March 2009 Archives

purely of historical interest.

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Some days it seems like the caches have churned just right, and El Goog is giving me more useful information than I know what to do with. . . circa two years ago.  This is that day.  I know I've used these search strings before, but some of these links are positively delicious.

Anyway, here's an interesting post on using Perl to communicate with Xen via the XenAPI.

http://unixfoo.blogspot.com/2007/12/perl-xen-api.html
So, when installing CentOS 5.2 (and possibly other distros) with virt-manager, console output disappears after the "mounting /sys filesystem" line.  This might only happen in low-memory conditions.  (The fact that anything less than 512 MB is considered low-memory for an _installer_, by the way, I find appalling.)

To work around this issue, install using the extra kernel argument "xencons=tty" (no quotes.)

on xen vanilla kernels

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Interesting thread on merging Xen dom0 support into the kernel:

http://thread.gmane.org/gmane.linux.kernel/800658/focus=800714

Obviously I'm biased toward moving Xen completely in-kernel -- it's ridiculous to rely on out-of-kernel patches that haven't been updated to work with newer kernels -- but I don't have the deep familiarity needed to give reasons why this is bad off the top of my head.  Jeremy Fitzhardinge does, and it's quite enlightening.

the very most basic.

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One of the basic things that I think we forget to mention in an earlier chapter is how to get domains to start automatically on boot.  It can't stay where it is now, so I'm dumping it out here and tagging it as an orphan until we've got the chapter in shape.

By default, Xen ships with a script installed as
/etc/init.d/xendomains , and creates symlinks so that it starts in
runlevels 3, 4, and 5.

The xendomains script will iterate through the /etc/xen/auto
directory, and start each domain with a config file in that directory.
When the machine shuts down, it calls xendomains with a stop argument,
which shuts down all running domains.  (Not just the ones in
/etc/xen/auto.)

We usually use symlinks -- simply link each domain that you want
started at boot into that directory
Today I spent some time revamping the Solaris sections, which have hitherto been a source of some vexation.  Plus side, I can get both the OpenSolaris and Solaris Express installers running in paravirtualized mode, no problem.

See, Solaris actually supports Xen so well that it's intensely frustrating when something doesn't work -- but I also find some of their decisions so confusing that I mess up and make stuff fail to work properly ALL THE TIME.

Sorry, I seem to have been sidetracked.  Anyway, one benefit of this modern world is the ability to install distros directly from install media.  Both SolExp and OpenSol support booting the installer directly as a domU.  So, the first step is:

1. Download either OpenSolaris or Solaris Express.

This is easy enough.  Both are available at http://opensolaris.org/os/downloads .  OpenSol's a CD, SolExp's a DVD.  Pick the one you want.

2. Create an appropriate domU config file.

You'll want to include the usual stuff.  The important Solaris-specific bits are the kernel and miniroot location, and some boot arguments.

OpenSolaris:
kernel='/platform/i86xpv/kernel/amd64/unix'
ramdisk= '/boot/x86.microroot'
extra= '/platform/i86xpv/kernel/amd64/unix - nowin -B install_media=cdrom'

Solaris Express:
kernel='/boot/platform/i86xpv/kernel/amd64/unix'
ramdisk= '/boot/amd64/x86.miniroot'
extra='/boot/platform/i86xpv/kernel/amd64/unix -B install_media=cdrom'

(I'm not sure how important those parameters are.)  Make sure that you include the usual config file trappings -- stuff like root device, name, and so forth.

If you're using a prgmr.com brand VPS, we'll have done these things already.  That leaves the last step:

3. Start the domain and run the installer.

Solaris Express will start the installer automatically.  One warning, though -- the installer hangs if you configure the network with it on our setup.  Your mileage may vary.  I just opted to claim the system was non-networked and set the network up later.

Now, OpenSolaris doesn't include a text-mode installer, and we don't give you framebuffers, so you'll have to do a couple things before you run the OpenSolaris installer.  First, change your password.  (Use the normal passwd command.)  Then, enable sshd:

$ pfexec svcadm enable network/ssh

Give yourself your assigned IP, SSH in, and run the installer:

$ pfexec ifconfig <ip> netmask <netmask>
$ pfexec route add default <gateway addr>

(local desktop) $ ssh -X <ip>
$ pfexec /usr/bin/gui-install

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This page is an archive of entries from March 2009 listed from newest to oldest.

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