Title: OpenBSD - golang web server in chroot
Tags: OpenBSD, golang, web, chroot
Updated: Nov 04, 2025 - 21:52:37

## Golang web server in chroot in OpenBSD

Create file web-server.go containing simple Golang web server example:

	package main

	import (
		"fmt"
		"log"
		"net/http"
	)

	func handler(w http.ResponseWriter, r *http.Request) {
		fmt.Fprintf(w, "Hello OpenBSD")
	}

	func main() {
		fmt.Printf("Starting server at localhost:8080")
		http.HandleFunc("/", handler)
		log.Fatal(http.ListenAndServe(":8080", nil))
	}

To simplify the things we can create fully static go binary so we don't
need to copy runtime libraries into chroot:

	$ env CGO_ENABLED=0 GOOS=openbsd GOARCH=amd64 \
	  go build -a -o web-server

Copy web-server binary into /var/www/bin:

	$ doas cp web-server /var/www/bin

Start server:

	$ doas chroot -u www -g www /var/www /bin/web-server

Test it in the browser:

	$ firefox http://localhost:8080

As a bonus you can try to run some benchmark and compare the result with
any other technology.  Here I'm using https://github.com/rakyll/hey

	Summary:
	  Total:        0.0312 secs
	  Slowest:      0.0197 secs
	  Fastest:      0.0002 secs
	  Average:      0.0062 secs
	  Requests/sec: 6415.9075
	  Total data:   1000 bytes
	  Size/request: 5 bytes

	Response time histogram:
	  0.000 [1]     |∎
	  0.002 [42]    |∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎
	  0.004 [63]    |∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎
	  0.006 [22]    |∎∎∎∎∎∎∎∎∎∎∎∎∎∎
	  0.008 [12]    |∎∎∎∎∎∎∎∎
	  0.010 [14]    |∎∎∎∎∎∎∎∎∎
	  0.012 [9]     |∎∎∎∎∎∎
	  0.014 [16]    |∎∎∎∎∎∎∎∎∎∎
	  0.016 [10]    |∎∎∎∎∎∎
	  0.018 [8]     |∎∎∎∎∎
	  0.020 [3]     |∎∎

	Latency distribution:
	  10% in 0.0012 secs
	  25% in 0.0025 secs
	  50% in 0.0040 secs
	  75% in 0.0096 secs
	  90% in 0.0143 secs
	  95% in 0.0161 secs
	  99% in 0.0194 secs

	Details (average, fastest, slowest):
	  DNS+dialup:    0.0013 secs, 0.0000 secs, 0.0088 secs
	  DNS-lookup:    0.0001 secs, 0.0000 secs, 0.0038 secs
	  req write:     0.0003 secs, 0.0000 secs, 0.0025 secs
	  resp wait:     0.0032 secs, 0.0002 secs, 0.0088 secs
	  resp read:     0.0001 secs, 0.0000 secs, 0.0021 secs

	Status code distribution:
	  [200] 200 responses