Located under /var/lib/one/remotes/datastore/<ds_mad>

• cp: copies/dumps the image to the datastore
  • ARGUMENTS: datastore_image_dump image_id
  • RETURNS: image_source size
  • datastore_image_dump is an XML dump of the driver action encoded in Base 64. See a decoded example.
  • image_source is the image source which will be later sent to the transfer manager
• mkfs: creates a new empty image in the datastore
  • ARGUMENTS: datastore_image_dump image_id
  • RETURNS: image_source size
  • datastore_image_dump is an XML dump of the driver action encoded in Base 64. See a decoded example.
  • image_source is the image source which will be later sent to the transfer manager.
• rm: removes an image fromthe datastore
  • ARGUMENTS: datastore_image_dump image_id
  • RETURNS: -
  • datastore_image_dump is an XML dump of the driver action encoded in Base 64. See a decoded example.
• stat: returns the size of an image in Mb
  • ARGUMENTS: datastore_image_dump image_id
  • RETURNS: size
  • datastore_image_dump is an XML dump of the driver action encoded in Base 64. See a decoded example.
  • size the size of the image in Mb.
• clone: clones an image.
  • ARGUMENTS: datastore_action_dump image_id
  • RETURNS: source
  • datastore_image_dump is an XML dump of the driver action encoded in Base 64. See a decoded example.
  • source the new source for the image.

image_source has to be dynamically generated by the cp and mkfs script. It will be passed later on to the transfer manager, so it should provide all the information the transfer manager needs to locate the image. To illustrate a few examples:

• FS driver: DATASTORE_BASE_PATH + md5sum(date + id)
• iSCSI driver: <base_iqn>:<host>.<vg-name>.<lv-name>

This is a list of the TM drivers and their action. Note that they don't return anything. If the exit code is not 0, the driver will have failed.

Located under /var/lib/one/remotes/tm/<tm_mad>. There are two types of action scripts: the first group applies to general image datastores and includes (clone, ln, mv and mvds); the second one is only used in conjunction with the system datastore.

Action scripts for generic image datastores:

• clone: clones the image from the datastore (non-persistent images)
  • ARGUMENTS: fe:SOURCE host:remote_system_ds/disk.i vm_id ds_id
  • fe is the front-end hostname
  • SOURCE is the path of the disk image in the form DS_BASE_PATH/disk
  • host is the target host to deploy the VM
  • remote_system_ds is the path for the system datastore in the host
  • vm_id is the id of the VM
  • ds_id is the target datastore (the system datastore)
• ln: Links the image from the datastore (persistent images)
  • ARGUMENTS: fe:SOURCE host:remote_system_ds/disk.i vm_id ds_id
  • fe is the front-end hostname
  • SOURCE is the path of the disk image in the form DS_BASE_PATH/disk
  • host is the target host to deploy the VM
  • remote_system_ds is the path for the system datastore in the host
  • vm_id is the id of the VM
  • ds_id is the target datastore (the system datastore)
• mvds: moves an image back to its datastore (persitent images or deferred snapshots)
  • ARGUMENTS: host:remote_system_ds/disk.i fe:SOURCE vm_id ds_id
  • fe is the front-end hostname
  • SOURCE is the path of the disk image in the form DS_BASE_PATH/disk
  • host is the target host to deploy the VM
  • remote_system_ds is the path for the system datastore in the host
  • vm_id is the id of the VM
  • ds_id is the target datastore (the original datastore for the image)
• cpds: moves an image back to its datastore (executed for life disk snapshots)
  • ARGUMENTS: host:remote_system_ds/disk.i fe:SOURCE vm_id ds_id
  • fe is the front-end hostname
  • SOURCE is the path of the disk image in the form DS_BASE_PATH/disk
  • host is the target host to deploy the VM
  • remote_system_ds is the path for the system datastore in the host
  • vm_id is the id of the VM
  • ds_id is the target datastore (the original datastore for the image)

Action scripts needed when the TM is used for the system datastore:

• context: creates an ISO that contains all the files passed as an argument.
  • ARGUMENTS: file1 file2 … fileN host:remote_system_ds/disk.i vm_id ds_id
  • host is the target host to deploy the VM
  • remote_system_ds is the path for the system datastore in the host
  • vm_id is the id of the VM
  • ds_id is the target datastore (the system datastore)
• delete: removes the eithr system datastore's directory of the VM or a disk itself.
  • ARGUMENTS: host:remote_system_ds/disk.i|host:remote_system_ds/ vm_id ds_id
  • host is the target host to deploy the VM
  • remote_system_ds is the path for the system datastore in the host
  • vm_id is the id of the VM
  • ds_id is the target datastore (the system datastore)
• mkimage: creates an image on-the-fly bypassing the datastore/image workflow
  • ARGUMENTS: size format host:remote_system_ds/disk.i vm_id ds_id
  • size size in MB of the image
  • format format for the image
  • host is the target host to deploy the VM
  • remote_system_ds is the path for the system datastore in the host
  • vm_id is the id of the VM
  • ds_id is the target datastore (the system datastore)
• mkswap: creates a swap image
  • ARGUMENTS: size host:remote_system_ds/disk.i vm_id ds_id
  • size size in MB of the image
  • host is the target host to deploy the VM
  • remote_system_ds is the path for the system datastore in the host
  • vm_id is the id of the VM
  • ds_id is the target datastore (the system datastore)
• mv: moves images/directories across system_ds in different hosts. When used for the system datastore the script will received the directory ARGUMENT
  • ARGUMENTS: hostA:system_ds/disk.i|hostB:system_ds/disk.i vm_id ds_id OR hostA:system_ds/|hostB:system_ds/ vm_id ds_id
  • hostA is the host the VM is in.
  • hostB is the target host to deploy the VM
  • system_ds is the path for the system datastore in the host
  • vm_id is the id of the VM
  • ds_id is the target datastore (the system datastore)
• premigrate: It is executed before a livemigration operation is issued to the hypervisor. Note that only the premigrate script from the system datastore will be used. Any customization must be done for the premigrate script of the system datastore, although you will probably add operations for other backends than that used by the system datastore.
  • ARGUMENTS: source_host dst_host remote_system_dir vmid dsid template
  • src_host is the host the VM is in.
  • dst_host is the target host to migrate the VM to
  • remote_system_ds_dir is the path for the VM directory in the system datastore in the host
  • vmid is the id of the VM
  • dsid is the target datastore
  • template is the template of the VM in XML and base64 encoded
• postmigrate: It is executed after a livemigration operation. Note that only the postmigrate script from the system datastore will be used. Any customization must be done for the postmigrate script of the system datastore, although you will probably add operations for other backends than that used by the system datastore.
  • ARGUMENTS: source_host dst_host remote_system_dir vmid dsid template
  • see premigrate description.

You only need to implement one mv script, but consider the arguments received when the TM is used for the system datastore, a regular image datastore or both.

If the TM is only for regular images you only need to implement the first group.

Consider a VM with two disks:

NAME   = vm01
CPU    = 0.1
MEMORY = 64
 
DISK   = [ IMAGE_ID = 0 ] # non-persistent disk
DISK   = [ IMAGE_ID = 1 ] # persistent disk

This a list of TM actions that will be called upon the events listed:

CREATE

<tm_mad>/clone <frontend>:<non_pers_image_source> <host01>:<ds_path>/<vm_id>/disk.0
<tm_mad>/ln <frontend>:<pers_image_source> <host01>:<ds_path>/<vm_id>/disk.1

STOP

<tm_mad>/mv <host01>:<ds_path>/<vm_id>/disk.0 <frontend>:<ds_path>/<vm_id>/disk.0
<tm_mad>/mv <host01>:<ds_path>/<vm_id>/disk.1 <frontend>:<ds_path>/<vm_id>/disk.1
<tm_mad_sysds>/mv <host01>:<ds_path>/<vm_id> <frontend>:<ds_path>/<vm_id>

RESUME

<tm_mad>/mv <frontend>:<ds_path>/<vm_id>/disk.0 <host01>:<ds_path>/<vm_id>/disk.0
<tm_mad>/mv <frontend>:<ds_path>/<vm_id>/disk.1 <host01>:<ds_path>/<vm_id>/disk.1
<tm_mad_sysds>/mv <frontend>:<ds_path>/<vm_id> <host01>:<ds_path>/<vm_id>

MIGRATE host01 → host02

<tm_mad>/mv <host01>:<ds_path>/<vm_id>/disk.0 <host02>:<ds_path>/<vm_id>/disk.0
<tm_mad>/mv <host01>:<ds_path>/<vm_id>/disk.1 <host02>:<ds_path>/<vm_id>/disk.1
<tm_mad_sysds>/mv <host01>:<ds_path>/<vm_id> <host02>:<ds_path>/<vm_id>

SHUTDOWN

<tm_mad>/delete <host02>:<ds_path>/<vm_id>/disk.0
<tm_mad>/mvds <host02>:<ds_path>/<vm_id>/disk.1 <pers_image_source>
<tm_mad_sysds>/delete <host02>:<ds_path>/<vm_id>

• non_pers_image_source: Source of the non persistent image.
• pers_image_source : Source of the persistent image.
• frontend: hostname of the frontend
• host01: hostname of host01
• host02: hostname of host02
• tm_mad: TM driver of the datastore where the image is registered
• tm_mad_sysds: TM driver of the system datastore

There is a helper shell script with some functions defined to do some common tasks. It is located in /var/lib/one/remotes/scripts_common.sh

Here are the description of those functions.

• log: Takes one parameter that is a message that will be logged into the VM log file.

log "Creating directory $DST_DIR"

• error_message: sends an exit message to oned surrounding it by separators, use to send the error message when a command fails.

error_message "File '$FILE' not found"

• arg_host: gets the hostname part from a parameter

SRC_HOST=`arg_host $SRC`

• arg_path: gets the path part from a parameter

SRC_PATH=`arg_path $SRC`

• exec_and_log: executes a command and logs its execution. If the command fails the error message is sent to oned and the script ends

exec_and_log "chmod g+w $DST_PATH"

• ssh_exec_and_log: This function executes $2 at $1 host and report error $3

ssh_exec_and_log "$HOST" "chmod g+w $DST_PATH" "Error message"

• timeout_exec_and_log: like exec_and_log but takes as first parameter the max number of seconds the command can run

timeout_exec_and_log 15 "cp $SRC_PATH $DST_PATH"