configuration_tips.md

OpenNebula configuration tips

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 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.

/etc/one/oned.conf

edit the VM_MAD configuration for kvm and change the ARGUMENTS line as follow

    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",

/var/lib/one/remotes/addon-storpoolrc

Add VMSNAPSHOT_OVERRIDE configuration variable

VMSNAPSHOT_OVERRIDE=1

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!