A cooperative is scheduling generator maintenance at an unmanned POP that will briefly cut power to a router. To avoid filesystem corruption, an engineer wants to gracefully halt the Junos OS before power is physically removed. Which command should be run first?
Select an answer to reveal the explanation.
Short Explanation
Pulling power on a running computer without shutting it down first risks corrupting whatever it was in the middle of writing. request system halt lets the router close everything down cleanly first, so the generator work can proceed without risking the filesystem.
Full Explanation
request system halt brings Junos to a cleanly stopped state — flushing buffers, unmounting filesystems, and stopping the software — so that someone else can then physically remove power without the corruption risk an abrupt, unplanned power loss would carry. That handoff is exactly the scenario here: the crew, not the router, is going to cut power. request system power-off also halts the OS first, but then additionally tries to remove power in software; that's redundant and even counterproductive when external power is about to be pulled anyway, and on many platforms it leaves the chassis unable to power back on by itself once power returns, requiring a manual or remote power cycle. request system reboot restarts the operating system and brings it back up on its own; it's the wrong tool because the goal is to stay halted through the generator work, not cycle back to a running state moments later. request system software validate <package> checks a candidate software package for compatibility and has nothing to do with shutdown procedures. A caveat specific to unmanned sites: with nobody on hand to press a power button afterward, confirm in advance whether remote power control exists to bring the router back once the maintenance window ends. A concrete check: watch for the halt message and console prompt confirming the OS has fully stopped before the generator crew proceeds to cut power.