120 lines
5.5 KiB
Bash
Executable File
120 lines
5.5 KiB
Bash
Executable File
#!/bin/bash -
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# Author: Colin Johnson / colin@cloudavail.com
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# Date: 2012-09-21
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# Version 0.1
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# License Type: GNU GENERAL PUBLIC LICENSE, Version 3
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#
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#confirms that executables required for succesful script execution are available
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prerequisite_check()
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{
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for prerequisite in basename ec2-create-snapshot ec2-create-tags
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do
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#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.
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hash $prerequisite &> /dev/null
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if [[ $? == 1 ]] #has exits with exit status of 70, executable was not found
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then echo "In order to use `basename $0`, the executable \"$prerequisite\" must be installed." 1>&2 ; exit 70
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fi
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done
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}
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#get_EBS_List gets a list of available EBS instances depending upon the selection_method of EBS selection that is provided by user input
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get_EBS_List()
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{
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case $selection_method in
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volumeid)
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if [[ -z $volumeid ]]
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then echo "The selection method \"volumeid\" (which is $app_name's default selection_method of operation or requested by using the -s volumeid parameter) requires a volumeid (-v volumeid) for operation. Correct usage is as follows: \"-v vol-6d6a0527\",\"-s volumeid -v vol-6d6a0527\" or \"-v \"vol-6d6a0527 vol-636a0112\"\" if multiple volumes are to be selected." 1>&2 ; exit 64
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fi
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ebs_selection_string="$volumeid"
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;;
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tag)
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if [[ -z $tag ]]
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then echo "The selected selection_method \"tag\" (-s tag) requires a valid tag (-t key=value) for operation. Correct usage is as follows: \"-s tag -t backup=true\" or \"-s tag -t Name=my_tag.\"" 1>&2 ; exit 64
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fi
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ebs_selection_string="--filter tag:$tag"
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;;
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*) 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 ; exit 64 ;;
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esac
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#creates a list of all ebs volumes that match the selection string from above
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ebs_backup_list_complete=`ec2-describe-volumes --show-empty-fields --region $region $ebs_selection_string 2>&1`
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#takes the output of the previous command
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ebs_backup_list_result=`echo $?`
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if [[ $ebs_backup_list_result -gt 0 ]]
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then echo -e "An error occured when running ec2-describe-volumes. The error returned is below:\n$ebs_backup_list_complete" 1>&2 ; exit 70
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fi
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ebs_backup_list=`echo "$ebs_backup_list_complete" | grep ^VOLUME | cut -f 2`
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#code to right will output list of EBS volumes to be backed up: echo -e "Now outputting ebs_backup_list:\n$ebs_backup_list"
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}
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create_EBS_Snapshot_Tags()
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{
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#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
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snapshot_tags=""
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#if $name_tag_create is true then append ec2ab_${ebs_selected}_$date_current to the variable $snapshot_tags
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if $name_tag_create
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then
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ec2_snapshot_resource_id=`echo "$ec2_create_snapshot_result" | cut -f 2`
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snapshot_tags="$snapshot_tags --tag Name=ec2ab_${ebs_selected}_$date_current"
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fi
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#if $purge_after_days is true, then append $purge_after_date to the variable $snapshot_tags
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if [[ -n $purge_after_days ]]
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then
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snapshot_tags="$snapshot_tags --tag PurgeAfter=$purge_after_date --tag PurgeAllow=true"
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fi
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#if $snapshot_tags is not zero length then set the tag on the snapshot using ec2-create-tags
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if [[ -n $snapshot_tags ]]
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then ec2-create-tags $ec2_snapshot_resource_id --region $region $snapshot_tags
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fi
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}
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#calls prerequisitecheck function to ensure that all executables required for script execution are available
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prerequisite_check
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app_name=`basename $0`
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#sets defaults
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selection_method="volumeid"
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region="us-east-1"
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#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
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name_tag_create=false
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#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
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purge_snapshots=false
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#handles options processing
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while getopts :s:r:v:t:k:pn opt
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do
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case $opt in
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s) selection_method="$OPTARG";;
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r) region="$OPTARG";;
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v) volumeid="$OPTARG";;
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t) tag="$OPTARG";;
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k) purge_after_days="$OPTARG";;
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n) name_tag_create=true;;
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p) purge_snapshots=true;;
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*) 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;;
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esac
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done
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#sets date variable
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date_current=`date -u +%Y-%m-%d`
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#sets the PurgeAfter tag to the number of days that a snapshot should be retained
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if [[ -n $purge_after_days ]]
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then purge_after_date=`date -v+${purge_after_days}d -u +%Y-%m-%d`
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echo "Snapshots taken by $app_name will be eligible for purging after the following date: $purge_after_date."
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fi
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#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
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get_EBS_List
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#the loop below is called once for each volume in $ebs_backup_list - the currently selected EBS volume is passed in as "ebs_selected"
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for ebs_selected in $ebs_backup_list
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do
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ec2_snapshot_description="ec2ab_${ebs_selected}_$date_current"
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ec2_create_snapshot_result=`ec2-create-snapshot --region $region -d $ec2_snapshot_description $ebs_selected 2>&1`
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if [[ $? != 0 ]]
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then echo -e "An error occured when running ec2-create-snapshot. The error returned is below:\n$ec2_create_snapshot_result" 1>&2 ; exit 70
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else
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ec2_snapshot_resource_id=`echo "$ec2_create_snapshot_result" | cut -f 2`
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fi
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create_EBS_Snapshot_Tags
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done |