exercise-2: docker troubleshooting (#196)

Description of exercise-2.
The idea of this exercise is to teach some docker related things, and have students trouble-shoot it.

website/content/workbooks/workbook-8.md

@@ -18,7 +18,28 @@ weight=3
 - [ ] [Batch processing](../../projects/batch-processing)
 - [ ] [Buggy app](../../projects/buggy-app)
 - [ ] [Memcached Clusters](../../projects/memcached-clusters)
-- [ ] [Troubleshooting project #2](https://docs.google.com/document/d/1V6HEu_OcJ3MHH-aHzUfANf06VJa1rPcGHcpBwql7QLA/edit#heading=h.cjnguaxmynan) TOADD
+- [ ] Troubleshooting project #2
+    - This project is designed to get you familiar with docker.
+    - To log in: `ssh -i </path/to/the/ssh-private-key> <username>@<IP>`
+        - You have sudo access on the host, please give a shout if that doesn't work. (You'll need it.)
+        - There's a database (mysql) on the machine. If you have a mysql client, you can use `--host=127.0.0.1 --port=3306 --user=root --password` to log in.
+          (Ask any of the instructors for the password.)
+    - The goal of the exercise is:
+        - when you run `lynx -dump http://localhost/`, you will see a cute image of a cat on your terminal.
+          This shouldn't take more than a day or 2.
+        - secondary, once you've reached that, we'll ask you to hide the password that you can see in `ps auxww | grep miauw`.
+          (A password visible in `ps` is bad for security, so we want that to be somewhat hidden.)
+        - Along the way, we expect you'll be able to answer:
+            - How is systemd configured? Where are the logs?
+            - Can you describe what docker does?
+            - Can you describe the two ways that docker volumes are used in this setup?
+            - Docker uses images. What are images? And how do you create your own?
+    - Some knowledge to get you started:
+        - The webserver is called `httpurr`, with a corresponding systemd service (`httpurr`).
+          It's written in go, and you can see the source code in `/httpurr/`.
+        - The database is mysql, with a corresponding systemd service (`httpurr-db`).
+        - Both are run inside docker.
+    - While doing this exercise, I would recommend logging what you do.
 
 ## Product