/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.
The hosts-file writing moved to the node-names fact; what stays is the suffix
(configurable, MESH_INTERNAL_SUFFIX, defaulting to .internal which IANA reserved
for exactly this), a node's internal name, and the rule for what a node may be
called. Several things compose an internal name, and one of them writing the
suffix differently would be a name nothing answers to.
First attempt at this rewrote the file from memory and silently dropped the
configurable suffix. Restored from the original instead — deleting most of a
file is git surgery, not paraphrase.
Claude-Session: https://claude.ai/code/session_01D6qtiYU3P9jk3pnAXyAFyx
Step 5 of the connectivity order. Every node's internal name resolves to its
overlay address, on every node, computed centrally because it needs every node
at once.
Under `.internal`, which IANA reserved for exactly this in 2024 -- a name there
can never collide with a public one, so an internal name that leaks into a
public resolver fails rather than reaching a stranger's machine. The suffix is
settable for a mesh that wants its own.
Delivered in the same declaration as the peer list rather than a second one. A
node holding the peers and not the names, or the reverse, is half on the
network for as long as that lasts.
This is not the /etc/hosts floor the design removes. That floor existed because
a node had to reach the mesh's database before its own DNS worked -- a fallback
for a circularity that is now gone. This is the mechanism: the complete set of
names, generated whole and owned by the mesh, rather than a patch written
underneath something else. A resolver daemon becomes necessary when names are
wanted that are not one-per-node, and that is not yet true.
A node resolves its own name to its overlay address rather than a loopback,
because a service binding to the name it was given would otherwise listen
somewhere nothing else can reach -- and the failure would appear on every other
machine rather than that one.
A node with no address gets no name. A name resolving to nothing is worse than
no name: connecting to an address that does not answer hangs, where a name that
does not resolve fails at once and says which name it was.
Found while writing it: a test asserting every file in the declaration is mode
0600 would have forced /etc/hosts to 0600 and broken every lookup on the
machine, to protect a file that is not secret.
Verified in the lab: three machines, nine name lookups, each resolving to the
right overlay address and reaching it.
jochen
jschoubben