Chef for AWS Spot Instances

Chef is a powerful automation platform, that allows you to manage thousands of servers as one.

One of the greatest challenges of using Chef in the Cloud is when using it in dynamic workloads that scale up and down.
While on-demand instances can be stopped gracefully and guarantees to run infinitely, Spot Instances, are more likely to be terminated over time and the Chef server is unaware of Spot Instance interruptions, which causes a ‘Zombie’ scenario and potential errors.

Our Chef integration is using Chef API calls to trigger register and deregister operations for instances that were spun up via Spotinst. This ensures that whenever instances are terminated and Spotinst spins up new replacements, Chef will be fully aware.

Configuration

1. Create a Security Group
   • On your AWS account, create a security group that allows inbound traffic specifically from Spotinst servers
     • IP Addresses available here: Spotinst Whitelabeled IPs
     • Ports: 80, 443, 9683
2. Create a User
   • On your Chef server, create a user that will serve the integration, the user must be granted ‘delete’ and ‘Update’ permissions.
3. Configure Instance Registration

#!/bin/bash

chef_role="role"

chef_environment="env"

chef_organization="org"

chef_server_ip="12.34.56.78"

chef_version="11.4.4"

chef_validation_client_name="spotinst-user"

chef_validation_key="

-----BEGIN RSA PRIVATE KEY-----

MIIEpQIBAAKCAQ.....69qqJC/564=

-----END RSA PRIVATE KEY-----

"

echo "spotinst_chef : Installing Python 2.7"

(apt-get install python jq curl -y -q || yum install python curl jq -y) 2>/dev/null

curl -sL https://bootstrap.pypa.io/get-pip.py | python

curl -fsSL https://s3.amazonaws.com/spotinst-labs/integrations/chef/v1/init.sh | \

SPOTINST_TOKEN="$spotinst_token" \

CHEF_VERSION="$chef_version" \

CHEF_ROLE="$chef_role" \

CHEF_ENVIRONMENT="$chef_environment" \

CHEF_SERVER_IP="$chef_server_ip" \

CHEF_VALIDATION_KEY="$chef_validation_key" \

CHEF_VALIDATION_CLIENT_NAME="$chef_validation_client_name" \

EC2_INSTANCE_ID=$(curl -s http://169.254.169.254/latest/meta-data/instance-id) \

bash

4. Configure Instance Deregistration:

• While creating your Elastigroup, on the compute screen, you will find a ‘3rd Party Integrations’ section
• Check the Chef integration and enter the following data

1. 1. 1. API Server – Public DNS record or Public IP (e.g. ec2-52-206-204-15.compute-1.amazonaws.com or 52.206.204.1).
      2. Organization – Organization name (e.g. myOrg)
      3. Version – The Chef Version in use. We need this information to send the right API call
      4. User – Please enter the name of the user you have created in step #2
      5. Pem Key – Please enter the new user key

That’s it. Your Chef integration is all set.