ec2_kamino.sh

#!/bin/bash
# Syntax: ec2_kamino.sh <source instance 'Name' tag> [target new instance 'Name' tag].
#           If target name is not given <source name>-clone is used.
# Description: Builds a temporary template from a given instance and runs the latest found ami from that template.
#              New instance settings can be overriden by $overrides.
#              AMI selection is filtered by $ami_select.
#              New instance in also tagged with 'clone-source' tag of source instance.
#              New instance EBS volumes are tagged with the same 'Name' tag of the new instance.
#              Written by Shoko, Oct2019.
# Requires: jq, awscli, standard gnu utils.
# Bugs: `aws ec2 get-launch-template-data` does not return 'CreditSpecification>CpuCredits' for t3.
#         If you need 'standard' add an override. Tested with awscli 1.16.138.

help_output="Syntax: ec2_kamino.sh [-h] [-s <source instance name tag>] [-t <target instance name>] [-o <instance start cmd overrides>] [-a <specific ami-id>] [-n <subnet id>]"

# opts default
##############

# template overrides for run-instances
overrides="--placement Tenancy=default --instance-type c4.xlarge"
#overrides="--placement Tenancy=default"

# getopts
#########

while [ ! -z "$*" ]; do
        case "$1" in
                # source instance name
                -s|--source)       shift; ins_name="$1"; target_name="${ins_name}-clone";;
                # target instance name
                -t|-target-name)   shift; target_name="$1";;
                # instace start overrides
                -o|--overrides)    shift; overrides="$1";;
                # source AMI
                -a|--ami-id)       shift; ami="$1";;
                -n|--subnet)       shift; subnet="$1";;
                -h|--help|*)       echo "$help_output"; exit;;
        esac
        shift
done

if [ -z "$ami" ]; then
        ami_select="Name=tag:origin,Values=$ins_name Name=tag:type,Values=EC2amibackup"
else
        ami_select="Name=image-id,Values=$ami"
fi

echo "Input Vars:
        Source Name     $ins_name
        Target Name     $target_name
        Overrides       $overrides
        AMI select      $ami_select
"
[ -z "$ins_name" ] && echo "$help_output" && exit

dbg_var(){ echo "${!1}" | sed "s#^#   $1: #" >&2; }
aws_cmd(){
        local S="$1"; local A="$2";
        #for w in "$@"; do echo "   >$S/$A>>> $w"; done >&2
        #echo aws "$@" | sed 's#^# >> #' >&2
        local O=$(aws "$@" 2>&1); local E="$?";
        # test for valid json since awscli exit codes are shit
        if [[ $* =~ "--output json" ]] || ([[ ! $* =~ --output ]] && [ `aws configure get output` = "json" ]); then
                echo "$O" | jq . &>/dev/null; E=$?
        fi
        if [ $E -eq 0 ]; then
                echo "AWS $S $A - OK" >&2
                echo "$O"
        else
                (tput setaf 1; echo "AWS $S $A - FAIL"; echo "$O" | sed 's#^#   ERROR:#'; tput sgr0) >&2
        fi
        return $E
}

# get instance id by Name tag
#############################

ins_id=`aws ec2 describe-instances --filter "Name=tag:Name,Values=${ins_name}" "Name=instance-state-name,Values=running" --query 'Reservations[].Instances[0].InstanceId' | head -1`
echo "Cloning $ins_name ($ins_id) > $target_name"
echo "   AMI filter: $ami_select"
echo

# get latest ami
################

# this strange usage of json output with jq flattening at the end (instead of text output) is just for using the json validation in aws_cmd()
# cause some developers think that exit codes are not that important and all the rest of the world can just go fuck themselves
output_ami=`aws_cmd ec2 describe-images --owners self --output json --filter $ami_select \
        --query "Images[].[Name,ImageId,CreationDate,State]" | jq -r '.[] | join(" ")' | \
        grep available | sort -k 3r | head -1`
[ -z "$output_ami" ] && echo "CRITICAL: AMI not found" && exit 2

read ami_name ami_id ami_date X <<< "$output_ami"
ami_age=$((`date +%s`-`date -d "$ami_date" +%s`))
echo "   Found AMI '$ami_name' ($ami_id), $(($ami_age/3600)) hours old"
echo

# create template
#################

tmpl_source=`aws_cmd ec2 get-launch-template-data --instance-id $ins_id --query 'LaunchTemplateData' --output json`
# removals are required to launch template from an ami
tmpl_fix=`echo "$tmpl_source" |\
        jq 'delpaths([path(.BlockDeviceMappings), path(.NetworkInterfaces[].PrivateIpAddresses), path(.CpuOptions)])'`
if [ ! -z "$subnet" ]; then
        tmpl_fix=`echo "$tmpl_fix" |\
                jq --arg subnet "$subnet" '.NetworkInterfaces[0].SubnetId = $subnet' |\
                jq 'delpaths([path(.Placement.AvailabilityZone)])'`
fi
#echo "$tmpl_fix" | sed 's#^#  fixed template: #' | cat -n
echo
#exit
output_create=$(aws_cmd ec2 create-launch-template --launch-template-name ${ins_name}-tmp-clone \
        --launch-template-data "${tmpl_fix//"/\\"}" --output json --query "LaunchTemplate.CreateTime")
[ $? -ne 0 ] && echo "CRITICAL: Create template failed" && exit 2

# run instance
##############

output_run=$(aws_cmd ec2 run-instances --output json --launch-template LaunchTemplateName=${ins_name}-tmp-clone,Version=1\
        --image-id $ami_id \
        $overrides \
        --tag-specifications \
                "ResourceType=instance,Tags=[{Key=Name,Value=$target_name},{Key=clone-source,Value=$ins_name}]" \
                "ResourceType=volume,Tags=[{Key=Name,Value=$target_name}]")
new_ins_id=`echo "$output_run" | jq -r '.Instances[] | "\(.InstanceId)"'`
new_ins_tenancy=`echo "$output_run" | jq -r '.Instances[] | "\(.Placement.Tenancy)"'`
echo "  New instance ID - $new_ins_id"
echo "  New instance tenancy - $new_ins_tenancy"
echo

# tidy up
#########
output_delete=`aws_cmd ec2 delete-launch-template --launch-template-name ${ins_name}-tmp-clone`