Disabling Userland Helper Scripts (`before-resync-target`)

In a purely LINSTOR®, or containerized environment such as Kubernetes, the userland helper scripts should be disabled by default. However, if you’re loading the kernel modules outside of the module loading containers, you will need to disable them.

You will almost always want to load the kernel modules by using the kernel-module-loader containers. However, there might occasionally be some requirement to load the kernel module either from source or by using LINBIT® RPM packages. If doing so, you will want to disable the default helper scripts (before-resync-target and after-resync-target). You can do this several ways.

Firstly, you can do this temporarily for testing by switching something with the /sys file system, or setting the option when you load the module.

# echo disabled > /sys/module/drbd/parameters/usermode_helper

# modprobe drbd usermode_helper=disabled

To make this change be permanent and persist through reboots you will need to create a /etc/modprobe.d/drbd.conf file. Create the file like the example below:

# in k8s environment we don't want `before-resync-helper` scripts

options drbd usermode_helper=disabled

⚠️ WARN: Creating the modeprobe.d file will not alone automatically load the DRBD module at boot. You still need to add the DRBD kernel module to /etc/modules.

Reviewed 2020/12/02 - DGT