(RADIATOR) HA Radiator under djb's daemontools

[Hugh Irvine]

Hi Mariano -

Many thanks as always!

cheers

Hugh


At 12:17 -0300 01/11/8, Mariano Absatz wrote:
>Hi,
>
>I'd like to share a "high availability" configuration I've been using whith
>Radiator for a couple of months. It uses a freely available software called
>"daemontools" (http://cr.yp.to/daemontools.html).
>
>These are a set of tools that make the life of a server programmer easier.
>They are tiny pieces of software very simple and each one does JUST ONE THING
>(in the old Unix fashion).
>
>They were developed by Dan J. Bernstein (http://cr.yp.to/djb.html) who I
>don't know personally, but, as evident from his messages in different mailing
>lists, suffers of an excess in personality. Nevertheless he's an excellent
>programmer and, if you don't try to argue with him, you can very happily use
>his software. He's mostly know as the developer of qmail
>(http://cr.yp.to/qmail.html) one of the good mail servers hanging around.
>
>Enough intro... given that you have daemontools installed
>(http://cr.yp.to/daemontools/install.html), you should have a /service
>directory and a "svscan /service" process running.
>
>Now you have to prepare a Radiator service directory. I use
>/app/Radiator/service, but you can use whatever you like.
>
>This directory must have a "run" script executable by root that replaces
>itself (via exec) with Radiator running in the foreground, like the following
>one:
>
>====================================================================
>#!/bin/sh
># script to start Radiator with daemontools
>#
>
>exec 2>&1
>
>exec /usr/bin/radiusd -config_file /etc/raddb/radius.cfg -foreground
>====================================================================
>
>
>Now, if you link -s this service directory to /service, svscan automatically
>starts "supervise" on this directory. eg:
>ln -s /app/Radiator/service /service/Radiator
>
>supervise, executes the run script and, if the server stops, waits a few
>seconds, and starts it again.... forever and ever.
>
>You also have a utility called svc to send signals to Radiator. If you say:
>svc -h /service/Radiator (-h = hangup)
>it would send a HUP signal.
>
>If you say:
>svc -t /service/Radiator (-t = terminate)
>it would send a TERM signal and, if the server stops (which Radiator would),
>it'll start it again (effectively equivalent to a stop/start cycle).
>
>If you say:
>svc -d /service/Radiator (-d = down)
>it would send a TERM signal but won't try to start it again.
>
>svc -u /service/Radiator (-u = up)
>will start Radiator again.
>
>You also have
>svstat /service/Radiator
>which will tell you if Radiator is up or down, how it should normally be and,
>if it's up, for how long it's been up.
>
>svok /service/Radiator
>exists silently, but gives you a return value indicating if Radiator is
>running or not, which you can use from inside a shell script.
>
>There are more options which I don't use, but you can check all of it in the
>daemontools on-line documentation.
>
>In fact, I personally have more than one instance of Radiator on the same
>machine (I have up to 4 in one), I created one service directory for each
>instance and link the all of them to /service.
>
>
>If you want, you can capture the standard output and standard error from
>Radiator (e.g. DBD usually sends error messages to stderr).
>
>You must create a subdirectory of your service directory named "log", and put
>there an executable script named "run" which would run a logger.
>
>daemontools include such a logger which is called multilog.
>
>My "run" script looks like these 2 lines:
>#!/bin/sh
>exec multilog t ./main
>
>this creates an auto-rotated log in /service/Radiator/log/main which includes
>every line sent by Radiator (or any included module) to standard output or
>standard error, preceded by a timestamp in tai format (see
>http://cr.yp.to/daemontools/tai64n.html).
>
>If I want to check this log I do the following
>tai64nlocal </service/Radiator/log/main/current | more
>
>If I want to follow this output:
>tail -f /service/Radiator/log/main/current | tai64nlocal
>
>(tai64nlocal is used to translate the tai timestamps into humanly readable
>local times)
>
>
>Hugh, Mike, if you want to add this explanation (however adapted) in the docs
>I don't have any problems (and I don't think Dan Bernstein would care either,
>see http://cr.yp.to/rights.html for his opinion on these kind of things).
>
>http://www.open.com.au/radiator/ref.html#pgfId=361565
>
>--
>Mariano Absatz
>El Baby
>----------------------------------------------------------
>My computer's sick. I think my modem is a carrier.
>
>
>===
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-- 

NB: I am travelling this week, so there may be delays in our correspondence.

Radiator: the most portable, flexible and configurable RADIUS server
anywhere. SQL, proxy, DBM, files, LDAP, NIS+, password, NT, Emerald,
Platypus, Freeside, Interbiller, TACACS+, PAM, external, etc, etc.
Available on Unix, Linux, FreeBSD, Windows 95/98/2000, NT, MacOS X.
===
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