Mdev

mdev is the default device manager on Alpine Linux. It is provided by busybox as alternative to systemd's udev. mdev is not a drop in replacement for udev. See eudev for that instead. mdev lacks some features which makes it not recommended for a full blown desktop enviroment.

Installation

The easy way to setup mdev is throught the setup script. For custom installation see the manually section. Note that a manual installation is only recommended for advanced users.

Setup Script

The alpine-conf package privides setup-devd to easily install and setup device managers.

Install alpine-conf if it is not already installed.

# apk add alpine-conf

Setup mdev.

# setup-devd mdev

Manually

Mdev is provided by the busybox package which is pre installed on any alpine installation. To run mdev the OpenRC init scripts are required too. If it isn't already installed install it:

# apk add busybox-mdev-openrc

Note: If you already have a device manager installed you need to stop it before you start mdev.

Enable the mdev service.

# rc-update add mdev sysinit

# rc-update add hwdrivers sysinit

If you are not running in a chroot you will also want to start mdev.

# rc-service mdev start

# rc-service hwdrivers start

You might also want to take a look at libudev replacement if programms you want to use depend on udev.

Remove

Warning: Use Setup script to change device manager. Manual removal of a device manager without first setting up an alternative may cause unexpected issues.

First stop the service. This step can be skipped when you are running in a chroot.

# rc-service mdev stop

Then disable it.

# rc-update delete mdev sysinit

You might also want to uninstall the init scripts since they are not used anymore.

# apk del busybox-mdev-openrc

The mdev binary is part of the busybox package and therefor can't be uninstalled.

libudev replacement

libudev-zero provides udev apis but is independent from the device manager used. When installed it will make some udev reliant programms work with mdev. See What doesn't work.

Configuration

mdev reads /etc/mdev.conf and according to mdev documentation one can define a command to be executed per device definition.

Custom network interface name

The command nameif is used to change network interface name to set custom network interface name.

The file /etc/mdev.conf needs to be edited as follows:

Contents of /etc/mdev.conf

-SUBSYSTEM=net;DEVPATH=.*/net/.*;.* root:root 600 @/sbin/nameif -s

The above command tell mdev to call nameif for devices found in /sys/class/net/.

# ls -d -C -1 /sys/class/net/eth* /sys/class/net/eth1 /sys/class/net/eth2 /sys/class/net/eth3 /sys/class/net/eth4 /sys/class/net/eth5

To view hwaddr or mac address with interface name eth0, use the command

# cat /sys/class/net/eth0/address

The command nameif reads /etc/mactab by default. To set custom network interface name as dmz0 for hwaddr 90:e2:ba:04:28:c0, add an entry in the file /etc/mactab as follows:

Contents of /etc/mactab

dmz0 90:e2:ba:04:28:c0

Since /etc/mdev.conf is part of ramdisk, ramdisk rebuild is required. Issue the following command to configure:

# grep /etc/mdev.conf /etc/mkinitfs/features.d/*.files /etc/mkinitfs/features.d/base.files:/etc/mdev.conf

To rebuild ramdisk:

# mkinitfs $(ls /lib/modules/) ==> initramfs: creating /boot/initramfs-lts

To use renamed network interface without reboot, just call nameif while the network interface is down:

# nameif -s

USB Printer

See configure mdev for USB printers

Raspberry Pi Bluetooth Speaker

See Raspberry Pi Bluetooth Speaker

See Also

• Device Managers
• Gentoo wiki Mdev
• mdev doc
• mdev like a boss