AWS: restart EC2 on failure

For this blog here i have an ec2 instance. To avoid costs, i don’t have a loadbalancer, just an ASG with a desired size of 1 instance. Sometimes the DB-connection can become buggy in which case the easiest automated fix is to simply restart this instance. Without LB that’s not totally trivial so I drop a note here.

• Create a route 53 health check
• Select the created CloudWatch Alarm and attach an SNS topic
• Let’s send it an Email to you + let it trigger a lambda function
• Make sure, your lambda can reboot ec2 (IAM Role)

Here’s the lambda code i found on the internet, make sure you choose python 2.7 (and not python 3.x)

import boto3

region = ‘us-west-1’

instances = [‘i-12345cb6de4f78g9h’, ‘i-08ce9b2d7eccf6d26’]

def lambda_handler(event, context):

    ec2 = boto3.client(‘ec2’, region_name=region)

    ec2.stop_instances(InstanceIds=instances)

    print ‘stopped your instances: ‘ + str(instances)