Ensure that br_netfilter module is loaded

README.md

@@ -199,6 +199,7 @@ Documentation=https://k3s.io
 After=network.target
 
 [Service]
+ExecStartPre=-/sbin/modprobe br_netfilter
 ExecStartPre=-/sbin/modprobe overlay
 ExecStart=/usr/local/bin/k3s server
 KillMode=process

k3s.service

@@ -4,6 +4,7 @@ Documentation=https://k3s.io
 After=network.target
 
 [Service]
+ExecStartPre=-/sbin/modprobe br_netfilter
 ExecStartPre=-/sbin/modprobe overlay
 ExecStart=/usr/local/bin/k3s server
 KillMode=process

pkg/agent/syssetup/setup.go

@@ -2,6 +2,7 @@ package syssetup
 
 import (
 	"io/ioutil"
+	"os/exec"
 
 	"github.com/sirupsen/logrus"
 )
@@ -11,6 +12,7 @@ var (
 )
 
 func Configure() error {
+	exec.Command("modprobe", "br_netfilter").Run()
 	if err := ioutil.WriteFile(callIPTablesFile, []byte("1"), 0640); err != nil {
 		logrus.Warnf("failed to write value 1 at %s: %v", callIPTablesFile, err)
 	}