94 lines
2.5 KiB
ReStructuredText
94 lines
2.5 KiB
ReStructuredText
:title: Hello world daemon example
|
|
:description: A simple hello world daemon example with Docker
|
|
:keywords: docker, example, hello world, daemon
|
|
|
|
.. _hello_world_daemon:
|
|
|
|
Hello World Daemon
|
|
==================
|
|
|
|
.. include:: example_header.inc
|
|
|
|
The most boring daemon ever written.
|
|
|
|
This example assumes you have Docker installed and with the Ubuntu
|
|
image already imported ``docker pull ubuntu``. We will use the Ubuntu
|
|
image to run a simple hello world daemon that will just print hello
|
|
world to standard out every second. It will continue to do this until
|
|
we stop it.
|
|
|
|
**Steps:**
|
|
|
|
.. code-block:: bash
|
|
|
|
CONTAINER_ID=$(sudo docker run -d ubuntu /bin/sh -c "while true; do echo hello world; sleep 1; done")
|
|
|
|
We are going to run a simple hello world daemon in a new container
|
|
made from the *ubuntu* image.
|
|
|
|
- **"docker run -d "** run a command in a new container. We pass "-d"
|
|
so it runs as a daemon.
|
|
- **"ubuntu"** is the image we want to run the command inside of.
|
|
- **"/bin/sh -c"** is the command we want to run in the container
|
|
- **"while true; do echo hello world; sleep 1; done"** is the mini
|
|
script we want to run, that will just print hello world once a
|
|
second until we stop it.
|
|
- **$CONTAINER_ID** the output of the run command will return a
|
|
container id, we can use in future commands to see what is going on
|
|
with this process.
|
|
|
|
.. code-block:: bash
|
|
|
|
sudo docker logs $CONTAINER_ID
|
|
|
|
Check the logs make sure it is working correctly.
|
|
|
|
- **"docker logs**" This will return the logs for a container
|
|
- **$CONTAINER_ID** The Id of the container we want the logs for.
|
|
|
|
.. code-block:: bash
|
|
|
|
sudo docker attach $CONTAINER_ID
|
|
|
|
Attach to the container to see the results in realtime.
|
|
|
|
- **"docker attach**" This will allow us to attach to a background
|
|
process to see what is going on.
|
|
- **$CONTAINER_ID** The Id of the container we want to attach too.
|
|
|
|
.. code-block:: bash
|
|
|
|
sudo docker ps
|
|
|
|
Check the process list to make sure it is running.
|
|
|
|
- **"docker ps"** this shows all running process managed by docker
|
|
|
|
.. code-block:: bash
|
|
|
|
sudo docker stop $CONTAINER_ID
|
|
|
|
Stop the container, since we don't need it anymore.
|
|
|
|
- **"docker stop"** This stops a container
|
|
- **$CONTAINER_ID** The Id of the container we want to stop.
|
|
|
|
.. code-block:: bash
|
|
|
|
sudo docker ps
|
|
|
|
Make sure it is really stopped.
|
|
|
|
|
|
**Video:**
|
|
|
|
See the example in action
|
|
|
|
.. raw:: html
|
|
|
|
<div style="margin-top:10px;">
|
|
<iframe width="560" height="350" src="http://ascii.io/a/2562/raw" frameborder="0"></iframe>
|
|
</div>
|
|
|
|
Continue to the :ref:`python_web_app` example.
|