Configuration management tools

There are a variety of configuration management tools available. The most popular ones include Puppet (https://puppet.com), Chef (https://www.chef.io), and Ansible (https://www.ansible.com). 

AWS OpsWorks (https://aws.amazon.com/opsworks/) provides a managed Chef platform on AWS Cloud. The following screenshot shows a Chef recipe (configuration) of an installation of the Amazon CloudWatch Log agent using AWS OpsWorks. AWS OpsWorks automates the installation of the CloudWatch Log agent when launching an EC2 instance:

AWS CloudFormation (https://aws.amazon.com/cloudformation/) helps to achieve infrastructure as code. It supports the automation of AWS operations, so that we can perform the following functions:

• Creating a VPC
• Creating a subnet on VPC
• Creating an internet gateway on VPC
• Creating a routing table to associate a subnet to the internet gateway
• Creating a security group
• Creating a VM instance
• Associating a security group to a VM instance

The configuration of CloudFormation is written by JSON, as shown in the following screenshot:

CloudFormation supports parameterizing, so it's easy to create an additional environment with different parameters (such as VPC and CIDR) using a JSON file with the same configuration. It also supports the update operation. If we need to change a part of the infrastructure, there's no need to recreate the whole thing. CloudFormation can identify a delta of configuration and perform only the necessary infrastructure operations on your behalf.

AWS CodeDeploy (https://aws.amazon.com/codedeploy/) is another useful automation tool that focuses on software deployment. It allows the user to define the deployment steps. You can carry out the following actions on the YAML file:

• Specify where to download and install the application
• Specify how to stop the application
• Specify how to install the application
• Specify how to start and configure an application

The following screenshot is an example of the AWS CodeDeploy configuration file, appspec.yml: