Kubernetes: challenges and opportunities for DevOps
In the case of large-scaled containerised applications, the benefits offered by Kubernetes are unmatched. But the path of its adaptation isn't always clear. Yet, in order to make it less complicated we present 7 principles that will allow you to easily plan and deploy containers, as well as, scale them to the desired state, and manage their lifecycle.
Kubernetes: what is it and why do I need it?
Kubernetes(K8s) is an open-source platform that is used for large-scale container management. The name comes from the Greek language “κυβερνήτης” meaning “steersman”, which perfectly conveys the purpose of the platform. The tool was created by Google nearly 20 years ago to handle the company’s production load. In 2014, the project was transferred to the Cloud Native Computing Foundation and made public – since then, the platform is still being developed.
K8s supports the automation of deployments, scaling applications, container management, and monitors workloads and changes. Application owners and development teams using the platform can focus more on the development of their product than on DevOps activities (infrastructure management and matching the product to its requirements). Besides, Kubernetes can easily manage a cluster (group of servers working together) thanks to its orchestrator capabilities. When K8s accepts deployment, it divides it into workloads and distributes it across servers in a cluster. Workloads in K8s are created as containers and wrapped into standard cluster resources called Pods. Complex applications are frequently operating over complex distributed infrastructure, Kubernetes provides more insight into what is happening within an application, making it easier to identify and fix security problems.
7 principles
To achieve the best possible results with Kubernetes you need to follow the 7 principles listed by the Department of Defense Enterprise DevSecOps Reference Design.
- Remove bottlenecks and manual actions
Kubernetes allows developers, testers, and administrators to work hand in hand, making it easy for them to solve defects quickly and accurately. With Kubernetes, you can get rid of long delays associated with replicating development and test environments. Besides, thanks to standardized instances, Kubernetes helps testers and developers quickly exchange precise information. - Automate as much as possible
Thanks to Kubernetes, you can automate many time-consuming tasks regarding development and deployment. Eliminating manual activities means less work and fewer errors which translates into a shorter time to market. - Adopt common tools from planning and requirements through deployment and operations
Kubernetes provides many capabilities that allow one container to support many environment configuration contexts. In this case, there is no need for specialised containers for different environment configurations. Besides, the configmaps object supports configuration data used at runtime. What is of much importance, it simplifies the management of the whole deployment process thanks to the declarative syntax used to describe each of needed deployments. - Leverage agile software principles with frequent updates
Thanks to the structure, microservices benefit the most from Kubernetes. It is said that software designed with twelve-factor app methodology and communicating through APIs work best for scalable deployments on clusters. Thus, Kubernetes is the best choice for orchestrating cloud-native applications as modular distributed services favor scaling and fast recovery from failures. - Apply the cross-functional skill sets of development, cybersecurity and operations throughout the software life cycle
Kubernetes is constructed with health reporting metrics to enable the platform to manage life cycle events if an instance becomes unhealthy. Thanks to robust telemetry data alerting operators they can take the decisions instantly. It is also worth noting that Kubernetes supports liveness and readiness probes providing a clear view of the state of containerised workloads. - Security risks of the underlying infrastructure must be measured and quantified
Kubernetes offers many different layers and components that ensure the highest security standards, including a scheduler that manages how workloads are distributed, controllers that manage the state of Kubernetes itself, agents that run on each node within a cluster and a key-value store where cluster configuration data is stored.
Of course, to remain immune to all types of vulnerabilities one has to implement a cohesive defence strategy consisting of the following points. First of all, you need to use security code scanning tools to check if the vulnerabilities exist within the container code itself. There is also a need for isolation of Kubernetes nodes (servers) in a separate network, to isolate them from public networks. Not to mention restricting access to the cluster resources by role-based access control (RBAC) policies as well as using resource quotas that allow you to mitigate any disruptions.
One has to remember to restrict pod-to-pod traffic using Kubernetes core data types for specifying network access controls between pods and implement network border controls to enforce some ingress and egress controls at the network border. Besides, application-layer access control can be hardened with strong application-layer authentication, such as mutual transport-level security protocols.
In addition to the aforementioned, segment your Kubernetes clusters by integrity level which translates into hosting the dev and test environments in a different cluster than the production environment. We also advise utilising security monitoring and auditing to capture application logs, host-level logs, Kubernetes API audit logs and cloud provider logs. Yet, for security audit purposes, consider streaming your logs to an external location with append-only access from within your cluster.
Some may consider it obvious, but remember to keep your Kubernetes versions up to date and use process whitelisting which will allow you to spot unexpected running processes. - Deploy immutable infrastructure, such as containers
Kubernetes promotes scenarios in which deployed components are completely replaced rather than being updated. In this case, utilising standardisation and emulation of common infrastructure components allow achieving predictable results.
Summary
As applications grow larger, spanning multiple containers deployed on multiple servers makes their maintenance more complex. To manage this complexity, Kubernetes provides an open-source API that allows you to control how and where these containers will run. Thanks to this platform you can perform fully automated application deployment and let K8s scale containers to the desired state. Of course, there are some challenges, yet by following the rules published by the Department of Defense Enterprise DevSecOps Reference Design you will be able to easily face them all.
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