bootc-usr-overlay - Adds a transient overlayfs on /usr that will be discarded
on reboot
bootc usr-overlay [OPTIONS...]
Adds a transient overlayfs on /usr that will be discarded on reboot. The
overlayfs is read/write by default.
A common pattern is wanting to use tracing/debugging tools, such as
strace that may not be in the base image. A system package manager
such as apt or dnf can apply changes into this transient overlay
that will be discarded on reboot.
However, this command has no effect on /etc and /var - changes
written there will persist. It is common for package installations to
modify these directories.
Almost always, a system process will hold a reference to the open mount
point. You can however invoke umount -l /usr to perform a "lazy
unmount".
--read-only
Mount the overlayfs as read-only. A read-only overlayfs is useful since it may be remounted as read/write in a private mount namespace and written to while the mount point remains read-only to the rest of the system