Libvirt error: Unable to resolve address error while migrating.

The QEMU quest end user is to end up with a pop-up error message while migrating. Such a type of error usually occurs when the source host can’t resolve to the destination IP that leads to migration failure.

As a part of our server management services, we use to handle QEMU guests, libvirt error while migrating. You can take our technical team support for further assistance.

Causes ‘Libvirt error: Unable to resolve address error.

Usually, this type of error caused when QEMU guest migration fails.

# virsh migrate qemu qemu+tcp://192.168.122.12/system

Error: Unable to resolve address name_of_host service ‘49155’: Name or service not known

For example: If the destination hostname is ‘Arizona, the below error will be displayed on the screen.

# virsh migrate qemu qemu+tcp://192.168.122.12/system

# virsh migrate qemu qemu+tcp://192.168.122.12/system

Error: Unable to resolve address ‘arizona’ service ‘49155’: Name or service not known.

This was a quite strange error on the screen, where we didn’t even use any name that related to Arizona host.

Cause for this error:

This can happen if DNS is not properly configured or /etc/hosts has the hostname associated with the local loopback address (127.0.0.1).

How to fix ‘Libvirt error.

In order to resolve this error, all you need to do is to configure DNS correctly, so all hosts involved in migration will be able to resolve the error or the hostnames.

If you can’t able to configure the DNS correctly, you need to add the list of all host used for migration manually to the /etc/hosts file on each of the hosts. this will become a difficult task in order to maintain all the list consistently in a dynamic environment. After doing the above configuration if it doesn’t resolve the hostnames error, then you can use the following virsh command which supports migration.

# virsh migrate qemu qemu+tcp://192.168.122.12/system tcp://192.168.122.12

Destination libvirtd will take the tcp://192.168.122.12 URI and append an automatically generated port number. If this is not desirable, the port number can be specified in the command:

# virsh migrate qemu qemu+tcp://192.168.122.12/system tcp://192.168.122.12:12345

Another option is to use tunneled migration.

Whereas the tunneled migration doesn’t create a separate connection for the migration data, this connection is used for communication with destination libvirtd:

# virsh migrate qemu qemu+tcp://192.168.122.12/system --p2p --tunnelled

Conclusion

In brief, fixing ‘Libvirt error’ this type of error usually occurs when the source host can’t resolve to the destination IP that leads to migration failure. Need some expert support, have a conversation with our technical support team to fix Libvirt error on your behalf.