In order to use VMware hypervisors in your OpenNebula cloud you will need to use VMFS Datastores. To configure them, it is important to keep in mind that there are (at least) two datastores to define, the system datastore (where the running VMs and their images reside, only need transfer manager drivers) and the images datastore (where the images are stored, needs both datastore and transfer manager drivers).

inlinetoc

• In order to use the VMFS datastore, the ESX servers need to have the SSH access configured for the oneadmin account.

• If the VMFS volumes are exported through a SAN, it should be accesible and configured so the ESX server can mount the iSCSI export.

This storage model implies that all the volumes involved in the image staging are purely VMFS volumes, taking full advantage of the VMware filesystem (VM image locking and improved performance).

• The OpenNebula front-end doesn't need to mount any datastore.

• The ESX servers needs to present or mount (as iSCSI or NFS) both the system datastore and the image datastore (naming them with just the <datastore-id>, for instance 0 for the system datastore and 1 for the image datastore).

The system datastore can be other than the default one (““0””). In this case, the ESX will need to mount the datastore with the same id as the datastores has in OpenNebula. More details in the System Datastore Guide.

The datastore location on ESX hypervisors is “/vmfs/volumes”. There are two choices:

• In homogeneous clouds (all the hosts are ESX) set the following in /etc/one/oned.conf:

DATASTORE_LOCATION=/vmfs/volumes

• In heterogeneous clouds (mix of ESX and other hypervisor hosts) put all the ESX hosts in clusters with the following attribute in their template (e.g. onecluster update):

DATASTORE_LOCATION=/vmfs/volumes

You need to configure the DATASTORE_LOCATION either in the target cluster or oned.conf before creating the datastore.

The system and images datastores needs to be configured with the following drivers:

vmfs drivers: the system datastore needs to be updated in OpenNebula (onedatastore update <ds_id>) to set the TM_MAD drivers to vmfs. There is no need to configure datastore drivers for the system datastore.

OpenNebula expects the system datastore to have the ID=0, but a system datastore with different ID can be defined per cluster. See the system datastore guide for more details.

The image datastore needs to be updated to use vmfs drivers for the datastore drivers, and vmfs drivers for the transfer manager drivers. The default datastore can be updated as:

<xterm> $ onedatastore update 1 DS_MAD=vmfs TM_MAD=vmfs BRIDGE_LIST=<space-separated list of ESXi host> </xterm>

Apart from DS_MAD, TM_MAD and BRIDGE_LIST; the following attributes can be set:

Attribute	Description
NAME	The name of the datastore
DS_MAD	The DS type, use vmware or vmfs
TM_MAD	Transfer drivers for the datastore: shared, ssh or vmfs, see below
RESTRICTED_DIRS	Paths that can not be used to register images. A space separated list of paths.
SAFE_DIRS	If you need to un-block a directory under one of the RESTRICTED_DIRS. A space separated list of paths.
UMASK	Default mask for the files created in the datastore. Defaults to 0007
BRIDGE_LIST	Space separated list of ESX servers that are going to be used as proxies to stage images into the datastore (vmfs datastores only)
DS_TMP_DIR	Path in the OpenNebula front-end to be used as a buffer to stage in files in vmfs datastores. Defaults to the value in /var/lib/one/remotes/datastore/vmfs/vmfs.conf.
NO_DECOMPRESS	Do not try to untar or decompress the file to be registered. Useful for specialized Transfer Managers
DATASTORE_CAPACITY_CHECK	If “yes”, the available capacity of the datastore is checked before creating a new image

SAFE_DIRS will prevent users registering important files as VM images and accessing them through their VMs. OpenNebula will automatically add its configuration directories: /var/lib/one, /etc/one and oneadmin's home. If users try to register an image from a restricted directory, they will get the following error message: “Not allowed to copy image file”.

These drivers trigger the events remotely through an ssh channel. The vmfs drivers are a specialization of the shared drivers to work with the VMware vmdk filesystem tools using the vmkfstool command. This comes with a number of advantages, like FS locking, easier VMDK cloning, format management, etc.

The vmfs datastore drivers allows the use of the VMware VM filesystem, which handles VM file locks and also boosts I/O performance.

• To correctly configure a vmfs datastore set of drivers there is the need to chose the ESX bridges, i.e., the ESX serves that are going to be used as proxies to stage images into the vmfs datastore. A list of bridges must be defined with the BRIDGE_LIST attribute of the datastore template (see the table below). The drivers will pick one ESX server from that list in a round robin fashion.

• The vmfs datastore needs to use the front-end as a buffer for the image staging in some cases, this buffer can be set in the DS_TMP_DIR attribute.

Drivers can be easily customized please refer to the specific guide for each datastore driver or to the Storage substystem developer's guide.

However you may find the files you need to modify here:

• /var/lib/one/remotes/datastore/<DS_DRIVER>
• /var/lib/one/remotes/tm/<TM_DRIVER>