How to use it: http://talk.ernestchiang.com/2013/11/how-to-create-ec2-snapshots-with.html

snapshot-multiple.sh

#!/bin/bash
filename_instance_info="instance_info.txt"
profile_list="profile_list"

for profile_name in $(cat $profile_list)
do
    export AWS_DEFAULT_PROFILE=$profile_name

    # Get running instances
    aws ec2 describe-instances --filters Name=instance-state-name,Values=running > $filename_instance_info

    # Get EBS volumes of running instances
    volumes_list=$(cat $filename_instance_info | grep "EBS" | awk '{print $5}')
    tag_name_list=$(cat $filename_instance_info | grep "TAGS" | awk '{print $3}')
    TAG_NAME_ARRAY={'tmp'}
    i="0"

    for tag_name in $tag_name_list
    do
        TAG_NAME_ARRAY=("${TAG_NAME_ARRAY[@]}" $tag_name)
    done

    # Create snapshots for $volumes_list
    for volume in $volumes_list
    do
        i=$(($i + 1))
        description="${volume}_${TAG_NAME_ARRAY[i]}_backup-`date +%Y-%m-%d`"
        aws ec2 create-snapshot --volume-id $volume --description $description
        echo $description
    done


    rm $filename_instance_info
    unset TAG_NAME_ARRAY

done