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Manual Reference Pages  -  VM::EC2::INSTANCE::METADATA (3)

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VM::EC2::Instance::Metadata - Object describing the metadata of a running instance



 # For use within a running EC2 instance only!

 use VM::EC2::Instance::Metadata;
 my $meta = VM::EC2::Instance::Metadata->new;

 # alternatively...
 my $meta = VM::EC2->instance_metadata;
 my $meta = $instance->metadata;

 # image information
 $image_id  = $meta->imageId;
 $index     = $meta->imageLaunchIndex;
 $path      = $meta->amiManifestPath;
 $location  = $meta->imageLocation;    # same as previous
 @ancestors = $meta->ancestorAmiIds;
 @ancestors = $meta->imageAncestorIds; # same as previous
 @codes     = $meta->productCodes;

 # launch and runtime information
 $inst_id   = $meta->instanceId;
 $kern_id   = $meta->kernelId;
 $rd_id     = $meta->ramdiskId;
 $res_id    = $meta->reservationId;
 $type      = $meta->instanceType;
 $zone      = $meta->availabilityZone;
 $userdata  = $meta->userData;
 @groups    = $meta->securityGroups;
 @keys      = $meta->publicKeys;
 $block_dev = $meta->blockDeviceMapping; # a hashref

 # Network information
 $priv_name = $meta->localHostname;
 $priv_name = $meta->privateDnsName;   # same as previous
 $priv_ip   = $meta->localIpv4;
 $priv_ip   = $meta->privateIpAddress;
 $mac       = $meta->mac;
 $pub_name  = $meta->publicHostname;
 $pub_name  = $meta->dnsName;          # same as previous
 $pub_ip    = $meta->publicIpv4;
 $pub_ip    = $meta->ipAddress;
 $interfaces= $meta->interfaces;       # a hashref

 # IAM information
 $iam_info   = $metadata->iam_info;         # a hashref
 $iam_role   = $metadata->iam_role;         # name of the role
 $credentials= $metadata->iam_credentials;  # VM::EC2::Security::Credentials object

 # Undocumented fields
 $action    = $meta->instanceAction;
 $profile   = $meta->profile;


This is an interface to the metadata that is provided to a running instance via the URL, as described in

Each metadata object caches its values, so there is no overhead in calling a method repeatedly. Methods return scalar values, lists and hashrefs as appropriate.

The methods from this class should only be called within the context of a running EC2 instance. Attempts to call outside of this context will result in long delays as the module attempts to connect to an invalid hostname.


CW$meta = VM::EC2::Instance::Metadata->new()

CW$meta = CW$ec2->instance_metadata()

CW$meta = CW$instance->metadata()

You can create a new metadata object either using this class’s new() constructor, or by calling an VM::EC2 object’s instance_metadata() method, or by calling a VM::EC2::Instance object’s metadata () method.

    Methods that return scalar values

The following methods all return single-valued results:
Image information:

 imageId                -- ID of AMI used to launch this instance
 imageLaunchIndex       -- This indexs launch index. If four instances
                           were launched by one $image->run_instances()
                           call, they will be numbered from 0 to 3.
 amiManifestPath        -- S3 path to the image
 imageLocation          -- Same as amiManifestPath(), for consistency with

Launch and runtime information:

 instanceId             -- ID of this instance
 kernelId               -- ID of this instances kernel.
 ramdiskId              -- This instances ramdisk ID
 reservationId          -- This instances reservation ID
 instanceType           -- Machine type, e.g. "m1.small"
 availabilityZone       -- This instances availability zone.
 region                 -- This instances region.
 endpoint               -- This instances endpoint.
 userData               -- User data passed at launch time.

Network information:

 localHostname          -- The instance hostname corresponding to its
                           internal EC2 IP address.
 privateDnsName         -- Same as localHostname(), for consistency with
 localIpv4              -- The instance IP address on the internal EC2 network.
 privateIpAddress       -- Same as localIpv4(), for consistency with
 mac                    -- This instances MAC (ethernet) address.
 publicHostname         -- This instances public hostname.
 dnsName                -- Same as publicHostname() for consistency with
 publicIpv4             -- This instances public IP address.
 ipAddress              -- Same as publicIpv4() for consistency with

IAM information These routines return information about the instance’s IAM role, if any. These calls also provide a temporary security credentials for making EC2 calls, as described here:

Note that these routines require installation of the perl JSON module, and will cause a fatal error if this module cannot be loaded.

 iam_info               -- Returns a hash containing the fields LastUpdated,
                           InstanceProfileArn, and InstanceProfileId. These
                           provide information about the instances IAM role.
 iam_role               -- Returns the IAM role name for the currently running
 iam_credentials        -- Returns a VM::EC2::Security::Credentials object that can
                           be passed to VM::EC2->new(-security_token=>$credentials).

Unknown information:

 profile                -- An undocumented field that contains the virtualization
                           type in the form "default-paravirtual".
 instanceAction         -- Undocumented metadata field named "instance-action"

    Methods that return lists

The following methods all return lists.
Image information

 ancestorAmiIds        -- List of  AMIs from which the current one was derived
 imageAncestorIds      -- Same as ancestorAmiIds() but easier to read.
 productCodes          -- List of product codes applying to the image from which
                          this instance was launched.

Launch and runtime information

 securityGroups        -- List of security groups to which this instance is assigned.
                          For non-VPC instances, this will be the security group
                          name. For VPC instances, this will be the security group ID.
 publicKeys            -- List of public key pair names attached to this instance.

    Methods that return a hashref

The following methods return a hashref for representing complex data structures:
$devices = $meta->blockDeviceMapping This returns a hashref in which the keys are the names of instance block devices, such as /dev/sda1, and the values are the EC2 virtual machine names. For example:

 x $meta->blockDeviceMapping
 0  HASH(0x9b4f2f8)
   /dev/sda1 => root
   /dev/sda2 => ephemeral0
   /dev/sdg => ebs1
   /dev/sdh => ebs9
   /dev/sdi => ebs10
   sda3 => swap

For reasons that are not entirely clear, the swap device is reported as sda3 rather than as /dev/sda3.

$interfaces = $meta->interfaces Returns a mapping of all virtual ethernet devices owned by this instance. This is primarily useful for VPC instances, which can have more than one device. The hash keys are the MAC addresses of each ethernet device, and the values are hashes that have the following keys:

 localIpv4s        (an array ref)
 publicIpv4s       (an array ref)
 securityGroupIds  (an array ref)

For example:

 x $meta->interfaces       
 0 HASH(0x9b4f518)
   12:31:38:01:b8:97 => HASH(0x9eaa090)
      localHostname => domU-12-31-38-01-B8-97.compute-1.internal
      localIpv4s => ARRAY(0x9b4f8a8)
      mac => 12:31:38:01:b8:97
      publicIpv4s => ARRAY(0x9ea9e40)
      securityGroupIds => ARRAY(0x9eaa490)
           empty array
      subnetId => undef
      subnetIpv4CidrBlock => undef
      vpcId => undef
      vpcIpv4CidrBlock => undef


VM::EC2 VM::EC2::Generic VM::EC2::BlockDevice VM::EC2::State::Reason VM::EC2::State VM::EC2::Instance VM::EC2::Tag


Lincoln Stein <>.

Copyright (c) 2011 Ontario Institute for Cancer Research

This package and its accompanying libraries is free software; you can redistribute it and/or modify it under the terms of the GPL (either version 1, or at your option, any later version) or the Artistic License 2.0. Refer to LICENSE for the full license text. In addition, please see DISCLAIMER.txt for disclaimers of warranty.

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