Hook Manager configuration is set in /etc/one/oned.conf. Hooks can be tied to changes in host or virtual machine states, and they can be executed locally to the OpenNebula front-end and remotely in the relevant worker node.

In general, hook definition in /etc/one/oned.conf has two paremeters:

• executable: path of the hook driver executable, can be an absolute path or relative to /usr/lib/one/mads

• arguments: for the driver executable, can be an absolute path or relative to /etc/one/

In the case of VirtualMachine hooks, the following can be defined:

• name : for the hook, useful to track the hook (OPTIONAL)
• on : when the hook should be executed,
  • CREATE, when the VM is created (onevm create)
  • RUNNING, after the VM is successfully booted
  • SHUTDOWN, after the VM is shutdown
  • STOP, after the VM is stopped (including VM image transfers)
  • DONE, after the VM is deleted or shutdown
  • FAILED, when the VM enters the failed state
• command : path can be absolute or relative to /var/lib/one/remotes/hooks
• arguments : for the hook. You can access the following VM attributes with $
  • $VMID, the ID of the VM that triggered the hook execution
  • $TEMPLATE, the template of the VM that triggered the hook, in xml and base64 encoded
• remote : values,
  • YES, The hook is executed in the host where the VM was allocated
  • NO, The hook is executed in the OpenNebula server (default)

The following is an example of a hook tied to the DONE state of a VM:

#-------------------------------- Image Hook -----------------------------------
# This hook is used to handle image saving and overwriting when virtual machines
# reach the DONE state after being shutdown.

VM_HOOK = [
    name      = "image",
    on        = "DONE",
    command   = "image.rb",
    arguments = "$VMID" ]

#-------------------------------------------------------------------------------

In the case of Host hooks, the following can be defined:

• name : for the hook, useful to track the hook (OPTIONAL)
• on : when the hook should be executed,
  • CREATE, when the Host is created (onehost create)
  • ERROR, when the Host enters the error state
  • DISABLE, when the Host is disabled
• command : path can be absolute or relative to /var/lib/one/remotes/hooks
• arguments : for the hook. You can use the following Host attributes with $
  • $HID, the ID of the Host that triggered the hook execution
  • $TEMPLATE, the full Host information, in xml and base64 encoded
• remote : values,
  • YES, The hook is executed in the host
  • NO, The hook is executed in the OpenNebula server (default)

The following is an example of a hook tied to the ERROR state of a Host:

#-------------------------------- Host Hook -----------------------------------
# This hook is used to perform recovery actions when a host fails. The VMs
# running in the host can be deleted (use -d option) or resubmitted (-r) in
# other host
# Last argument (force) can be "y", so suspended VMs in the host will be 
# resubmitted/deleted, or "n", so suspended VMs in the host will be ignored

HOST_HOOK = [
    name      = "error",
    on        = "ERROR",
    command   = "host_error.rb",
    arguments = "$HID -r n",
    remote    = no ]
#-------------------------------------------------------------------------------