/etc/hosts is the machine's: the distribution's localhost lines, the
operator's own entries, and marked blocks other tools maintain there.
Writing node-names whole replaced all of it the moment the private
network was taken, and every later write by those tools was lost at
the next machine joining. The node-names fact is now emitted with
into: "block", so the host owns only its marked region and keeps the
rest byte for byte. The region holds only the mesh's names: no header
claiming the file, no localhost, no 127.0.1.1 line — the floor was
never the mesh's to write. How a fact is written is a property of the
fact in the closed table; node-zones stays a whole file the mesh owns.
Sequencing: a host older than the block mode refuses the whole
declaration on an unknown into, so every host must be upgraded before
this controller is rolled out.
jochen
51163b9f14