100+ Docker Concepts you Need to Know

Summary

Docker 101 introduces containerization as a powerful solution for software deployment challenges, such as 'it works on my machine' and scaling issues in the cloud. The video covers the basics of computer components, operating systems, networking, and scaling strategies. It explains how Docker enables OS-level virtualization, allowing applications to share the same kernel and allocate resources dynamically. The script walks through creating a Dockerfile, building an image, and running it as a container, emphasizing Docker's portability and scalability. It also touches on Docker Compose for multi-container applications and introduces orchestration tools like Kubernetes for large-scale deployments, concluding with a nod to Docker's role in simplifying complex infrastructure management.

Takeaways

• 📦 Docker is a powerful tool for containerization, which helps solve the 'it works on my machine' problem and improves scalability in the cloud.
• 💻 The basic components of a computer include a CPU, RAM, and a disc, with the operating system's kernel providing the foundation for software applications to run.
• 🌐 Networking plays a crucial role in modern software delivery, where clients receive data from servers, which can face challenges as user numbers grow.
• ⚙️ Scaling infrastructure can be done vertically by increasing server resources or horizontally by distributing the load across multiple servers or microservices.
• 🔧 Virtual machines offer a way to run multiple operating systems on a single machine using hypervisors, but Docker provides a more efficient solution with dynamic resource allocation.
• 🛠️ Docker uses a Dockerfile as a blueprint to configure the environment for an application, which is then built into an image containing the OS, dependencies, and code.
• 📜 The Dockerfile includes instructions like FROM, WORKDIR, RUN, COPY, ENV, EXPOSE, USER, and CMD to set up the container environment.
• 🏷️ Docker allows for adding labels and health checks to the Dockerfile, and the use of volumes for persistent storage across containers.
• 🔄 Docker images are built in layers, with changes only rebuilding the affected layers, improving efficiency and workflow for developers.
• 🔍 Docker Desktop provides tools to inspect images, identify security vulnerabilities, and manage running containers with commands like docker run, docker stop, and docker kill.
• 🌐 Beyond local development, Docker images can be pushed to remote registries and run on various cloud platforms or serverless environments.
• 🔄 Docker Compose simplifies the management of multi-container applications by defining and running multiple services with a single command.
• 🤖 For large-scale deployments, orchestration tools like Kubernetes are used to manage and scale containers across multiple nodes and machines.

Q & A

What is the main problem that containerization aims to solve?

Containerization aims to solve the problem of software compatibility and scalability issues, such as 'it works on my machine' during local development and difficulties in scaling architecture in the cloud.

What are the three main components of a computer as mentioned in the script?

The three main components of a computer are the CPU for calculations, random access memory (RAM) for the applications currently in use, and a disc for storing data that might be used later.

What does the kernel do in an operating system?

The kernel in an operating system sits on top of the bare metal hardware and provides a layer that allows software applications to run on the system.

What are the two ways a server can scale?

A server can scale either vertically by increasing its RAM and CPU or horizontally by distributing the code to multiple smaller servers, often broken down into microservices.

What is a Dockerfile and what is its purpose?

A Dockerfile is a blueprint that contains a collection of instructions to configure the environment that runs an application. It is used to build an image which is a template for running the application.

How does Docker enable applications to share the same host operating system kernel?

Docker uses a daemon or persistent process that provides OS-level virtualization, allowing applications to share the same host operating system kernel and use resources dynamically based on their needs.

What is the significance of the 'FROM' instruction in a Dockerfile?

The 'FROM' instruction is usually the first in a Dockerfile and points to a base image, often a Linux distribution, which serves as the starting point for building the application environment.

What is the role of the 'RUN' instruction in a Dockerfile?

The 'RUN' instruction is used to execute any command in the Docker container, similar to running commands from the command line, and is commonly used to install dependencies.

What does 'Docker push' do and why is it important for cloud deployment?

Docker push uploads the Docker image to a remote registry, making it accessible for deployment on cloud platforms like AWS or serverless platforms like Google Cloud Run.

What is Docker Compose and how does it help with multi-container applications?

Docker Compose is a tool for managing multi-container applications. It allows you to define multiple applications and their Docker images in a single YAML file and start or stop all containers simultaneously with the 'up' and 'down' commands.

What is Kubernetes and why is it used for container orchestration at scale?

Kubernetes is an orchestration tool used for running and managing containers at scale. It has a control plane that exposes an API to manage the cluster, which consists of multiple nodes or machines, each containing a kubelet and multiple pods. It is effective for describing the desired state of the system and automatically scaling or healing the system as needed.

Outlines

00:00

📦 Introduction to Docker and Containerization

This paragraph introduces Docker 101 and the concept of containerization as a powerful tool for software shipping in the real world. It addresses common issues like 'it works on my machine' and scaling challenges in cloud deployments. The script explains the basic components of a computer, the role of the operating system and kernel, and the evolution of software delivery from physical stores to the internet. It also touches on the problems that arise with scaling, such as CPU exhaustion, slow I/O, network bandwidth issues, and database inefficiencies. The paragraph concludes with an introduction to virtual machines and how Docker offers a solution with OS-level virtualization, allowing applications to share the same host OS kernel and use resources dynamically.

05:01

🛠 Docker Workflow and Best Practices

This paragraph delves into the Docker workflow, starting with the creation of a Dockerfile, which serves as a blueprint for configuring the application environment. It explains the process of building an image from the Dockerfile, which includes the OS, dependencies, and code, and how this image can be shared via Docker Hub. The script discusses the three-step process of using Docker: creating a Dockerfile, building an image, and running it as a container. It also covers the stateless nature of containers, their portability across cloud platforms, and the avoidance of vendor lock-in. The paragraph further explains additional Dockerfile instructions like ENV for environment variables, EXPOSE for making ports accessible, and the importance of the CMD instruction for running the container. It also touches on Docker CLI commands, the benefits of layer caching, the use of .dockerignore for excluding files, and security features like Docker Scout. The paragraph concludes with instructions on running and managing containers locally and in the cloud, and introduces Docker Compose for multi-container applications, as well as orchestration tools like Kubernetes for large-scale deployments.

Keywords

💡Containerization

Containerization is the process of packaging software applications into containers that can be run on any system without modification. It is a key concept in the video as it addresses the problem of software not working consistently across different environments, often referred to as 'it works on my machine'. The script discusses how containerization, through Docker, allows for consistent deployment in various environments, including local development and cloud-based systems.

💡Docker

Docker is an open-source platform designed to automate the deployment of applications inside containers. In the script, Docker is introduced as a powerful tool for containerization, allowing developers to avoid the complexities of system dependencies and environment differences. It is central to the video's theme of simplifying software deployment and scaling.

💡Kernel

The kernel is the core component of an operating system that manages system resources and provides services for applications. In the context of the video, the kernel is mentioned as the base layer that Docker containers share, enabling efficient resource utilization and avoiding the overhead of multiple kernels as in traditional virtual machines.

💡Virtual Machines (VMs)

Virtual machines are software-based emulations of physical machines that allow for the running of multiple operating systems on a single host. The script contrasts VMs with Docker containers, highlighting that while VMs can isolate applications, they are less efficient in terms of resource allocation compared to the dynamic resource sharing enabled by Docker.

💡Dockerfile

A Dockerfile is a text document that contains all the commands a user could call on the command line to assemble an image. In the video, the Dockerfile is described as a blueprint for Docker to build an application's environment, illustrating the process of creating a Docker image from scratch.

💡Image

In the context of Docker, an image is a read-only template with instructions for creating a Docker container. The script explains that images contain an operating system, dependencies, and the application code, serving as a template for running applications in containers.

💡Container

A container is a lightweight, standalone, and executable software package that includes everything needed to run a piece of software, including the code, runtime, system tools, libraries, and settings. The video emphasizes that containers are isolated and stateless, which makes them portable and able to run on any infrastructure without vendor lock-in.

💡Docker Hub

Docker Hub is a cloud-based registry service that allows users to link code repositories, store and distribute Docker images, and automate the building and testing of images. The script mentions Docker Hub as a place to upload and share Docker images with others.

💡Docker CLI

The Docker CLI (Command Line Interface) is a command-line tool for Docker that allows users to interact with Docker and manage the lifecycle of containers. The video script describes using the Docker CLI to build images, run containers, and manage Docker objects.

💡Docker Compose

Docker Compose is a tool for defining and running multi-container Docker applications. The script introduces Docker Compose as a way to manage multiple containers with a single command, allowing for the orchestration of different services like front-end, back-end, and databases within a single YAML file.

💡Kubernetes

Kubernetes is an open-source container orchestration system for automating deployment, scaling, and management of containerized applications. The video briefly touches on Kubernetes as a tool for managing large-scale container deployments, emphasizing its ability to handle complex, high-traffic systems with its control plane and node architecture.

Highlights

Containerization is a powerful concept for shipping software in the real world, solving the 'it works on my machine' and scaling issues.

A computer's three important components are the CPU, RAM, and disc.

The operating system's kernel allows software applications to run on bare metal hardware.

Software is now often delivered via the Internet, with clients and servers playing key roles in networking.

Scaling infrastructure can be done vertically by increasing server resources or horizontally by distributing code across multiple servers.

Docker provides OS-level virtualization, allowing applications to share the same host OS kernel and use resources dynamically.

Developers can harness Docker's power by installing Docker Desktop, facilitating local software development without major system changes.

A Dockerfile is a blueprint for configuring the environment that runs an application.

Docker images contain an OS, dependencies, and code, serving as a template for running applications.

Containers are stateless, portable, and can run on every major cloud platform without vendor lock-in.

The Docker CLI allows for building images from Dockerfiles and running containers.

Docker images are built in layers, with changes only rebuilding the affected layers for developer efficiency.

Docker Desktop provides a detailed breakdown of images and security vulnerability identification for each layer.

Docker can be used to run containers locally and manage them through its UI or the terminal.

Docker push uploads images to a remote registry for cloud deployment on platforms like AWS ECS or serverless platforms like Google Cloud Run.

Docker pull allows downloading others' Docker images from the cloud for local use.

Docker Compose is a tool for managing multi-container applications, defined in a single YAML file.

Kubernetes is an orchestration tool for running and managing containers at scale, with a control plane and nodes containing pods.

Kubernetes allows describing the desired state of the system for automatic scaling and self-healing in case of server failure.

Docker Desktop extensions can be used to debug Kubernetes pods.

Transcripts

welcome to Docker 101 if your goal is to

ship software in the real world one of

the most powerful Concepts to understand

is containerization When developing

locally it solves the age-old problem of

it works on my machine and when

deploying in the cloud it solves the

age-old problem of this architecture

doesn't scale over the next few minutes

we'll unlock the power inside this

container by learning 101 different

concepts and terms related to computer

science the cloud and of course Docker

I'm guessing you know what a computer is

right it's a box that has three

important components inside a CPU for

calculating things random access memory

for the applications you're using right

now and a disc to store things you might

use later this is bare metal hardware

but in order to use it we need an

operating system most importantly the OS

provides a kernel that sits on top of

the bare metal allowing software

applications to run on it in the olden

days you would go to the store and buy

software to physically install it on

your machine but nowadays most software

is delivered via the Internet through

the magic of networking when you watch a

YouTube video your computer is called

the client but but you and billions of

other users are getting that data from

remote computers called servers when an

app starts reaching millions of people

weird things begin to happen the CPU

becomes exhausted handling all the

incoming requests disio slows down

Network bandwidth gets maxed out and the

database becomes too large to query

effectively on top of that you wrote

some garbage code that's causing race

conditions memory leaks and unhandled

errors that will eventually grind your

server to a halt the big question is how

do we scale our infrastructure a server

can scale up in two ways vertically or

horiz ially to scale vertically you take

your one server and increase its RAM and

CPU this can take you pretty far but

eventually you hit a ceiling the other

option is to scale horizontally where

you distribute your code to multiple

smaller servers which are often broken

down into microservices that can run and

scale independently but distributed

systems like this aren't very practical

when talking about bare metal because

actual resource allocation varies One

Way Engineers address this is with

virtual machines using tools like

hypervisor it can isolate and run

multiple operating systems systems on a

single machine that helps but a vm's

allocation of CPU and memory is still

fixed and that's where Docker comes in

the sponsor of today's video

applications running on top of the

docker engine all share the same host

operating system kernel and use

resources dynamically based on their

needs under the hood docker's running a

demon or persistent process that makes

all this magic possible and gives us OS

level virtualization what's awesome is

that any developer can easily harness

this power by simply installing Docker

desktop it allows you to develop

software without having to make massive

changes to your local system but here's

how Docker Works in three easy steps

first you start with a Docker file this

is like a blueprint that tells Docker

how to configure the environment that

runs your application the docker file is

then used to build an image which

contains an OS your dependencies and

your code like a template for running

your application and we can upload this

image to the cloud to places like Docker

Hub and share it with the world but an

image by itself doesn't do anything you

need to run it as a container which

itself is an isolated package running

your code that in theory could scale

infinitely in the cloud containers are

stateless which means when they shut

down all the data inside them is lost

but that makes them portable and they

can run on every major Cloud platform

without vendor lock in pretty cool but

the best way to learn Docker is to

actually run a container let's do that

right now by creating a Docker file a

Docker file contains a collection of

instructions which by convention are in

all caps from is usually the first

instruction you'll see which points to a

base image to get started this will

often be a Linux drro and may be

followed by a colon which is an optional

image tag and in this case specifies the

version of the OS next we have the

working directory instruction which

creates a source directory and CDs into

it and that's where we'll put our source

code all commands from here on out will

be executed from this working directory

next we can use the Run instruction to

use a Linux package manager to install

our dependencies run lets you run any

command just like you would from the

command line currently we're running as

the root user but for better security we

could also create a non-root user with

the user instruction now we can use copy

to copy the code on our local machine

over over to the image you're halfway

there let's take a brief

[Music]

[Applause]

intermission now to run this code we

have an API key which we can set as an

environment variable with the EnV

instruction we're building a web server

that people can connect to which

requires a port for external traffic use

the expose instruction to make that Port

accessible finally that brings us to the

command instruction which is the command

you want to run when starting up a

container in this case it will run our

web server there can only be one command

per container although you might also

add an entry point allowing you to pass

arguments to the command when you run it

that's everything we need for the docker

file but as an Added Touch we could also

use label to add some extra metadata or

we could run a health check to make sure

it's running properly or if the

container needs to store data that's

going to be used later or be used by

multiple containers we could mount a

volume to it with a persistent disc okay

we have a Docker file so now what when

you install Docker desktop that also

installed the docker CLI which you can

run from the terminal run Docker help to

see all the possible commands but the

one we need right now is Docker build

which will turn this Docker file into an

image when you run the command it's a

good idea to use the T flag to tag it

with a recognizable name notice how it

builds the image in layers every layer

is identified by a Shaw 256 hash which

means if you modify your Docker file

each layer will be cached so it only has

to rebuild what is actually changed and

that makes your workflow as a developer

far more efficient in addition it's

important to point out that sometimes

you don't want certain files to end up

in a Docker image in which case you can

add them to the docker ignore file to

exclude them from the actual files that

get copied there now open Docker desktop

and view the image there not only does

it give us a detailed breakdown but

thanks to Docker Scout we're able to

proactively identify any security

vulnerabilities for each layer of the

image it works by extracting the

software bill of material from the image

and Compares it to a bunch of security

advisory databases when there's a match

it's given a severity rating so you can

prioritize your security efforts but now

the time has finally come to run a

container we can accompl accomplish that

by simply clicking on the Run button

under the hood it executes the docker

run command and we can now access our

server on Local Host in addition we can

see the running container here in Docker

desktop which is the equivalent to the

docker command which you can run from

the terminal to get a breakdown of all

the running and stop containers on your

machine if we click on it though we can

inspect the logs from this container or

view the file system and we can even

execute commands directly inside the

running container now when it comes time

to shut it down we can use dock or stop

to stop it gracefully or dock kill to

forcefully stop it you can still see the

shutdown container here in the UI or use

remove to get rid of it but now you

might want to run your container in the

cloud Docker push will upload your image

to a remote registry where it can then

run on a cloud like AWS with elastic

container service or it can be launched

on serverless platforms like Google

Cloud run conversely you may want to use

someone else's Docker image which can be

downloaded from the cloud with Docker

pull and now you can run any developers

code without having to make any changes

to your local environment or machine

congratulations you're now a Bonafide

and certified Docker expert I hereby

Grant you permission to print out this

certificate and bring it to your next

job interview but Docker itself is only

the beginning there's a good chance your

application has more than one service in

which case you'll want to know about

Docker canose a tool for managing

multicontainer applications it allows

you to Define multiple applications and

their Docker images in a single yaml

file like a front end a backend and a

database the docker compose up command

will spin up all the containers

simultaneously while the down command

will stop them that works on an

individual server but once you reach

massive scale you'll likely need an

orchestration tool like kubernetes to

run and manage containers all over the

world it works like this you have a

control plane that exposes an API that

can manage the cluster now the cluster

has multiple nodes or machines each one

containing a cubet and multiple pods a

pod is the minimum Deployable unit in

kubernetes which itself has one or more

containers inside of it what makes

kubernetes so effective is that you can

describe the desired state of the system

and it will automatically scale up or

scale down while also providing fa

tolerance to automatically heal if one

of your servers goes down it gets pretty

complicated but the good news is that

you probably don't need kubernetes it

was developed at Google based on its

Borg system and is really only necessary

for highly complex hight trffic systems

if that sounds like you though you can

also use extensions on Docker desktop to

debug your pods and with that we've

looked at 100 concepts related to

containerization Big shout out to Docker

for making this video possible thanks

for watching and I will see you in the

next one