Who’s On Phirst

Amazon Elastic Compute Cloud (EC2) has generated enormous amounts of buzz in the last couple of months. EC2 allows scalable deployment of applications by providing a way for customers to create server “instances” which can run any number of operating systems, such as Windows XP and Vista, and any number of Linux distributions. The customer can load any software of their choice on to the machines, and customize them at will. A customer can create, launch, and terminate server instances as needed, paying only for usage.

In addition to providing a Amazon Management Console to manage these instances, Amazon also provides command line tools which allow for the automation of instance administration. By combining these tools with some basic shell commands, you can customize the startup of your EC2 instances. I will provide an example that shows how this can be accomplished.

This example assumes you have the following available:

• EC2 Ubuntu Linux instance
• ESB (Elastic Storage Block) volume
• Elastic IP address
• EC2 API Tools
• EC2 key and cert files
• SSH
• FreeNX Server

export EC2_HOME=/opt/ec2/tools/ec2-api-tools-1.3-30349/
export EC2_PRIVATE_KEY=~/ec2/pk-HGHEBCKY657B2ZUH7YIVXZKT5QVNBWFM.pem
export EC2_CERT=~/ec2/cert-HGHEBCKY657B2ZUH7YIVXZKT5QVNBWFM.pem
export amiid="ami-cccb2ca5"
export key="mykey"
export zone="us-east-1c"
export group="server"
export id_file="mykey.pem"
export vol_name="vol-8abe59e3"
export mount_point="/mnt/vol"
export device_name="/dev/sdf"
export ip="174.129.232.50"

• Amazon Image ID
• Key name associated with this instance
• The zone in which this instance was created
• The group associated with this instance
• The name of the user's EC2 identity file
• The ESB volume ID
• The mount directory within the EC2 instance
• The device name to associate with the ESB volume when attached
• The Elastic IP address to associate with the instance

#
# Start the instance
# Capture the output so that
# we can grab the INSTANCE ID field
# and use it to determine when
# the instance is running 
#
echo Launching AMI ${amiid}
${EC2_HOME}/bin/ec2-run-instances ${amiid} -z ${zone} -k ${key} --group ${group} 
--group default > /tmp/a
if [ $? != 0 ]; then
   echo Error starting instance for image ${amiid}
   exit 1
fi
export iid=`cat /tmp/a | grep INSTANCE | cut -f2`

#
# Loop until the status changes to “running”
#
sleep 30
echo Starting instance ${iid}
export RUNNING="running"
export done="false"
while [ $done == "false" ]
do
   export status=`${EC2_HOME}/bin/ec2-describe-instances ${iid} | grep INSTANCE | cut -f6`
   if [ $status == ${RUNNING} ]; then
      export done="true"
   else
      echo Waiting...
      sleep 10
   fi
done
echo Instance ${iid} is running

#
# Attach the volume to the running instance
#
echo Attaching volume ${vol_name}
${EC2_HOME}/bin/ec2-attach-volume ${vol_name} -i ${iid} -d ${device_name} 
sleep 15

#
# Loop until the volume status changes
# to "attached" 
#
export ATTACHED="attached"
export done="false"
while [ $done == "false" ]
do
   export status=`${EC2_HOME}/bin/ec2-describe-volumes | grep ATTACHMENT | grep ${iid} | cut -f5`
   if [ $status == ${ATTACHED} ]; then
      export done="true"
   else 
      echo Waiting...
      sleep 10
   fi
done
echo Volume ${vol_name} is attached

#
# Associate the Elastic IP with the instance
# After this operation we just sleep a bit
#
echo Associating elastic IP address ${ip}
${EC2_HOME}/bin/ec2-associate-address 174.129.232.50 -i ${iid}
sleep 30

#
# Start the operations within the instance
# Copy over the mount script and execute it
# The script setup_vol does:
#     mkdir /mnt/vol
#     mount /mnt./vol
# 
scp -i ${id_file} setup_vol root@${ip}:/root
ssh -i ${id_file} root@${ip} . ./setup_vol

ssh -i ${id_file} root@${ip} /usr/NX/bin/nxserver --stop
ssh -i ${id_file} root@${ip} /usr/NX/bin/nxserver --start

echo Image ${amiid} instance ${iid} is ready to go!
echo ${iid} > current_instance