[CentOS] error creating Centos 5.1x32 dum_Uinstance on CentOS5.1x64

[Ross S. W. Walker]

Rudi Ahlers wrote:
> Ross S. W. Walker wrote: 
> > That shouldn't be, the list acts like any other CentOS list, maybe
> > you entered your email address incorrectly, got spam filtered, or
> > is just temporarily broken, but it should send you an email upon
> > subscribing to confirm your subscription.
> >   
> Really? Maybe I subscribed to the wrong list then, but this 
> is the reply 
> I got:
> 
> Your mail to 'CentOS-virt' with the subject
> 
>     subscribe centos-virt
> 
> Is being held until the list moderator can review it for approval.
> 
> The reason it is being held:
> 
>     Message may contain administrivia

Try subscribing through the mailman web site:

http://lists.centos.org/mailman/listinfo



> > Did you verify that selinux is indeed disabled by looking in
> > /etc/selinux/config that the line SELINUX=disabled is in there?
> >
> >   
> Yep:
> 
> # This file controls the state of SELinux on the system.
> # SELINUX= can take one of these three values:
> #       enforcing - SELinux security policy is enforced.
> #       permissive - SELinux prints warnings instead of enforcing.
> #       disabled - SELinux is fully disabled.
> SELINUX=disabled
> # SELINUXTYPE= type of policy in use. Possible values are:
> #       targeted - Only targeted network daemons are protected.
> #       strict - Full SELinux protection.
> SELINUXTYPE=targeted

Good, just some users use setenforce 0 and think that's it done
and then reboot and wonder why things are still not working
properly.

> > What was the actual contents of your domU's config file?
> >
> >   
> This is what I changed:
> 
> # Dom0 will balloon out when needed to free memory for domU.
> # dom0-min-mem is the lowest memory level (in MB) dom0 will 
> get down to.
> # If dom0-min-mem=0, dom0 will never balloon out.
> (dom0-min-mem 512)
> 
> It was:
> (dom0-min-mem 256)

Misunderstanding, I was hoping to see the config file of the
domU you were trying to create.

> > Also is this a workstation with Xen domU's for testing/development
> > or a full blown Xen server for running production VMs?
> >
> > -Ross
> >   
> 
> This will be a full blown Xen server for production purposes. It will 
> run max 8 Xen guests with cPanel on each one.

In that case if you don't want to shell out the $ for Xen Enterprise
I would do these steps for setting up a Xen server:

- for each server, minimal install, no X to reduce any possible dom0
issues, and to allow you to minimize dom0 memory usage, you can then
run in 256MB with no X windows!

- use the Xen 3.2 packages off of xen.org, compiled 64-bit, compile on
separate 64-bit platform as the compilation will pull in a lot of other
development packages and X. These packages use the Xen kernel from
CentOS for the kernel image, and that package comes with the 3.1 Xen
image so you'll need to edit the grub.conf to make sure the Xen 3.2
image is used instead of the 3.1 image every time you upgrade the kernel.
These packages provide the latest features and fixes as well as the more
capable management tools and API which will become a necessity when you
manage from the command line and/or have more then 1 server which
eventually you will for scalability, redundancy, etc.

- Start seriously thinking about implementing an iSCSI SAN, your
storage requirements will balloon crazy until your virtualization
environment stabilizes, and SANs allows for better storage
utilization, scalability and also allows for VM migration from one host
to another and are a bitch to migrate to after the fact.

- Build your Xen config files by hand, it's the only way to assure
they are setup properly and the way you want.

Since a Xen environment will be sensitive to change, maybe not as
much as a LAMP environment, but still probably second to, you may
want to manage your Xen build yourself, at least for the servers,
as Redhat's Xen implementation is still evolving.

I would use Redhat's Xen environments once they have a pure Xen 3.2
build, as their current Frankenstein environment is really aimed
at workstation deployments, especially their hoaky X tool.

-Ross

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