"open /compat/linux/proc: no such file or directory" error on FreeBSD

The system metricsets rely on a Linux compatibility layer to retrieve metrics on FreeBSD. You need to mount the Linux procfs filesystem using the following commands. You may want to add these filesystems to your /etc/fstab so they are mounted automatically.

sudo mount -t procfs proc /proc
sudo mkdir -p /compat/linux/proc
sudo mount -t linprocfs /dev/null /compat/linux/proc