| | 1 | [[PageOutline]] |
| | 2 | = Transforming Xen guests into KVM guests = |
| | 3 | |
| | 4 | We have some Xen systems. They're configured in a certain way. We want to transfer the Xen guests to a KVM host, which we want configured in a slightly different way. |
| | 5 | |
| | 6 | This page documents that process. it's a work in progress. |
| | 7 | |
| | 8 | == Shorthand == |
| | 9 | |
| | 10 | * `$guest` -- this is the name of the guest being transferred |
| | 11 | * `$xenhost` -- this is the dom0 running the xen setup we are transferring from |
| | 12 | * `$kvmhost` -- this is the machine we are transferring to (note that this is not the same machine as `$xenhost`, though such a transfer might be possible for some people; that's not what we're working with, so some choices here might be different) |
| | 13 | |
| | 14 | == disk differences == |
| | 15 | |
| | 16 | Our Xen setup (via [DebianPackage:xen-tools xen-tools]) has `$xenhost` serving `$guest` its partitions as individual volumes. So `$xenhost` has them broken out in LVM directly, and `$guest` doesn't use LVM at all, or even see a parent `/dev/sda` -- it only sees `/dev/sda1`,`/dev/sda2`, etc. |
| | 17 | |
| | 18 | Our KVM setup typically has `$kvmhost` serving a single volume to `$guest`, and `$guest` carves it up however it sees fit. |
| | 19 | |
| | 20 | == booting differences == |
| | 21 | |
| | 22 | Our Xen setup has `$xenhost` hold a kernel and initrd outside of `$guest`, and boots `$guest` into those systems directly (no bootloader, no "BIOS"-level disk access at boot). |
| | 23 | |
| | 24 | Our KVM setup has `$kvmhost` pass the virtual disk to `$guest`, which uses an emulated BIOS to pull a bootloader off the disk, and start from there. |
| | 25 | |
| | 26 | == architecture differences == |
| | 27 | |
| | 28 | All our KVM hosts are amd64. Most of our remaining Xen hosts (and guests) are 32-bit (686). We'd like all the guests to end up 64-bit clean eventually, but a non-invasive transfer that is relatively opaque to the guest might be preferable, even if it means the guest doesn't move to 64-bits immediately. |
