Ever since Kubernetes emerged as a top-contender for multi-cloud container management, automation and security challenges have been holding back the adoption of this innovative solution. This is sparking a new revolutionary technology: Kubernetes policy management engines. These policy engines allow for the automation and secure handling of Kubernetes configurations — essentially restricting what applications can run within a given cluster.
A few years ago, the best way to manage security within Kubernetes systems was through the use of Role-Based Access Control (RBAC). However, RBACs were unable to provide adequate oversight at the level of specific resources, meaning intervention at higher levels is not possible. Pod Security Policies (PSPs) were designed as a built-in solution to provide cluster-level security. PSPs enable fine-grained control over the authorization and update of different pods. Unfortunately, the decision has been made to deprecate the use of PSPs due to complexities in the understanding and configuration of these policies.
Currently, the consensus on how to properly manage Kubernetes policy comes down to one debate: Kyverno vs. OPA. Both Kubernetes policy management engines are developed to help enforce management policy across stacks; however, they have some significant differences. For C-suite executives and high-end stakeholders to make informed decisions, it’s important to understand exactly what you’ll get from Kyverno vs. OPA.
But before we get to that debate, let’s go over the exact function of a Kubernetes policy management engine.
Kubernetes and Policy Management
As enterprise companies continue to adopt hybrid- and multi-cloud systems, there is an increasing need to manage the different containers that are being used to house various components of their digital infrastructure. This management system needs to operate across public and private clouds, centralized servers, and other critical infrastructures. This is where Kubernetes comes into the picture.
Kubernetes uses declarative programming to understand, compare, and modify any discrepancies between a container’s observable and desired states. Essentially, it ensures that all programs are running according to a user’s preferred policies and, if they aren’t, can rectify issues through internal logic.
But as these systems continue to increase in complexity, a higher-order solution is needed to manage all of the Kubernetes policies enacted across the multi-cloud infrastructure. This need resulted in the development of two distinct policy engines that can be leveraged to manage policies in a Kubernetes environment. The first, OPA/Gatekeeper, is a general system that operates independently of applications to manage their policy decisions through a specialized programming language. Kyverno, on the other hand, was created specifically to manage Kubernetes policies and is written in an easy-to-use native language.
Open Policy Agent
OPA is a general policy engine that can be leveraged across Kubernetes, Envoy, and other container environments. OPA was initially developed as an engine applicable for systems outside the realm of Kubernetes and then adapted to include the container management system upon its development. Gatekeeper is the specific webhook built on the OPA project used to manage policies in Kubernetes environments.
By decoupling policy management from the domain of specific codes, each software can be specified in a declarative way, and decisions offloaded from the individual systems themselves. The OPA/Gatekeeper engine allows for the validation and mutation of different resources. Each policy decision begins with a request, known as a query, which OPA processes through a specific declarative language known as Rego.
While incredibly well-suited for application across any container management system, the custom Rego language is not Kubernetes-native. This means all relevant DevOps teams will need to invest additional time and resources to gain proficiency in a new programming language before they can apply OPA Gatekeeper for Kubernetes policy management.
The younger of the two police management engines, Kyverno, has been developed as an answer to the highly complex, overly demanding nature of OPA Gatekeeper. Originally developed by Nirmata and now part of CNCF sandbox projects, this Kubernetes policy engine provides DevOps departments with a host of benefits — from its Kubernetes-native design to its ability to generate policies.
In response to the complex task of learning the OPA’s Rego language, Kyverno is designed specifically to use Kubernetes-style composition. This means that its policy expression capabilities provide users with a higher degree of simplicity and flexibility while enabling the development of more powerful policies. This Kubernetes-native design also makes Kyverno highly compatible with the dynamic configuration, GitOps, and tools commonly applied in a Kubernetes environment.
Policy engines are created with key capabilities that enable them to validate and mutate policies as needed. Kyverno, in addition to the validation and mutation functions that OPA Gatekeeper performs, also has built-in generation capabilities. Generation rules allow for supplementary and supporting resources every time a resource is updated or created.
Kyverno vs OPA: The Decision
At the end of the day, the decision regarding how best to modernize your Kubernetes policy management will come down to the specific criteria of your enterprise operations. For digital infrastructures comprising multiple different DevOps teams that require the development of complex policies, OPA Gatekeeper may be the right solution. But for any company that is singularly dedicated to the use of Kubernetes for their container management needs, Kyverno is unparalleled in its ability to modernize policy management processes. As it currently stands, CIOs leveraging Kubernetes as their predominant container management solutions can benefit greatly from the application of Kyverno as their policy management engine.
About the Author
Ritesh Patel is the Co-Founder at Nirmata, a cloud computing company responsible for Kyverno and other Kubernetes policy management solutions. While Ritesh has spent decades in the tech industry, his experience covers a wide range of roles and responsibilities, including software engineering, market strategy, and business development.