what is the use of docker and kubernetes

What is the use of docker and kubernetes software#
What is the use of docker and kubernetes code#
What is the use of docker and kubernetes iso#

For example, if the pod being deployed is for the application ”frontend” and within “frontend” the pod is running code for login, upon deployment it can be labeled. Ideally a pod is given a label identifying which part of the overall application the pod belongs to. When a pod is deployed in Kubernetes, apart from other specifications, the pod can be assigned labels. A pod contains running instances of one or more containers. Application Labels and Services LabelsĪ very interesting aspect of Kubernetes is the way Kubernetes combines the use of Labels and Services to create tremendous possibilities.Īt the heart of Kubernetes is a pod. This guide demonstrates a basic method of providing services to pods. In Kubernetes, a Service is an abstraction which defines a logical set of pods and a policy by which to access them. The container is now deployed to Kubernetes but there is no way to communicate with it, the next step is to turn the deployment into a Service by establishing communication. Once that’s done, the hello world container is deployed in a Kubernetes pod. To deploy the application on a Kubernetes cluster, you can submit a YAML file using a kubectl command similar to the following. # Hello World Deployment YAML apiVersion : apps/v1 kind : Deployment metadata : name : helloworld spec : selector : matchLabels : app : helloworld template : metadata : labels : app : helloworld spec : containers : - name : helloworld image : boskey/helloworld resources : limits : memory : '128Mi' cpu : '500m' To make the relationship between the Dockerfile and the image concrete, here’s an example of a Dockerfile that creates a “Hello World” app from scratch:

Build a corresponding YAML file to define how Kubernetes deploys the appĭockerfile to Create a Hello World Container ImageĪ manifest, called a Dockerfile, describes how the image and its parts are to run in a container deployed on a host.

Create a container image from a Dockerfile.Here’s what it takes to move a Docker container to a Kubernetes cluster. The containerized app instance running on the Kubernetes node derives the container runtime from the Kubernetes node along with compute, network, and storage resources, if needed.

A set of instructions for running the imageĪ containerized application image along with a set of declarative instructions can be passed to Kubernetes to deploy an application.The environment in which the image is executed.A runtime instance of a Docker image consists of three parts:

What is the use of docker and kubernetes iso#

Docker provides a standard format for packaging and porting software, much like ISO containers define a standard for shipping freight.

What is the use of docker and kubernetes software#

Docker ContainersĪ Docker container image is a lightweight, standalone, executable software package that includes everything needed to run an application: code, runtime, system tools, system libraries and settings. The Docker environment also includes a container runtime as well as build and image management. You can build, run and distribute applications in Docker containers to run on Linux, Windows, Macs and almost anywhere else–both on-premises and in the cloud. Containers are isolated from each other and are designed to be easily portable. What is Docker?ĭocker is an open source container platform that uses OS-level virtualization to package your software in units called containers. This guide provides an example of containerizing a simple application using Docker and deploying it on Kubernetes. Once you understand what containers and Kubernetes are, the next step is to learn how the two work together. So yes, you could break down how part of Kubernetes is built by looking at runc, containerd, and the container engine.Getting Started with Docker Containers on Kubernetes This is what allows multiple container solutions that follow OCI specifications to integrate with Kubernetes. Because Kubernetes uses containerd, it will also use runc. When you look at most Kubernetes diagrams they will not show containerd or runc as they are abstracted away into the container engine you use (e.g., Docker, rkt). This has become a standard and defines how Docker and other tooling interacts with containerd and runc.

These tools are designed to follow the Open Container Initiative (OCI) specifications. Runc as defined by the project is a 'CLI tool for spawning and running containers according to the OCI specification'. Containerd requires runc in order to function. While containerd is used in Docker, it can also be used as a daemon for other container solutions. The Docker blog has a nice write up explaining how this fits into Docker. Containerd is a daemon for running containers.