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Merge pull request #440 from rillig/we-you 

Replace "we" with "you", as per the style guide
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Misty Stanley-Jones 2016-11-07 14:51:32 -08:00 committed by GitHub
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engine/tutorials/dockerizing.md
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@ -62,7 +62,7 @@ In this example:
* `ubuntu` is the image you would like to run.
* `-t` flag assigns a pseudo-tty or terminal inside the new container.
* `-i` flag allows you to make an interactive connection by
grabbing the standard in (`STDIN`) of the container.
grabbing the standard input (`STDIN`) of the container.
* `/bin/bash` launches a Bash shell inside our container.
The container launches. We can see there is a
@ -192,7 +192,7 @@ ran an *interactive container* that ran in the foreground. You also ran a
about several Docker commands:
* `docker ps` - Lists containers.
* `docker logs` - Shows us the standard output of a container.
* `docker logs` - Shows the standard output of a container.
* `docker stop` - Stops running containers.
Now, you have the basis learn more about Docker and how to do some more advanced

173
engine/tutorials/usingdocker.md
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@ -3,22 +3,29 @@ redirect_from:
- /engine/userguide/containers/usingdocker/
description: Learn how to manage and operate Docker containers.
keywords:
- docker, the docker guide, documentation, docker.io, monitoring containers, docker top, docker inspect, docker port, ports, docker logs, log, Logs
- docker, the docker guide, documentation, docker.io, monitoring containers,
docker top, docker inspect, docker port, ports, docker logs, log, logs
menu:
main:
parent: engine_learn_menu
weight: -5
title: Run a simple application
---
In the ["*Hello world in a container*"](dockerizing.md) you launched your
first containers using the `docker run` command. You ran an *interactive container* that ran in the foreground. You also ran a *detached container* that ran in the background. In the process you learned about several Docker commands:
# Run a simple application
In the ["*Hello world in a container*"](dockerizing.md) you launched your first
containers using the `docker run` command. You ran an *interactive container*
that ran in the foreground. You also ran a *detached container* that ran in the
background. In the process you learned about several Docker commands:
* `docker ps` - Lists containers.
* `docker logs` - Shows us the standard output of a container.
* `docker logs` - Shows the standard output of a container.
* `docker stop` - Stops running containers.
## Learn about the Docker client
If you didn't realize it yet, you've been using the Docker client each time you
typed `docker` in your Bash terminal. The client is a simple command line client
also known as a command-line interface (CLI). Each action you can take with
The `docker` program is called the Docker client. Each action you can take with
the client is a command and each command can take a series of flags and arguments.
# Usage: [sudo] docker [subcommand] [flags] [arguments] ..
@ -35,20 +42,20 @@ daemon you are using, but also the version of Go (the programming
language powering Docker).
Client:
Version: 1.8.1
API version: 1.20
Go version: go1.4.2
Git commit: d12ea79
Built: Thu Aug 13 02:35:49 UTC 2015
OS/Arch: linux/amd64
Version: 1.12.2
API version: 1.24
Go version: go1.6.3
Git commit: bb80604
Built: Tue Oct 11 17:00:50 2016
OS/Arch: windows/amd64
Server:
Version: 1.8.1
API version: 1.20
Go version: go1.4.2
Git commit: d12ea79
Built: Thu Aug 13 02:35:49 UTC 2015
OS/Arch: linux/amd64
Version: 1.12.3
API version: 1.24
Go version: go1.6.3
Git commit: 6b644ec
Built: Wed Oct 26 23:26:11 2016
OS/Arch: linux/amd64
## Get Docker command help
@ -76,36 +83,34 @@ To see usage for a specific command, specify the command with the `--help` flag:
> For further details and examples of each command, see the
> [command reference](../reference/commandline/cli.md) in this guide.
## Running a web application in Docker
## Run a web application in Docker
So now you've learned a bit more about the `docker` client you can move onto
Now that you've learned a bit more about the Docker client, you can move onto
the important stuff: running more containers. So far none of the
containers you've run did anything particularly useful, so you can
change that by running an example web application in Docker.
For our web application we're going to run a Python Flask application.
For the web application you're going to run a Python Flask application.
Start with a `docker run` command.
$ docker run -d -P training/webapp python app.py
Review what the command did. You've specified two flags: `-d` and
`-P`. You've already seen the `-d` flag which tells Docker to run the
container in the background. The `-P` flag is new and tells Docker to
map any required network ports inside our container to our host. This
lets us view our web application.
This command consists of the following parts:
You've specified an image: `training/webapp`. This image is a
pre-built image you've created that contains a simple Python Flask web
application.
Lastly, you've specified a command for our container to run: `python app.py`. This launches our web application.
* The `-d` flag runs the container in the background (as a so-called daemon).
* The `-P` flag maps any required network ports inside the container to your
host. This lets you view the web application.
* The `training/webapp` image is a pre-built image that contains a simple Python
Flask web application.
* The remaining arguments make up the command that is run inside
the container. The `python app.py` command launches the web application.
> **Note:**
> You can see more detail on the `docker run` command in the [command
> reference](../reference/commandline/run.md) and the [Docker Run
> Reference](../reference/run.md).
> You can see more detail on the `docker run` command
> in the [command reference](../reference/commandline/run.md)
> and the [docker run reference](../reference/run.md).
## Viewing our web application container
## View the web application container
Now you can see your running container using the `docker ps` command.
@ -114,72 +119,69 @@ Now you can see your running container using the `docker ps` command.
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
bc533791f3f5 training/webapp:latest python app.py 5 seconds ago Up 2 seconds 0.0.0.0:49155->5000/tcp nostalgic_morse
You can see you've specified a new flag, `-l`, for the `docker ps`
command. This tells the `docker ps` command to return the details of the
*last* container started.
The `-l` flag shows only the details of the *last* container started.
> **Note:**
> By default, the `docker ps` command only shows information about running
> containers. If you want to see stopped containers too use the `-a` flag.
> containers. If you want to see stopped containers too, use the `-a` flag.
We can see the same details we saw [when we first Dockerized a
container](dockerizing.md) with one important addition in the `PORTS`
You can see the same details you saw [when you first dockerized a
container](dockerizing.md), with one important addition in the `PORTS`
column.
PORTS
0.0.0.0:49155->5000/tcp
When we passed the `-P` flag to the `docker run` command Docker mapped any
ports exposed in our image to our host.
When you passed the `-P` flag to the `docker run` command,
Docker mapped any ports exposed in the container to your host.
> **Note:**
> We'll learn more about how to expose ports in Docker images when
> [we learn how to build images](dockerimages.md).
> You'll learn more about how to expose ports in Docker images when
> [you learn how to build images](dockerimages.md).
In this case Docker has exposed port 5000 (the default Python Flask
port) on port 49155.
Network port bindings are very configurable in Docker. In our last example the
Network port bindings are very configurable in Docker. In the last example the
`-P` flag is a shortcut for `-p 5000` that maps port 5000 inside the container
to a high port (from *ephemeral port range* which typically ranges from 32768
to 61000) on the local Docker host. We can also bind Docker containers to
to 61000) on the local Docker host. You can also bind Docker containers to
specific ports using the `-p` flag, for example:
$ docker run -d -p 80:5000 training/webapp python app.py
This would map port 5000 inside our container to port 80 on our local
This would map port 5000 inside your container to port 80 on your local
host. You might be asking about now: why wouldn't we just want to always
use 1:1 port mappings in Docker containers rather than mapping to high
ports? Well 1:1 mappings have the constraint of only being able to map
ports? Well, 1:1 mappings have the constraint of only being able to map
one of each port on your local host.
Suppose you want to test two Python applications: both bound to port 5000 inside
their own containers. Without Docker's port mapping you could only access one at
a time on the Docker host.
So you can now browse to port 49155 in a web browser to
see the application.
So you can now browse to port 49155 in a web browser to see the application.
![Viewing the web application](webapp1.png).
![Screenshot of the running web application](webapp1.png).
Our Python application is live!
Your Python web application is live!
> **Note:**
> If you have been using a virtual machine on macOS, Windows or Linux,
> you'll need to get the IP of the virtual host instead of using localhost.
> You can do this by running the `docker-machine ip your_vm_name` from your command line or terminal application, for example:
> You can do this by running `docker-machine ip` from the command line:
>
> $ docker-machine ip my-docker-vm
> $ docker-machine ip
> 192.168.99.100
>
> In this case you'd browse to `http://192.168.99.100:49155` for the above example.
## A network port shortcut
Using the `docker ps` command to return the mapped port is a bit clumsy so
Docker has a useful shortcut we can use: `docker port`. To use `docker port` we
specify the ID or name of our container and then the port for which we need the
corresponding public-facing port.
Using the `docker ps` command to return the mapped port is a bit clumsy,
so Docker has a useful shortcut you can use: `docker port`.
To use `docker port`, specify the ID or name of your container and then
the port for which you need the corresponding public-facing port.
$ docker port nostalgic_morse 5000
@ -188,25 +190,24 @@ corresponding public-facing port.
In this case you've looked up what port is mapped externally to port 5000 inside
the container.
## Viewing the web application's logs
## View the web application's logs
You can also find out a bit more about what's happening with our application and
use another of the commands you've learned, `docker logs`.
You can also find out a bit more about what's happening with your
application and use another of the commands you've learned, `docker logs`.
$ docker logs -f nostalgic_morse
* Running on http://0.0.0.0:5000/
10.0.2.2 - - [23/May/2014 20:16:31] "GET / HTTP/1.1" 200 -
10.0.2.2 - - [23/May/2014 20:16:31] "GET /favicon.ico HTTP/1.1" 404 -
10.0.2.2 - - [06/Nov/2016 20:16:31] "GET / HTTP/1.1" 200 -
10.0.2.2 - - [06/Nov/2016 20:16:31] "GET /favicon.ico HTTP/1.1" 404 -
This time though you've added a new flag, `-f`. This causes the `docker
logs` command to act like the `tail -f` command and watch the
container's standard out. We can see here the logs from Flask showing
the application running on port 5000 and the access log entries for it.
The `-f` flag causes the `docker logs` command to act like the `tail -f` command
and watch the container's standard output. You can see here the logs from Flask
showing the application running on port 5000 and the access log entries for it.
## Looking at our web application container's processes
## Look at the web application container's processes
In addition to the container's logs we can also examine the processes
In addition to the container's logs you can also examine the processes
running inside it using the `docker top` command.
$ docker top nostalgic_morse
@ -214,12 +215,12 @@ running inside it using the `docker top` command.
PID USER COMMAND
854 root python app.py
Here we can see our `python app.py` command is the only process running inside
the container.
Here you can see that the `python app.py` command is the only process
running inside the container.
## Inspecting our web application container
## Inspect the web application container
Lastly, we can take a low-level dive into our Docker container using the
Lastly, you can take a low-level dive into the Docker container using the
`docker inspect` command. It returns a JSON document containing useful
configuration and status information for the specified container.
@ -240,8 +241,8 @@ You can see a sample of that JSON output.
"User": "",
. . .
We can also narrow down the information we want to return by requesting a
specific element, for example to return the container's IP address we would:
You can also narrow down the information you want to return by requesting a
specific element, for example to return the container's IP address, you would:
{% raw %}
$ docker inspect -f '{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' nostalgic_morse
@ -249,21 +250,21 @@ specific element, for example to return the container's IP address we would:
172.17.0.5
## Stopping our web application container
## Stop the web application container
Okay you've seen web application working. Now you can stop it using the
`docker stop` command and the name of our container: `nostalgic_morse`.
The web application is still running inside the container. You can stop it using
the `docker stop` command and the name of the container: `nostalgic_morse`.
$ docker stop nostalgic_morse
nostalgic_morse
We can now use the `docker ps` command to check if the container has
You can now use the `docker ps` command to check if the container has
been stopped.
$ docker ps -l
## Restarting our web application container
## Restart the web application container
Oops! Just after you stopped the container you get a call to say another
developer needs the container back. From here you have two choices: you
@ -282,7 +283,7 @@ responds.
> Also available is the `docker restart` command that runs a stop and
> then start on the container.
## Removing our web application container
## Remove the web application container
Your colleague has let you know that they've now finished with the container
and won't need it again. Now, you can remove it using the `docker rm` command.
@ -292,7 +293,7 @@ and won't need it again. Now, you can remove it using the `docker rm` command.
Error: Impossible to remove a running container, please stop it first or use -f
2014/05/24 08:12:56 Error: failed to remove one or more containers
What happened? We can't actually remove a running container. This protects
What happened? You can't actually remove a running container. This protects
you from accidentally removing a running container you might need. You can try
this again by stopping the container first.
@ -304,7 +305,7 @@ this again by stopping the container first.
nostalgic_morse
And now our container is stopped and deleted.
And now the container is stopped and deleted.
> **Note:**
> Always remember that removing a container is final!
@ -312,6 +313,6 @@ And now our container is stopped and deleted.
# Next steps
Until now you've only used images that you've downloaded from Docker Hub. Next,
you can get introduced to building and sharing our own images.
you can get introduced to building and sharing your own images.
Go to [Working with Docker Images](dockerimages.md).