Archive for August, 2009

Ubuntu 9.04 Desktop

Just did an install of the 9.04 desktop. Very clean. Intend to do some testing with kvm, virtual box and win4lin.

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vmbuilder, virtio and fstab

nic@vm-base:~$ sudo blkid /dev/vda2
/dev/vda2: UUID=”0c75b2dd-6c6f-4729-b041-0d95475dc171″ TYPE=”swap”

If you install a vm with vmbuilder without virtio the swap section of /etc/fstab will use /dev/sda2 instead of /dev/vda2. You can use blkid

nic@vm-base:~$ sudo blkid
/dev/vda1: UUID="bac299c4-c545-46ca-aed3-26da4a56f6d7" TYPE="ext3"
/dev/vda2: TYPE="swap" UUID="0c75b2dd-6c6f-4729-b041-0d95475dc171"
/dev/vdb: UUID="jIkLcQ-zXUo-KIWR-zvmm-cpKP-9PpT-eE9RY3" TYPE="lvm2pv"
and then add this UUID to fstab:
nic@vm-base:~$ cat /etc/fstab
# /etc/fstab: static file system information.
# <file system>                                 <mount point>   <type>  <options>       <dump>  <pass>
proc                                            /proc           proc    defaults        0       0
/dev/sda1                                       /               ext3    defaults        0       0
UUID="0c75b2dd-6c6f-4729-b041-0d95475dc171"     swap            swap    defaults        0       0

in order to get swap working with different driver types.

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Shared Storage and Virtualisation

Recent issues and 18 months of experience have shown me that shared storage for a small (2-4 node) virtualisation cluster is hard.

It is still practical and possible to build a shared storage cluster using Solaris, rather than buying super experience appliance storage. But you must always spec at least two storage nodes, otherwise you lock yourself into a structure that can be difficult to change. That includes changes that involve upgrades.

Virtualisation technology has moved a long way in the last couple years. And while I’m still formulating a new approach, there are many more options for flexible micro virtualisation clusters.

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KVM, disk formats and disposable computing

I’ve got a couple XenServer vms that I never migrated to ESX. Time and complexity got in the way. In fact one of the reasons why I dislike XenServer is that fact that way it ran disk images was not portable.   Where as with ESX and KVM I can migrate disk images between the two hypervisors without needing to chance anything in the guest. With XenServer at the time this was not easy. XenOSS has a similar issue with PV domains, although with KVM+xenner  is meant to be able to run these.

Anyway here are a few links for converting disk images between formats.

I found though in the end that kvm-img or qemu-img has able to handle all the images I use: VHD, VMDK, RAW, and QCOW2. For example kvm-image convert disk.vhd -O raw disk.raw will work.

This leads to the nicest thing I found about KVM. With either ESXi 3.5 or vSphere 4 ubuntu 8.04 or 8.10 VMDK files I was able to: kvm-img convert -O raw disk.vmdk disk.raw. Then run this new disk in raw format with KVM plus virtio drivers and do so without any changes in the guest.

This truely is disposable computing!

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Running KVM

I’ve started running KVM recently and I’ll post a review at some point. I’m finding it very flexible and much much easier to use that Xen.

There are still a few questions regarding file caches and disk images. In general I’m happy that it’s ready for production.

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