A OpenVZ cluster hosts GNU/Linux based virtual machines. The disk is extracted with rsync and uploaded to the glance OpenStack image service with glance add … disk_format=ami…. It is associated with a kernel image compatible with both OpenStack and the existing file system with glance update … kernel_id=0dfff976-1f55-4184-954c-a111f4a28eef ramdisk_id=aa87c84c-d3be-41d0-a272-0b4a85801a34 ….
copying the file system to a disk image
A virgin disk image is created with:
qemu-img create temporary.img 5G
The 5G size is chosen to be large enough to contain the file system of the OpenVZ container to be migrated. The image is initialized with a ext4 file system:
# mkfs.ext4 temporary.img
mke2fs 1.42.5 (29-Jul-2012)
temporary.img is not a block special device.
Proceed anyway? (y,n) y
Discarding device blocks: done
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
327680 inodes, 1310720 blocks
65536 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=1342177280
40 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736
Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
The image is mounted with
# mount -o loop temporary.img /mnt # df -h /mnt Filesystem Size Used Avail Use% Mounted on /dev/loop1 5.0G 203M 4.6G 5% /mnt
After login into the OpenVZ container, the entire file system is transfered to the disk with
openvz# rsync -avHSz --numeric-ids --exclude=/proc --exclude=/sys \
/ bm0001.the.re:/mnt/
When it completes, the /proc and /sys directories must to be created:
mkdir /mnt/proc /mnt/sys
And the eth0 interface must be added to /mnt/etc/network/interfaces as follows:
auto eth0 iface eth0 inet dhcp
The file system can then be umounted and reduced to its minimal size with:
# umount /mnt # fsck -f $(pwd)/temporary.img # resize2fs -M temporary.img
uploading to glance
Assuming the OpenVZ container was running on a 2.6.32 linux kernel, a compatible kernel and the corresponding initrd are uploaded to glance with:
glance add is_public=true name='initrd-2.6.32-5-amd64' disk_format=ari \ container_format=ari < initrd.img-2.6.32-5-amd64 glance add is_public=true name='linux-2.6.32-5-amd64' disk_format=aki \ container_format=aki < vmlinuz-2.6.32-5-amd64
The uuid of the kernel and initrd are listed with:
# glance --limit=400 index | grep 2.6.32 6bd78e8c-7ada-4e6f-bf5c-158de71c7664 initrd-2.6.32-5-amd64 ari ari 9309460 42d6e697-28b2-40b7-adcb-7c77b209bf97 linux-2.6.32-5-amd64 aki aki 2424448
The temporary.img file system can then be uploaded with:
glance add disk_format=ami container_format=ami name="exemple" \ is_public=false \ kernel_id="42d6e697-28b2-40b7-adcb-7c77b209bf97" \ ramdisk_id="6bd78e8c-7ada-4e6f-bf5c-158de71c7664" < temporary.img
booting
The instance can then boot with
nova boot --image 'exemple' --flavor e.1-cpu.10GB-disk.1GB-ram --key_name loic --availability_zone=bm0001 --poll exemple
and the boot log should look like:
# nova console-log exemple ... INIT: version 2.88 booting Using makefile-style concurrent boot in runlevel S. Activating swap...done. Cleaning up ifupdown.... Activating lvm and md swap...done. Checking file systems...fsck from util-linux-ng 2.17.2 done. Setting up networking.... Mounting local filesystems...done. Activating swapfile swap...done. Cleaning up temporary files.... Configuring network interfaces...Internet Systems Consortium DHCP Client 4.1.1-P1 Copyright 2004-2010 Internet Systems Consortium. All rights reserved. For info, please visit https://www.isc.org/software/dhcp/ Listening on LPF/eth0/fa:16:3e:33:0a:bf Sending on LPF/eth0/fa:16:3e:33:0a:bf Sending on Socket/fallback [ 3.280425] eth0: IPv6 duplicate address fe80::f816:3eff:fe33:abf detected! Setting kernel variables ...done. DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 4 DHCPOFFER from 10.145.2.11 DHCPREQUEST on eth0 to 255.255.255.255 port 67 DHCPACK from 10.145.2.11 bound to 10.145.2.9 -- renewal in 50 seconds. venet0: ERROR while getting interface flags: No such device Failed to bring up venet0. SIOCSIFADDR: No such device venet0:0: ERROR while getting interface flags: No such device SIOCSIFNETMASK: No such device venet0:0: ERROR while getting interface flags: No such device Failed to bring up venet0:0. done. Cleaning up temporary files....