While doing research on Kubernetes, I was getting tired of running the same nginx server with no pizzazz, so I set up a couple of simple apps to make things more interesting.
I decided to modify nginx to display different colors for each instance: Red and Blue. For each instance I did similar steps
mkdir red && cd red
echo Red > index.html
echo 'FROM nginx
COPY index.html /usr/share/nginx/html' > Dockerfile
sudo docker build .
Successfully built 7bb6d362f021
Now that we have an image, let’s tag it and send it to our local docker registry.
sudo docker tag 7bb6d362f021 localhost:5000/red
This results in a new image on our registry
sudo docker images |grep red
localhost:5000/red latest 7bb6d362f021 2 minutes ago 109MB
And run it with docker
$ docker run -d -p 8085:80 localhost:5000/red
$ curl localhost:8085
In general, when converting an application to using docker, we:
- Get a (simple) working version of the application
- Create a new docker image that starts with a known-good base and adds application specifics.
- Repeat steps 2 and 3
- Publish to a docker registry.