Gain insights into Docker fundamentals, delve into advanced concepts like database connectivity and Docker Compose, and discover how to monitor and scale services with Docker Swarm.

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Flask App_new

docker-compose

Docker_build

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Flask_demo_test

add db to container

Exercise

Exercise 2

exercise 3

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Bonus Section - Flask

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Exercise 2-copy

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Whether you are a DevOps beginner or just a developer who wants to start working with containers, you’re in the right place. Docker is an in-demand technology that you will be exposed to frequently while on the job.

 

Docker is used for setting up, deploying, and running applications, at scale, by containerizing them. More on that later. Docker also provides developers with a consistent environment for product development, and along with Kubernetes, makes managing the development lifecycle a breeze.

 

In this course, you will learn the fundamentals of Docker such as containers, images, and commands. You’ll then progress to more advanced concepts like connecting to a database container and how to simplify workflows with Docker Compose. At the end, you’ll learn how to monitor clusters and scale Docker services with Swarm.

Working with Containers: Docker & Docker Compose

# Docker Hub
Docker Hub is a remote repository for custom and Docker's official images. To push or pull images to and fro from the Docker Hub, you need a Docker Hub account. If you have one, you can skip the next section.

## Docker Hub account

To create a Docker Hub account, follow these steps:

1. Open the [Docker Hub website](https://hub.docker.com/)
![](/api/collection/4581872065576960/4866501796429824/page/5780661627518976/image/6281030194429952)

2. Click on the sign up button in the upper right corner
![](/api/collection/4581872065576960/4866501796429824/page/5780661627518976/image/6313784286117888)
 
3. Enter a unique id, email and password. That's it. You have a Docker Hub account now.

## Pushing an app image

Why should we push images to Docker Hub? There are many reasons. Some of them are:
1. Saves space: In the previous lesson "Troubleshooting in Docker", we discussed the space issue. If we build our image and push it to Docker Hub, we don't have to rebuild the image on production systems. This will save us a lot of space and time.
2. Easy access: You can access your image from any other machine, provided you have an active internet connection.

### Steps to push an image

* type `docker login` on the command prompt or terminal
* enter your login credentials
```
$ docker login
Login with your Docker ID to push and pull images from Docker Hub. If you don't have a Docker ID, head over to https://hub.docker.com to create one.
Username: Myusername
Password:
Login Succeeded
```

Once you are logged in,

* Tag the app image with your username

```
$ docker tag flask_app:1.0 venky8283/flask_app:1.0

$ docker images
REPOSITORY                                 TAG                 IMAGE ID            CREATED             SIZE
flask_app                                  1.0                 3507ec2e1851        35 hours ago        952MB
venky8283/flask_app                        1.0                 3507ec2e1851        35 hours ago        952MB
```

* Push the image using `docker push <username>/flask_app:1.0`

It will take some time but once it's done, go to your Docker Hub homepage and check out the image you just pushed.

## Running an app on different machines

Let's try to access the pushed image from different machines. If you don't have another laptop, no worries. Login to your laptop using another user account.

Check to make sure that you can access Docker without any issues by running the `$docker version` command.

If everything goes well, proceed or check out the previous lesson "Troubleshooting in Docker", if you face any issue.

* Type `docker run -p 5000:5000 <username>/flask_app:1.0`


This command will pull the image and run your app.

If you just want to pull the image, then type `docker pull <username>/flask_app:1.0`.

We are nearly at the end of the Docker fundamentals. From the next section, we will move into a more advanced section. 

So, I advise you to solve all exercises and revise one more time. 

Congratulations to you. You've made it so far. Take a break now and grab a cup of coffee.



Remote repository for all custom and standard images

Docker Hub - Remote Repository of Images

Introduction to Course

Why Docker?

Getting Started With Docker

Docker Fundamentals

Automation using Dockerfile

Advance Docker

Introduction to Docker-Compose

Exposure to Docker Swarm

Bonus Section

Docker Hub - Remote Repository of Images

Docker Hub

Docker Hub account

Pushing an app image