Migrate Linux RHEL 6.5 from XenServer to Nutanix AHV

October 7, 2015

Next part of my migration blog series, this time how to migrate Linux RHEL 6.5 from XenServer to Nutanix AHV.

So far you could read:

Requirements:

AOS – 4.6.1.1 or newer
AHV – 20160217.2 or newer
XenServer 6.5 or newer with XenCenter lastest buil
connectivity between legacy XenServer servers and Nutanix CVMs over NFS
remove all snapshots from VM

Let’s get started 🙂

check what Linux kernel is used if you can see xen somwhere this means you have to install default kernel

[root@rhel65xc ~]# uname -a
Linux rhel65xc.gso.lab 2.6.32-431.el6.x86_64 #1 SMP Sun Nov 10 22:19:54 EST 2013 x86_64 x86_64 x86_64 GNU/Linux
[root@rhel65xc ~]#

Check if you have virtIO drivers present in system

[root@rhel65xc ~]# grep -i virtio /boot/config-2.6.32-431.el6.x86_64
CONFIG_NET_9P_VIRTIO=m
CONFIG_VIRTIO_BLK=m
CONFIG_SCSI_VIRTIO=m
CONFIG_VIRTIO_NET=m
CONFIG_VIRTIO_CONSOLE=m
CONFIG_HW_RANDOM_VIRTIO=m
CONFIG_VIRTIO=m
CONFIG_VIRTIO_RING=m
CONFIG_VIRTIO_PCI=m
CONFIG_VIRTIO_BALLOON=m
[root@rhel65xc ~]#

Check if virtio modules are part of the initramfs. RHEL 6.5 has virtio drivers build it. If there is not output – no modules, meaning you have to create either new initrd or initramfs images.

[root@rhel65xc ~]# zcat /boot/initramfs-2.6.32-431.el6.x86_64.img | cpio -it | grep virtio
lib/modules/2.6.32-431.el6.x86_64/kernel/drivers/block/virtio_blk.ko
lib/modules/2.6.32-431.el6.x86_64/kernel/drivers/scsi/virtio_scsi.ko
lib/modules/2.6.32-431.el6.x86_64/kernel/drivers/virtio
lib/modules/2.6.32-431.el6.x86_64/kernel/drivers/virtio/virtio.ko
lib/modules/2.6.32-431.el6.x86_64/kernel/drivers/virtio/virtio_pci.ko
lib/modules/2.6.32-431.el6.x86_64/kernel/drivers/virtio/virtio_ring.ko

create new initrd with virtio modules – RHEL 5.X

[root@rhel65xc ~]# mkinitrd --with="virtio_blk virtio_pci" -f -v /boot/initrd-`uname -r`.img `uname -r`

create new initrd with virtio modules – RHEL 6.X

[root@rhel65xc ~]# dracut --add-drivers "virtio_pci virtio_blk" -f -v /boot/initramfs-`uname -r`.img `uname -r`

check new initrd (RHEL 6.X), virtio modules are there. we can stop server

[root@rhel65xc ~]# zcat /boot/initramfs-`uname -r`.img | cpio -it | grep virtio
lib/modules/2.6.32-431.el6.x86_64/kernel/drivers/block/virtio_blk.ko
lib/modules/2.6.32-431.el6.x86_64/kernel/drivers/scsi/virtio_scsi.ko
lib/modules/2.6.32-431.el6.x86_64/kernel/drivers/virtio
lib/modules/2.6.32-431.el6.x86_64/kernel/drivers/virtio/virtio.ko
lib/modules/2.6.32-431.el6.x86_64/kernel/drivers/virtio/virtio_pci.ko
lib/modules/2.6.32-431.el6.x86_64/kernel/drivers/virtio/virtio_ring.ko
96407 blocks

Update /boot/grub/grub.conf so that console=ttyS0 rather then console=hvc0.
In /etc/fstab remove disk UUID which is next to /boot and replace it by /dev/hda
Update /boot/grub/device.map and replace xvda with hda
Make sure VM boots in HVM mode with ‘xe vm-param-set uuid=[vm uuid] HVM-boot-policy=”BIOS order”‘ (you can get the vm uuid with xe vm-list) from the XenServer
Reboot the VM.

[root@xenserver01 ~]# xe vm-list
uuid ( RO) : 480a7144-bf18-4c2e-a623-ee404fd8e70f
 name-label ( RW): Control domain on host: xenserver01.gso.lab
 power-state ( RO): running

uuid ( RO) : 021a6ea2-f11d-8590-931e-2bbd434f0998
 name-label ( RW): rhel65xs
 power-state ( RO): halted

[root@xenserver01 ~]# xe vm-param-set uuid=021a6ea2-f11d-8590-931e-2bbd434f0998 HVM-boot-policy="BIOS order"
[root@xenserver01 ~]# xe vm-param-get uuid=021a6ea2-f11d-8590-931e-2bbd434f0998 param-name=HVM-boot-policy
BIOS order
[root@xenserver01 ~]#

Stop VM
List all VM disk, use command xe vm-disk-list uuid=<VM-UUID> – see example below. Note down UUID for VDI entry.

[root@xenserver01 ~]# xe vm-list
uuid ( RO) : 480a7144-bf18-4c2e-a623-ee404fd8e70f
 name-label ( RW): Control domain on host: xenserver01.gso.lab
 power-state ( RO): running

uuid ( RO) : 021a6ea2-f11d-8590-931e-2bbd434f0998
 name-label ( RW): rhel65xs
 power-state ( RO): halted

[root@xenserver01 ~]# xe vm-disk-list uuid=021a6ea2-f11d-8590-931e-2bbd434f0998
Disk 0 VBD:
uuid ( RO) : 547baeb1-b117-68df-d423-f3b4b6764bd8
 vm-name-label ( RO): rhel65xs
 userdevice ( RW): 0

Disk 0 VDI:
uuid ( RO) : 1433eadb-218c-4c22-b7bb-5931a5aec369
 name-label ( RW): rhel65xs 0
 sr-name-label ( RO): NFS virtual disk storage
 virtual-size ( RO): 8589934592

Use qemu-img tool to convert disk from VHD to RAW – see example below

[root@kvm01]# qemu-img convert -f vpc 1433eadb-218c-4c22-b7bb-5931a5aec369.vhd -O raw rhel65xs01.img

Transfer file onto Nutanix container
Log in to Nutanix Acropolis and provision VM
Add new disk
- Type: DISK
- Operation: CLONE FROM ADSF FILE
- Bus type: SCSI
- Path – provide path to VM file image in raw format

add network adapter
Take VM snaphot
Power VM on

Now we have to fix networking.

Remove below file and reboot VM

[root@rhel65xs ~]# rm -f /etc/udev/rules.d/70-persistent-net.rules

Edit the same file and:
- note down MAC address
- change eth1 to eth0

# This file was automatically generated by the /lib/udev/write_net_rules
# program, run by the persistent-net-generator.rules rules file.
#
# You can modify it, as long as you keep each rule on a single
# line, and change only the value of the NAME= key.

# PCI device 0x1af4:0x1000 (virtio-pci)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="52:54:00:2a:43:c6", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"

Edit network configuration file and:
- remove UUID
- change MAC address

[root@rhel65xs ~]# vi /etc/sysconfig/network-scripts/ifcfg-eth0

DEVICE=eth0
TYPE=Ethernet
ONBOOT=yes
NM_CONTROLLED=yes
BOOTPROTO=none
HWADDR=52:54:00:2a:43:c6
IPADDR=10.4.92.22
PREFIX=24
GATEWAY=10.4.92.1
DNS1=10.4.89.111
DEFROUTE=yes
IPV4_FAILURE_FATAL=yes
IPV6INIT=no
NAME="System eth0"

restart networking services and you should have network up and running

[root@rhel65xs ~]# service network restart
Shutting down interface eth0: [ OK ]
Shutting down loopback interface: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface eth0: Determining if ip address 10.4.92.22 is already in use for device eth0...
 [ OK ]
[root@rhel65xs ~]#

If you have time, watch video