Guest agents

“Guest agents” are special programs which run inside VMs which can be controlled via the XenAPI.

One communication method between XenAPI clients is via Xenstore.

Adding Xenstore entries to VMs

Developers may wish to install guest agents into VMs which take special action based on the type of the VM. In order to communicate this information into the guest, a special Xenstore name-space known as vm-data is available which is populated at VM creation time. It is populated from the xenstore-data map in the VM record.

Set the xenstore-data parameter in the VM record:

xe vm-param-set uuid= xenstore-data:vm-data/foo=bar

Start the VM.

If it is a Linux-based VM, install the COMPANY_TOOLS and use the xenstore-read to verify that the node exists in Xenstore.


Only prefixes beginning with vm-data are permitted, and anything not in this name-space will be silently ignored when starting the VM.