KVM
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Using VirtualBox and KVM together
Using VirtualBox and KVM together at the same server at the same time is NOT possible!!!
Use VirtualBox
sudo service qemu-kvm stop sudo service vboxdrv start
OR use KVM
sudo service vboxdrv stop sudo service qemu-kvm start
Decide!
comand line foo
Show running machines
sudo apt-get install ubuntu-vm-builde virsh -c qemu:///system list
Show bridges
brctl show
Migration from VirtualBox to KVM
This boils down to
- having a lot of time
- having a lot of free harddisk space
- creating a clone of the vbox-machine with VBoxManage clonehd (this can take a looooong time!). Kloning is the easiest way of getting rid of snapshots of an existing virtual machine.
- converting the images from vdi to qcow-format with qemu-img convert
- creating and configuring a new kvm-guest
- adding some fou to NAT with a qemu-hook (see next section)
To clone an image - on the same machine - you have to STOP kvm and start vboxdr (see above). Also be aware, that the raw-images take up a lot of space!
# The conversion can take some time. Other virtual machines are not accessible in this time VBoxManage clonehd -format RAW myOldVM.vdi /home/vm-exports/myNewVM.raw 0%...
cd /home/vm-exports/ qemu-img convert -f raw myNewVM.raw -O qcow2 myNewVM.qcow
Cloning a Snapshot:
# for a snapshot do (not tested) cd /to/the/SnapShot/dir VBoxManage clonehd -format RAW "SNAPSHOT_UUID" /home/vm-exports/myNewVM.raw
Accessing services on KVM guests behind a NAT
This is done by editing a hook-script for quemu:
/etc/libvirt/hooks/qemu
I am referring to this article:
which ist mentioned in the libvirt wiki:
I installed the qemu-python script of the first article under ubuntu 12.04 LTS, which worked like expected.
So I can access a port in the virtualmachine-guest with the IP/Port of the host (!). From within the host, it is possible to reach the guest via it's real ip. I am using the virtio-Interface (performance).
Control NAT rules
iptables -nvL -t nat
Then you should see something like the following.
These PREROUTING rules open up the ports 80, 443 and 8080 (fantasy services!) for the NAT'ed virtual machine with the IP 192.168.122.2. So they are accessible from the outside world (webserver, e-mail-server, ...). They have to be applied by the qemu-hook script mentioned above.
The POSTROUTING chains are set automatically by virt-manager and allow the virtual-machine accessing the internet from inside of the machine using NAT.
root@myHost:# iptables -nvL -t nat Chain PREROUTING (policy ACCEPT 216 packets, 14658 bytes) pkts bytes target prot opt in out source destination 6 312 DNAT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:1222 to:192.168.122.2:80 2 120 DNAT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:1223 to:192.168.122.2:443 0 0 DNAT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:1444 to:192.168.122.2:8080 Chain INPUT (policy ACCEPT 14 packets, 2628 bytes) pkts bytes target prot opt in out source destination Chain OUTPUT (policy ACCEPT 12 packets, 818 bytes) pkts bytes target prot opt in out source destination Chain POSTROUTING (policy ACCEPT 17 packets, 1048 bytes) pkts bytes target prot opt in out source destination 0 0 MASQUERADE tcp -- * * 192.168.122.0/24 !192.168.122.0/24 masq ports: 1024-65535 6 406 MASQUERADE udp -- * * 192.168.122.0/24 !192.168.122.0/24 masq ports: 1024-65535 0 0 MASQUERADE all -- * * 192.168.122.0/24 !192.168.122.0/24
A script from here is a little bit altered:
- Guest port same as host port
- ability to apply more than ohne port
- ability to serve more than one guest
Delete NAT rules
iptables -t nat -D PREROUTING 1
Where "1" is the first PREROUTING rule that appears with the above command.
In the above example the first line is the PREROUTING chain with the number "6" and the port 80. This is the FIRST rule.
Autostart at boot time
Set the 'autostart' flag so the domain is started upon boot time:
virsh autostart myMachine
Shutdown
On Ubuntu 12.04 LTS (Precise Pangolin) the shutdown scripts already take care of stopping the virtual machines (at least in the newest version of the libvirt-bin package). However, by default the script will only wait 30 seconds for the VMs to shutdown. Depending on the services running in the VM, this can be too short.
In this case, you have to create a file /etc/init/libvirt-bin.override with the following content:
> vim /etc/init/libvirt-bin.override # extend wait time for vms to shut down to 4 minutes env libvirtd_shutdown_timeout=240
Backup KVM
Via LVM
- http://pof.eslack.org/2010/12/23/best-solution-to-fully-backup-kvm-virtual-machines
- http://sandilands.info/sgordon/automatic-backup-of-running-kvm-virtual-machines
LiveBackup (under development - --Apos (talk) 18:07, 30 October 2013 (CET))