jochen
e4d2868679
A module that holds the distribution's scrub timer for the pool the operator names
(zfs-scrub-weekly@<pool>.timer) cannot write the pool into its definition (hq ADR 0112). Settings were
substituted only into file content, so the unit reached the machine as
"zfs-scrub-weekly@${setting:scrub-pool}.timer", a unit no machine has, and the apply failed far from its
cause (second review of mesh-catalog #147).
A service's unit now takes ${setting:} from the same layers a file does, and is refused by key when
nothing sets it. A value is also refused unless it is only letters, digits, ':', '_', '.' and '-': the
name ends up in unit files and systemctl arguments, and a space, a slash or a newline must never reach
them. A key a unit asks for is not called stray.