3 Aug 2013 mikal   » (Journeyer)

Exploring a single database migration

Yesterday I was having some troubles with a database migration download step, and a Joshua Hesketh suggested I step through the migrations one at a time and see what they were doing to my sqlite test database. That's a great idea, but it wasn't immediately obvious to me how to do it. Now that I've figured out the steps required, I thought I'd document them here.

First off we need a test environment. I'm hacking on nova at the moment, and tend to build throw away test environments in the cloud because its cheap and easy. So, I created a new Ubuntu 12.04 server instance in Rackspace's Sydney data center, and then configured it like this:

    $ sudo apt-get update
    $ sudo apt-get install -y git python-pip git-review libxml2-dev libxml2-utils
    libxslt-dev libmysqlclient-dev pep8 postgresql-server-dev-9.1 python2.7-dev
    python-coverage python-netaddr python-mysqldb python-git virtualenvwrapper
    python-numpy virtualenvwrapper sqlite3
    $ source /etc/bash_completion.d/virtualenvwrapper
    $ mkvirtualenv migrate_204
    $ toggleglobalsitepackages

    Simple! I should note here that we probably don't need the virtualenv because this machine is disposable, but its still a good habit to be in. Now I need to fetch the code I am testing. In this case its from my personal fork of nova, and the git location to fetch will obviously change for other people:

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