Configuration tips

The main configuration information is provided in OpenNebula configuration. Here you can find additional configuration details.

Recommended configuration

/etc/one/vmm_exec/vmm_exec_kvm.conf

Note that these are the default values and could be overridden in the IMAGE and VM templates!

Activate the qemu guest agent socket in libvirt

The addon could use fstrim/fsthaw to create consistent snapshots/backups. The option enables the host side of the setup. The qemu-guest-agent must be running inside the VM.

Default:

FEATURES = [ PAE = "no", ACPI = "yes", APIC = "no", HYPERV = "no", GUEST_AGENT = "no" ]
Suggested:

FEATURES = [ PAE = "no", ACPI = "yes", APIC = "no", HYPERV = "no", GUEST_AGENT = "yes" ]

Change defaults for IO and discard

Add defaults for io and discard.

Default:

DISK = [ driver = "raw" , cache = "none"]
Suggested:

DISK = [ driver = "raw" , cache = "none" , io = "native" , discard = "unmap" ]

/var/lib/one/remotes/etc/vmm/kvm/kvmrc

Or /var/lib/one/remotes/vmm/kvm/kvmrc, for OpenNebula before version 5.6.

DEFAULT_ATTACH_CACHE

Uncomment to enable.

Default:

#DEFAULT_ATTACH_CACHE=none
Suggested:

DEFAULT_ATTACH_CACHE=none

DEFAULT_ATTACH_DISCARD

Uncomment to enable

Default:

#DEFAULT_ATTACH_DISCARD=unmap
Suggested:

DEFAULT_ATTACH_DISCARD=unmap

DEFAULT_ATTACH_IO

Uncomment and set to native

Default:

#DEFAULT_ATTACH_IO=
Suggested:

DEFAULT_ATTACH_IO=native

Extras

!!! Warning !!! These features are changing the defalt behavior of OpenNebula and should be used when the StorPool addon is the only storage driver, and when used for both SYSTEM and IMAGE datastores!

VM snapshots

The feature is working only with recent version of StorPool. Please contact StorPool Support for details.

The StorPool addon can re-purpose the OpenNebula’s interface for VM snapshots to do atomic snapshots on all VM disks at once. In addition, there is an option to enable FSFREEZE before snapshotting and FSTHAW after the snapshots are taken.

To enable the feature do the following changes.

In /etc/one/oned.conf:

Edit the VM_MAD configuration for kvm and change the ARGUMENTS line as follows:

    ARGUMENTS      = "-t 15 -r 0 kvm -l snapshotcreate=snapshot_create-storpool,snapshotrevert=snapshot_revert-storpool,snapshotdelete=snapshot_delete-storpool",

Edit the VM_MAD configuration for kvm and change KEEP_SNAPSHOTS to ‘yes’:
```
    KEEP_SNAPSHOTS = "yes",
```

In /var/lib/one/remotes/addon-storpoolrc:
1. Add VMSNAPSHOT_OVERRIDE configuration variable:
  
  VMSNAPSHOT_OVERRIDE=1
2. To enable the optional fsfreeze/fsthaw:
```
VMSNAPSHOT_FSFREEZE=1
```

Please restart the opennebula service to activate the changes.

Using StorPool SYSTEM datastore when there are other SYSTEM datastores available

Using scheduler filters

To tell the OpenNebula’s scheduler to deploy the VMs only on StorPool backed SYSTEM datastores, set SCHED_DS_REQUIREMENTS in the VM template:

SCHED_DS_REQUIREMENTS="TM_MAD=storpool"

Using sunstone, it is located in “Update VM template” -> “Scheduling” -> “Placement” -> “Datastore Requirements”. Set the “Expression” to TM_MAD=storpool.

Using Cluster definition

Define an OpenNebula cluster selecting only StorPool backed SYSTEM and IMAGE datastores. Keep in mind that in this case the images used in the VM templates must be on the datastore selected in the cluster!