[pifm_guy]

You should also design all your code to be rollbackable... But for the very rare case that a rollback won't solve the problem (eg. An outage is caused by changes outside your organisation's control), you also need to be able to do a rapid code change, recompile and push. Many companies aren't able to do this for example their release process involves multiple days worth of interlocked manual steps.

Don't get yourself in that position.