Backup Storage ¶

Table of contents

Overview ¶

A backup Storage is a storage system that stores images for creating volumes. Backup storage can be filesystem based storage(e.g. NFS) or object store based storage(e.g. OpenStack swift), as long as the storage is network shared storage. Besides providing templates for creating volumes, backup storage also allow users to backup entities including volumes and volume snapshots.

A backup storage must be attached to a zone before the zone’s descendant resources can access it. Admins can take this advantage to share images across multiple zones, for example:

In the early stage of a cloud, there may be only one zone(Zone1) with a single backup storage. In pace with business development, admins may decide to create another zone(Zone2) but still use existing images for VMs; then admins can attach the backup storage to Zone2, so both Zone1 and Zone2 share the same images.

Note

In this ZStack version, the only supported backup storage is SFTP backup storage

Inventory ¶

Properties ¶

Name	Description	Optional	Choices	Since
uuid	see Resource Properties			0.6
name	see Resource Properties			0.6
description	see Resource Properties	true		0.6
url	see url			0.6
totalCapacity	total disk capacity in bytes, see capacity			0.6
availableCapacity	available disk capacity in bytes, see capacity			0.6
type	backup storage type		SftpBackupStorage	0.6
state	see state		Enabled Disabled	0.6
status	see status		Connecting Connected Disconnected	0.6
attachedZoneUuids	a list of zone UUID the backup storage has been attached			0.6
createDate	see Resource Properties			0.6
lastOpDate	see Resource Properties			0.6

Example ¶

{
    "attachedZoneUuids": [
        "36de66d82f424639af67215a465418f6"
    ],
    "availableCapacity": 1258407346176,
    "name": "sftp",
    "state": "Enabled",
    "status": "Connected",
    "totalCapacity": 1585341214720,
    "type": "SftpBackupStorage",
    "url": "/export/backupStorage/sftp",
    "uuid": "33a35f75885f45ab96ea2626ce9c05a6",
    "lastOpDate": "Jun 1, 2015 3:42:26 PM",
    "createDate": "Jun 1, 2015 3:42:26 PM"
}

URL ¶

URL is a string that contains information needed by backup storage plugins for manipulating storage systems. Although it’s named as URL, the certain format of the string is up to backup storage types and is not necessary to strictly follow the URL convention, to give flexibilities to plugins to encode information that may not be able to fit in the URL format.

SFTP Backup Storage URL ¶

For SFTP backup storage, the URL is the absolute path of a directory in the filesystem. For example, /storage/sftp.

Capacity ¶

ZStack keeps tracking disk capacities of backup storage in order to select suitable one when allocating space for storing images. The capacity is calculated by below formulas:

totalCapacity = backup storage's total capacity
availableCapacity = totalCapacity - sum(images' real sizes)

State ¶

Backup storage have two states:

Enabled:

The state that allows images to be registered, backup, and downloaded
Disabled:

The state that DOESN’T allow images to be registered, backup, and downloaded. Especially, if an image is only stored on a disabled backup storage, and if that image is not downloaded to image caches of primary storage yet, no VMs can be created from that image.

Status ¶

Status reflects the status of command channels amid ZStack management nodes and backup storage.

Connecting:

A ZStack management node is trying to establish the command channel between itself and a backup storage. No operations can be performed to the backup storage.
Connected

The command channel has been successfully established between a ZStack management node and a backup storage. Operations can be performed to the backup storage.
Disconnected

The command channel has lost between a ZStack management node and a backup storage. No operations can be performed to the backup storage.

ZStack management nodes will try to setup command channels every time when they boot, and will periodically send ping commands to backup storage to check the health of command channels. Once a backup storage fails to respond, or a ping command times out, the command channel is considered as lost and the backup storage will be placed in the status of Disconnected.

Here is the transition diagram:

SFTP Backup Storage ¶

SFTP backup storage is a Linux server that stores images in native filesystem and uses OpenSSH server/client to transfer images. ZStack uses a python agent (SftpBackupStorageAgent) to manage the Linux server; images are uploaded/downloaded to/from the server by SCP. Besides properties in backup storage inventory, SFTP backup storage has an extra property:

Name	Description	Optional	Choices	Since
hostname	the IP address or DNS name of the SFTP backup storage			0.6

Example ¶

{
    "attachedZoneUuids": [
        "36de66d82f424639af67215a465418f6"
    ],
    "availableCapacity": 1258407346176,
    "hostname": "172.16.0.220",
    "name": "sftp",
    "state": "Enabled",
    "status": "Connected",
    "totalCapacity": 1585341214720,
    "type": "SftpBackupStorage",
    "url": "/export/backupStorage/sftp",
    "uuid": "33a35f75885f45ab96ea2626ce9c05a6",
    "lastOpDate": "Jun 1, 2015 3:42:26 PM",
    "createDate": "Jun 1, 2015 3:42:26 PM"
}

Operations ¶

Add Backup Storage ¶

The commands to add a backup storage vary for different backup storage types.

Add SFTP Backup Storage ¶

Admins can use AddSftpBackupStorage to add a new backup storage. For example:

AddSftpBackupStorage name=sftp1 url=/storage/sftp1 hostname=192.168.0.220 username=root password=password

Parameters ¶

Name	Description	Optional	Choices	Since
name	resource name, see Resource Properties			0.6
resourceUuid	resource uuid, see Create Resources	true		0.6
description	resource description, see Resource Properties	true		0.6
url	see url			0.6
hostname	the IP address or DNS name of the SFTP backup storage			0.6
username	the user root		root	0.6
password	the SSH password for user root			0.6

Delete Backup Storage ¶

Admins can use DeleteBackupStorage to delete a backup storage. For example:

DeleteBackupStorage uuid=1613b627cb2e4ffcb30e7e59935064be

Warning

When deleting, a backup storage will be detached from attached zones. Copies of images and of volume snapshots on the backup storage will be deleted; if a copy is the only copy of an image or a volume snapshot, the image or the volume snapshot will be deleted as well. There is no way to recover a deleted backup storage.

Parameters ¶

Name	Description	Optional	Choices	Since
uuid	backup storage uuid			0.6
deleteMode	see Delete Resources	true	Permissive Enforcing	0.6

Change State ¶

Admins can use ChangeBackupStorageState to change the state of a backup storage. For example:

ChangeBackupStorageState uuid=33a35f75885f45ab96ea2626ce9c05a6 stateEvent=enable

Parameters ¶

Name

Description

Optional

Choices

Since

uuid

backup storage uuid

0.6

stateEvent

state trigger event

enable: change the state to Enabled
disable: change the state to Disabled

enable
disable

0.6

Attach Zone ¶

Admins can use AttachBackupStorageToZone to attach a backup storage to a zone. For example:

AttachBackupStorageToZone backupStorageUuid=d086c30f33914c98a6078269bab7bc8f zoneUuid=d086c30f33914c98a6078269bab7bc8f

Parameters ¶

Name	Description	Optional	Choices	Since
backupStorageUuid	the backup storage uuid			0.6
zoneUuid	the zone uuid			0.6

Detach Zone ¶

Admins can use DetachBackupStorageFromZone to detach a backup storage from a zone. For example:

DetachBackupStorageFromZone backupStorageUuid=d086c30f33914c98a6078269bab7bc8f zoneUuid=d086c30f33914c98a6078269bab7bc8f

Parameters ¶

Name	Description	Optional	Choices	Since
backupStorageUuid	the backup storage uuid			0.6
zoneUuid	the zone uuid			0.6

Query Backup Storage ¶

Admins can use QueryBackupStorage to query backup storage. For example:

QueryBackupStorage state=Enabled

QueryBackupStorage image.platform=Linux

Primitive Fields of Query ¶

see backup storage inventory

Nested And Expanded Fields of Query ¶

Field	Inventory	Description	Since
zone	zone inventory	zones this backup storage is attached to	0.6
image	image inventory	images this backup storage contains	0.6
volumeSnapshot	volume snapshot inventory	volume snapshots this backup storage contains	0.6

Query SFTP Backup Storage ¶

Admins can use QuerySftpBackupStorage to query SFTP backup storage:

QuerySftpBackupStorage name=sftp

Name	Category	Default Value	Choices
ping.interval	backupStorage	60	> 0

The interval that management nodes send ping commands to backup storage, in seconds.

ping.parallelismDegree ¶

Name	Category	Default Value	Choices
ping.parallelismDegree	backupStorage	50	> 0

The max number of backup storage that management nodes will ping in parallel.

Tags ¶

Admins can create user tags on a backup storage with resourceType=BackupStorageVO. For example:

CreateUserTag tag=lab1 resourceType=BackupStorageVO resourceUuid=2906471068802c501773d3ee55b7766e

Backup Storage ¶

Overview ¶

Inventory ¶

Properties ¶

Example ¶

URL ¶

SFTP Backup Storage URL ¶

Capacity ¶

State ¶

Status ¶

SFTP Backup Storage ¶

Example ¶

Operations ¶

Add Backup Storage ¶

Add SFTP Backup Storage ¶

Parameters ¶

Delete Backup Storage ¶

Parameters ¶

Change State ¶

Parameters ¶

Attach Zone ¶

Parameters ¶

Detach Zone ¶

Parameters ¶

Query Backup Storage ¶

Primitive Fields of Query ¶

Nested And Expanded Fields of Query ¶

Query SFTP Backup Storage ¶

Primitive Fields of Query ¶

Nested and Expanded Fields of Query ¶

Global Configurations ¶

ping.interval ¶

ping.parallelismDegree ¶

Tags ¶