How to reload udev rules without reboot?
Udev uses the inotify mechanism to watch for changes in the rules directory, in both the library and in the local configuration trees (typically located at /lib/udev/rules.d and /etc/udev/rules.d ). So most of the time you don’t need to do anything when you change a rules file.
You only need to notify the udev daemon explicitly if you’re doing something unusual, for example if you have a rule that includes files in another directory. Then you can use the usual convention for asking daemons to reload their configuration: send a SIGHUP ( pkill -HUP udevd ). Or you can use the udevadm command: udevadm control —reload-rules .
However, beware that different versions of udev have historically had different triggers for reloading the rules automatically. So if in doubt, call udevadm control —reload-rules : it won’t do any harm anyway.
The udev rules are only applied when a device is added. If you want to reapply the rules to a device that is already connected, you need to do this explicitly, by calling udevadm trigger with the right options to match the device(s) whose configuration has changed, e.g. udevadm trigger —attr-match=vendor=’Yoyodyne’ —attr-match=model=’Frobnicator 300′ .
Solution 3
I’m adding this because some day I will need it. again.
Sometimes you get an incorrect matching of ethernet device numbers and MAC addresses. Sometimes this is really important, like when running in a VM and each device is assigned to a different VLAN.
- Bring the network interfaces down, then
- modify /etc/udev/rules.d/70-persistent-net.rules (or its equivalent)
- re-load with udevadm control —reload-rules
- re-trigger with udevadm trigger —attr-match=subsystem=net
- bring the network interfaces up.
I was surprised how well this worked.
Solution 4
I am not sure if this applies, and this is definitely an older post but it came up pretty high my web search for udev info so I thought I might share some knowledge.
You can trigger udev rules manually for specific devices. This applies only to redhat-related distros (centos fedora etc etc etc)
Once you make the relevant changes in your rules file ( /etc/udev/rules.d/whateveryoucalledyourrules ), you can echo change in to the device’s uevent.
echo change > /sys/block/devname/partname1/uevent This will force a udev rule reading for ONLY this device. Much better, and more targeted in my opinion.
Solution 5
For me, below command sequence has worked as it is desired.
I have done modifications in /etc/udev/rules.d/70-persistent-net.rules to change the eth number and to reload them without rebooting.
/etc/init.d/networking stop /etc/init.d/udev stop udevadm control --reload-rules /etc/init.d/udev start /etc/init.d/networking start By following this, It was successfully loaded in run time without rebooting the machine.
Any suggestion or recommendations on this are welcome, as I have discovered this on my own by reading the man pages.
How to reload udev rules without reboot?
How should one reload udev rules, so that newly created one can function? I’m running Arch Linux, and I don’t have a udevstart command here. Also checked /etc/rc.d , no udev service there.
Please note that more recent versions of udev have dropped the inotify support so the reloading of the rules on change is needed more often these days.
8 Answers 8
# udevadm control --reload-rules && udevadm trigger @Nils Actually, you may need udevtrigger (or rather udevadm trigger on most distributions) instead (that, or plug the device out and back it). —reload-rules is almost always useless as it happens automatically.
udevtrigger or udevadm trigger did not work for me. I found some devices will work after unloading and loading the module for the same (assuming it is loadable module). What I found out is one does not necessarily have to reboot the system. Example for a network device, I do rmmod ixgbe , rmmod tg3 , rmmod e1000 then modprobe ixgbe , modprobe tg3 , modprobe e1000 depending on type of network driver.
I did have to sudo udevadm trigger after this, though removing the sudo didn’t show any error, I didn’t actually see any change until I ran it w/ sudo
Udev uses the inotify mechanism to watch for changes in the rules directory, in both the library and in the local configuration trees (typically located at /lib/udev/rules.d and /etc/udev/rules.d ). So most of the time you don’t need to do anything when you change a rules file.
You only need to notify the udev daemon explicitly if you’re doing something unusual, for example if you have a rule that includes files in another directory. Then you can use the usual convention for asking daemons to reload their configuration: send a SIGHUP ( pkill -HUP udevd ). Or you can use the udevadm command: udevadm control —reload-rules .
However, beware that different versions of udev have historically had different triggers for reloading the rules automatically. So if in doubt, call udevadm control —reload-rules : it won’t do any harm anyway.
The udev rules are only applied when a device is added. If you want to reapply the rules to a device that is already connected, you need to do this explicitly, by calling udevadm trigger with the right options to match the device(s) whose configuration has changed, e.g. udevadm trigger —attr-match=vendor=’Yoyodyne’ —attr-match=model=’Frobnicator 300′ .