Repository: Sareenh1/https-github.com-iam-veeramalla-Docker-Zero-to-Hero
Branch: main
Commit: 0e4f7630dc4d
Files: 29
Total size: 33.8 KB
Directory structure:
gitextract_4g2qhtl8/
├── README.md
├── commands.md
├── examples/
│ ├── first-docker-file/
│ │ ├── Dockerfile
│ │ └── app.py
│ ├── golang-multi-stage-docker-build/
│ │ ├── Dockerfile
│ │ ├── README.md
│ │ ├── calculator.go
│ │ └── dockerfile-without-multistage/
│ │ ├── Dockerfile
│ │ └── calculator.go
│ └── python-web-app/
│ ├── Dockerfile
│ ├── devops/
│ │ ├── db.sqlite3
│ │ ├── demo/
│ │ │ ├── __init__.py
│ │ │ ├── admin.py
│ │ │ ├── apps.py
│ │ │ ├── migrations/
│ │ │ │ └── __init__.py
│ │ │ ├── models.py
│ │ │ ├── templates/
│ │ │ │ └── demo_site.html
│ │ │ ├── tests.py
│ │ │ ├── urls.py
│ │ │ └── views.py
│ │ ├── devops/
│ │ │ ├── __init__.py
│ │ │ ├── asgi.py
│ │ │ ├── settings.py
│ │ │ ├── urls.py
│ │ │ └── wsgi.py
│ │ └── manage.py
│ └── requirements.txt
├── networking.md
└── volumes.md
================================================
FILE CONTENTS
================================================
================================================
FILE: README.md
================================================
# Repo to learn Docker with examples. Contributions are most welcome.
## If you found this repo useful, give it a STAR 🌠
You can watch the video version of this repo on my youtube channel -> https://www.youtube.com/@AbhishekVeeramalla
## What is a container ?
A container is a standard unit of software that packages up code and all its dependencies so the application runs quickly and reliably from one computing environment to another. A Docker container image is a lightweight, standalone, executable package of software that includes everything needed to run an application: code, runtime, system tools, system libraries and settings.
Ok, let me make it easy !!!
A container is a bundle of Application, Application libraries required to run your application and the minimum system dependencies.
## Containers vs Virtual Machine
Containers and virtual machines are both technologies used to isolate applications and their dependencies, but they have some key differences:
1. Resource Utilization: Containers share the host operating system kernel, making them lighter and faster than VMs. VMs have a full-fledged OS and hypervisor, making them more resource-intensive.
2. Portability: Containers are designed to be portable and can run on any system with a compatible host operating system. VMs are less portable as they need a compatible hypervisor to run.
3. Security: VMs provide a higher level of security as each VM has its own operating system and can be isolated from the host and other VMs. Containers provide less isolation, as they share the host operating system.
4. Management: Managing containers is typically easier than managing VMs, as containers are designed to be lightweight and fast-moving.
## Why are containers light weight ?
Containers are lightweight because they use a technology called containerization, which allows them to share the host operating system's kernel and libraries, while still providing isolation for the application and its dependencies. This results in a smaller footprint compared to traditional virtual machines, as the containers do not need to include a full operating system. Additionally, Docker containers are designed to be minimal, only including what is necessary for the application to run, further reducing their size.
Let's try to understand this with an example:
Below is the screenshot of official ubuntu base image which you can use for your container. It's just ~ 22 MB, isn't it very small ? on a contrary if you look at official ubuntu VM image it will be close to ~ 2.3 GB. So the container base image is almost 100 times less than VM image.
To provide a better picture of files and folders that containers base images have and files and folders that containers use from host operating system (not 100 percent accurate -> varies from base image to base image). Refer below.
### Files and Folders in containers base images
```
/bin: contains binary executable files, such as the ls, cp, and ps commands.
/sbin: contains system binary executable files, such as the init and shutdown commands.
/etc: contains configuration files for various system services.
/lib: contains library files that are used by the binary executables.
/usr: contains user-related files and utilities, such as applications, libraries, and documentation.
/var: contains variable data, such as log files, spool files, and temporary files.
/root: is the home directory of the root user.
```
### Files and Folders that containers use from host operating system
```
The host's file system: Docker containers can access the host file system using bind mounts, which allow the container to read and write files in the host file system.
Networking stack: The host's networking stack is used to provide network connectivity to the container. Docker containers can be connected to the host's network directly or through a virtual network.
System calls: The host's kernel handles system calls from the container, which is how the container accesses the host's resources, such as CPU, memory, and I/O.
Namespaces: Docker containers use Linux namespaces to create isolated environments for the container's processes. Namespaces provide isolation for resources such as the file system, process ID, and network.
Control groups (cgroups): Docker containers use cgroups to limit and control the amount of resources, such as CPU, memory, and I/O, that a container can access.
```
It's important to note that while a container uses resources from the host operating system, it is still isolated from the host and other containers, so changes to the container do not affect the host or other containers.
**Note:** There are multiple ways to reduce your VM image size as well, but I am just talking about the default for easy comparision and understanding.
so, in a nutshell, container base images are typically smaller compared to VM images because they are designed to be minimalist and only contain the necessary components for running a specific application or service. VMs, on the other hand, emulate an entire operating system, including all its libraries, utilities, and system files, resulting in a much larger size.
I hope it is now very clear why containers are light weight in nature.
## Docker
### What is Docker ?
Docker is a containerization platform that provides easy way to containerize your applications, which means, using Docker you can build container images, run the images to create containers and also push these containers to container regestries such as DockerHub, Quay.io and so on.
In simple words, you can understand as `containerization is a concept or technology` and `Docker Implements Containerization`.
### Docker Architecture ?
The above picture, clearly indicates that Docker Deamon is brain of Docker. If Docker Deamon is killed, stops working for some reasons, Docker is brain dead :p (sarcasm intended).
### Docker LifeCycle
We can use the above Image as reference to understand the lifecycle of Docker.
There are three important things,
1. docker build -> builds docker images from Dockerfile
2. docker run -> runs container from docker images
3. docker push -> push the container image to public/private regestries to share the docker images.
### Understanding the terminology (Inspired from Docker Docs)
#### Docker daemon
The Docker daemon (dockerd) listens for Docker API requests and manages Docker objects such as images, containers, networks, and volumes. A daemon can also communicate with other daemons to manage Docker services.
#### Docker client
The Docker client (docker) is the primary way that many Docker users interact with Docker. When you use commands such as docker run, the client sends these commands to dockerd, which carries them out. The docker command uses the Docker API. The Docker client can communicate with more than one daemon.
#### Docker Desktop
Docker Desktop is an easy-to-install application for your Mac, Windows or Linux environment that enables you to build and share containerized applications and microservices. Docker Desktop includes the Docker daemon (dockerd), the Docker client (docker), Docker Compose, Docker Content Trust, Kubernetes, and Credential Helper. For more information, see Docker Desktop.
#### Docker registries
A Docker registry stores Docker images. Docker Hub is a public registry that anyone can use, and Docker is configured to look for images on Docker Hub by default. You can even run your own private registry.
When you use the docker pull or docker run commands, the required images are pulled from your configured registry. When you use the docker push command, your image is pushed to your configured registry.
Docker objects
When you use Docker, you are creating and using images, containers, networks, volumes, plugins, and other objects. This section is a brief overview of some of those objects.
#### Dockerfile
Dockerfile is a file where you provide the steps to build your Docker Image.
#### Images
An image is a read-only template with instructions for creating a Docker container. Often, an image is based on another image, with some additional customization. For example, you may build an image which is based on the ubuntu image, but installs the Apache web server and your application, as well as the configuration details needed to make your application run.
You might create your own images or you might only use those created by others and published in a registry. To build your own image, you create a Dockerfile with a simple syntax for defining the steps needed to create the image and run it. Each instruction in a Dockerfile creates a layer in the image. When you change the Dockerfile and rebuild the image, only those layers which have changed are rebuilt. This is part of what makes images so lightweight, small, and fast, when compared to other virtualization technologies.
## INSTALL DOCKER
A very detailed instructions to install Docker are provide in the below link
https://docs.docker.com/get-docker/
For Demo,
You can create an Ubuntu EC2 Instance on AWS and run the below commands to install docker.
```
sudo apt update
sudo apt install docker.io -y
```
### Start Docker and Grant Access
A very common mistake that many beginners do is, After they install docker using the sudo access, they miss the step to Start the Docker daemon and grant acess to the user they want to use to interact with docker and run docker commands.
Always ensure the docker daemon is up and running.
A easy way to verify your Docker installation is by running the below command
```
docker run hello-world
```
If the output says:
```
docker: Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Post "http://%2Fvar%2Frun%2Fdocker.sock/v1.24/containers/create": dial unix /var/run/docker.sock: connect: permission denied.
See 'docker run --help'.
```
This can mean two things,
1. Docker deamon is not running.
2. Your user does not have access to run docker commands.
### Start Docker daemon
You use the below command to verify if the docker daemon is actually started and Active
```
sudo systemctl status docker
```
If you notice that the docker daemon is not running, you can start the daemon using the below command
```
sudo systemctl start docker
```
### Grant Access to your user to run docker commands
To grant access to your user to run the docker command, you should add the user to the Docker Linux group. Docker group is create by default when docker is installed.
```
sudo usermod -aG docker ubuntu
```
In the above command `ubuntu` is the name of the user, you can change the username appropriately.
**NOTE:** : You need to logout and login back for the changes to be reflected.
### Docker is Installed, up and running 🥳🥳
Use the same command again, to verify that docker is up and running.
```
docker run hello-world
```
Output should look like:
```
....
....
Hello from Docker!
This message shows that your installation appears to be working correctly.
...
...
```
## Great Job, Now start with the examples folder to write your first Dockerfile and move to the next examples. Happy Learning :)
### Clone this repository and move to example folder
```
git clone https://github.com/iam-veeramalla/Docker-Zero-to-Hero
cd examples
```
### Login to Docker [Create an account with https://hub.docker.com/]
```
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: abhishekf5
Password:
WARNING! Your password will be stored unencrypted in /home/ubuntu/.docker/config.json.
Configure a credential helper to remove this warning. See
https://docs.docker.com/engine/reference/commandline/login/#credentials-store
Login Succeeded
```
### Build your first Docker Image
You need to change the username accoringly in the below command
```
docker build -t abhishekf5/my-first-docker-image:latest .
```
Output of the above command
```
Sending build context to Docker daemon 992.8kB
Step 1/6 : FROM ubuntu:latest
latest: Pulling from library/ubuntu
677076032cca: Pull complete
Digest: sha256:9a0bdde4188b896a372804be2384015e90e3f84906b750c1a53539b585fbbe7f
Status: Downloaded newer image for ubuntu:latest
---> 58db3edaf2be
Step 2/6 : WORKDIR /app
---> Running in 630f5e4db7d3
Removing intermediate container 630f5e4db7d3
---> 6b1d9f654263
Step 3/6 : COPY . /app
---> 984edffabc23
Step 4/6 : RUN apt-get update && apt-get install -y python3 python3-pip
---> Running in a558acdc9b03
Step 5/6 : ENV NAME World
---> Running in 733207001f2e
Removing intermediate container 733207001f2e
---> 94128cf6be21
Step 6/6 : CMD ["python3", "app.py"]
---> Running in 5d60ad3a59ff
Removing intermediate container 5d60ad3a59ff
---> 960d37536dcd
Successfully built 960d37536dcd
Successfully tagged abhishekf5/my-first-docker-image:latest
```
### Verify Docker Image is created
```
docker images
```
Output
```
REPOSITORY TAG IMAGE ID CREATED SIZE
abhishekf5/my-first-docker-image latest 960d37536dcd 26 seconds ago 467MB
ubuntu latest 58db3edaf2be 13 days ago 77.8MB
hello-world latest feb5d9fea6a5 16 months ago 13.3kB
```
### Run your First Docker Container
```
docker run -it abhishekf5/my-first-docker-image
```
Output
```
Hello World
```
### Push the Image to DockerHub and share it with the world
```
docker push abhishekf5/my-first-docker-image
```
Output
```
Using default tag: latest
The push refers to repository [docker.io/abhishekf5/my-first-docker-image]
896818320e80: Pushed
b8088c305a52: Pushed
69dd4ccec1a0: Pushed
c5ff2d88f679: Mounted from library/ubuntu
latest: digest: sha256:6e49841ad9e720a7baedcd41f9b666fcd7b583151d0763fe78101bb8221b1d88 size: 1157
```
### You must be feeling like a champ already
================================================
FILE: commands.md
================================================
# Docker Commands
Some of the most commonly used docker commands are
### docker images
Lists docker images on the host machine.
### docker build
Builds image from Dockerfile.
### docker run
Runs a Docker container.
There are many arguments which you can pass to this command for example,
`docker run -d` -> Run container in background and print container ID
`docker run -p` -> Port mapping
use `docker run --help` to look into more arguments.
### docker ps
Lists running containers on the host machine.
### docker stop
Stops running container.
### docker start
Starts a stopped container.
### docker rm
Removes a stopped container.
### docker rmi
Removes an image from the host machine.
### docker pull
Downloads an image from the configured registry.
### docker push
Uploads an image to the configured registry.
### docker exec
Run a command in a running container.
### docker network
Manage Docker networks such as creating and removing networks, and connecting containers to networks.
================================================
FILE: examples/first-docker-file/Dockerfile
================================================
FROM ubuntu:latest
# Set the working directory in the image
WORKDIR /app
# Copy the files from the host file system to the image file system
COPY . /app
# Install the necessary packages
RUN apt-get update && apt-get install -y python3 python3-pip
# Set environment variables
ENV NAME World
# Run a command to start the application
CMD ["python3", "app.py"]
================================================
FILE: examples/first-docker-file/app.py
================================================
print("Hello World")
================================================
FILE: examples/golang-multi-stage-docker-build/Dockerfile
================================================
###########################################
# BASE IMAGE
###########################################
FROM ubuntu AS build
RUN apt-get update && apt-get install -y golang-go
ENV GO111MODULE=off
COPY . .
RUN CGO_ENABLED=0 go build -o /app .
############################################
# HERE STARTS THE MAGIC OF MULTI STAGE BUILD
############################################
FROM scratch
# Copy the compiled binary from the build stage
COPY --from=build /app /app
# Set the entrypoint for the container to run the binary
ENTRYPOINT ["/app"]
================================================
FILE: examples/golang-multi-stage-docker-build/README.md
================================================
# Multi Stage Docker Build
The main purpose of choosing a golang based applciation to demostrate this example is golang is a statically-typed programming language that does not require a runtime in the traditional sense. Unlike dynamically-typed languages like Python, Ruby, and JavaScript, which rely on a runtime environment to execute their code, Go compiles directly to machine code, which can then be executed directly by the operating system.
So the real advantage of multi stage docker build and distro less images can be understand with a drastic decrease in the Image size.
================================================
FILE: examples/golang-multi-stage-docker-build/calculator.go
================================================
package main
import (
"bufio"
"fmt"
"os"
"strconv"
"strings"
)
func main() {
fmt.Println("Hi Abhishek.Veeramalla, I am a calculator app ....")
for {
// Read input from the user
reader := bufio.NewReader(os.Stdin)
fmt.Print("Enter any calculation (Example: 1 + 2 (or) 2 * 5 -> Please maintain spaces as shown in example): ")
text, _ := reader.ReadString('\n')
// Trim the newline character from the input
text = strings.TrimSpace(text)
// Check if the user entered "exit" to quit the program
if text == "exit" {
break
}
// Split the input into two parts: the left operand and the right operand
parts := strings.Split(text, " ")
if len(parts) != 3 {
fmt.Println("Invalid input. Try again.")
continue
}
// Convert the operands to integers
left, err := strconv.Atoi(parts[0])
if err != nil {
fmt.Println("Invalid input. Try again.")
continue
}
right, err := strconv.Atoi(parts[2])
if err != nil {
fmt.Println("Invalid input. Try again.")
continue
}
// Perform the calculation based on the operator
var result int
switch parts[1] {
case "+":
result = left + right
case "-":
result = left - right
case "*":
result = left * right
case "/":
result = left / right
default:
fmt.Println("Invalid operator. Try again.")
continue
}
// Print the result
fmt.Printf("Result: %d\n", result)
}
}
================================================
FILE: examples/golang-multi-stage-docker-build/dockerfile-without-multistage/Dockerfile
================================================
###########################################
# BASE IMAGE
###########################################
FROM ubuntu AS build
RUN apt-get update && apt-get install -y golang-go
ENV GO111MODULE=off
COPY . .
RUN CGO_ENABLED=0 go build -o /app .
ENTRYPOINT ["/app"]
================================================
FILE: examples/golang-multi-stage-docker-build/dockerfile-without-multistage/calculator.go
================================================
package main
import (
"bufio"
"fmt"
"os"
"strconv"
"strings"
)
func main() {
fmt.Println("Hi Abhishek.Veeramalla, I am a calculator app ....")
for {
// Read input from the user
reader := bufio.NewReader(os.Stdin)
fmt.Print("Enter any calculation (Example: 1 + 2 (or) 2 * 5 -> Please maintain spaces as shown in example): ")
text, _ := reader.ReadString('\n')
// Trim the newline character from the input
text = strings.TrimSpace(text)
// Check if the user entered "exit" to quit the program
if text == "exit" {
break
}
// Split the input into two parts: the left operand and the right operand
parts := strings.Split(text, " ")
if len(parts) != 3 {
fmt.Println("Invalid input. Try again.")
continue
}
// Convert the operands to integers
left, err := strconv.Atoi(parts[0])
if err != nil {
fmt.Println("Invalid input. Try again.")
continue
}
right, err := strconv.Atoi(parts[2])
if err != nil {
fmt.Println("Invalid input. Try again.")
continue
}
// Perform the calculation based on the operator
var result int
switch parts[1] {
case "+":
result = left + right
case "-":
result = left - right
case "*":
result = left * right
case "/":
result = left / right
default:
fmt.Println("Invalid operator. Try again.")
continue
}
// Print the result
fmt.Printf("Result: %d\n", result)
}
}
================================================
FILE: examples/python-web-app/Dockerfile
================================================
FROM ubuntu
WORKDIR /app
COPY requirements.txt /app
COPY devops /app
RUN apt-get update && \
apt-get install -y python3 python3-pip && \
pip install -r requirements.txt && \
cd devops
ENTRYPOINT ["python3"]
CMD ["manage.py", "runserver", "0.0.0.0:8000"]
================================================
FILE: examples/python-web-app/devops/db.sqlite3
================================================
================================================
FILE: examples/python-web-app/devops/demo/__init__.py
================================================
================================================
FILE: examples/python-web-app/devops/demo/admin.py
================================================
from django.contrib import admin
# Register your models here.
================================================
FILE: examples/python-web-app/devops/demo/apps.py
================================================
from django.apps import AppConfig
class DemoConfig(AppConfig):
default_auto_field = 'django.db.models.BigAutoField'
name = 'demo'
================================================
FILE: examples/python-web-app/devops/demo/migrations/__init__.py
================================================
================================================
FILE: examples/python-web-app/devops/demo/models.py
================================================
from django.db import models
# Create your models here.
================================================
FILE: examples/python-web-app/devops/demo/templates/demo_site.html
================================================
<!DOCTYPE html>
<html lang="en">
<head>
<title>CSS Template</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
* {
box-sizing: border-box;
}
body {
font-family: Arial, Helvetica, sans-serif;
}
/* Style the header */
header {
background-color: #666;
padding: 30px;
text-align: center;
font-size: 35px;
color: yellow;
}
/* Create two columns/boxes that floats next to each other */
nav {
float: left;
width: 30%;
height: 300px; /* only for demonstration, should be removed */
background: #ccc;
padding: 20px;
}
/* Style the list inside the menu */
nav ul {
list-style-type: none;
padding: 0;
}
article {
float: left;
padding: 20px;
width: 70%;
background-color: #f1f1f1;
height: 300px; /* only for demonstration, should be removed */
}
/* Clear floats after the columns */
section::after {
content: "";
display: table;
clear: both;
}
/* Style the footer */
footer {
background-color: #777;
padding: 10px;
text-align: center;
color: yellow;
}
/* Responsive layout - makes the two columns/boxes stack on top of each other instead of next to each other, on small screens */
@media (max-width: 600px) {
nav, article {
width: 100%;
height: auto;
}
}
</style>
</head>
<body>
<header>
<h2>Free DevOps Course By Abhishek</h2>
</header>
<section>
<nav>
<ul>
<li><a href="www.youtube.com/@AbhishekVeeramalla">YouTube</a></li>
<li><a href="www.linkedin.com/in/abhishek-veeramalla-77b33996/">LinkedIn</a></li>
<li><a href="https://telegram.me/abhishekveeramalla">Telegram</a></li>
</ul>
</nav>
<article>
<h1>Agenda</h1>
<p>Learn DevOps with strong foundational knowledge and practical understanding</p>
<p>Please Share the Channel with your friends and colleagues</p>
</article>
</section>
<footer>
<p>@AbhishekVeeramalla</p>
</footer>
</body>
</html>
================================================
FILE: examples/python-web-app/devops/demo/tests.py
================================================
from django.test import TestCase
# Create your tests here.
================================================
FILE: examples/python-web-app/devops/demo/urls.py
================================================
from django.urls import path
from . import views
urlpatterns = [
path('', views.index, name='index'),
]
================================================
FILE: examples/python-web-app/devops/demo/views.py
================================================
from django.http import HttpResponse
from django.shortcuts import render
def index(request):
return render(request, 'demo_site.html')
================================================
FILE: examples/python-web-app/devops/devops/__init__.py
================================================
================================================
FILE: examples/python-web-app/devops/devops/asgi.py
================================================
"""
ASGI config for devops project.
It exposes the ASGI callable as a module-level variable named ``application``.
For more information on this file, see
https://docs.djangoproject.com/en/4.1/howto/deployment/asgi/
"""
import os
from django.core.asgi import get_asgi_application
os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'devops.settings')
application = get_asgi_application()
================================================
FILE: examples/python-web-app/devops/devops/settings.py
================================================
"""
Django settings for devops project.
Generated by 'django-admin startproject' using Django 4.1.6.
For more information on this file, see
https://docs.djangoproject.com/en/4.1/topics/settings/
For the full list of settings and their values, see
https://docs.djangoproject.com/en/4.1/ref/settings/
"""
import os
from pathlib import Path
# Build paths inside the project like this: BASE_DIR / 'subdir'.
BASE_DIR = Path(__file__).resolve().parent.parent
# Quick-start development settings - unsuitable for production
# See https://docs.djangoproject.com/en/4.1/howto/deployment/checklist/
# SECURITY WARNING: keep the secret key used in production secret!
SECRET_KEY = 'django-insecure-js0^(n81j2j1@&5fn!a_jh92*_05id$3tegf@g8frdo!q$fdm*'
# SECURITY WARNING: don't run with debug turned on in production!
DEBUG = True
ALLOWED_HOSTS = ['*']
# Application definition
INSTALLED_APPS = [
'django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',
]
MIDDLEWARE = [
'django.middleware.security.SecurityMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.common.CommonMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
'django.middleware.clickjacking.XFrameOptionsMiddleware',
]
ROOT_URLCONF = 'devops.urls'
TEMPLATES = [
{
'BACKEND': 'django.template.backends.django.DjangoTemplates',
'DIRS': [os.path.join(BASE_DIR, 'demo/templates')],
'APP_DIRS': True,
'OPTIONS': {
'context_processors': [
'django.template.context_processors.debug',
'django.template.context_processors.request',
'django.contrib.auth.context_processors.auth',
'django.contrib.messages.context_processors.messages',
],
},
},
]
WSGI_APPLICATION = 'devops.wsgi.application'
# Database
# https://docs.djangoproject.com/en/4.1/ref/settings/#databases
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.sqlite3',
'NAME': BASE_DIR / 'db.sqlite3',
}
}
# Password validation
# https://docs.djangoproject.com/en/4.1/ref/settings/#auth-password-validators
AUTH_PASSWORD_VALIDATORS = [
{
'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
},
{
'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
},
{
'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
},
{
'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
},
]
# Internationalization
# https://docs.djangoproject.com/en/4.1/topics/i18n/
LANGUAGE_CODE = 'en-us'
TIME_ZONE = 'UTC'
USE_I18N = True
USE_TZ = True
# Static files (CSS, JavaScript, Images)
# https://docs.djangoproject.com/en/4.1/howto/static-files/
STATIC_URL = 'static/'
# Default primary key field type
# https://docs.djangoproject.com/en/4.1/ref/settings/#default-auto-field
DEFAULT_AUTO_FIELD = 'django.db.models.BigAutoField'
================================================
FILE: examples/python-web-app/devops/devops/urls.py
================================================
"""devops URL Configuration
The `urlpatterns` list routes URLs to views. For more information please see:
https://docs.djangoproject.com/en/4.1/topics/http/urls/
Examples:
Function views
1. Add an import: from my_app import views
2. Add a URL to urlpatterns: path('', views.home, name='home')
Class-based views
1. Add an import: from other_app.views import Home
2. Add a URL to urlpatterns: path('', Home.as_view(), name='home')
Including another URLconf
1. Import the include() function: from django.urls import include, path
2. Add a URL to urlpatterns: path('blog/', include('blog.urls'))
"""
from django.contrib import admin
from django.urls import include, path
urlpatterns = [
path('demo/', include('demo.urls')),
path('admin/', admin.site.urls),
]
================================================
FILE: examples/python-web-app/devops/devops/wsgi.py
================================================
"""
WSGI config for devops project.
It exposes the WSGI callable as a module-level variable named ``application``.
For more information on this file, see
https://docs.djangoproject.com/en/4.1/howto/deployment/wsgi/
"""
import os
from django.core.wsgi import get_wsgi_application
os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'devops.settings')
application = get_wsgi_application()
================================================
FILE: examples/python-web-app/devops/manage.py
================================================
#!/usr/bin/env python
"""Django's command-line utility for administrative tasks."""
import os
import sys
def main():
"""Run administrative tasks."""
os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'devops.settings')
try:
from django.core.management import execute_from_command_line
except ImportError as exc:
raise ImportError(
"Couldn't import Django. Are you sure it's installed and "
"available on your PYTHONPATH environment variable? Did you "
"forget to activate a virtual environment?"
) from exc
execute_from_command_line(sys.argv)
if __name__ == '__main__':
main()
================================================
FILE: examples/python-web-app/requirements.txt
================================================
Django
tzdata
================================================
FILE: networking.md
================================================
# Docker Networking
Networking allows containers to communicate with each other and with the host system. Containers run isolated from the host system
and need a way to communicate with each other and with the host system.
By default, Docker provides two network drivers for you, the bridge and the overlay drivers.
```
docker network ls
```
```
NETWORK ID NAME DRIVER
xxxxxxxxxxxx none null
xxxxxxxxxxxx host host
xxxxxxxxxxxx bridge bridge
```
### Bridge Networking
The default network mode in Docker. It creates a private network between the host and containers, allowing
containers to communicate with each other and with the host system.
If you want to secure your containers and isolate them from the default bridge network you can also create your own bridge network.
```
docker network create -d bridge my_bridge
```
Now, if you list the docker networks, you will see a new network.
```
docker network ls
NETWORK ID NAME DRIVER
xxxxxxxxxxxx bridge bridge
xxxxxxxxxxxx my_bridge bridge
xxxxxxxxxxxx none null
xxxxxxxxxxxx host host
```
This new network can be attached to the containers, when you run these containers.
```
docker run -d --net=my_bridge --name db training/postgres
```
This way, you can run multiple containers on a single host platform where one container is attached to the default network and
the other is attached to the my_bridge network.
These containers are completely isolated with their private networks and cannot talk to each other.
However, you can at any point of time, attach the first container to my_bridge network and enable communication
```
docker network connect my_bridge web
```
### Host Networking
This mode allows containers to share the host system's network stack, providing direct access to the host system's network.
To attach a host network to a Docker container, you can use the --network="host" option when running a docker run command. When you use this option, the container has access to the host's network stack, and shares the host's network namespace. This means that the container will use the same IP address and network configuration as the host.
Here's an example of how to run a Docker container with the host network:
```
docker run --network="host" <image_name> <command>
```
Keep in mind that when you use the host network, the container is less isolated from the host system, and has access to all of the host's network resources. This can be a security risk, so use the host network with caution.
Additionally, not all Docker image and command combinations are compatible with the host network, so it's important to check the image documentation or run the image with the --network="bridge" option (the default network mode) first to see if there are any compatibility issues.
### Overlay Networking
This mode enables communication between containers across multiple Docker host machines, allowing containers to be connected to a single network even when they are running on different hosts.
### Macvlan Networking
This mode allows a container to appear on the network as a physical host rather than as a container.
================================================
FILE: volumes.md
================================================
# Docker Volumes
## Problem Statement
It is a very common requirement to persist the data in a Docker container beyond the lifetime of the container. However, the file system
of a Docker container is deleted/removed when the container dies.
## Solution
There are 2 different ways how docker solves this problem.
1. Volumes
2. Bind Directory on a host as a Mount
### Volumes
Volumes aims to solve the same problem by providing a way to store data on the host file system, separate from the container's file system,
so that the data can persist even if the container is deleted and recreated.
Volumes can be created and managed using the docker volume command. You can create a new volume using the following command:
```
docker volume create <volume_name>
```
Once a volume is created, you can mount it to a container using the -v or --mount option when running a docker run command.
For example:
```
docker run -it -v <volume_name>:/data <image_name> /bin/bash
```
This command will mount the volume <volume_name> to the /data directory in the container. Any data written to the /data directory
inside the container will be persisted in the volume on the host file system.
### Bind Directory on a host as a Mount
Bind mounts also aims to solve the same problem but in a complete different way.
Using this way, user can mount a directory from the host file system into a container. Bind mounts have the same behavior as volumes, but
are specified using a host path instead of a volume name.
For example,
```
docker run -it -v <host_path>:<container_path> <image_name> /bin/bash
```
## Key Differences between Volumes and Bind Directory on a host as a Mount
Volumes are managed, created, mounted and deleted using the Docker API. However, Volumes are more flexible than bind mounts, as
they can be managed and backed up separately from the host file system, and can be moved between containers and hosts.
In a nutshell, Bind Directory on a host as a Mount are appropriate for simple use cases where you need to mount a directory from the host file system into
a container, while volumes are better suited for more complex use cases where you need more control over the data being persisted
in the container.
gitextract_4g2qhtl8/ ├── README.md ├── commands.md ├── examples/ │ ├── first-docker-file/ │ │ ├── Dockerfile │ │ └── app.py │ ├── golang-multi-stage-docker-build/ │ │ ├── Dockerfile │ │ ├── README.md │ │ ├── calculator.go │ │ └── dockerfile-without-multistage/ │ │ ├── Dockerfile │ │ └── calculator.go │ └── python-web-app/ │ ├── Dockerfile │ ├── devops/ │ │ ├── db.sqlite3 │ │ ├── demo/ │ │ │ ├── __init__.py │ │ │ ├── admin.py │ │ │ ├── apps.py │ │ │ ├── migrations/ │ │ │ │ └── __init__.py │ │ │ ├── models.py │ │ │ ├── templates/ │ │ │ │ └── demo_site.html │ │ │ ├── tests.py │ │ │ ├── urls.py │ │ │ └── views.py │ │ ├── devops/ │ │ │ ├── __init__.py │ │ │ ├── asgi.py │ │ │ ├── settings.py │ │ │ ├── urls.py │ │ │ └── wsgi.py │ │ └── manage.py │ └── requirements.txt ├── networking.md └── volumes.md
SYMBOL INDEX (5 symbols across 5 files)
FILE: examples/golang-multi-stage-docker-build/calculator.go
function main (line 11) | func main() {
FILE: examples/golang-multi-stage-docker-build/dockerfile-without-multistage/calculator.go
function main (line 11) | func main() {
FILE: examples/python-web-app/devops/demo/apps.py
class DemoConfig (line 4) | class DemoConfig(AppConfig):
FILE: examples/python-web-app/devops/demo/views.py
function index (line 5) | def index(request):
FILE: examples/python-web-app/devops/manage.py
function main (line 7) | def main():
Condensed preview — 29 files, each showing path, character count, and a content snippet. Download the .json file or copy for the full structured content (38K chars).
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About this extraction
This page contains the full source code of the Sareenh1/https-github.com-iam-veeramalla-Docker-Zero-to-Hero GitHub repository, extracted and formatted as plain text for AI agents and large language models (LLMs). The extraction includes 29 files (33.8 KB), approximately 9.0k tokens, and a symbol index with 5 extracted functions, classes, methods, constants, and types. Use this with OpenClaw, Claude, ChatGPT, Cursor, Windsurf, or any other AI tool that accepts text input. You can copy the full output to your clipboard or download it as a .txt file.
Extracted by GitExtract — free GitHub repo to text converter for AI. Built by Nikandr Surkov.