On 5 Feb 2022, at 13:24, Trond Myklebust wrote:
On Sat, 2022-02-05 at 10:03 -0500, Benjamin Coddington wrote:
Hi all,
Is anyone using a udev(-like) implementation with
NETLINK_LISTEN_ALL_NSID?
It looks like that is at least necessary to allow the init namespaced
udev
to receive notifications on /sys/fs/nfs/net/nfs_client/identifier,
which
would be a pre-req to automatically uniquify in containers.
I'md interested since it will inform whether I need to send patches
to
systemd's udev, and potentially open the can of worms over there.
Yet its
not yet clear to me how an init namespaced udev process can write to
a netns
sysfs path.
Another option might be to create yet another daemon/tool that would
listen
specifically for these notifications. Ugh.
Ben
I don't understand. Why do you need a new daemon/tool?
I have the following entry in /etc/udev/rules.d:
[trondmy@leira ~]$ cat /etc/udev/rules.d/50-nfs4.rules
ACTION=="add" KERNEL=="nfs_client" ATTR{identifier}=="(null)"
PROGRAM="/usr/sbin/nfs4_uuid" ATTR{identifier}="%c"
...and a very simple script /usr/sbin/nfs4_uuid that reads as follows:
#!/bin/bash
#
if [ ! -f /etc/nfs4_uuid ]
then
uuid="$(uuidgen -r)"
echo -n ${uuid} > /etc/nfs4_uuid
else
uuid="$(cat /etc/nfs4_uuid)"
fi
echo ${uuid}
We're in the same place, but what I see is that when I create a new
network
namespace with:
ip netns add testnamespace
Everything in the kernel works up to the point where the userspace udevd
never gets a notification. I suspect thats because it hasn't used
NETLINK_LISTEN_ALL_NSID, so the kernel's skipping the notification in
do_one_broadcast().
If your udev is getting notified of new network namespaces and firing
that
rule each time, something's different between our setups, and I'd like
to
figure out what it might be.
Ben
