VanLUG Email Archive
andrew@daviel.org
Thu, 9 Sep 1999 00:14:41 -0700 (PDT)
I have a watchdog circuit I built a couple of years ago
(http://vancouver-webpages.com/watchdog/), which may predate watchdog
support in the kernel.
I was probably getting ping-of-death or something with 1.1 kernel when I
built it - anyhow, the idea is to reset the system if it hangs without
someone having to push a button at 3am.
The basic problem is that if the watchdog triggers a reset the system
reboots with dirty filesystems, and can sometimes require "manual
intervention". I wondered if it was possible to bring up the network
etc. with a ramdisk or read-only filesystem, and maybe even httpd
in read-only mode, pending remote intervention. An attempt I made to
start sshd, inetd, network normally from this state left me able to ssh
out (not so useful) but not in, and I could ping and telnet but not start
a login process due to some problem with pseudo-terminals. No doubt the
"final solution" is to build a system with serial console available via
modem or serial port on a second system :-) ......
Actually, has anyone built a system that is supposed to recover itself -
monitor for system load, disk space, dead processes etc. and restart
things, reboot if desperate etc. - automatically ? I have made odd
moves in this direction but nothing really comprehensive.
Andrew Daviel
http://vancouver-webpages.com/andrew
Deniable unless digitally signed.
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