Introduction

Kubernetes Architecture and Components

The market has seen the rise and fall of several open-source engines, but some like Kubernetes have left their mark on the industry. Kubernetes is amidst one of the most efficient open-source container-orchestration engines to manage hosts’ full-stack containers and proceedings.

The platform can be used for scaling, deployment, rolling updates, and load balancing as it ensured the optimal state of your apps. Kubernetes routinely receives updates to keep up with the ever-changing needs of users.

The updates mainly focus on security, extensibility, and statefulness. If you are still in the dark about the platform, this blog will help you gain more knowledge. Here is everything you need to know about Kubernetes:

Architecture Types of Kubernetes

Kubernetes Cluster works in worker and master architecture, where the master monitors every management activity. After the monitoring, the task is dispatched to a relevant worker node with some restrictions.

Kubernetes Components

Master Node Architecture

The Kubernetes Master handles scheduler, controller, and the API server integrating ETCD. UI, CLI, and API are an integral part of the section playing crucial roles.

API Server of Kube

The API Server of Kubernetes plays the primary role in every contact point to the Kubernetes cluster. It also manages activities like authorization, authentication, and additional activities related to the Kubernetes cluster. The server stores every data in the ETCD database (a distributed information store.)

How to Set Up ETCD Cluster?

ETCD can be defined as the database storing data in key-values format. ETCD is also compatible with high availability and distributed architecture possessing a robust consistency model. Manufactured by CoreOS, ETCD is written in one of the most renowned languages, GoLang.

Kubernetes holds every data within ETCD such as configurations, metrics, and metadata regarding service, deployment, and pods of Kubernetes cluster.

Kube-Controller-Manager

Another aspect of Kubernetes Cluster, kube-controller-manager handles scaling and replication of pods. It prepares the system in an apt state with the help of Kubernetes API server.

Some additional controllers within the system are:

1. Job Controller
2. Replication controller
3. DaemonSet Controller
4. Namespace controller
5. Endpoints controller
6. Service accounts controller
7. Kube-Scheduler

Another aspect of Kubernetes architecture, kube-scheduler checks performance, capacity, and availability of the worker nodes of Kubernetes. It then prepares plans for making/eradicating new pods in cluster to keep it stable in every department.

It also assesses the cluster and reports to the API server for storing every metric regarding the resource availability, performance, and utilization.

It can also be used for scheduling pods for specific nodes as per submission manifested for pods.

Worker Node Architecture

The worker architecture deals with docker, kubeket, kube-proxy, fluentd, DNS, UI, addons, and numerous pods to formulate an ideal platform.

Kubelet

Kubelet acts as a component within the worker architecture accountable for the node level management of pods.

The API server puts every HTTP request on the kubelet API for executing the pods definition from worker nodes’ manifested files. It also ensures that every container is working healthily. Kubelets directly talk with containers runtime like RKT or docker.

Kube-Proxy

It is a networking factor of Kubernetes architecture running on every node, performing functions like:

• Handling the DNS entry for every pod and service.
• Providing the IP address and hostname to every pod.
• Forwarding traffic from IP address/Cluster to specific pod set.
• Altering IPtablets on every node so they can interact with outside world/each other.

Docker

It is an open-source container developed by the docker for running, sharing, and building containerized apps. It focuses on launching one app within a single container as an atomic unit.

They can be categorized into:

• Open-Source
• Lightweight
• Most Popular

RKT by CoreOS

It is another one of the container runtimes for containerized apps by CoreOS focusing on security and open standards. It has categories like:

• Pod-Native
• Open-Source
• Pluggable Execution

Managed Kubernetes Supervisor

It’s a lightweight process handling framework for running container engine and kubelet in the running form.

Logging with the Fluentd

It’s an open source data collection framework for the Kubernetes cluster logs.

Standard Kubernetes Concepts

Nodes in Kubernetes are worker nodes within Kubernetes cluster, and they can be either metal servers or virtual machines. It possesses every needed service to run pods and is managed by master node. It offers services like:

• Kubelet
• Docker
• Fluentd
• Kube-Proxy

Docker Container

It’s an executable, standalone package of software comprising of everything, such as runtime, configuration, code, and libraries.

Pods

Pod is the smallest unit within the Kubernetes framework and can contain more than a container. It’s modelled after a Docker containers’ group with shared volumes and namespaces.

Kubernetes Deployment

It is either a YAML or JSON file declaring Replica and Pods definitions. You merely need to explain the deployment object and controller’s state for changing the controlled rate to a desired variant. It also helps in creating any new resources or updating any existing resources.

JSON/YAML Managed Service

Kubernetes Services are defined in JSON or YAML format creating a logical pods’ set and policies for every pod type and the assignable IP address. It used the label selector for identifying the target’s set.

Replication Controller

A controller ensuring every pod replica is running aptly.

• Every pod must be running.
• Every pod must be within the desired replica count.
• Managing every pod within the worker node of managed Kubernetes.

Labels

They are value/key pairs added within any Kubernetes object like deployment, service, and pod. They are easy to use within Kubernetes configuration files.

Container Registry

It’s a public or private digital storage strong every container image and allowing their distribution. The market is filled with reputed registries by Azure, Docker, and Google.

Microservices App

You can call Kubernetes an API’s collection interaction with storage, network, and computer. There are separate ways for interacting with managed Kubernetes like:

• CLI
• Dashboard
• API

You can also avail the direct Kubernetes API for every task starting from deployment ranging to the maintenance of something within the cluster.

Dashboard is innovative and straightforward for routine tasks and can also handle cluster from dashboard.

CLI, aka kubectl, is coded/written in GoLang and is one of the most utilized tools for interacting with remote or local cluster.

Best Practices and Methods for Monitoring Kubernetes

With Kubernetes, you get an easy way for managing and creating frameworks via numerous abstractions like replication controllers, pods, node, and services. This simplifies the concern of where apps run and help the resources act properly. For ensuring optimal performance, routine monitoring of deployed containers and apps is needed.

cAdvisor for Monitoring Kubernetes

It’s an open-source tool used for monitoring Kubernetes’ resource performance and usage. It identifies every deployed container in nodes and gathers data such as memory, file system, CPU, and network. It also facilitates us with a visualized monitored dashboard.

Using Grafana for Monitoring

It’s also an open-source visualization and analytics suite utilized for envisioning time series analysis for apps. Here is how you can create a dashboard on Grafana:

1. Hesper gathers the data from Kubernetes environment.
2. After that, the data is provided to the influxdb.
3. Now metrics are executed by Grafana through influxdb for collecting necessary data.
4. After you get necessary data, it is visualized in graphs.

Industry Solutions and Production Cluster

Kubernetes 1.9 with Workloads API GA

With general availability in Kubernetes 1.9, the API groups deployment, replicaset, statefulset, and daemonset for forming foundation of workloads in kubernetes.

Windows Support

In Kubernetes 1.9, you get comprehensive support for Windows.

Storage Enhancement

Kubernetes 1.9 comes with CSI simplifying the new volume plugin installation procedure. It also enables 3rd party storage for developing custom solutions needed for base Kubernetes codebase.

Wrapping Up

The open source containers ideal to manage full stack containers and operations. The blog has described how Kubernetes’ components function and how you can use it optimally. With regular updates and industrial-standard features, the platform serves every need you may possess. Therefore, it is only viable for you to integrate Kubernetes in your proceedings.