So, we occasionally get customers who are having issues creating a new server from an image of a previous server. Normally this is caused by the nova-agent not being set to start on boot, or the xe-linux-distribution being missing from the VM. It’s possible to check whether a virtual machine is configured right and I put together this little piece with the help of my colleague and friend Zoltan.

1. Checking if Nova Agent is installed and can be started

# /etc/init.d/nova-agent start

2. Check if nova-agent and xe-linux-distribution is running on VM

# ps auxf | grep nova
# ps auxf | grep xe-daemon

If processes called nova-agent or xe-daemon return then you know they are running OK.

3. Ensure that both services do start during boot

# chkconfig nova-agent on
# chkconfig xe-linux-distribution on

For Debian and Ubuntu Systems you may need to use

update-rc.d -f nova-agent defaults

Once you confirm that these services are running it’s safe to take an image, and create a new VM with it. These 2 processes need to be running because when the new server is built the way that the VM gets its networking set is using xenstore and novaagent to retrieve and set the network interfaces file with correct ip, subnet and gateway.

– A