Synnefo » snf-ganeti

Ganeti remote API

=================

Documents Ganeti version |version|

.. contents::

Introduction

------------

Ganeti supports a remote API for enable external tools to easily

retrieve information about a cluster's state. The remote API daemon,

*ganeti-rapi*, is automatically started on the master node. By default

it runs on TCP port 5080, but this can be changed either in

``.../constants.py`` or via the command line parameter *-p*. SSL mode,

which is used by default, can also be disabled by passing command line

parameters.

Users and passwords

-------------------

``ganeti-rapi`` reads users and passwords from a file (usually

``/var/lib/ganeti/rapi_users``) on startup. After modifying the password

file, ``ganeti-rapi`` must be restarted.

Each line consists of two or three fields separated by whitespace. The

first two fields are for username and password. The third field is

optional and can be used to specify per-user options. Currently,

``write`` is the only option supported and enables the user to execute

operations modifying the cluster. Lines starting with the hash sign

(``#``) are treated as comments.

Passwords can either be written in clear text or as a hash. Clear text

passwords may not start with an opening brace (``{``) or they must be

prefixed with ``{cleartext}``. To use the hashed form, get the MD5 hash

of the string ``$username:Ganeti Remote API:$password`` (e.g. ``echo -n

'jack:Ganeti Remote API:abc123' | openssl md5``) [#pwhash]_ and prefix

it with ``{ha1}``. Using the scheme prefix for all passwords is

recommended. Scheme prefixes are not case sensitive.

Example::

  # Give Jack and Fred read-only access

  jack abc123

  fred {cleartext}foo555

  # Give write access to an imaginary instance creation script

  autocreator xyz789 write

  # Hashed password for Jessica

  jessica {HA1}7046452df2cbb530877058712cf17bd4 write

.. [#pwhash] Using the MD5 hash of username, realm and password is

   described in RFC2617_ ("HTTP Authentication"), sections 3.2.2.2 and

   3.3. The reason for using it over another algorithm is forward

   compatibility. If ``ganeti-rapi`` were to implement HTTP Digest

   authentication in the future, the same hash could be used.

   In the current version ``ganeti-rapi``'s realm, ``Ganeti Remote

   API``, can only be changed by modifying the source code.

Protocol

--------

The protocol used is JSON_ over HTTP designed after the REST_ principle.

HTTP Basic authentication as per RFC2617_ is supported.

.. _JSON: http://www.json.org/

.. _REST: http://en.wikipedia.org/wiki/Representational_State_Transfer

.. _RFC2617: http://tools.ietf.org/rfc/rfc2617.txt

PUT or POST?

------------

According to RFC2616 the main difference between PUT and POST is that

POST can create new resources but PUT can only create the resource the

URI was pointing to on the PUT request.

Unfortunately, due to historic reasons, the Ganeti RAPI library is not

consistent with this usage, so just use the methods as documented below

for each resource.

For more details have a look in the source code at

``lib/rapi/rlib2.py``.

Generic parameter types

-----------------------

A few generic refered parameter types and the values they allow.

``bool``

++++++++

A boolean option will accept ``1`` or ``0`` as numbers but not

i.e. ``True`` or ``False``.

Generic parameters

------------------

A few parameter mean the same thing across all resources which implement

it.

``bulk``

++++++++

Bulk-mode means that for the resources which usually return just a list

of child resources (e.g. ``/2/instances`` which returns just instance

names), the output will instead contain detailed data for all these

subresources. This is more efficient than query-ing the sub-resources

themselves.

``dry-run``

+++++++++++

The boolean *dry-run* argument, if provided and set, signals to Ganeti

that the job should not be executed, only the pre-execution checks will

be done.

This is useful in trying to determine (without guarantees though, as in

the meantime the cluster state could have changed) if the operation is

likely to succeed or at least start executing.

``force``

+++++++++++

Force operation to continue even if it will cause the cluster to become

inconsistent (e.g. because there are not enough master candidates).

Usage examples

--------------

You can access the API using your favorite programming language as long

as it supports network connections.

Shell

+++++

.. highlight:: sh

Using wget::

   wget -q -O - https://CLUSTERNAME:5080/2/info

or curl::

  curl https://CLUSTERNAME:5080/2/info

Python

++++++

.. highlight:: python

::

  import urllib2

  f = urllib2.urlopen('https://CLUSTERNAME:5080/2/info')

  print f.read()

JavaScript

++++++++++

.. warning:: While it's possible to use JavaScript, it poses several

   potential problems, including browser blocking request due to

   non-standard ports or different domain names. Fetching the data on

   the webserver is easier.

.. highlight:: javascript

::

  var url = 'https://CLUSTERNAME:5080/2/info';

  var info;

  var xmlreq = new XMLHttpRequest();

  xmlreq.onreadystatechange = function () {

    if (xmlreq.readyState != 4) return;

    if (xmlreq.status == 200) {

      info = eval("(" + xmlreq.responseText + ")");

      alert(info);

    } else {

      alert('Error fetching cluster info');

    }

    xmlreq = null;

  };

  xmlreq.open('GET', url, true);

  xmlreq.send(null);

Resources

---------

.. highlight:: javascript

``/``

+++++

The root resource.

It supports the following commands: ``GET``.

``GET``

~~~~~~~

Shows the list of mapped resources.

Returns: a dictionary with 'name' and 'uri' keys for each of them.

``/2``

++++++

The ``/2`` resource, the root of the version 2 API.

It supports the following commands: ``GET``.

``GET``

~~~~~~~

Show the list of mapped resources.

Returns: a dictionary with ``name`` and ``uri`` keys for each of them.

``/2/info``

+++++++++++

Cluster information resource.

It supports the following commands: ``GET``.

``GET``

~~~~~~~

Returns cluster information.

Example::

  {

    "config_version": 2000000,

    "name": "cluster",

    "software_version": "2.0.0~beta2",

    "os_api_version": 10,

    "export_version": 0,

    "candidate_pool_size": 10,

    "enabled_hypervisors": [

      "fake"

    ],

    "hvparams": {

      "fake": {}

     },

    "default_hypervisor": "fake",

    "master": "node1.example.com",

    "architecture": [

      "64bit",

      "x86_64"

    ],

    "protocol_version": 20,

    "beparams": {

      "default": {

        "auto_balance": true,

        "vcpus": 1,

        "memory": 128

       }

      }

    }

``/2/redistribute-config``

++++++++++++++++++++++++++

Redistribute configuration to all nodes.

It supports the following commands: ``PUT``.

``PUT``

~~~~~~~

Redistribute configuration to all nodes. The result will be a job id.

``/2/features``

+++++++++++++++

``GET``

~~~~~~~

Returns a list of features supported by the RAPI server. Available

features:

``instance-create-reqv1``

  Instance creation request data version 1 supported.

``/2/instances``

++++++++++++++++

The instances resource.

It supports the following commands: ``GET``, ``POST``.

``GET``

~~~~~~~

Returns a list of all available instances.

Example::

    [

      {

        "name": "web.example.com",

        "uri": "\/instances\/web.example.com"

      },

      {

        "name": "mail.example.com",

        "uri": "\/instances\/mail.example.com"

      }

    ]

If the optional bool *bulk* argument is provided and set to a true value

(i.e ``?bulk=1``), the output contains detailed information about

instances as a list.

Example::

    [

      {

         "status": "running",

         "disk_usage": 20480,

         "nic.bridges": [

           "xen-br0"

          ],

         "name": "web.example.com",

         "tags": ["tag1", "tag2"],

         "beparams": {

           "vcpus": 2,

           "memory": 512

         },

         "disk.sizes": [

             20480

         ],

         "pnode": "node1.example.com",

         "nic.macs": ["01:23:45:67:89:01"],

         "snodes": ["node2.example.com"],

         "disk_template": "drbd",

         "admin_state": true,

         "os": "debian-etch",

         "oper_state": true

      },

      ...

    ]

``POST``

~~~~~~~~

Creates an instance.

If the optional bool *dry-run* argument is provided, the job will not be

actually executed, only the pre-execution checks will be done. Query-ing

the job result will return, in both dry-run and normal case, the list of

nodes selected for the instance.

Returns: a job ID that can be used later for polling.

``/2/instances/[instance_name]``

++++++++++++++++++++++++++++++++

Instance-specific resource.

It supports the following commands: ``GET``, ``DELETE``.

``GET``

~~~~~~~

Returns information about an instance, similar to the bulk output from

the instance list.

``DELETE``

~~~~~~~~~~

Deletes an instance.

It supports the ``dry-run`` argument.

``/2/instances/[instance_name]/info``

+++++++++++++++++++++++++++++++++++++++

It supports the following commands: ``GET``.

``GET``

~~~~~~~

Requests detailed information about the instance. An optional parameter,

``static`` (bool), can be set to return only static information from the

configuration without querying the instance's nodes. The result will be

a job id.

``/2/instances/[instance_name]/reboot``

+++++++++++++++++++++++++++++++++++++++

Reboots URI for an instance.

It supports the following commands: ``POST``.

``POST``

~~~~~~~~

Reboots the instance.

The URI takes optional ``type=soft|hard|full`` and

``ignore_secondaries=0|1`` parameters.

``type`` defines the reboot type. ``soft`` is just a normal reboot,

without terminating the hypervisor. ``hard`` means full shutdown

(including terminating the hypervisor process) and startup again.

``full`` is like ``hard`` but also recreates the configuration from

ground up as if you would have done a ``gnt-instance shutdown`` and

``gnt-instance start`` on it.

``ignore_secondaries`` is a bool argument indicating if we start the

instance even if secondary disks are failing.

It supports the ``dry-run`` argument.

``/2/instances/[instance_name]/shutdown``

+++++++++++++++++++++++++++++++++++++++++

Instance shutdown URI.

It supports the following commands: ``PUT``.

``PUT``

~~~~~~~

Shutdowns an instance.

It supports the ``dry-run`` argument.

``/2/instances/[instance_name]/startup``

++++++++++++++++++++++++++++++++++++++++

Instance startup URI.

It supports the following commands: ``PUT``.

``PUT``

~~~~~~~

Startup an instance.

The URI takes an optional ``force=1|0`` parameter to start the

instance even if secondary disks are failing.

It supports the ``dry-run`` argument.

``/2/instances/[instance_name]/reinstall``

++++++++++++++++++++++++++++++++++++++++++++++

Installs the operating system again.

It supports the following commands: ``POST``.

``POST``

~~~~~~~~

Takes the parameters ``os`` (OS template name) and ``nostartup`` (bool).

``/2/instances/[instance_name]/replace-disks``

++++++++++++++++++++++++++++++++++++++++++++++

Replaces disks on an instance.

It supports the following commands: ``POST``.

``POST``

~~~~~~~~

Takes the parameters ``mode`` (one of ``replace_on_primary``,

``replace_on_secondary``, ``replace_new_secondary`` or

``replace_auto``), ``disks`` (comma separated list of disk indexes),

``remote_node`` and ``iallocator``.

Either ``remote_node`` or ``iallocator`` needs to be defined when using

``mode=replace_new_secondary``.

``mode`` is a mandatory parameter. ``replace_auto`` tries to determine

the broken disk(s) on its own and replacing it.

``/2/instances/[instance_name]/activate-disks``

+++++++++++++++++++++++++++++++++++++++++++++++

Activate disks on an instance.

It supports the following commands: ``PUT``.

``PUT``

~~~~~~~

Takes the bool parameter ``ignore_size``. When set ignore the recorded

size (useful for forcing activation when recorded size is wrong).

``/2/instances/[instance_name]/deactivate-disks``

+++++++++++++++++++++++++++++++++++++++++++++++++

Deactivate disks on an instance.

It supports the following commands: ``PUT``.

``PUT``

~~~~~~~

Takes no parameters.

``/2/instances/[instance_name]/tags``

+++++++++++++++++++++++++++++++++++++

Manages per-instance tags.

It supports the following commands: ``GET``, ``PUT``, ``DELETE``.

``GET``

~~~~~~~

Returns a list of tags.

Example::

    ["tag1", "tag2", "tag3"]

``PUT``

~~~~~~~

Add a set of tags.

The request as a list of strings should be ``PUT`` to this URI. The

result will be a job id.

It supports the ``dry-run`` argument.

``DELETE``

~~~~~~~~~~

Delete a tag.

In order to delete a set of tags, the DELETE request should be addressed

to URI like::

    /tags?tag=[tag]&tag=[tag]

It supports the ``dry-run`` argument.

``/2/jobs``

+++++++++++

The ``/2/jobs`` resource.

It supports the following commands: ``GET``.

``GET``

~~~~~~~

Returns a dictionary of jobs.

Returns: a dictionary with jobs id and uri.

``/2/jobs/[job_id]``

++++++++++++++++++++

Individual job URI.

It supports the following commands: ``GET``, ``DELETE``.

``GET``

~~~~~~~

Returns a job status.

Returns: a dictionary with job parameters.

The result includes:

- id: job ID as a number

- status: current job status as a string

- ops: involved OpCodes as a list of dictionaries for each opcodes in

  the job

- opstatus: OpCodes status as a list

- opresult: OpCodes results as a list

For a successful opcode, the ``opresult`` field corresponding to it will

contain the raw result from its :term:`LogicalUnit`. In case an opcode

has failed, its element in the opresult list will be a list of two

elements:

- first element the error type (the Ganeti internal error name)

- second element a list of either one or two elements:

  - the first element is the textual error description

  - the second element, if any, will hold an error classification

The error classification is most useful for the ``OpPrereqError``

error type - these errors happen before the OpCode has started

executing, so it's possible to retry the OpCode without side

effects. But whether it make sense to retry depends on the error

classification:

``resolver_error``

  Resolver errors. This usually means that a name doesn't exist in DNS,

  so if it's a case of slow DNS propagation the operation can be retried

  later.

``insufficient_resources``

  Not enough resources (iallocator failure, disk space, memory,

  etc.). If the resources on the cluster increase, the operation might

  succeed.

``wrong_input``

  Wrong arguments (at syntax level). The operation will not ever be

  accepted unless the arguments change.

``wrong_state``

  Wrong entity state. For example, live migration has been requested for

  a down instance, or instance creation on an offline node. The

  operation can be retried once the resource has changed state.

``unknown_entity``

  Entity not found. For example, information has been requested for an

  unknown instance.

``already_exists``

  Entity already exists. For example, instance creation has been

  requested for an already-existing instance.

``resource_not_unique``

  Resource not unique (e.g. MAC or IP duplication).

``internal_error``

  Internal cluster error. For example, a node is unreachable but not set

  offline, or the ganeti node daemons are not working, etc. A

  ``gnt-cluster verify`` should be run.

``environment_error``

  Environment error (e.g. node disk error). A ``gnt-cluster verify``

  should be run.

Note that in the above list, by entity we refer to a node or instance,

while by a resource we refer to an instance's disk, or NIC, etc.

``DELETE``

~~~~~~~~~~

Cancel a not-yet-started job.

``/2/jobs/[job_id]/wait``

+++++++++++++++++++++++++

``GET``

~~~~~~~

Waits for changes on a job. Takes the following body parameters in a

dict:

``fields``

  The job fields on which to watch for changes.

``previous_job_info``

  Previously received field values or None if not yet available.

``previous_log_serial``

  Highest log serial number received so far or None if not yet

  available.

Returns None if no changes have been detected and a dict with two keys,

``job_info`` and ``log_entries`` otherwise.

``/2/nodes``

++++++++++++

Nodes resource.

It supports the following commands: ``GET``.

``GET``

~~~~~~~

Returns a list of all nodes.

Example::

    [

      {

        "id": "node1.example.com",

        "uri": "\/nodes\/node1.example.com"

      },

      {

        "id": "node2.example.com",

        "uri": "\/nodes\/node2.example.com"

      }

    ]

If the optional 'bulk' argument is provided and set to 'true' value (i.e

'?bulk=1'), the output contains detailed information about nodes as a

list.

Example::

    [

      {

        "pinst_cnt": 1,

        "mfree": 31280,

        "mtotal": 32763,

        "name": "www.example.com",

        "tags": [],

        "mnode": 512,

        "dtotal": 5246208,

        "sinst_cnt": 2,

        "dfree": 5171712,

        "offline": false

      },

      ...

    ]

``/2/nodes/[node_name]``

+++++++++++++++++++++++++++++++++

Returns information about a node.

It supports the following commands: ``GET``.

``/2/nodes/[node_name]/evacuate``

+++++++++++++++++++++++++++++++++

Evacuates all secondary instances off a node.

It supports the following commands: ``POST``.

``POST``

~~~~~~~~

To evacuate a node, either one of the ``iallocator`` or ``remote_node``

parameters must be passed::

    evacuate?iallocator=[iallocator]

    evacuate?remote_node=[nodeX.example.com]

``/2/nodes/[node_name]/migrate``

+++++++++++++++++++++++++++++++++

Migrates all primary instances from a node.

It supports the following commands: ``POST``.

``POST``

~~~~~~~~

No parameters are required, but the bool parameter ``live`` can be set

to use live migration (if available).

    migrate?live=[0|1]

``/2/nodes/[node_name]/role``

+++++++++++++++++++++++++++++

Manages node role.

It supports the following commands: ``GET``, ``PUT``.

The role is always one of the following:

  - drained

  - master

  - master-candidate

  - offline

  - regular

``GET``

~~~~~~~

Returns the current node role.

Example::

    "master-candidate"

``PUT``

~~~~~~~

Change the node role.

The request is a string which should be PUT to this URI. The result will

be a job id.

It supports the bool ``force`` argument.

``/2/nodes/[node_name]/storage``

++++++++++++++++++++++++++++++++

Manages storage units on the node.

``GET``

~~~~~~~

Requests a list of storage units on a node. Requires the parameters

``storage_type`` (one of ``file``, ``lvm-pv`` or ``lvm-vg``) and

``output_fields``. The result will be a job id, using which the result

can be retrieved.

``/2/nodes/[node_name]/storage/modify``

+++++++++++++++++++++++++++++++++++++++

Modifies storage units on the node.

``PUT``

~~~~~~~

Modifies parameters of storage units on the node. Requires the

parameters ``storage_type`` (one of ``file``, ``lvm-pv`` or ``lvm-vg``)

and ``name`` (name of the storage unit).  Parameters can be passed

additionally. Currently only ``allocatable`` (bool) is supported. The

result will be a job id.

``/2/nodes/[node_name]/storage/repair``

+++++++++++++++++++++++++++++++++++++++

Repairs a storage unit on the node.

``PUT``

~~~~~~~

Repairs a storage unit on the node. Requires the parameters

``storage_type`` (currently only ``lvm-vg`` can be repaired) and

``name`` (name of the storage unit). The result will be a job id.

``/2/nodes/[node_name]/tags``

+++++++++++++++++++++++++++++

Manages per-node tags.

It supports the following commands: ``GET``, ``PUT``, ``DELETE``.

``GET``

~~~~~~~

Returns a list of tags.

Example::

    ["tag1", "tag2", "tag3"]

``PUT``

~~~~~~~

Add a set of tags.

The request as a list of strings should be PUT to this URI. The result

will be a job id.

It supports the ``dry-run`` argument.

``DELETE``

~~~~~~~~~~

Deletes tags.

In order to delete a set of tags, the DELETE request should be addressed

to URI like::

    /tags?tag=[tag]&tag=[tag]

It supports the ``dry-run`` argument.

``/2/os``

+++++++++

OS resource.

It supports the following commands: ``GET``.

``GET``

~~~~~~~

Return a list of all OSes.

Can return error 500 in case of a problem. Since this is a costly

operation for Ganeti 2.0, it is not recommended to execute it too often.

Example::

    ["debian-etch"]

``/2/tags``

+++++++++++

Manages cluster tags.

It supports the following commands: ``GET``, ``PUT``, ``DELETE``.

``GET``

~~~~~~~

Returns the cluster tags.

Example::

    ["tag1", "tag2", "tag3"]

``PUT``

~~~~~~~

Adds a set of tags.

The request as a list of strings should be PUT to this URI. The result

will be a job id.

It supports the ``dry-run`` argument.

``DELETE``

~~~~~~~~~~

Deletes tags.

In order to delete a set of tags, the DELETE request should be addressed

to URI like::

    /tags?tag=[tag]&tag=[tag]

It supports the ``dry-run`` argument.

``/version``

++++++++++++

The version resource.

This resource should be used to determine the remote API version and to

adapt clients accordingly.

It supports the following commands: ``GET``.

``GET``

~~~~~~~

Returns the remote API version. Ganeti 1.2 returned ``1`` and Ganeti 2.0

returns ``2``.

.. vim: set textwidth=72 :