pfi-gx10 moved from desk Wi-Fi (10.100.10.226, VLAN 10) to the rack on
10.100.50.60 (nh3-servers, VLAN 50), reachable as pfi-gx10.nh3.internal.
The address is a DHCP RESERVATION on the UDM, not a host static. Operator
ruling during the move, and the better design: a host-side static works
until the box moves and is then a stale netplan file on a machine whose
address you no longer know. The pre-written playbook wrote a host static;
it is kept for its safety ordering and annotated as retired.
The port arrived on the native VLAN, not the server VLAN, so switch port 22
was repointed first. port_overrides is a whole-array PUT — two unrelated
overrides on ports 21 and 23 were read, preserved and written back, with the
original array backed up to a file before the change.
Wi-Fi stayed up as the escape hatch until the wired path was proven from
outside, and was downed last as its own step. The step worth keeping: while
Wi-Fi was up, traffic to nh3-dev still preferred wlP9s9 because that
interface sits directly on the userland subnet, so reachability proved
nothing about the wired path. `ping -I enP7s7` across the VLAN boundary is
what actually settled it before the hatch came down.
Target settled: nh3-servers VLAN 50, static 10.100.50.60. Clear of the four
existing statics and below the .150 DHCP pool where fleet statics live.
The playbook never leaves itself one path back. Wi-Fi stays up throughout while
the wired interface is configured beside it; the new address is verified from
outside before anything is torn down, and Wi-Fi teardown is explicitly a
separate later change. A botched netplan therefore costs a retry over Wi-Fi
rather than a trip to the rack — which is what substitutes for 'netplan try',
whose interactive rollback needs a TTY that elway cannot provide.
Two preconditions are asserted as steps rather than assumed: the interface must
have carrier (writing a static config for a dead NIC and reporting success is
the failure this avoids), and its MAC must match, since interface names can
renumber across kernels but MACs do not.
Requires nothing from the operator beyond racking the box. The wired NIC has a
distinct MAC from the Wi-Fi one, so the post-move address and switch port are
both discoverable from the UDM rather than needing to be relayed.
vh