ec2-automate-backup now includes support for purging old snapshots.

This commit is contained in:
Colin Johnson 2012-09-24 23:34:15 +00:00
parent c1025a4188
commit eee4ad0637
3 changed files with 43 additions and 6 deletions

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@ -23,6 +23,7 @@ $ec2ab_exec -v "$volume_1_id $volume_2_id" -n
$ec2ab_exec -v "$volume_1_id $volume_2_id" -k 14
#expected result - snapshot only taken of volume_1 and volume_2 each with tags "PurgeAfter=$date_current+14" and "PurgeAllow=true"
#
#test backing up only EBS volume with IDs "x" and "y" and tagging them with a tag "PurgeAfter=1"
#test backing up only EBS volume with IDs "x" and "y" and tagging them with a tag "PurgeAfter=14"
$ec2ab_exec -v "$volume_1_id $volume_2_id" -k 14 -n
#expected result - snapshot only taken of volume_1 and volume_2 each with tag "name" set to ec2ab_$volume_id_$date_current
#expected result - snapshot only taken of volume_1 and volume_2 each with tag "name" set to ec2ab_$volume_id_$date_current
#

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@ -23,7 +23,8 @@ ec2-automate-backup requires one of the following two parameters be provided:
-r <region> - the region that contains the EBS volumes for which you wish to have a snapshot created.
-s <selection_method> - the selection method by which EBS volumes will be selected. Currently supported selection methods are "volumeid" and "tag." The selection method "volumeid" identifies EBS volumes for which a snapshot should be taken by volume id whereas the selection method "tag" identifies EBS volumes for which a snapshot should be taken by a key=value format tag.
-n - tag snapshots "Name" tag as well as description
-k <purge_after_days> - the period after which a snapshot can be purged. For example, running "ec2-automate-backup.sh -v "vol-6d6a0527 vol-636a0112" -k 31" would allow snapshots to be removed after 31 days
-k <purge_after_days> - the period after which a snapshot can be purged. For example, running "ec2-automate-backup.sh -v "vol-6d6a0527 vol-636a0112" -k 31" would allow snapshots to be removed after 31 days. purge_after_days creates two tags for each volume that was backed up - a PurgeAllow tag which is set to PurgeAllow=true and a PurgeAfter tag which is set to the present day (in UTC) + the value provided by -k.
-p - the -p flag will purge (meaning delete) all snapshots that were created more than "purge after days" ago. ec2-automate-backup looks at two tags to determine which snapshots should be deleted - the PurgeAllow and PurgeAfter tags. The tags must be set as follows: PurgeAllow=true and PurgeAfter=YYYY-MM-DD where YYYY-MM-DD must be before the present date.
#
# Potential Uses and Methods of Use:
#

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@ -1,13 +1,13 @@
#!/bin/bash -
# Author: Colin Johnson / colin@cloudavail.com
# Date: 2012-09-21
# 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
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
@ -67,6 +67,35 @@ create_EBS_Snapshot_Tags()
fi
}
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 $snapshot_id_evaluated should be purged." 1>&2
else
#convert both the date_current and purge_after_date into epoch time to allow for comparison
date_current_epoch=`date -j -f "%Y-%m-%d" "$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 $snapshot_id_evaluated
fi
fi
done
}
#calls prerequisitecheck function to ensure that all executables required for script execution are available
prerequisite_check
@ -117,4 +146,10 @@ do
ec2_snapshot_resource_id=`echo "$ec2_create_snapshot_result" | cut -f 2`
fi
create_EBS_Snapshot_Tags
done
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