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)
Solution:
First of all, run the command lines:
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 mounting the new mountpoint and restarting the service:
mount -a
systemctl restart polkit
This should be solved!
