As we continue to recognize the importance of DevOps—particularly its automation and orchestration aspects—to achieve the agility necessary for continuous deployment of apps, the question of how the term “Infrastructure as Code” (IaC) applies to traditionally network-bound systems and services is bound to crop up more frequently. After all, in addition to core IP-based networking characteristics required for an app to communicate and serve up content, an entire ecosystem of app services that support, secure and scale it must be considered.
IaC is driven by the application of development principles to network infrastructure. Configuration, scripts, templates, profiles and the like are treated as code, in that they should be reviewed, versioned and provisioned from a centralized repository (one hopes on-premises) rather than managed as discrete network elements.
In a recent article in TechBeacon, Boyd Hemphill, director of evangelism at StackEngine, noted, “The basic principle is that operators (admins, system engineers, etc.) should not log in to a new machine and configure it from documentation.”
Christopher Null, CEO of Null Media and author of the article, then wrote, ” … But IaC is a concept that extends beyond simple infrastructure automation. IaC requires applying DevOps practices to automation scripts to ensure they’re free of errors, are able to be redeployed on multiple servers, can be rolled back in case of problems, and can be engaged by both operations and development teams.”
The idea is that you can describe any given service as a set of artifacts and deploy (and redeploy) them at will. So rather than set up a system and configure it directly, its configuration any associated artifacts (such as profiles or templates) are treated as code and stored in a common repository. A controller—the orchestrator—is responsible for distributing those artifacts when necessary. The controller uses an API (or protocol such as OpenFlow) to manage the configuration of services across a distributed infrastructure. It’s decoupling the service definition from the service and its platform.
Read that again. It decouples the service definition from the service and its platform and assigns responsibility for provisioning and configuration to a controller. Kind of like decoupling the control plane from the actual forwarding and switching actions (the data plane) and assigning operational responsibility to an external controller.
At its simplest, treating infrastructure as code is separating configuration from the platform and enabling a software-driven or software-defined approach to provisioning, configuring and managing infrastructure. It’s applying the principles of software-defined networking (SDN) to operations, rather than to devices and systems.
But as Null makes clear in his article, IaC goes beyond just automation and orchestration, adopting the best practices of development with respect to code reviews, versioning and management of that “code” to ensure consistent, predictable and repeatable deployments.
It’s all driven by software, ultimately, and deployed by software, and defined by software but always under the auspices of the operational experts: the engineers and architects.
Treating infrastructure as code is basically applying the architectural principles of SDN to operations itself. It’s SDN for ops.