Kubernetes Architecture - The Basics
Kubernetes is an open-source container orchestrator popular among Software Engineers, DevOps Engineers, and it’s gaining momentum in Data. In this post, I’m sharing the notes I took while studying Kubernetes Architecture. Before starting, I’d like to summarize some key-words. The Jargon Agent: it’s a software that acts in behalf of an user or other software, which can also be an agent. Container: containers are all about resources isolation. An application running in a container shares the same hardware as the host, but it only gets the amount of computing resources, i.e. CPU, memory and network, that the developer allows. It’s like setting a slice of a computer dedicated to run an application. Containerized Application: an application running in a container. Container Engine: it’s a high-level software tool responsible for automating the process of creating isolated, lightweight environments. It’s the component humans usually interact with in order to create containers. This include managing container images and container orchestration. Container engines use a container runtime to process requests made by an user. Container Runtime: it’s the container engine component responsible for the interactions between the application in a container and the host operating system, resource allocation and container execution. Controller: controllers are non-terminating loops that regulates the state of a system. For example, a thermostat in a room keeps checking the temperature in order to decide to turn on or off an air-conditioner. Cluster: is a set of computers (nodes) connected in a network in order to work together as they were a single computer. Orchestrator: an orchestrator is a system that reacts to a demand for computing resources. The orchestrator is responsible for allocating the desired amount of resources when tasks are submitted, checking if the proper amount of resources are available during the execution of an application and self-healing when something breaks. Pods: are the smallest deployable unit of computing that you can create and manage in Kubernetes. Pods are composed by one or more containers, depending on the need. Containers in a Pod share the same network, storage, and run in the same node. The Big Picture A 40000ft look on Kubernetes Architecture looks like this: ...