Infrastructure as code

IaC evolved to help solve the problem of “environment drift”. Cloud applications usually have separate deployment environments for the stages of their release lifecycle. It’s common to have development, staging, and production environments. These environments are composed of networked resources like application servers, load balancers, and databases. Environment drift occurs when the infrastructure between these different environments falls out of sync. 

Without IaC, infrastructure management can be a disorganized and fragile process. System administrators manually connect to remote cloud providers and use API or web dashboards to provision new hardware and resources. This manual workflow does not give a holistic view of the application infrastructure. Administrators may manually make changes to one environment and forget to follow through on the other. This is how environment drift happens.

Environment drift becomes an expensive business waste. Bugs and failures happen because teams build against a staging or development environment and then find upon deployment that the production environment is out of sync, which leads to a time-consuming investigation of why and what is missing. 

Without IaC, manual infrastructure management is a slow process. If a required infrastructure change is identified due to environment drift, spikes in traffic, or some other issue, it can take an unknown amount of time for a systems administrator to react and adapt. This leads to outages and customer frustration. With IaC in place, infrastructure can automatically adapt to changes in configuration and react to spikes in traffic with auto-scaling features.

Infrastructure as code brings more oversight and visibility to manual systems administration. With the infrastructure configuration files committed to a central version control repository, all team members can view and edit infrastructure data. This enables powerful auditing capabilities. For example, if your team undergoes a PCI compliance audit, you'll need to know if a specific part of your infrastructure is using SSL encryption. With IaC you can quickly see how SSL is configured and execute the code to make sure the live infrastructure matches the configuration files, which identifies if SSL is enabled. The version control commit history also acts as a log to review when it was added or removed.

There are a few dependencies that need to be in place to fully achieve infrastructure as code.

With these dependencies in place, let's consider an example scenario in which a developer wants to add a new application service to a system. This scenario helps demonstrate an IaC workflow

1. The developer edits a YAML configuration text file in their configuration management platform of choice, Terraform. The edits specify that a new hosting server is needed.
2. The developer commits edits to a feature branch in the Git repository. Because the project's Git repository is hosted on Bitbucket, the developer opens up a pull request. Another team member reviews the pull request and becomes aware of the new infrastructure changes. The team member approves the pull request and the developer then merges the commit to the main branch of the repository.
3. At this point, the configuration platform is needed to execute an update. The update can be manually triggered by the developer. Because the team is using Bitbucket they also have access to Bitbucket Pipelines and can automate this step with a pipeline.
4. Upon execution Terraform interfaces with the team's IaaS. Terraform executes a series of commands against the IaaS API to bring the IaaS up to date with the expected infrastructure configuration.

IaC is a highly productive form of configuration management that focuses on automating cloud IT infrastructure management. Once IaC is in place it can be used to achieve levels of CI/CD automation for changes to a project's infrastructure. IaC enables many beneficial insights into communication and transparency around infrastructure changes. IaC requires a set of dependencies like hosting platforms and automation tools, that are widely available from modern hosting companies.