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@dipaish
dipaish committed Aug 15, 2024
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Expand Up @@ -15,7 +15,9 @@ The *getting started* guide on Docker has detailed instructions for setting up D
Once you are done installing Docker, test your Docker installation by running the following:

```
$ docker run hello-world
docker run hello-world
```

Unable to find image 'hello-world:latest' locally
latest: Pulling from library/hello-world
03f4658f8b78: Pull complete
Expand All @@ -26,7 +28,7 @@ Status: Downloaded newer image for hello-world:latest
Hello from Docker.
This message shows that your installation appears to be working correctly.
...
```

## The Docker Dashboard
It provides a quick view of the containers running on your machine. You have quick access to container logs, and you can get a shell inside the container. You can easily manage containers, such as stopping, starting, or removing them.
![Docker Dashboard](assets/docker.png "Docker Dashboard").
Expand All @@ -37,24 +39,26 @@ In this section, you will run an [Alpine Linux](http://www.alpinelinux.org/) con

To get started, let's run the following in our terminal:
```
$ docker pull alpine
docker pull alpine
```

> **Note:** Depending on how you've installed docker on your system, you might see a `permission denied` error after running the above command. Try the commands from the Getting Started tutorial to [verify your installation](https://docs.docker.com/engine/getstarted/step_one/#/step-3-verify-your-installation). If you're on Linux, you may need to prefix your `docker` commands with `sudo`. Alternatively you can [create a docker group](https://docs.docker.com/engine/installation/linux/ubuntulinux/#/create-a-docker-group) to get rid of this issue.
The `pull` command fetches the alpine **image** from the **Docker registry** and saves it in your system. You can use the `docker images` command to see a list of all images on your system.
```
$ docker images
docker images
```
REPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZE
alpine latest c51f86c28340 4 weeks ago 1.109 MB
hello-world latest 690ed74de00f 5 months ago 960 B
```


### Docker Run
Great! Let's now run a Docker **container** based on this image. To do that you are going to use the `docker run` command.

```
$ docker run alpine ls -l
docker run alpine ls -l
```
total 48
drwxr-xr-x 2 root root 4096 Mar 2 16:20 bin
drwxr-xr-x 5 root root 360 Mar 18 09:47 dev
Expand All @@ -63,7 +67,7 @@ drwxr-xr-x 2 root root 4096 Mar 2 16:20 home
drwxr-xr-x 5 root root 4096 Mar 2 16:20 lib
......
......
```

What happened? Behind the scenes, a lot of stuff happened. When you call `run`,
1. The Docker client contacts the Docker daemon.
2. The Docker daemon checks local store if the image (alpine in this case) is available locally, and if not, downloads it from Docker Store. (Since we have issued `docker pull alpine` before, the download step is not necessary)
Expand All @@ -75,14 +79,16 @@ When you run `docker run alpine`, you provided a command (`ls -l`), so Docker st
Let's try something more exciting.

```
$ docker run alpine echo "hello from alpine"
hello from alpine
docker run alpine echo "hello from alpine"
```
hello from alpine

OK, that's some actual output. In this case, the Docker client dutifully ran the `echo` command in our alpine container and then exited it. If you've noticed, all of that happened pretty quickly. Imagine booting up a virtual machine, running a command and then killing it. Now you know why they say containers are fast!

Try another command.
```
$ docker run alpine /bin/sh
docker run alpine /bin/sh
```

Wait, nothing happened! Is that a bug? Well, no. These interactive shells will exit after running any scripted commands, unless they are run in an interactive terminal - so for this example to not exit, you need to `docker run -it alpine /bin/sh`.
Expand All @@ -93,30 +99,33 @@ You are now inside the container shell and you can try out a few commands like `
Ok, now it's time to see the `docker ps` command. The `docker ps` command shows you all containers that are currently running.

```
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
docker ps
```
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES


Since no containers are running, you see a blank line. Let's try a more useful variant: `docker ps -a`

```
$ docker ps -a
docker ps -a
```
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
36171a5da744 alpine "/bin/sh" 5 minutes ago Exited (0) 2 minutes ago fervent_newton
a6a9d46d0b2f alpine "echo 'hello from alp" 6 minutes ago Exited (0) 6 minutes ago lonely_kilby
ff0a5c3750b9 alpine "ls -l" 8 minutes ago Exited (0) 8 minutes ago elated_ramanujan
c317d0a9e3d2 hello-world "/hello" 34 seconds ago Exited (0) 12 minutes ago stupefied_mcclintock
```


What you see above is a list of all containers that you ran. Notice that the `STATUS` column shows that these containers exited a few minutes ago. You're probably wondering if there is a way to run more than just one command in a container. Let's try that now:

```
$ docker run -it alpine /bin/sh
docker run -it alpine /bin/sh
```
/ # ls
bin dev etc home lib linuxrc media mnt proc root run sbin sys tmp usr var
/ # uname -a
Linux 97916e8cb5dc 4.4.27-moby #1 SMP Wed Oct 26 14:01:48 UTC 2016 x86_64 Linux
```

Running the `run` command with the `-it` flags attaches us to an interactive tty in the container. Now you can run as many commands in the container as you want. Take some time to run your favorite commands.

To find out more about `run`, use `docker run --help` to see a list of all flags it supports. As you proceed further, we'll see a few more variants of `docker run`.
Expand Down Expand Up @@ -154,7 +163,7 @@ In the last section, you saw a lot of Docker-specific jargon which might be conf
***Example Launching a container in detached mode***

```
$ docker run --name cname -e MYSQL_ROOT_PASSWORD=yourpassword -d mysql:tag
docker run --name cname -e MYSQL_ROOT_PASSWORD=yourpassword -d mysql:tag
```
In the above command:
Expand Down

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