On centos 7, there are instances where you get the error Unable to register authentication agent: GDBus.Error:org.freedesktop.PolicyKit1.Error.Failed: Cannot determine user of subject
Error registering authentication agent: GDBus.Error:org.freedesktop.PolicyKit1.Error.Failed: Cannot determine user of subject (polkit-error-quark, 0)
How to fix this error.
groupadd -g 23 nohidproc
usermod -a -G nohidproc polkitd
mount -o remount,rw,hidepid=2,gid=nohidproc /proc
systemctl restart polkit
Add the following in /etc/fstab as well
echo "proc /proc proc defaults,hidepid=2,gid=nohidproc 0 0" >> /etc/fstab
After mount the new mountpoint and restart the service.
mount -a
systemctl restart polkit