
>
> > - Is this the intended way of installing Xen?
> > I mean, should I use my configured and personalised original machine
> > (postgresql, apache, firefox, thunderbird, /home, etc) on top of Xen as
> > Dom0 and from time to time to create DomUs for specific task? Or should
> > I use a minimal debian for Dom0, just for hosting the DomUs and use one
> > of the DomU as workstation, with all my configuration and selection of
> > packages inside and the other DomUs for working as needed?
>
> I wouldn't do what you are doing, but to each his own.
>
> > - If I use Dom0 for my workstation, I think I will have full control of
> > all the others DomUs, and I could use them as I wanted. I could access
> > it with xm console without problems. But if I use one DomU for my
> > workstation how could I access the other DomUs? With ssh or vnc only?
> > What happend if I wanted to access the DomO from DomU? I think that I
> > couldn't do that.
>
> ssh or vnc or whatever! The only thing you lose is console access from 
> your desktop to the DomUs, but that can be done by ssh-ing to DomO and 
> 'xm console' from there.
> > - What will pass with the updates of my kernel in Dom0?  Will I need to
> > redo all the steps for configuring my new xen-enabled kernel, creating
> > an initrd image, compiling nvidia drivers and, when my Dom0 was updated,
> > then update all of my DomUs?
>
> You can specify a default kernel in /boot/grub/menu.lst you will 
> sidestep any kernels installed via apt-get (or aptitude)
> > A don't want to create a flame war, but I would like to hear the
> > scenarios you used and the decisions you made when configuring Xen.
> > Also, I would like to read your toughts about your use of Xen.
>
> Using LVM was a good idea. LVM snapshots are also interesting way to 
> save disk space and have multiple systems based on a common denominator, 
> but I have yet to get that going. If anyone else has, I'd sure like to 
> know how to set it up "right".
> Good luck.
I think I'll try them soon.

Thanks

_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users