Operating system customization in an on-demand network code execution system

A computer-implemented method comprising:

• receiving user-submitted code executable on an on-demand code execution system;
• determining, based at least in part on the user-submitted code, a first set of operating system (“OS”) functionality associated with executing the user-submitted code on the on-demand code execution system;
• identifying, based at least in part on the first set of OS functionality associated with executing the user-submitted code, a first variant of a plurality of variants of an OS kernel to be used to provide the first set of OS functionality during execution of the user-submitted code, wherein individual variants of the plurality of variants provide different subsets of a set of OS functionality provided by the OS kernel;
• and
• in response to a request to execute the user-submitted code, executing the user-submitted code on a first virtual machine instance, the first virtual machine instance having the first variant of the OS kernel.

One or more non-transitory computer-readable media including computer-executable instructions that, when executed on an on-demand code execution system, cause the on-demand code execution system to:

• obtain user-submitted code executable on an on-demand code execution system;
• determine, based at least in part on the user-submitted code, a first subset of operating system (“OS”) functionality associated with executing the user-submitted code;
• identify, based at least in part on the first subset of OS functionality associated with executing the user-submitted code, a first variant of an OS kernel from a plurality of variants of the OS kernel to provide the first subset of the OS functionality during execution of the user-submitted code, wherein individual variants of the plurality of variants of the OS kernel provide different subsets of a set of OS functionality, and wherein the first variant of the OS kernel provides at least the first subset of OS functionality;
• and
• in response to a request to execute the user-submitted code, execute the user-submitted code on a first virtual machine instance having the first variant of the OS kernel.