Automount EBS volume in Amazon EC2 Windows Instance

Question

Does anyone know how to auto-mount an Elastic Block Storage (EBS) volume when starting a Windows 2003 instance in Amazon\'s Elastic Compute Cloud (EC2)?

Answer 1

Setup:

• Make sure the EBS volume is formatted and labeled (in the example I used the label PDRIVE).
• Setup a drive mapping using Ec2ConfigServiceSettings.exe
• Install Java on the instance
• Install the EC2 API command line tools
• Install a copy of your cert and private key
• Install a copy of curl.exe (open source tool)

You can use the group policy editor to set this script as your startup script. See http://technet.microsoft.com/en-us/library/cc739591(WS.10).aspx for more information.

REM @echo off
REM setlocal ENABLEDELAYEDEXPANSION

C:\WINDOWS\system32\eventcreate /l SYSTEM /t information /id 100 /so AttachEbsBoot /d "Starting attach-ebs-boot.cmd"

REM local variables
REM Make sure you include the directory with curl.exe and the EC2 command line tools in the path
set path=C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;c:\Utils;C:\ebin\ec2\bin
set JAVA_HOME=c:\java
set EC2_HOME=c:\ebin\ec2
set EC2_CERT=<your_cert>
set EC2_PRIVATE_KEY=<your_private_key>

REM Please note: you should use the Ec2 Config Serive Settings application to ensure
REM that your EBS volume is mapped to a particular drive letter.
REM
REM edit as needed
set EBS_DRIVE=P:
set EBS_DEVICE=xvdp

REM Test to see if the drive is already attached. If it is then we're done.
if exist %EBS_DRIVE%\nul (goto done)

REM get the EBS volume ID from the user data and the instance ID from the meta-data
for /f "delims=" %%a in ('curl http://169.254.169.254/latest/user-data') do (set EBS_VOLUME=%%a)
for /f "delims=" %%b in ('curl http://169.254.169.254/latest/meta-data/instance-id') do (set INSTANCE_ID=%%b)

C:\WINDOWS\system32\eventcreate /l SYSTEM /t information /id 102 /so AttachEbsBoot /d "Volume == %EBS_VOLUME%"
C:\WINDOWS\system32\eventcreate /l SYSTEM /t information /id 103 /so AttachEbsBoot /d "Instance == %INSTANCE_ID%"

REM attach the volume
REM 
REM Use a series of set command to build the command line
SET COMMAND_LINE=%EBS_VOLUME%
SET COMMAND_LINE=%COMMAND_LINE% -i
SET COMMAND_LINE=%COMMAND_LINE% %INSTANCE_ID%
SET COMMAND_LINE=%COMMAND_LINE% -d
SET COMMAND_LINE=%COMMAND_LINE% %EBS_DEVICE%

C:\WINDOWS\system32\eventcreate /l SYSTEM /t information /id 104 /so AttachEbsBoot /d "calling ec2attvole %COMMAND_LINE%"

call ec2attvol.cmd %COMMAND_LINE%

:DONE
C:\WINDOWS\system32\eventcreate /l SYSTEM /t information /id 101 /so AttachEbsBoot /d "Exiting attach-ebs-boot.cmd"

REM Events logged in the System event log
REM source === AttachEbsBoot
REM 
REM Event 100 - Script start
REM Event 101 - Script end
REM Event 102 - Volume ID
REM Event 103 - Instance ID
REM Event 104 - Command line for ec2attvol

Answer 2

I found the following Ruby code at http://www.ioncannon.net/system-administration/199/automounting-amazon-ebs-volumes-on-ec2-instances/ courtesy of Carson McDonald. It's for Linux/Unix but maybe you can re-swizzle this for Ruby on Windows 2003 or have it serve as a model for doing it in some other scripting language.

Note that you could pass things into your image as user data such as the ECS EBS volume ID and the device name (e.g., /dev/sdh in the following example or whatever it would be in Windows for your case). You can access the user data from the instance itself as meta-data as is roughly done below to get the instance-id. More specifically, you'd access http://169.254.169.254/1.0/user-data to get to the user-data.

#!/usr/bin/ruby

require 'rubygems'
require 'right_aws'
require 'net/http'

url = 'http://169.254.169.254/2008-02-01/meta-data/instance-id'
instance_id = Net::HTTP.get_response(URI.parse(url)).body

AMAZON_PUBLIC_KEY='your public key'
AMAZON_PRIVATE_KEY='your private key'
EC2_LOG_VOL='the volume id'

ec2 = RightAws::Ec2.new(AMAZON_PUBLIC_KEY, AMAZON_PRIVATE_KEY)

vol = ec2.attach_volume(EC2_LOG_VOL, instance_id, '/dev/sdh')
puts vol

# It can take a few seconds for the volume to become ready.
# This is just to make sure it is ready before mounting it.
sleep 20

system('mount /dev/sdh /mymountpoint')