README: document that max_bonds=0 is the way to go for bonding.ko

Everything else just is annoying, hence let's list this among the
requirements we make on the kernel in order to minimize confusion
leading to #6184 and suchlike.

diff --git a/README b/README
index 2bf8bdc92097220c2c9aadc0d7b02d186631eca3..5ae581e338c73c7e585f5bf4b9874adf42ce97cd 100644 (file)
--- a/README
+++ b/README
@@ -107,6 +107,15 @@ REQUIREMENTS:
         fixed, and it's best to disable group scheduling hence.
            CONFIG_RT_GROUP_SCHED=n
 
+        It's a good idea to disable the implicit creation of networking bonding
+        devices by the kernel networking bonding module, so that the
+        automatically created "bond0" interface doesn't conflict with any such
+        device created by systemd-networkd (or other tools). Please make sure
+        that the kernel module bonding.ko is shipped with max_bonds=0 set by
+        default. Ideally there would be a kernel compile-time option for this,
+        but there currently isn't. The next best thing is to make this change
+        through a modprobe.d drop-in.
+
         Note that kernel auditing is broken when used with systemd's
         container code. When using systemd in conjunction with
         containers, please make sure to either turn off auditing at