Connect to Amazon EC2 instances

ec2-connect.sh

#!/bin/sh
#
# Look up the public IP address of an Amazon EC2 instance via
# the Amazon API, and connect to it using ssh.

# Defaults
region=eu-west-1
identity_file=~/amazon/identity.pem
username=ubuntu

usage() {
    cat >&2 <<EOF
usage: $0 [options] name

Connects to the given instance via ssh.

Options:

  -n             Dry-run; print the ssh command line instead of
                 actually connecting
  -r REGION      Amazon AWS region to connect to [$region]
  -i IDENTITY_FILE
                 SSH identity file [$identity_file]
  -u USERNAME    SSH username [$username]

Arguments:

  name           Value of the Name tag of the instance

EOF
    exit 2
}

while getopts nr:i:u: f; do
    case $f in
        n)   dryrun=1 ;;
        r)   region=$OPTARG ;;
        i)   identity_file=$OPTARG ;;
        u)   username=$OPTARG ;;
        \?)  usage
    esac
done
shift $(expr $OPTIND - 1)

[ $# -ne 1 ] && usage
[ -z "$1" ] && usage
name=$1

instance=$(ec2din --region $region -F "tag:Name=$name")
if [ -z "$instance" ]; then
    echo >&2 "Instance $name was not found in region $region"
    exit 1
fi

ip=$(echo "$instance" | grep ^INSTANCE | awk '{ print $4 }' | grep compute.amazonaws.com)

cmd="ssh -i $identity_file $username@$ip"
if [ -n "$dryrun" ]; then
    echo $cmd
else
    exec "$cmd"
fi