ec2dns

ec2dns is a set of command line tools that makes it easy to display public hostnames of EC2 instances and ssh into them via their tag name.

Usage

ec2host

Get a list of ec2 instances

$ ec2host
i-12345678: appserver-1    ec9-99-99-99-99.compute-1.amazonaws.com
i-87654321: appserver-2    ec1-11-11-11-11.compute-1.amazonaws.com
$

Get the hostname of an ec2 instance by its name tag

$ ec2host appserver-1
ec9-99-99-99-99.compute-1.amazonaws.com
$

combine ec2host with other commands by using backticks

$ mysql --host=`ec2host appserver-1` --user=someUser --password=somePassword someDatabase
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 348
Server version: 5.5.25a Source distribution

Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql>

ec2ssh

ssh into an instance via its name tag

$ ec2ssh appserver-2
ubuntu@ip-1-11-11-11:~$

ssh into an instance via its name tag and execute commands

$ ec2ssh appserver-1 uptime
 13:09:10 up 1 day, 14:23,  0 users,  load average: 0.35, 0.36, 0.35
$

$ ec2ssh appserver-1 'uname -a'
 Linux ip-10-140-78-75 3.2.0-23-virtual #36-Ubuntu SMP Tue Apr 10 22:29:03 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
$

Prerequisites

• Obviously an AWS account and at least one running EC2 instance.
• Correctly set AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY environment variables.
• You need Composer to install the dependencies - you should install it globally, as described here.
• You should have a ~/bin directory and it should be included in your PATH environment variable.

Installation

• Create the file ~/bin/composer.json with your favourite text editor and paste the following content (or update your existing composer.json accordingly, if you already use this approach for something else).

{
    "require" : {

        "fruux/ec2dns" : "dev-master"

    },
    "config" : {
        "bin-dir" : "."
    }
}

• Save the file.
• Run composer install in your ~/bin directory.
• Composer will now install ec2host and its dependencies.

Updating

cd ~/bin
composer update

Roadmap

• Set a nice prompt with the tag name when sshing into a machine via ec2ssh appserver-1.
• A cli tool (ec2dns) that updates /etc/hosts with the current public hostnames of all ec2 instances.

Acknowledgements

ec2dns is inspired by ec2-ssh and powered by aws-sdk-for-php.

Copyright and license

Copyright (C) 2012 fruux GmbH. All rights reserved.

fruux is a free service that takes care of your contacts, calendars and more so you don't have to (powered by CardDAV and CalDAV).

Check the license.