ebs_backup

#!/bin/bash
#
# This script is to ensure the consistent backup of our EBS volume onto Amazon Simple Storage Service via snapshots

# Script paramaters

days=30

echo -e "Automated Daily Snapshot of Important Volumes\r\n"

placement=$(wget -q -O - http://169.254.169.254/latest/meta-data/placement/availability-zone)
region=$(echo ${placement%?})

myid=$(wget -q -O - http://169.254.169.254/latest/meta-data/instance-id)

volumes=$(aws ec2 describe-volumes --filters Name=attachment.instance-id,Values="${myid}" Name=attachment.delete-on-termination,Values=false --region $region)
vol_id=$(echo ${volumes} | jq '.Volumes[].VolumeId' | tr -d '"')

# Define new array for volume names and IDs, to be filled from the volume ID query above.
vol_names=()
vol_ids=()
counter=0
for id in $vol_id
do
        # Populate two arrays, one contains the volume IDs to be snapshotted, and the second containing the names for use later.
        vol_ids[$counter]=$id
        vol_names[$counter]=$(aws ec2 describe-tags --region $region --filters "Name=resource-id,Values=$id" "Name=key,Values=Name" | jq '.Tags[].Value' | tr -d '"')
	
	# If the volume has no name, use the volume ID for the snapshot description instead
	if [ -z ${vol_names[$counter]} ]; then
		vol_names[$counter]=$id
	fi
        ((counter++))
done

DESC_DATE=$(date +"%Y-%m-%d_%H:%M:%S")
LOG_DATE=$(date +"%b %d %R:%S")

process=0
while [ $process -lt $counter ]
do
        Description="Automated - ${vol_names[$process]} snapshot - "${DESC_DATE}

        echo "$LOG_DATE Creating snapshot of ${vol_names[$process]} on ${vol_ids[$process]} in $region with Description: ${Description}" >> /var/log/ebs_backups.log
        aws ec2 create-snapshot --volume-id ${vol_ids[$process]} --description "${Description}" --region $region --output text >> /var/log/ec2snapshot.log
        ((process++))
done

# Reset process variable for next loop
process=0

# Purge old backups
OLD='`'$(date +%Y%m%d --date "$days days ago")'`'

# get snapshot id for all snapshots older than $OLD
while [ $process -lt $counter ]
do
        snap_ids=$(aws ec2 describe-snapshots --region $region --filters Name=description,Values="Automated - ${vol_names[$process]} *" --query "Snapshots[?StartTime<$OLD]" | jq '.[].SnapshotId' | tr -d '"')

        if [ ${#snap_ids} -eq 0 ]; then
                echo "No snapshots to purge"
                exit 0
        fi

        readarray snapshots <<< "${snap_ids}"

        for snapshot in "${snapshots[@]}"
        do
                        echo "Deleting snapshot $snapshot"
                        aws ec2 delete-snapshot --snapshot-id $snapshot --region $region >> /var/log/snapshot_purge.log
        done
done