read-only file system in kubernetes environments

[horacimacias]

first of all, thanks for sharing!

I'm testing this in a kubernetes environment.
My pod uses secrets which I believe end up mounted in a readonly file system which makes the copy operation fail:

copying [36/39]: sbin
copying [37/39]: srv
copying [38/39]: usr
copying [39/39]: var
panic: Error response from daemon: Error processing tar file(exit status 1): remove /var/run/secrets/kubernetes.io/serviceaccount/..data: read-only file system

This is the 'df' output inside my pod:

# df
Filesystem           1K-blocks      Used Available Use% Mounted on
overlay              102044664  64268072  33513944  66% /
tmpfs                    65536         0     65536   0% /dev
tmpfs                  8132592         0   8132592   0% /sys/fs/cgroup
/dev/mapper/vg_os-lv_root
                     102044664  64268072  33513944  66% /dev/termination-log
/dev/mapper/vg_os-lv_root
                     102044664  64268072  33513944  66% /etc/resolv.conf
/dev/mapper/vg_os-lv_root
                     102044664  64268072  33513944  66% /etc/hostname
/dev/mapper/vg_os-lv_root
                     102044664  64268072  33513944  66% /etc/hosts
shm                      65536         0     65536   0% /dev/shm
tmpfs                  8132592        12   8132580   0% /var/run/secrets/kubernetes.io/serviceaccount
tmpfs                  8132592         0   8132592   0% /proc/acpi
tmpfs                    65536         0     65536   0% /proc/kcore
tmpfs                    65536         0     65536   0% /proc/keys
tmpfs                    65536         0     65536   0% /proc/timer_list
tmpfs                    65536         0     65536   0% /proc/timer_stats
tmpfs                    65536         0     65536   0% /proc/sched_debug
tmpfs                  8132592         0   8132592   0% /proc/scsi
tmpfs                  8132592         0   8132592   0% /sys/firmware

still, I'm lucky the other files (outside /var) have been successfully copied but may be worth to think about this edge case.