The contents of /etc/fstab is:
# stock fstab - you probably want to override this with a machine specific one
/dev/root / auto ro 1 0
proc /proc proc defaults 0 0
devpts /dev/pts devpts mode=0620,gid=5 0 0
tmpfs /run tmpfs mode=0755,nodev,nosuid,stri ctatime 0 0
tmpfs /var/volatile tmpfs defaults 0 0
# uncomment this if your device has a SD/MMC/Transflash slot
#/dev/mmcblk0p1 /media/card auto defaults,sync,noauto 0 0
The output of mount is:
proc on /proc type proc (rw,relatime)
sysfs on /sys type sysfs (rw,relatime)
devtmpfs on /dev type devtmpfs (rw,relatime,size=491368k,nr_inodes=122842,mode=7 55)
/dev/mmcblk0p2 on /mnt/sysroot/active type ext4 (rw,relatime,data=ordered)
/dev/mmcblk0p5 on /mnt/state type ext4 (rw,relatime,data=ordered)
/dev/mmcblk0p5 on /etc/machine-id type ext4 (rw,relatime,data=ordered)
/dev/mmcblk0p2 on /mnt/sysroot/active/balena/aufs type ext4 (rw,relatime,data=or dered)
none on / type aufs (ro,relatime,si=59b0f339,dio,dirperm1)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev)
devpts on /dev/pts type devpts (rw,relatime,gid=5,mode=620,ptmxmode=000)
tmpfs on /run type tmpfs (rw,nosuid,nodev,mode=755)
tmpfs on /sys/fs/cgroup type tmpfs (ro,nosuid,nodev,noexec,mode=755)
cgroup on /sys/fs/cgroup/unified type cgroup2 (rw,nosuid,nodev,noexec,relatime,n sdelegate)
cgroup on /sys/fs/cgroup/systemd type cgroup (rw,nosuid,nodev,noexec,relatime,xa ttr,name=systemd)
cgroup on /sys/fs/cgroup/blkio type cgroup (rw,nosuid,nodev,noexec,relatime,blki o)
cgroup on /sys/fs/cgroup/net_cls type cgroup (rw,nosuid,nodev,noexec,relatime,ne t_cls)
cgroup on /sys/fs/cgroup/cpu,cpuacct type cgroup (rw,nosuid,nodev,noexec,relatim e,cpu,cpuacct)
cgroup on /sys/fs/cgroup/cpuset type cgroup (rw,nosuid,nodev,noexec,relatime,cpu set)
cgroup on /sys/fs/cgroup/memory type cgroup (rw,nosuid,nodev,noexec,relatime,mem ory)
cgroup on /sys/fs/cgroup/freezer type cgroup (rw,nosuid,nodev,noexec,relatime,fr eezer)
cgroup on /sys/fs/cgroup/devices type cgroup (rw,nosuid,nodev,noexec,relatime,de vices)
tmpfs on /tmp type tmpfs (rw,nosuid,nodev)
mqueue on /dev/mqueue type mqueue (rw,relatime)
debugfs on /sys/kernel/debug type debugfs (rw,relatime)
/dev/mmcblk0p1 on /mnt/boot type vfat (rw,relatime,fmask=0022,dmask=0022,codepag e=437,iocharset=ascii,shortname=mixed,errors=remount-ro)
configfs on /sys/kernel/config type configfs (rw,relatime)
tmpfs on /var/volatile type tmpfs (rw,relatime)
tmpfs on /srv type tmpfs (rw,relatime)
tmpfs on /var/spool type tmpfs (rw,relatime)
tmpfs on /var/cache type tmpfs (rw,relatime)
tmpfs on /var/lib type tmpfs (rw,relatime)
/dev/mmcblk0p5 on /var/lib/NetworkManager type ext4 (rw,relatime,data=ordered)
/dev/mmcblk0p5 on /var/volatile/lib/NetworkManager type ext4 (rw,relatime,data=o rdered)
/dev/mmcblk0p5 on /etc/docker type ext4 (rw,relatime,data=ordered)
/dev/mmcblk0p5 on /home/root/.docker type ext4 (rw,relatime,data=ordered)
/dev/mmcblk0p5 on /etc/hostname type ext4 (rw,relatime,data=ordered)
/dev/mmcblk0p5 on /etc/NetworkManager/system-connections type ext4 (rw,relatime, data=ordered)
/dev/mmcblk0p5 on /etc/resin-supervisor type ext4 (rw,relatime,data=ordered)
/dev/mmcblk0p5 on /etc/openvpn type ext4 (rw,relatime,data=ordered)
/dev/mmcblk0p5 on /home/root/.ssh type ext4 (rw,relatime,data=ordered)
/dev/mmcblk0p5 on /home/root/.rnd type ext4 (rw,relatime,data=ordered)
/dev/mmcblk0p5 on /var/lib/chrony type ext4 (rw,relatime,data=ordered)
/dev/mmcblk0p5 on /var/volatile/lib/chrony type ext4 (rw,relatime,data=ordered)
/dev/mmcblk0p5 on /etc/dropbear type ext4 (rw,relatime,data=ordered)
/dev/mmcblk0p5 on /var/lib/systemd type ext4 (rw,relatime,data=ordered)
/dev/mmcblk0p5 on /var/volatile/lib/systemd type ext4 (rw,relatime,data=ordered)
/dev/mmcblk0p3 on /mnt/sysroot/inactive type ext4 (rw,relatime,data=ordered)
/dev/mmcblk0p6 on /mnt/data type ext4 (rw,relatime,data=ordered)
/dev/mmcblk0p6 on /resin-data type ext4 (rw,relatime,data=ordered)
/dev/mmcblk0p6 on /var/lib/docker type ext4 (rw,relatime,data=ordered)
/dev/mmcblk0p6 on /var/volatile/lib/docker type ext4 (rw,relatime,data=ordered)
Where does all that come from?