Importing arcpy explicitly from an ArcGIS Server install

I had an Amazon EC2 instance with ArcGIS for Server. This server also had ArcGIS for Desktop on it, but no licensing for Desktop anymore. I had tested some Python scripts while it had a Desktop license, but after the Desktop license was gone, my scripts were failing with no module named arcpy errors.

After some Googling, I ran across this Esri KB article. You can get all of the gory details in the KB article, but the gist of it is that the .py extension gets associated with whichever version of Python was installed last - in my case it was 32-bit Python with the Desktop install. So, when I was no longer licensed for Desktop and ran my script, 32-bit Python ran, but it couldn't import arcpy.

The simple solution here is to explicitly call the 64-bit version of Python that installs with ArcGIS for Server, like so:

C:\Users\Administrator>c:\PYTHON27\ArcGISx6410.3\python.exe
Python 2.7.8 (default, Jun 30 2014, 16:08:48) [MSC v.1500 64 bit (AMD64)] on win
32
Type "help", "copyright", "credits" or "license" for more information.
>>> import arcpy
>>>
Written on September 26, 2015