Colors of Noise

Entries from October 2008.

Libvirt munin plugins 0.0.4
31st October 2008

The libvirt munin plugins improved quiet a bit since their initial release:

Tags: libvirt, munin.
Installing Debian Lenny in a Xen DomU using virtinst
31st October 2008

Now that Debian Installer supports Xen guests (many thanks to the d-i team for that) it was about time that virtinst/virt-manager could make use of it. Debian's virtinst package in experimental now supports this (the patch is also already included in upstream's mercurial repository). To install a paravirtialized guest on an existing block device use:

virt-install -n xenfoo1 -r 96 --disk path=/dev/blockdevice,device=disk --location=

To install into an image file you additionally have to specify the file size in GB:

virt-install -n xenfoo1 -r 96 --disk path=/path/to/file,device=disk,size=1 --location=

if you don't want to use a sparse file also add sparse=false. In all cases the disk will become /dev/xvda in the domU and the device will be partitioned during installation (so no need to pass in single partitions, booting will happen using pygrub).

--location above points to the Debian Installer daily builds since there hasn't been a d-i release with Xen support yet (this should happen really soon now). Once this has happened you can use any Debian mirror to install. (--location=

Tags: libvirt.
krb5-auth-dialog: new icon
18th October 2008

Since it should be obvious at a glance when the ticket is about to expire I added a third icon:

expiring ticket

It gets shown together with the first notification, which is tunable via the /apps/krb5-auth-dialog/prompt_minutes gconf key:

gconftool-2 --type=int --set /apps/krb5-auth-dialog/prompt_minutes 30

The code landed on the pkinit branch so the build instructions stay the same. I also added a gconf schema to ease configuration and fixed a possible segfault on startup.

Tags: single-sign-on.
Libvirt KVM device hotplug
17th October 2008

My top three remaining "annoyances" in libvirt when it comes to KVM are:

  1. missing hotplug for disks
  2. daemon restart kills VMs
  3. missing migration support

Since KVM now supports PCI hotadd since a couple of releases I fixed up 1 today. I already sent a partial patch for 2 some time ago which I need to finish and clean up. Hopefully 3 is resolved upstream until then.

Once this is done libvirt plus kvm will be a great tandem for virtualization. On the desktop virt-manager does a great job while for H/A purposes it integrates with Redhat's cluster suite - you can use the resource script for this after removing the xen specific code and replacing it with calls to ''virsh''.

Tags: libvirt.
Libvirt munin plugins
16th October 2008

Here are two munin plugins that monitor disk and network I/O of virtual machines using libvirt. These are also two simple examples on using the libvirt python bindings. You need python-libvirt and python-libxml2 installed in order to use them. If you don't want to use the default uri, try:

env.uri qemu:///system

Munin-node needs to have read access to libvirt's socket. This is the case in Debian's default installation.

Tags: libvirt, munin.
Swirlberry Debian package
5th October 2008

There's now a swirlberry package available for the Freerunner:

    echo <<EOF >/etc/apt.conf.d/99_swirlberry.list
    deb unstable/
    apt-get install swirlberry

This brings all the necessary dependencies and sets up your X-session. It makes most of the configuration steps superflous, only thing left is setting up your kerberos principal and your tmut accounts. Make sure you restart your zhone-session once after installing the package.

Also make sure that:

hostname --fqdn

returns a valid hostname (if it doesn't check /etc/hosts and /etc/hostname) and that you have something like ntpdate installed for proper timekeeping. Note: if you want to use network manager you still have to add allow-hotplug eth0 in /etc/network/interfaces.

Tags: freerunner.

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