You have to identify the components/programs/libraries of an Odoo server and install them yourself.
First of all Odoo uses PostgreSQL as its DBMS. I do not think that PostgreSQL has been ported to Android. But I do know that it is written in C and you can compile it with android NDK tool-chain. Thing is that you have to see which libraries (dependencies) does postgres have.
https://groups.google.com/forum/#!topic/pgandroid/STg8xObGFlo
Second Odoo business logic is written in Python. You therefore need to install a Python interpreter to your Android device. A quick search gave this:
Python Interpreter on Android
Third you have to identify which Python modules does Odoo use beside its own (ie. libraries that are managed and installed by PyPA on a desktop machine). Some of which are these:
http://pastebin.com/2cju5BRA
These three are the gist, but many other issues could arise later on even if you do manage to get all the libraries (they are too many, trust me).
Odoo is a resource intensive kind of application (reads/writes on the database for almost every action possible.
Conclusion: For educational purposes I would do it. So that I can learn from it. But I believe that the time you will save by having your server on the android device will definitely outweigh the time you will waste porting the whole thing to android.