Powers nodes on, off, or through a reset.
omf tell <command> -t <topology>
| Command | Does |
|---|---|
on |
power on |
off |
power off |
offs |
soft off — asks the OS to shut down |
offh |
hard off — cuts power immediately |
reset |
hard power-cycle |
reboot |
reboot |
offhis not listed byomf tell --help— the help shows
on/off/offs/reset/reboot— but it is accepted and widely used, and it is
what you want when a node is unresponsive. Verified on a console 2026-09-11:
omf tell offh -t <node>returnsReply: OK.
| Option | Meaning |
|---|---|
-t, --topology TOPO |
the node set |
-a, --command CMD |
the power command, if you prefer a flag to a positional |
--action CMD |
backward-compatible alias for -a |
-d, --domain / -v / --debug |
as for every command |
Both forms work:
omf tell on -t node1-1
omf tell -a on -t node1-1
omf tell on -t node1-1,node1-2 # power on
omf tell offs -t all # graceful shutdown of the sandbox
omf tell reset -t node1-1 # hard power-cycle one node
omf tell on -t system:topo:imaged # power on whatever was just imaged
Real output:
-----------------------------------------------
Node: node1-4.sb4.cosmos-lab.org Reply: OK
Node: node1-5.sb4.cosmos-lab.org Reply: OK
-----------------------------------------------
omf load leaves nodes OFF — you must power them onA load that ends "successfully imaged" has booted nothing:
omf load -t node1-1 -i baseline-sdr.ndz -r 0
omf tell on -t node1-1 # <- required
offh, wait, then onIf a node pings and SSH connects but key auth is refused, it is almost
certainly still in the PXE stage OS rather than your image. A power cycle
clears it:
omf tell offh -t node1-1
sleep 20
omf tell on -t node1-1
ssh root@node1-1 'cat /.omf-image-name' # verify
UniFi PoE and USP-PDU controllers have 20–60 s of control-plane latency. An
off immediately followed by on can be absorbed entirely, leaving the node
never actually power-cycled. Wait for the node to stop responding before
powering it back on, or use reset.
A related case, measured on a wedged USRP: a 45-second de-power was not
enough to re-enumerate a USB radio; 120 seconds was. If you are power-cycling
to recover attached hardware rather than the host, give it two minutes and
check that the device's USB address actually changed.
Power commands are destructive to somebody's work if that somebody is not you.
Before touching a node you did not just image, look:
ssh root@<node> 'uptime -p; who; ls -lt /root | head'
Recent logins, recent files, or a long uptime with activity all mean ask
first. And a node whose CM reports Unknown (UNREACHABLE) should not be sent
power commands at all — see stat.
Author(s): COSMOS team · Last verified: 2026-09-11 — options from omf tell --help; offh acceptance and the Reply: OK output verified live on the grid console · Tags: omf, user-guide, reference