HP BL680c XenServer Software Development Kit Guide 4.1.0 - Page 21

Using the API

15

•

Remember to log out of active sessions to avoid leaking them; and

•

Be prepared to log in again to the server if a

SESSION_INVALID

error is caught.

In the following fragment a connection via the Unix domain socket is established and a session created:

import XenAPI

session = XenAPI.xapi_local()

try:

session.xenapi.login_with_password("root", "")

...

finally:

session.xenapi.session.logout()

4.1.3. Finding references to useful objects

Once an application has authenticated the next step is to acquire references to objects in order to query their

state or invoke operations on them. All objects have a set of "implicit" messages which include the following:

•

get_by_name_label

: return a list of all objects of a particular class with a particular label;

•

get_by_uuid

: return a single object named by its UUID;

•

get_all

: return a set of references to all objects of a particular class; and

•

get_all_records

: return a map of reference to records for each object of a particular class.

For example, to list all hosts:

hosts = session.xenapi.host.get_all()

To find all VMs with the name "my first VM":

vms = session.xenapi.VM.get_by_name_label('my first VM')

Note

Object

name_label

fields are not guaranteed to be unique and so the

get_by_name_label

API

call returns a set of references rather than a single reference.

In addition to the methods of finding objects described above, most objects also contain references to other

objects within fields. For example it is possible to find the set of VMs running on a particular host by calling:

vms = session.xenapi.host.get_resident_VMs(host)

4.1.4. Invoking synchronous operations on objects

Once object references have been acquired, operations may be invoked on them. For example to start a VM:

Section	Page
XenServer Software Development Kit Guide	1
Table of Contents	4
Chapter 1. Introduction	7
Chapter 2. Getting Started	8
2.1. System Requirements and Preparation	8
2.2. Downloading	8
2.3. Installation	8
2.4. What's new	8
2.5. Content Map	8
2.6. Building Samples for the Linux Platform	9
2.7. Building Samples for the Windows Platform	9
2.8. Running the CLI	9
2.8.1. Tab Completion	9
2.9. Accessing SDK reference	9
Chapter 3. Overview of the XenServer API	11
3.1. Getting Started with the API	11
3.1.1. Authentication: acquiring a session reference	11
3.1.2. Acquiring a list of templates to base a new VM installation on	11
3.1.3. Installing the VM based on a template	12
3.1.4. Taking the VM through a start/suspend/resume/stop cycle	12
3.1.5. Logging out	12
3.1.6. \	13
3.2. Object Model Overview	13
3.3. Working with VIFs and VBDs	15
3.3.1. Creating disks and attaching them to VMs	15
3.3.1.1. Creating a new blank disk image	16
3.3.1.2. Attaching the disk image to a VM	16
3.3.1.3. Hotplugging the VBD	17
3.3.2. Creating and attaching Network Devices to VMs	17
3.3.3. Host configuration for networking and storage	17
3.3.3.1. Host storage configuration: PBDs	18
3.3.3.2. Host networking configuration: PIFs	18
3.4. Exporting and Importing VMs	18
3.5. Where to look next	19
Chapter 4. Using the API	20
4.1. Anatomy of a typical application	20
4.1.1. Choosing a low-level transport	20
4.1.2. Authentication and session handling	20
4.1.3. Finding references to useful objects	21
4.1.4. Invoking synchronous operations on objects	21
4.1.5. Using Tasks to manage asynchronous operations	22
4.1.6. Subscribing to and listening for events	22
4.2. Language bindings	23
4.2.1. C	23
4.2.2. C#	24
4.2.3. Python	24
4.2.4. Command Line Interface (CLI)	25
4.3. Complete application examples	25
4.3.1. Simultaneously migrating VMs using XenMotion	25
4.3.2. Cloning a VM via the XE CLI	28
Chapter 5. XenServer API extensions	30
5.1. VM console forwarding	30
5.1.1. Retrieving VNC consoles via the API	30
5.1.2. Disabling VNC forwarding for Linux VM	31
5.2. Paravirtual Linux installation	32
5.2.1. Red Hat Enterprise Linux 4.1/4.4	32
5.2.2. Red Hat Enterprise Linux 4.5/5.0	32
5.2.3. SUSE Enterprise Linux 10 SP1	33
5.2.4. CentOS 4.5/5.0	33
5.3. Adding Xenstore entries to VMs	33
5.4. Security enhancements	33
5.5. Advanced settings for network interfaces	34
5.5.1. ethtool settings	34
5.5.2. Miscellaneous settings	35
5.6. Internationalization for SR names	35
5.7. Hiding objects from XenCenter	36

HP BL680c XenServer Software Development Kit Guide 4.1.0 - Page 21

Finding references to useful objects, 4.1.4. Invoking synchronous operations on objects

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