How to set up docker and those things I'm going to skip.. But where you have a problem is after running it per the instructions you'll get:
Spring Application context has not been set
This is due to permissions on the directory you created on the host.. One way to fix this (among several) is:
docker run -u root -v /data/confluence:/var/atlassian/application-data/confluence atlassian/confluence-server chown -R daemon /var/atlassian/application-data/confluence
You could really do that various ways, we chose to explain it as run that, then remove it.
docker rm confluence
Now you'll want to create your "real" confluence docker machine:
docker run -v /data/confluence:/var/atlassian/application-data/confluence --name="confluence" -d -p 8090:8090 atlassian/confluence-server
I happen to be given this GUID, yours may vary, but now we're going to commit / store this as local/confluence:
docker commit c739c95265b1dc062c55923d88d54158af465328fe89c06b4bbe90b64278bc7b local/confluence
Lastly let's run it:
docker run -v /data/confluence:/var/atlassian/application-data/confluence --name="confluence" -d -p 8090:8090 local/confluence
Now you may ask why did I create it then delete it - Because I'm writing this both a) as a beginner in docker (i.e. so perhaps not great advice) - But my goal is b) I want these exact steps to work anytime / at any stage - People may break things moving between servers or when new versions come out - The create / delete doesn't really rely on having your existing docker effected if you run the new "docker run" to set the permissions..
There are numerous things that can go wrong with using a setup like this, but this is a very quick/easy way to evaluate Confluecne with a matter of minutes to get you up and running. Happy wiki-ing..