100+ Docker Concepts you Need to Know
Summary
TLDRDocker 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
- đŠ Docker is a powerful tool for containerization, which helps solve the 'it works on my machine' problem and improves scalability in the cloud.
- đ» 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.
- đ Networking plays a crucial role in modern software delivery, where clients receive data from servers, which can face challenges as user numbers grow.
- âïž Scaling infrastructure can be done vertically by increasing server resources or horizontally by distributing the load across multiple servers or microservices.
- đ§ 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.
- đ ïž 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.
- đ The Dockerfile includes instructions like FROM, WORKDIR, RUN, COPY, ENV, EXPOSE, USER, and CMD to set up the container environment.
- đ·ïž Docker allows for adding labels and health checks to the Dockerfile, and the use of volumes for persistent storage across containers.
- đ Docker images are built in layers, with changes only rebuilding the affected layers, improving efficiency and workflow for developers.
- đ Docker Desktop provides tools to inspect images, identify security vulnerabilities, and manage running containers with commands like docker run, docker stop, and docker kill.
- đ Beyond local development, Docker images can be pushed to remote registries and run on various cloud platforms or serverless environments.
- đ Docker Compose simplifies the management of multi-container applications by defining and running multiple services with a single command.
- đ€ 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
đŠ 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.
đ 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.
Mindmap
Keywords
đĄContainerization
đĄDocker
đĄKernel
đĄVirtual Machines (VMs)
đĄDockerfile
đĄImage
đĄContainer
đĄDocker Hub
đĄDocker CLI
đĄDocker Compose
đĄKubernetes
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
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