Customize the hypervisor node definition to create network bridge
xCAT ships a postscript xHRM to create a network bridge on kvm host during installation/netbooting. Specify the xHRM with appropriate parameters in postscripts attribute. For example:
To create a bridge named 'br0' against the installation network device specified by installnic: :
chdef kvmhost1 -p postscripts="xHRM bridgeprereq br0"
To create a bridge with default name 'default' against the installation network device specified by installnic: :
chdef kvmhost1 -p postscripts="xHRM bridgeprereq"
To create a bridge named 'br0' against the network device 'eth0': :
chdef kvmhost1 -p postscripts="xHRM bridgeprereq eth0:br0"
Note: The network bridge name you use should not be the virtual bridges (vbrX) created by libvirt installation1.
Customize the hypervisor node definition to mount the shared kvm storage directory on management node (optional)
If the shared kvm storage directory on the management node has been exported, it can be mounted on PowerKVM hypervisor for virtual machines hosting.
An easy way to do this is to create another postscript named "mountvms" which creates a directory /install/vms on hypervisor and then mounts /install/vms from the management node, the content of "mountvms" can be: :
logger -t xcat "Install: setting vms mount in fstab" mkdir -p /install/vms echo "$MASTER:/install/vms /install/vms nfs \ rsize=8192,wsize=8192,timeo=14,intr,nfsvers=2 1 2" >> /etc/fstab
Then set the file permission and specify the script in postscripts attribute of hypervisor node definition: :
chmod 755 /install/postscripts/mountvms chdef kvmhost1 -p postscripts=mountvms
Provision the hypervisor node with the osimage :
nodeset kvmhost1 osimage=<osimage_name> rpower kvmhost1 boot
To launch VMs, a network bridge must be created on the KVM hypervisor.
If the hypervisor is provisioned successfully according to the steps described above, a network bridge will be created and attached to a physical interface. This can be checked by running brctl show
on the hypervisor to show the network bridge information, please make sure a network bridge has been created and configured according to the parameters passed to postscript "xHRM" :
# brctl show
bridge name bridge id STP enabled interfaces
br0 8000.000000000000 no eth0
If the network bridge is not created or configured successfully, run "xHRM" with updatenode on management node to create it manually::
updatenode kvmhost1 -P "xHRM bridgeprereq eth0:br0"
Verify libvirtd service is running: :
systemctl status libvirtd
If service is not running, it can be started with: :
systemctl start libvirtd
Every standard libvirt installation provides NAT based connectivity to virtual machines out of the box using the "virtual bridge" interfaces (virbr0, virbr1, etc) Those will be created by default.↩