Moving from CentOS 6 to 7

KVM: setting up bridged mode

• RedHat tell you to replace NetworkManager with network first: access.redhat.com/…ibvirt.html

systemctl disable NetworkManager
systemctl enable network
systemctl stop NetworkManager
systemctl start network

• The only problem with the above is that network does not seem to start on boot.

chkconfig --list network    # shows that it should be running
systemctl start network     # the new way of starting it
/etc/init.d/network restart # the old way of starting it

• Once you have disabled NetworkManager it is very easy to create a new bridged network in Virtual Machine Manager (see RH document above)

Moving LVM partitions

• To get the LVM gui tool, for now you have to:

wget https://kojipkgs.fedoraproject.org//packages/system-config-lvm/1.1.18/1.fc19/noarch/system-config-lvm-1.1.18-1.fc19.noarch.rpm
sudo yum install system-config-lvm

• Move zipped image and then unzip (uses fast version of algorithm, and the fast arcfour encryption)

dstserver=andrew@server7
srcvol=vg_old/<<VM>>
dstvol=vg_old/<<VM>>
volname=/home/andrew/<<VM>>.img.gz
dd if=/dev/$srcvol | gzip -c --fast | ssh -c arcfour $dstserver "dd of=$volname"
gunzip -c $volname | dd of=/dev/$dstvol

• In theory it could be done in one shot:

dd if=/dev/$srcvol | gzip -c --fast | ssh -c arcfour $dstserver "gunzip -c | dd of=/dev/$dstvol"

• Alternative method using netcat described here: serverfault.com/…nother#156514
• Note that the port must be open on the receiving machine!

nc -l 1234 | gunzip -c | dd of=/dev/vg_server7/<<VM>> #on new host. Tells netcat to listen on port
dd if=/dev/vg_old/<<VM>> | gzip -c --fast | nc <targetip> 1234 #on old host.

Moving KVM Virtual Machines

1. Create logical volume on the new server, the same size as the old.
2. Shutdown old VM.
3. Transfer image
4. rsync -av /etc/libvirt/qemu/«VM».xml root@server7:/etc/libvirt/qemu
   5. New machine: systemctl restart libvirtd
6. Open virt-manager and edit storage (and maybe network)
7. Start machine!