switch_instance_type.sh

#!/usr/bin/env bash
set -e

SCRIPT_NAME=$(basename $0)

USAGE="$SCRIPT_NAME <instance-name> <instance-type>\nFor example: $SCRIPT_NAME myserver t3.2xlarge"

if [ -z "$1" ]; then
  echo -e $USAGE
  exit 1
elif [ -z "$2" ]; then
  echo -e $USAGE
  exit 1
elif [[ $* == *-h* ]]; then
  echo -e $USAGE
  exit 0
else
  INSTANCE_NAME=$1
  INSTANCE_TYPE=$2
fi
export AWS_PROFILE=${AWS_PROFILE:=production_42}
export AWS_DEFAULT_REGION=${AWS_DEFAULT_REGION:=us-east-1}
AWS="aws ec2 --profile ${AWS_PROFILE} --region ${AWS_REGION:=$AWS_DEFAULT_REGION} "

report_i(){
    echo "[$(date "+%b %d %Y %T")] instance ${INSTANCE_ID} : $@"
}

stop_ec2(){
    report_i "Stopping" \
    && ${AWS} stop-instances --instance-ids ${INSTANCE_ID} \
    && report_i "wait instance-stopped" \
    && ${AWS} wait instance-stopped --instance-ids ${INSTANCE_ID} && return 0
return 1
}
start_ec2(){
    report_i "Starting" \
    && ${AWS} start-instances --instance-ids ${INSTANCE_ID} \
    && report_i "wait instance-running" \
    && ${AWS} wait instance-running --instance-ids ${INSTANCE_ID} \
    && report_i "wait instance-status-ok" \
    && ${AWS} wait instance-status-ok --instance-ids ${INSTANCE_ID} \
    && return 0
return 1
}
modify_instance(){
    report_i "Start modify" \
    && ${AWS} modify-instance-attribute \
      --instance-id $INSTANCE_ID \
      --instance-type $INSTANCE_TYPE && return 0


}

INSTANCE_ID=$(${AWS} describe-instances \
  --filter "Name=tag:Name,Values=${INSTANCE_NAME}" \
  --query "Reservations[].Instances[].InstanceId[]" \
  --output text)
if [[ -z $INSTANCE_ID ]];then
    echo "No INSTANCE_ID for ${INSTANCE_NAME}"
    exit 1
fi

INITIAL_INSTANCE_TYPE=$(${AWS} describe-instance-attribute \
  --instance-id $INSTANCE_ID \
  --attribute instanceType \
  --query 'InstanceType.Value' \
  --output text)

if [ $INITIAL_INSTANCE_TYPE == $INSTANCE_TYPE ]; then
  echo "$INSTANCE_NAME is already $INSTANCE_TYPE"
  exit 0
fi

stop_ec2
modify_instance
start_ec2

FINAL_INSTANCE_TYPE=$(aws ec2 describe-instance-attribute \
  --instance-id $INSTANCE_ID \
  --attribute instanceType \
  --query 'InstanceType.Value' \
  --output text)

MESSAGE="Switched $INSTANCE_NAME from $INITIAL_INSTANCE_TYPE to $FINAL_INSTANCE_TYPE"
echo $MESSAGE