Docker Project for DevOps Engineers

Lets build the first ngnix container and see it is working or not?

So we will give command as -docker run -d -p 80:80 nginx:latest

Breakdown of the Command:

• docker run: This is the command used to create and start a new container from a specified Docker image.
• -d: This flag stands for "detached mode". It runs the container in the background and returns the control to your terminal. Without this flag, the container would run in the foreground, and you would see its logs in the terminal.
• -p 80:80: This flag maps ports between the host and the container. The syntax is host_port:container_port.
• nginx:latest: This specifies the Docker image to use for the container. Here, it uses the nginx image with the latest tag.

How to Verify:

After running the command, you can verify that the container is running and accessible by:

Opening a web browser and navigating to https://localhost or https://<your-host-ip>. You should see the default NGINX welcome page.

Running docker ps to see a list of running containers. You should see your NGINX container in the list.

Introducing the Dockerfile

A Dockerfile is like a recipe for creating a Docker container. It contains a set of instructions to build a container image. A Dockerfile is a script containing a series of instructions on how to build a Docker image. Each instruction in the Dockerfile corresponds to a command-line command that sets up your environment inside the Docker container. Docker uses this script to automate the process of creating a Docker image, which can then be run as a container.

1. Choose a Base Image: The Dockerfile starts with selecting a base image, which serves as the foundation. For example, for a web app, we might choose a Node.js or Python image.
2. Layers: Each instruction in the Dockerfile creates a new layer in the image. Layers are stacked on top of each other, and Docker caches these layers to optimize builds.
3. Instructions: Commands in the Dockerfile that define what goes into the image. Common instructions include FROM, COPY, RUN, CMD, EXPOSE, etc.

So here lets us start to build docker file to deploy simple java project.

1. We will create our dockerfile - Here is simple example of dockerfile

Build and Run the Docker Container

1. Build the Docker Image:

2. Run the Docker Container:

You can push your images to docker hub also by doing simple steps.

1. Create an account on Docker Hub, if you don't have one.

Use the command docker login to log in your Dockerhub

Add your credentials

1. Tag your image to match your Docker Hub repository
2. Push the image to Docker Hub: