Ganeti remote API

Documents Ganeti version 2.2

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) [1] 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
[1]Using the MD5 hash of username, realm and password is described in RFC 2617 (“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 RFC 2617 is supported.

A note on JSON as used by RAPI

JSON as used by Ganeti RAPI does not conform to the specification in RFC 4627. Section 2 defines a JSON text to be either an object ({"key": "value", …}) or an array ([1, 2, 3, …]). In violation of this RAPI uses plain strings ("master-candidate", "1234") for some requests or responses. Changing this now would likely break existing clients and cause a lot of trouble.

Unlike Python’s JSON encoder and decoder, other programming languages or libraries may only provide a strict implementation, not allowing plain values. For those, responses can usually be wrapped in an array whose first element is then used, e.g. the response "1234" becomes ["1234"]. This works equally well for more complex values. Example in Ruby:

require "json"

# Insert code to get response here
response = "\"1234\""

decoded = JSON.parse("[#{response}]").first

Short of modifying the encoder to allow encoding to a less strict format, requests will have to be formatted by hand. Newer RAPI requests already use a dictionary as their input data and shouldn’t cause any problems.

PUT or POST?

According to RFC 2616 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.

Ganeti RAPI client

Ganeti includes a standalone RAPI client, lib/rapi/client.py.

Shell

Using wget:

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

or curl:

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

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.

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

/

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.

Body parameters:

__version__ (int, required)
Must be 1 (older Ganeti versions used a different format for instance creation requests, version 0, but that format is not documented).
mode (string, required)
Instance creation mode.
name (string, required)
Instance name.
disk_template (string, required)
Disk template for instance.
disks (list, required)
List of disk definitions. Example: [{"size": 100}, {"size": 5}]. Each disk definition must contain a size value and can contain an optional mode value denoting the disk access mode (ro or rw).
nics (list, required)
List of NIC (network interface) definitions. Example: [{}, {}, {"ip": "198.51.100.4"}]. Each NIC definition can contain the optional values ip, mode, link and bridge.
os (string, required)
Instance operating system.
osparams (dictionary)
Dictionary with OS parameters. If not valid for the given OS, the job will fail.
force_variant (bool)
Whether to force an unknown variant.
pnode (string)
Primary node.
snode (string)
Secondary node.
src_node (string)
Source node for import.
src_path (string)
Source directory for import.
start (bool)
Whether to start instance after creation.
ip_check (bool)
Whether to ensure instance’s IP address is inactive.
name_check (bool)
Whether to ensure instance’s name is resolvable.
file_storage_dir (string)
File storage directory.
file_driver (string)
File storage driver.
iallocator (string)
Instance allocator name.
source_handshake (list)
Signed handshake from source (remote import only).
source_x509_ca (string)
Source X509 CA in PEM format (remote import only).
source_instance_name (string)
Source instance name (remote import only).
hypervisor (string)
Hypervisor name.
hvparams (dict)
Hypervisor parameters, hypervisor-dependent.
beparams (dict)
Backend parameters.

/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]/prepare-export

Prepares an export of an instance.

It supports the following commands: PUT.

PUT

Takes one parameter, mode, for the export mode. Returns a job ID.

/2/instances/[instance_name]/export

Exports an instance.

It supports the following commands: PUT.

PUT

Returns a job ID.

Body parameters:

mode (string)
Export mode.
destination (required)
Destination information, depends on export mode.
shutdown (bool, required)
Whether to shutdown instance before export.
remove_instance (bool)
Whether to remove instance after export.
x509_key_name
Name of X509 key (remote export only).
destination_x509_ca
Destination X509 CA (remote export only).

/2/instances/[instance_name]/migrate

Migrates an instance.

Supports the following commands: PUT.

PUT

Returns a job ID.

Body parameters:

mode (string)
Migration mode.
cleanup (bool)
Whether a previously failed migration should be cleaned up.

/2/instances/[instance_name]/rename

Renames an instance.

Supports the following commands: PUT.

PUT

Returns a job ID.

Body parameters:

new_name (string, required)
New instance name.
ip_check (bool)
Whether to ensure instance’s IP address is inactive.
name_check (bool)
Whether to ensure instance’s name is resolvable.

/2/instances/[instance_name]/modify

Modifies an instance.

Supports the following commands: PUT.

PUT

Returns a job ID.

Body parameters:

osparams (dict)
Dictionary with OS parameters.
hvparams (dict)
Hypervisor parameters, hypervisor-dependent.
beparams (dict)
Backend parameters.
force (bool)
Whether to force the operation.
nics (list)
List of NIC changes. Each item is of the form (op, settings). op can be add to add a new NIC with the specified settings, remove to remove the last NIC or a number to modify the settings of the NIC with that index.
disks (list)
List of disk changes. See nics.
disk_template (string)
Disk template for instance.
remote_node (string)
Secondary node (used when changing disk template).
os_name (string)
Change instance’s OS name. Does not reinstall the instance.
force_variant (bool)
Whether to force an unknown variant.

/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 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]

The result value will be a list, each element being a triple of the job id (for this specific evacuation), the instance which is being evacuated by this job, and the node to which it is being relocated. In case the node is already empty, the result will be an empty list (without any jobs being submitted).

And additional parameter early_release signifies whether to try to parallelize the evacuations, at the risk of increasing I/O contention and increasing the chances of data loss, if the primary node of any of the instances being evacuated is not fully healthy.

If the dry-run parameter was specified, then the evacuation jobs were not actually submitted, and the job IDs will be null.

/2/nodes/[node_name]/migrate

Migrates all primary instances from a node.

It supports the following commands: POST.

POST

If no mode is explicitly specified, each instances’ hypervisor default migration mode will be used. Query parameters:

live (bool)
If set, use live migration if available.
mode (string)
Sets migration mode, live for live migration and non-live for non-live migration. Supported by Ganeti 2.2 and above.

/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.

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