Most of the data flows in Linux, including inter-process communication, sockets, etc., are implemented through file descriptors (fd) reading and writing. When troubleshooting, if you can peek at the fd traffic, many problems can be quickly proved/falsified. This article introduces an old tool peekfd, which can accomplish this task in a certain environment.

Understanding metrics from Linux ss command output

The normal HTTP request was responded with HTTP status code 400 after migrating to Istio. The problem traffic has HTTP headers that do not comply with the HTTP 1.1 specification. So I try to develop an Envoy WASM Network Filter to fix the illegal HTTP Header.