Windows Grab-Bag: SIGTERM That Doesn't Exist and Sparse Files That Break Docker

Sat, 03 Oct 2026 14:30:00 -0700

Two short ones from the Windows node of ephemerd from the last few weeks. Neither is complicated once you know what’s going on. Both took longer than they should have to find, because the failure showed up a long way from the cause.

Part 1: there is no SIGTERM on Windows

ephemerd can run a Cloudflare tunnel so GitHub webhooks reach a node behind NAT. It does that by running cloudflared as a managed subprocess. On Linux the child is tied to ephemerd’s lifetime by the kernel with Pdeathsig:

Docker on Luther Monson

Windows Grab-Bag: SIGTERM That Doesn't Exist and Sparse Files That Break Docker

Part 1: there is no SIGTERM on Windows