Home > ... > Sample Code & Libraries > Amazon Elastic Compute Cloud

Sample Code and Libraries

EC2 Instance Metadata Query Tool

Printer Friendly

Save to del.icio.us

A simple bash script that uses curl to query the EC2 instance Metadata from within a running EC2 instance.

Submitted By:	Ravi@AWS
AWS Products Used:	Amazon EC2
Language(s):	Other
License:	Apache License 2.0

Prerequisites

You must run this from within an EC2 instance running on linux/unix platform
Curl

Using the tool

Download the tool from http://s3.amazonaws.com/ec2metadata/ec2-metadata
```
$ wget http://s3.amazonaws.com/ec2metadata/ec2-metadata
```

Check file permissions and make sure that it is executable

$ls -l ec2-metadata
-rwxr-xr-x 1 root root 10912 2008-10-23 19:07 ec2-metadata

If not, change the file premissions and make it executable
```
$ chmod u+x ec2-metadata
```

Cool, now run help:

$ ec2-metadata --help
Usage: ec2-metadata <option>
Options:
--all                     Show all metadata information for this host (also default).
-a/--ami-id               The AMI ID used to launch this instance
-l/--ami-launch-index     The index of this instance in the reservation (per AMI).
-m/--ami-manifest-path    The manifest path of the AMI with which the instance was launched.
-n/--ancestor-ami-ids     The AMI IDs of any instances that were rebundled to create this AMI.
-b/--block-device-mapping Defines native device names to use when exposing virtual devices.
-i/--instance-id          The ID of this instance
-t/--instance-type        The type of instance to launch. For more information, see Instance Types.
-h/--local-hostname       The local hostname of the instance.
-o/--local-ipv4           Public IP address if launched with direct addressing; private IP address if launched with public addressing.
-k/--kernel-id            The ID of the kernel launched with this instance, if applicable.
-z/--availability-zone    The availability zone in which the instance launched. Same as placement
-c/--product-codes        Product codes associated with this instance.
-p/--public-hostname      The public hostname of the instance.
-v/--public-ipv4          NATted public IP Address
-u/--public-keys          Public keys. Only available if supplied at instance launch time
-r/--ramdisk-id           The ID of the RAM disk launched with this instance, if applicable.
-e/--reservation-id       ID of the reservation.
-s/--security-groups      Names of the security groups the instance is launched in. Only available if supplied at instance launch time
-d/--user-data            User-supplied data.Only available if supplied at instance launch time.

Examples

To get the ami-id of the instance, run
```
$ec2-metadata -a
ami-id: ami-xxxxxxx
```

To get the public hostname, run

$ec2-metadata -p
public-hostname: ec2-x-x-x-x.compute-1.amazonaws.com

To get the local ipv4, run
```
$ec2-metadata -o
local-ipv4: 10.x.x.x
```

You can copy this script to your /usr/bin folder.

For more information on EC2 metadata, consult the Amazon EC2 documentation at http://docs.amazonwebservices.com/AWSEC2/2008-08-08/DeveloperGuide/AESDG-chapter-instancedata.html

Discussion

The 5 most recent discussion messages. View full discussion.

Chris Markle

Posts: 5
Registered: 9/6/08

Should probably not smash all user-data lines together...
Posted: Jan 7, 2009 4:35 PM PST

Ravi,

Nice tool... But when I use it on multi-line user-data, the user-data is all crammed together on one line. For multi-line user-data, that is a problem. E.g., I had user-data on my instance of:

associate-address 1.2.3.4
attach-volume hfskjhfdsj /dev/sdh

but when I access it vi ec2_metadata -d, I get:

$ ./ec2-metadata -d
user-data: asssociate-address 75.101.141.64 attach-volume hfskjhfdsj /dev/sdh

It would be nice if multi-line user-data could retain it's line breaks, either all the time or at least as an option.

Thanks for listening,
Chris

godseyinc

Posts: 1
Registered: 11/7/07

Re: Should probably not smash all user-data lines together...
Posted: Jul 18, 2009 5:01 AM PDT

in response to: Chris Markle

This will preserve formatting of user-data provided the base64 or openssl command are found.

--- ec2-metadata.orig   2009-07-18 11:37:28.000000000 +0000
+++ ec2-metadata        2009-07-18 11:57:34.000000000 +0000
@@ -287,11 +287,21 @@
function print_user_data()
{
echo -n 'user-data: '
-x=$(curl -s http://169.254.169.254/latest/user-data)
-if [ $(echo $x|grep 404|wc -l) -eq 0 ]; then
-   echo $x
-   else
-   echo not available
+b64=`which base64 openssl 2>/dev/null | head -n1 | sed 's/openssl/openssl base64/'`
+if [ -z "$b64" ]; then
+   x=$(curl -s http://169.254.169.254/latest/user-data)
+   if [ $(echo $x|grep 404|wc -l) -eq 0 ]; then
+      echo $x
+      else
+      echo not available
+   fi
+else
+   x=$(curl -s http://169.254.169.254/latest/user-data|$b64)
+   if [ $(echo $x|$b64 -d|grep 404|wc -l) -eq 0 ]; then
+      echo $x | $b64 -d
+      else
+      echo not available
+   fi
fi
}

Victor Trac

Posts: 6
Registered: 5/17/06

Re: Should probably not smash all user-data lines together...
Posted: Jan 22, 2010 1:41 PM PST

in response to: Chris Markle

ec2-metadata.patch (7.6 K)

There's actually a pretty bad bug with this script. If you have '404' in any of your results (e.g. instance id i-abc12404), the script returns 'not available' for the result. I've attached a patch.

Reviews

Write a Review


Be the first to review this.

Welcome, Guest