Backing up your VM metadata

While a KVM stores some of the resources' configuration on the disk in a human readable format, it is a good idea to query libvirt for the configuration of your resources.

How to do it…

In this recipe we'll back up all relevant KVM metadata by performing the following steps:

Here's the network configuration:

~]# for i in $(virsh net-list --all | sed -e '1,2d' |awk '{print $1}'); do \
    virsh net-dumpxml --network $i --inactive > /tmp/net-$i.xml; \
done

Here's the storage configuration:

~]# for i in $(virsh pool-list --all | sed -e '1,2d' |awk '{print $1}'); do \
    for j in $(virsh vol-list --pool $i |sed -e '1,2d') | awk '{print $1}'; do \
        virsh vol-dumpxml --pool $i --vol $j > /tmp/vol-$j.xml; \
    done \
    virsh pool-dumpxml --pool $i --inactive > /tmp/pool-$i.xml; \
done

Here's the guest configuration:

~]# for i in $(virsh list --all | sed -e '1,2d' |awk '{print $1}'); do \
    virsh dumpxml --domain $i --inactive > /tmp/domain-$i.xml; \
done

How it works…

The virsh net-dumpxml command allows you to dump the precise configuration of the specified network. In combination with virsh net-list, you can create a loop that enumerates all networks and dumps them on the file. By specifying –-all, you will export all networks, even those that are not active. If you do not wish to back up the configuration for nonactive networks, substitute virsh net-list --all with virsh net-list.

Storage pools can be enumerated, similarly to networks, using virsh net-list. However, besides the individual storage pool configuration, we are also interested in the configuration of individual storage volumes. Luckily, both implement a list and dumpxml command! If you're not interested in nonactive pools, you can omit the --all option with virsh pool-list.

Guests can similarly be enumerated and their XML configuration dumped using dumpxml. Again, if you're not interested in nonactive guests, you can omit the --all option with virsh list.

See also

The man page for virsh (1) lists all the possible options for the commands used in the preceding section.