Kubernetes Architecture
Kubernetes is an open source framework developed by Google for building and operating containerized applications. It is easy to use and offers developers the ability to control and scale their applications. In this article, we will discuss the Kubernetes architecture, including the control plane and cluster architecture, as well as best practices for designing and deploying Kubernetes applications. Additional resources will also be provided.
Kubernetes Architecture Explained
Kubernetes provides a service discovery mechanism across clusters using a loosely coupled approach. A Kubernetes cluster has one or more control planes and compute nodes, with the control plane managing the cluster, providing an API, and controlling node scheduling. Each compute node runs a container runtime and communicates with the control plane using an agent called kubelet.
The key components of a Kubernetes environment include the control plane, kubelet, pods, and persistent volumes (PV). The control plane manages applications, updates, monitoring, and troubleshooting, while the kubelet keeps a copy of the cluster’s state and manages data distribution between pods. Pods are a group of containers running on a host, sharing a common code base, and divided into workers, while PV offers efficient and easy-to-scale systems with persistent storage.
Understanding Kubernetes’s data plane is crucial for efficient infrastructure architecture and operation.Kubernetes Control Plane: Components and Functions
The controller plane of a Kubernetes cluster controls the cluster and consists of multiple components, including:
– The Kubernetes API server, which exposes endpoints for the cluster and resource information, can update data in real-time, and can monitor and redeploy unhealthy pods.
– etcd, which stores table data that can be accessed via the API server, providing a view of the cluster’s state.
– Node controller, which works with the server component to allocate new servers to the appropriate workload and enforces policies.
– kube-controller-manager, which manages multiple controller functions.
– Replication controller, which ensures the correct number of pods are created.
– Endpoints object, a base class for controller interactions with services and pods.
– Service account, a standard account that expires after a set time.
– Cloud controller manager, which manages cloud resources and compliance.
– Route controllers, which help connect applications to cloud resources.
– Service controller, which handles the cloud provider’s load balancers.
Overall, the Kubernetes Control Plane is responsible for managing and maintaining the health of the Kubernetes cluster by controlling its state.
Kubernetes Cluster Architecture
As containers are updated with new software, the control plane ensures changes are pushed to all nodes and vice versa. Running on a cluster of nodes, instead of a single node, the control plane is more distributed and scalable. Kubernetes manages VMs running specific tasks. Pods are the building blocks of the cluster, containing one or more application containers. The container runtime engine runs and manages the lifecycle of containers. The kubelet manages monitoring and restarting containers. Kube-proxy serves as the network gateway for the Kubernetes network, filtering and routing traffic for external parties. Pods handle requests, scheduling tasks, and receiving data from the outside world.
Kubernetes Architecture Best Practices
The following are some best practices for designing Kubernetes clusters effectively, according to Gartner:
- Keeping all Kubernetes versions up to date is recommended, but always upgrade your cluster for critical updates.
- Teach developers to solve problems faster, identify bottlenecks, and provide training for better teamwork.
- Standardize tools and vendor ecosystems across the organization for compliance and efficiency.
- Scan code for issues and run a code quality check.
- Implement access control lists to limit access to resources and network.
- Choose images that are small and test containers to identify & correct issues.
- Try to keep verbosity to a minimum and group the most important functions into a single logical component.
- Use CI/CD tools to execute code coverage reports and manage the lifecycle of pods by utilizing probe injection and ready/liveness probe configuration options.
Kubernetes: A Powerful Platform for Container Orchestration
Kubernetes is an efficient system for deploying and automating containerized applications. It offers a user-friendly and highly flexible interface while providing complete control. This open-source solution works well with an array of container-based applications such as Docker containers, Mesos/YARN clusters, and Kubernetes clusters for both public and private clouds. Kubernetes streamlines application management with an all-in-one interface and features built-in services like monitoring, logging, and resource management. It is easy to use, extendable, and offers APIs for custom component development. With its wide acceptance, Kubernetes has become the widely used choice for container orchestration platforms.
Additional Resources
For those interested in further learning about Kubernetes, here are some helpful resources:
- Kubernetes Interview Questions
- Kubernetes Cheat Sheet
- Kubectl Commands
- Kubernetes vs Docker
- OpenShift vs Kubernetes
These resources can help you understand and master Kubernetes concepts and tools to improve your skills and knowledge.
