I have this script from Colin Johnson on Github - https://github.com/colinbjohnson/aws-missing-tools/tree/master/ec2-automate-backup

It seems great. I have modified it to send email to myself every time an EBS snapshot is created or deleted. The following works like a charm

ec2-automate-backup.sh -v "vol-myvolumeid" -k 3

However, it does not execute at all as part of my crontab (I didn't receive any emails)

#some command that got commented out

*/5 * * * * ec2-automate-backup.sh -v "vol-fb2fbcdf" -k 3;

* * * * * date >> /root/logs/crontab.log;

*/5 * * * * date >> /root/logs/crontab2.log

Please note that the 2nd and 3rd execute just fines as I can see the date and time in log files.

What could I have missed here?

The full ec2-automate-backup.sh is as follows:

#!/bin/bash -
# Author: Colin Johnson / [email protected]
# Date: 2012-09-24
# Version 0.1
# License Type: GNU GENERAL PUBLIC LICENSE, Version 3
#
#confirms that executables required for succesful script execution are available

prerequisite_check()
{
    for prerequisite in basename ec2-create-snapshot ec2-create-tags ec2-describe-snapshots ec2-delete-snapshot date
    do
        #use of "hash" chosen as it is a shell builtin and will add programs to hash table, possibly speeding execution. Use of type also considered - open to suggestions.
        hash $prerequisite &> /dev/null
        if [[ $? == 1 ]] #has exits with exit status of 70, executable was not found
            then echo "In order to use `basename $0`, the executable \"$prerequisite\" must be installed." 1>&2 | mailx -s "Error happened 0" [email protected] ; exit 70
        fi
    done
}

#get_EBS_List gets a list of available EBS instances depending upon the selection_method of EBS selection that is provided by user input
get_EBS_List()
{
    case $selection_method in
        volumeid)
            if [[ -z $volumeid ]]
                then echo "The selection method \"volumeid\" (which is $app_name's default selection_method of operation or requested by using the -s volumeid parameter) requires a volumeid (-v volumeid) for operation. Correct usage is as follows: \"-v vol-6d6a0527\",\"-s volumeid -v vol-6d6a0527\" or \"-v \"vol-6d6a0527 vol-636a0112\"\" if multiple volumes are to be selected." 1>&2 | mailx -s "Error happened 1" [email protected] ; exit 64
            fi
            ebs_selection_string="$volumeid"
            ;;
        tag) 
            if [[ -z $tag ]]
                then echo "The selected selection_method \"tag\" (-s tag) requires a valid tag (-t key=value) for operation. Correct usage is as follows: \"-s tag -t backup=true\" or \"-s tag -t Name=my_tag.\"" 1>&2 | mailx -s "Error happened 2" [email protected] ; exit 64
            fi
            ebs_selection_string="--filter tag:$tag"
            ;;
        *) echo "If you specify a selection_method (-s selection_method) for selecting EBS volumes you must select either \"volumeid\" (-s volumeid) or \"tag\" (-s tag)." 1>&2 | mailx -s "Error happened 3" [email protected] ; exit 64 ;;
    esac
    #creates a list of all ebs volumes that match the selection string from above
    ebs_backup_list_complete=`ec2-describe-volumes --show-empty-fields --region $region $ebs_selection_string 2>&1`
    #takes the output of the previous command 
    ebs_backup_list_result=`echo $?`
    if [[ $ebs_backup_list_result -gt 0 ]]
        then echo -e "An error occured when running ec2-describe-volumes. The error returned is below:\n$ebs_backup_list_complete" 1>&2 | mailx -s "Error happened 4" [email protected] ; exit 70
    fi
    ebs_backup_list=`echo "$ebs_backup_list_complete" | grep ^VOLUME | cut -f 2`
    #code to right will output list of EBS volumes to be backed up: echo -e "Now outputting ebs_backup_list:\n$ebs_backup_list"
}

create_EBS_Snapshot_Tags()
{
    #snapshot tags holds all tags that need to be applied to a given snapshot - by aggregating tags we ensure that ec2-create-tags is called only onece
    snapshot_tags=""
    #if $name_tag_create is true then append ec2ab_${ebs_selected}_$date_current to the variable $snapshot_tags
    if $name_tag_create
        then
        ec2_snapshot_resource_id=`echo "$ec2_create_snapshot_result" | cut -f 2`
        snapshot_tags="$snapshot_tags --tag Name=ec2ab_${ebs_selected}_$date_current"
    fi
    #if $purge_after_days is true, then append $purge_after_date to the variable $snapshot_tags
    if [[ -n $purge_after_days ]]
        then
        snapshot_tags="$snapshot_tags --tag PurgeAfter=$purge_after_date --tag PurgeAllow=true"
    fi
    #if $snapshot_tags is not zero length then set the tag on the snapshot using ec2-create-tags
    if [[ -n $snapshot_tags ]]
        then echo "Tagging Snapshot $ec2_snapshot_resource_id with the following Tags:"
        ec2-create-tags $ec2_snapshot_resource_id --region $region $snapshot_tags
        #echo "Snapshot tags successfully created" | mailx -s "Snapshot tags successfully created" [email protected]
    fi
}

date_command_get()
{
    #finds full path to date binary
    date_binary_full_path=`which date`
    #command below is used to determine if date binary is gnu, macosx or other
    date_binary_file_result=`file -b $date_binary_full_path`
    case $date_binary_file_result in
        "Mach-O 64-bit executable x86_64") date_binary="macosx" ;;
        "ELF 64-bit LSB executable, x86-64, version 1 (SYSV)"*) date_binary="gnu" ;;
        *) date_binary="unknown" ;;
    esac
    #based on the installed date binary the case statement below will determine the method to use to determine "purge_after_days" in the future
    case $date_binary in
        gnu) date_command="date -d +${purge_after_days}days -u +%Y-%m-%d" ;;
        macosx) date_command="date -v+${purge_after_days}d -u +%Y-%m-%d" ;;
        unknown) date_command="date -d +${purge_after_days}days -u +%Y-%m-%d" ;;
        *) date_command="date -d +${purge_after_days}days -u +%Y-%m-%d" ;;
    esac
}

purge_EBS_Snapshots()
{
    #snapshot_tag_list is a string that contains all snapshots with either the key PurgeAllow or PurgeAfter set
    snapshot_tag_list=`ec2-describe-tags --show-empty-fields --region $region --filter resource-type=snapshot --filter key=PurgeAllow,PurgeAfter`
    #snapshot_purge_allowed is a list of all snapshot_ids with PurgeAllow=true
    snapshot_purge_allowed=`echo "$snapshot_tag_list" | grep .*PurgeAllow'\t'true | cut -f 3`

    for snapshot_id_evaluated in $snapshot_purge_allowed
    do
        #gets the "PurgeAfter" date which is in UTC with YYYY-MM-DD format (or %Y-%m-%d)
        purge_after_date=`echo "$snapshot_tag_list" | grep .*$snapshot_id_evaluated'\t'PurgeAfter.* | cut -f 5`
        #if purge_after_date is not set then we have a problem. Need to alter user.
        if [[ -z $purge_after_date ]]
            #Alerts user to the fact that a Snapshot was found with PurgeAllow=true but with no PurgeAfter date.
            then echo "A Snapshot with the Snapshot ID $snapshot_id_evaluated has the tag \"PurgeAllow=true\" but does not have a \"PurgeAfter=YYYY-MM-DD\" date. $app_name is unable to determine if $snapshot_id_evaluated should be purged." 1>&2 | mailx -s "Error happened 5" [email protected]
        else
            #convert both the date_current and purge_after_date into epoch time to allow for comparison
            date_current_epoch=`date -j -f "%Y-%m-%d" "$date_current" "+%s"`
            purge_after_date_epoch=`date -j -f "%Y-%m-%d" "$purge_after_date" "+%s"`
            #perform compparison - if $purge_after_date_epoch is a lower number than $date_current_epoch than the PurgeAfter date is earlier than the current date - and the snapshot can be safely removed
            if [[ $purge_after_date_epoch < $date_current_epoch ]]
                then
                echo "The snapshot \"$snapshot_id_evaluated\" with the Purge After date of $purge_after_date will be deleted."
                ec2-delete-snapshot --region $region $snapshot_id_evaluated
                echo "Old snapshots successfully deleted for $volumeid" | mailx -s "Old snapshots successfully deleted for $volumeid" [email protected]
            fi
        fi
    done
}

#calls prerequisitecheck function to ensure that all executables required for script execution are available
prerequisite_check

app_name=`basename $0`

#sets defaults
selection_method="volumeid"
region="ap-southeast-1"
#date_binary allows a user to set the "date" binary that is installed on their system and, therefore, the options that will be given to the date binary to perform date calculations
date_binary=""

#sets the "Name" tag set for a snapshot to false - using "Name" requires that ec2-create-tags be called in addition to ec2-create-snapshot
name_tag_create=false
#sets the Purge Snapshot feature to false - this feature will eventually allow the removal of snapshots that have a "PurgeAfter" tag that is earlier than current date
purge_snapshots=false
#handles options processing
while getopts :s:r:v:t:k:pn opt
    do
        case $opt in
            s) selection_method="$OPTARG";;
            r) region="$OPTARG";;
            v) volumeid="$OPTARG";;
            t) tag="$OPTARG";;
            k) purge_after_days="$OPTARG";;
            n) name_tag_create=true;;
            p) purge_snapshots=true;;
            *) echo "Error with Options Input. Cause of failure is most likely that an unsupported parameter was passed or a parameter was passed without a corresponding option." 1>&2 ; exit 64;;
        esac
    done

#sets date variable
date_current=`date -u +%Y-%m-%d`
#sets the PurgeAfter tag to the number of days that a snapshot should be retained
if [[ -n $purge_after_days ]]
    then
    #if the date_binary is not set, call the date_command_get function
    if [[ -z $date_binary ]]
        then date_command_get
    fi
    purge_after_date=`$date_command`
    echo "Snapshots taken by $app_name will be eligible for purging after the following date: $purge_after_date."
fi

#get_EBS_List gets a list of EBS instances for which a snapshot is desired. The list of EBS instances depends upon the selection_method that is provided by user input
get_EBS_List

#the loop below is called once for each volume in $ebs_backup_list - the currently selected EBS volume is passed in as "ebs_selected"
for ebs_selected in $ebs_backup_list
do
    ec2_snapshot_description="ec2ab_${ebs_selected}_$date_current"
    ec2_create_snapshot_result=`ec2-create-snapshot --region $region -d $ec2_snapshot_description $ebs_selected 2>&1`
    if [[ $? != 0 ]]
        then echo -e "An error occured when running ec2-create-snapshot. The error returned is below:\n$ec2_create_snapshot_result" 1>&2 ; exit 70
    else
        ec2_snapshot_resource_id=`echo "$ec2_create_snapshot_result" | cut -f 2`
        echo "Snapshots successfully created for volume $volumeid" | mailx -s "Snapshots successfully created for $volumeid" [email protected]
    fi  
    create_EBS_Snapshot_Tags
done

#if purge_snapshots is true, then run purge_EBS_Snapshots function
if $purge_snapshots
    then echo "Snapshot Purging is Starting Now."
    purge_EBS_Snapshots
fi

cron log

Oct 23 10:24:01 ip-10-130-153-227 CROND[28214]: (root) CMD (root (ec2-automate-backup.sh -v "vol-fb2fbcdf" -k 3;))
Oct 23 10:24:01 ip-10-130-153-227 CROND[28215]: (root) CMD (date  >> /root/logs/crontab.log;)
Oct 23 10:25:01 ip-10-130-153-227 CROND[28228]: (root) CMD (date  >> /root/logs/crontab.log;)
Oct 23 10:25:01 ip-10-130-153-227 CROND[28229]: (root) CMD (date >> /root/logs/crontab2.log)
Oct 23 10:26:01 ip-10-130-153-227 CROND[28239]: (root) CMD (date  >> /root/logs/crontab.log;)
Oct 23 10:27:01 ip-10-130-153-227 CROND[28247]: (root) CMD (root (ec2-automate-backup.sh -v "vol-fb2fbcdf" -k 3;))
Oct 23 10:27:01 ip-10-130-153-227 CROND[28248]: (root) CMD (date  >> /root/logs/crontab.log;)
Oct 23 10:28:01 ip-10-130-153-227 CROND[28263]: (root) CMD (date  >> /root/logs/crontab.log;)
Oct 23 10:29:01 ip-10-130-153-227 CROND[28275]: (root) CMD (date  >> /root/logs/crontab.log;)
Oct 23 10:30:01 ip-10-130-153-227 CROND[28292]: (root) CMD (root (ec2-automate-backup.sh -v "vol-fb2fbcdf" -k 3;))
Oct 23 10:30:01 ip-10-130-153-227 CROND[28293]: (root) CMD (date  >> /root/logs/crontab.log;)
Oct 23 10:30:01 ip-10-130-153-227 CROND[28294]: (root) CMD (date >> /root/logs/crontab2.log)
Oct 23 10:31:01 ip-10-130-153-227 CROND[28312]: (root) CMD (date  >> /root/logs/crontab.log;)
Oct 23 10:32:01 ip-10-130-153-227 CROND[28319]: (root) CMD (date  >> /root/logs/crontab.log;)
Oct 23 10:33:01 ip-10-130-153-227 CROND[28325]: (root) CMD (date  >> /root/logs/crontab.log;)
Oct 23 10:33:01 ip-10-130-153-227 CROND[28324]: (root) CMD (root (ec2-automate-backup.sh -v "vol-fb2fbcdf" -k 3;))
Oct 23 10:34:01 ip-10-130-153-227 CROND[28345]: (root) CMD (date  >> /root/logs/crontab.log;)
Oct 23 10:35:01 ip-10-130-153-227 CROND[28362]: (root) CMD (date  >> /root/logs/crontab.log;)
Oct 23 10:35:01 ip-10-130-153-227 CROND[28363]: (root) CMD (date >> /root/logs/crontab2.log)

Mails to root

From [email protected]  Tue Oct 23 06:00:01 2012
Return-Path: <[email protected]>
Date: Tue, 23 Oct 2012 06:00:01 GMT
From: [email protected] (Cron Daemon)
To: [email protected]
Subject: Cron <root@ip-10-130-153-227> root ec2-automate-backup.sh -v "vol-fb2fbcdf" -k 3
Content-Type: text/plain; charset=UTF-8
Auto-Submitted: auto-generated
X-Cron-Env: <SHELL=/bin/sh>
X-Cron-Env: <HOME=/root>
X-Cron-Env: <PATH=/usr/bin:/bin>
X-Cron-Env: <LOGNAME=root>
X-Cron-Env: <USER=root>
Status: R

/bin/sh: root: command not found