11 Fundamental Docker Definitions for:

🏠Docker host
⚙️Docker engine
🖥️ Docker client
😈Docker daemon
📝Dockerfile
📦Docker Image
🐳Docker Container
🔗Docker Network
💾Docker volumes
🐙Docker Compose
🪣 Docker Registry

Keep reading for short definitions:
/thread⬇️
1/11 🏠Docker (Active) Host

A computer with Docker installed and the daemon running.

It can process Docker and non-Docker workloads.
2/11 ⚙️Docker Engine

A Client-Server application.
It has 3 components:

- CLI: A command-line interface client.

- daemon process: A server that is a type of long-running program.

- Rest API: to specify interfaces that programs can use to talk and interact with the daemon.
3/11 🖥️Docker Client

The main way of interacting 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.

One client can communicate with multiple daemons.
4/11 😈Docker Daemon

The Docker daemon (dockerd) is a process, which runs in the background, that manages the docker objects (images, containers, networks, volumes).

It processes Docker API requests
5/11 📝Dockerfile

It's a text document (capital D, no extensions).
You can use a different name.

It contains KEY VALUES pairs with all the commands a user could call on the command line to build an image.

During the build, the lines are executed in order
6/11 📦Docker Image

It's a file, composed of multiple layers, often based on another image, that contains everything you need to run your application.

For example:
-dependencies
-configuration
-binaries
-environment variables

Containers run on top of existing images.
7/11 🐳Docker Container

- It's a single unit of working software, with all its configurations and dependencies, packaged.

- From a technical point of view, the container is just a process, that runs on the machine, isolated from the other processes.
8/11 🔗Docker Network

It's how to link different containers and how they can communicate with each other on single/multiple hosts, agnostically.

You can have different behaviors using different drivers.
9/11 💾Docker Volumes

They are file systems mounted on Docker containers to save data.

You need this because containers are ephemerals, and when they are removed, all their data is lost, and this happens often.
10/11 🐙Docker Compose

It's a tool for defining and running multi-container Docker applications, called services.

You use a YAML file to configure the services, that can be created/started/stopped with a single command.

It works well in development, testing, and production.
11/11 🪣 Docker registry

It's a stateless server-side application to store Docker images where the images can be pulled/pushed (as GitHub for repositories).

It can be public or private.

Docker Hub is a public Docker registry.
If you enjoyed these definitions, please consider sharing this and following @FrancescoCiull4.

I am talking about Docker in this new YouTube Channel, can you help me to reach 100 subs? Thank you!
youtube.com/channel/UC21VA…

• • •

Missing some Tweet in this thread? You can try to force a refresh
 

Keep Current with Francesco Ciulla

Francesco Ciulla Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!

PDF

Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @FrancescoCiull4

30 Jul
Creating Content is not easy, and the reasons are many.

In about a year I have collected the most important BLOCKERS.
I have experienced all of them.

- Lack of time
- Lack of ideas
- Not feeling ready
- Fear of judgment

Here are my short answers to all of them:
/Thread
Lack of time 1/2

This has always been my favorite excuse.
If we really want to do something you will find the time.

If it ever happened to you, when you fall in love, suddenly you have a lot of free time.

If you really want to create some content, give it the right priority.
Lack of time 2/2

I wanted to start YouTube in 2010.

I released my first video on August 7, 2020.

I've posted 193 videos.

My "secret"? Many videos are of me talking to my friends or people I think are important to the tech world, and I'm really interested in their stories.
Read 8 tweets
22 May
What are dangling images in Docker?

Probably if you worked with docker locally, it happened to see something like this using `docker images`

The dangling images are those ones with <none> as [Repository] and [Tag]

Ugly uh?

Let me explain what's going on: a list of docker images, with a lot of <none> <none> as repo
A dangling image is one that is not tagged and is not referenced by any container.

Why are they there?

Reasons could be different, but the most common case is when you build another image using the same tag

(Side note: don't build a production-ready image with the same tag)
To see just the dangling images on your system, you can use the command:

`docker images -f dangling=true`

what a good show, right? only images with <none> <none>
Read 5 tweets
21 May
Lifecycle of Docker containers (Thread)

A diagram with some additional information below about the lifecycle of containers.

This is a simplified version, there are other commands (kill, ...) and other intermediate states

Let's see them:
docker create

Creates a new layer over an image with a writeable container.

It prepares it to run a specific command (the one specified in the Dockerfile)

Useful to set up a configuration so that it is ready to start when needed.

Status of the container: "CREATED"
docker start

Starts one (or more) container.

This command can either be used::
- To start a container just created with the docker create command
- To start a stopped container
Read 9 tweets
20 May
I've dealt with a lot of negative comments in my life.

When I was a coach I got yelled at by people who didn't agree with my choices.

That's why IDGAF about a comment written by an anonymous user who hides behind a keyboard.

But someone does.

This thread could help you.
🧵 Image
1- Never take it personally:

Think they:

- had a bad day,
- just broke up,
- lost their job,
- got their car stolen
- their house went up in flames

But don't take this as a direct attack on you or your family.
2- Responding is usually more harmful than ignoring.

This does not mean that we must passively accept any accusation, but probably answering it will only fuel discussions.

Also, there are people who like to argue all day long.
That's their hobby.
Read 8 tweets
19 May
Path to Learn Docker in 10 steps.

There are many resources online, many great ones even free to learn Docker

But what is the path to learning Docker from Zero, so you can choose your own videos/articles?

Here is the path I suggest in 10 steps.

Let's see them together:

...
1) Understanding WHAT it is and what it isn't, what are the building blocks of it

2) Understanding what containerization is and why it is so important. Differences Containers/Virtual Machines

3) Install Docker on your operating system and make sure it works (`docker info`)

...
4) Take a look at "Docker Hub" and make a bit of practice using one image there (eg Nginx) and understand the basic commands: start/stop/list containers.

5) Understand how the components are made and their configuration: commands inspect/exec/logs.

...
Read 7 tweets
18 May
The Computer Science degree helped me find a great job.

But not in the way you can imagine.

I always thought that after graduating in Computer Science I would immediately work as a freelancer, looking for clients and working remotely.

This was my plan.

But it changed.

👇
A University professor contacted me telling me that there was the possibility of working for the European Space Agency.

I was a bit torn but in the end, also out of curiosity, I went to the interview.

Two days later I got a great offer.

The next day I was working there.
This was a deviation from my initial project, but I adapted to this opportunity.

After about 4 years, and after leaving my 9-5 Job.

I don't regret my choice, which has given me stability and experience in the space sector, which I continue to love.
Read 5 tweets

Did Thread Reader help you today?

Support us! We are indie developers!


This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Too expensive? Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal Become our Patreon

Thank you for your support!

Follow Us on Twitter!

:(