Re: [Zope3-dev] Is there an alternative to zdaemon?
Jim Fulton wrote at 2006-12-22 15:55 -0500: Thoughts? We are using zdaemon widely and would be sad to loose it. The underdocumented argument is unjustified in my view: * zdaemon comes with reasonable online documentation (the help command) * like for all zconfig based programs, essential documentation can be found in the schema file. As the configuration options have been carefully documented (also quite common for zconfig based programs), this is sufficient documentation for the configuration. * There are other forms of documentation than testable documentation (aka doctests). -- Dieter ___ Zope3-dev mailing list Zope3-dev@zope.org Unsub: http://mail.zope.org/mailman/options/zope3-dev/archive%40mail-archive.com
[Zope3-dev] Is there an alternative to zdaemon?
Yesterday I started working on some updates to zdaemon. zdaemon is pretty cool. It is a Unix-only tool that: - Turns an arbitrary program into a fairly well-behaved daemon - Provides management of an applications output as a log file. - Provides start, stop and restart commands for starting or stopping applications. - Provides a status command for finding out if an app is running. - Provides a kill command for sending an app a signal (e.g. for log rotation). - Automatically restarts applications that exit abnormally, with a fairly reasonable approach for limiting restart attempts in case something is failing on startup. - Provides a number of useful configuration settings that can be managed using a clean (ZConfig-based) log file. It is written in Python, but it can control any program. We're using it to control spread, which is a C program. spread comes with it's own Red Hat startup script, but spread fails to detach from the controlling terminal. zdaemon makes it behave properly and provides a startup script that will work on any Unix-like system. It has 2 major disadvantages: - It is ours. :) We are bearing the burden of maintaining it. This is offset by the fact that it hasn't required much maintenance. - It is largely undocumented. This makes it much harder to use than it needs to be. It also makes it under appreciated. I made a start at fixing this yesterday: http://svn.zope.org/zdaemon/trunk/src/zdaemon/README.txt?view=auto It isn't very hard to use, so documenting it isn't really all that hard. I wonder if we should be using some other daemon manager. Arguably, there's no reason for the Zope project to maintain one if something is available that does what we need. Does anyone know of something that does what zdaemon does? daemontools seems somewhat close: http://cr.yp.to/daemontools.html Going from the documentation, it doesn't seem to be as clever about application restart. The documentation says nothing about distinguishing between normal and abnormal restarts or avoiding useless restarts when there are start-up errors. If we do continue to maintain zdaemon, we really should publicize it more widely, both to get credit and to get more people interested in maintaining it. Because I want the enhancements I'm making for another project I'm working on, I'm going to proceed with them for now. Thoughts? Jim -- Jim Fulton mailto:[EMAIL PROTECTED] Python Powered! CTO (540) 361-1714http://www.python.org Zope Corporation http://www.zope.com http://www.zope.org ___ Zope3-dev mailing list Zope3-dev@zope.org Unsub: http://mail.zope.org/mailman/options/zope3-dev/archive%40mail-archive.com
Re: [Zope3-dev] Is there an alternative to zdaemon?
Am Freitag, 22. Dezember 2006 21:55 schrieb Jim Fulton: Does anyone know of something that does what zdaemon does? daemontools seems somewhat close: http://cr.yp.to/daemontools.html Going from the documentation, it doesn't seem to be as clever about application restart. The documentation says nothing about distinguishing between normal and abnormal restarts or avoiding useless restarts when there are start-up errors. daeomontools are definetely worth looking, i use it for some years now, and never had problems. it wasn't updated in almost five years, since it just works. you are right about the restart issue: if a supervised process dies, it's restarted, no matter why it died. what would an abnormal restart be, that should not take place, anyway? in the sense, how would the supervisor know thats it's abnormal? FWIW, there's also runit, obviously developed in the same spirit but independend of daemontools: http://smarden.org/runit/useinit.html And the python coded Supervisor2 made by Chris McDonough http://www.plope.com/software/supervisor2/ i myself have no experinces with these two, though. Cheers, Sascha -- Lalisio GmbH www.lalisio.com Puschkinstraße 1 fon +49-(0)361/541 43 80 99084 Erfurt fax +49-(0)361/541 43 79 [EMAIL PROTECTED] + AKTUELLER HINWEIS (November 2006) Wussten Sie schon, dass Sie mit der Literatursuchmaschine von Lalisio in mehr als 12 Millionen Titeln suchen und bei vielen Publikationen sogar die Abstracts lesen können? Testen Sie unser Angebot unter www.lalisio.com! + ___ Zope3-dev mailing list Zope3-dev@zope.org Unsub: http://mail.zope.org/mailman/options/zope3-dev/archive%40mail-archive.com
Re: [Zope3-dev] Is there an alternative to zdaemon?
Sascha Ottolski wrote: Am Freitag, 22. Dezember 2006 21:55 schrieb Jim Fulton: Does anyone know of something that does what zdaemon does? daemontools seems somewhat close: http://cr.yp.to/daemontools.html Going from the documentation, it doesn't seem to be as clever about application restart. The documentation says nothing about distinguishing between normal and abnormal restarts or avoiding useless restarts when there are start-up errors. daeomontools are definetely worth looking, i use it for some years now, and never had problems. it wasn't updated in almost five years, since it just works. you are right about the restart issue: if a supervised process dies, it's restarted, no matter why it died. what would an abnormal restart be, that should not take place, anyway? An abnormal exit is an exit due to some error, such as a segmentation fault or running out of memory. in the sense, how would the supervisor know thats it's abnormal? It can check the exit status. Normal shutdowns typycally exit with status 0. zdaemon (and supervisor2, which was obviously inspired by zdaemon) has an exit-codes option to configure which exit codes are normal. If the supervisor exists with one of these exit codes, it should not be restarted. FWIW, there's also runit, obviously developed in the same spirit but independend of daemontools: http://smarden.org/runit/useinit.html This wants to run as process 1. This seems a bit intrusive. And the python coded Supervisor2 made by Chris McDonough http://www.plope.com/software/supervisor2/ This is interesting. Jim -- Jim Fulton mailto:[EMAIL PROTECTED] Python Powered! CTO (540) 361-1714http://www.python.org Zope Corporation http://www.zope.com http://www.zope.org ___ Zope3-dev mailing list Zope3-dev@zope.org Unsub: http://mail.zope.org/mailman/options/zope3-dev/archive%40mail-archive.com
Re: [Zope3-dev] Is there an alternative to zdaemon?
On Fri, Dec 22, 2006 at 05:04:37PM -0500, Jim Fulton wrote: Sascha Ottolski wrote: And the python coded Supervisor2 made by Chris McDonough http://www.plope.com/software/supervisor2/ This is interesting. We've been using supervisor (previous version) for all our zope applications for a year or so. Works as advertised, pretty easy to set up. At my previous job, we used daemontools, which was OK, except we never found a solution to the problem of I want to get email notifications when the system is restarting unexpectedly, but I don't want my mail to get a DOS attack when the system can't start successfully so it keeps restarting forever. -- Paul Winkler http://www.slinkp.com ___ Zope3-dev mailing list Zope3-dev@zope.org Unsub: http://mail.zope.org/mailman/options/zope3-dev/archive%40mail-archive.com
Re: [Zope3-dev] Is there an alternative to zdaemon?
Am Freitag, 22. Dezember 2006 23:04 schrieb Jim Fulton: An abnormal exit is an exit due to some error, such as a segmentation fault or running out of memory. in the sense, how would the supervisor know thats it's abnormal? It can check the exit status. Normal shutdowns typycally exit with status 0. zdaemon (and supervisor2, which was obviously inspired by zdaemon) has an exit-codes option to configure which exit codes are normal. If the supervisor exists with one of these exit codes, it should not be restarted. i see. however, i guess the idea of a supervisor is just for such cases: to take care to restart a server that broke. there's svc -o to run a service only once, which comes handy if one is not sure if the server will survive a start. what i think to make more sense would be that the supervisor could detect if a server is restarted too frequently. in my experience, thats more often a situation that needs special attention. FWIW, there's also runit, obviously developed in the same spirit but independend of daemontools: http://smarden.org/runit/useinit.html This wants to run as process 1. This seems a bit intrusive. yes and no. the page i linked to explains how to use it while _not_ replacing init. in that mode it seems to be quite like daemontools (see The sv program, The runsvdir program, The runsvchdir program and The runsv program on the main runit page). i guess there is at least some support for your use case, see http://smarden.sunsite.dk/runit/runsv.8.html: one can define a finish script, which is started with the exit code of the supervised process as one of its parameters. Cheers, Sascha -- Lalisio GmbH www.lalisio.com Puschkinstraße 1 fon +49-(0)361/541 43 80 99084 Erfurt fax +49-(0)361/541 43 79 [EMAIL PROTECTED] ___ Zope3-dev mailing list Zope3-dev@zope.org Unsub: http://mail.zope.org/mailman/options/zope3-dev/archive%40mail-archive.com
Re: [Zope3-dev] Is there an alternative to zdaemon?
Am Freitag, 22. Dezember 2006 23:23 schrieb Paul Winkler: On Fri, Dec 22, 2006 at 05:04:37PM -0500, Jim Fulton wrote: Sascha Ottolski wrote: And the python coded Supervisor2 made by Chris McDonough http://www.plope.com/software/supervisor2/ This is interesting. We've been using supervisor (previous version) for all our zope applications for a year or so. Works as advertised, pretty easy to set up. At my previous job, we used daemontools, which was OK, except we never found a solution to the problem of I want to get email notifications when the system is restarting unexpectedly, but I don't want my mail to get a DOS attack when the system can't start successfully so it keeps restarting forever. hmm, what about: let the run script touch or write some status file; the very same script would send an email on a normal restart, but may stop to do so if the status file is to new. hmm, thinking further, the script could even delay or block the restart, if desired. i guess the run script could also be written in python. Cheers, Sascha -- Lalisio GmbH www.lalisio.com Puschkinstraße 1 fon +49-(0)361/541 43 80 99084 Erfurt fax +49-(0)361/541 43 79 [EMAIL PROTECTED] ___ Zope3-dev mailing list Zope3-dev@zope.org Unsub: http://mail.zope.org/mailman/options/zope3-dev/archive%40mail-archive.com
Re: [Zope3-dev] Is there an alternative to zdaemon?
Sascha Ottolski wrote: Am Freitag, 22. Dezember 2006 23:04 schrieb Jim Fulton: An abnormal exit is an exit due to some error, such as a segmentation fault or running out of memory. in the sense, how would the supervisor know thats it's abnormal? It can check the exit status. Normal shutdowns typycally exit with status 0. zdaemon (and supervisor2, which was obviously inspired by zdaemon) has an exit-codes option to configure which exit codes are normal. If the supervisor exists with one of these exit codes, it should not be restarted. i see. however, i guess the idea of a supervisor is just for such cases: to take care to restart a server that broke. there's svc -o to run a service only once, which comes handy if one is not sure if the server will survive a start. Yes what i think to make more sense would be that the supervisor could detect if a server is restarted too frequently. in my experience, thats more often a situation that needs special attention. Yes, that's a case that zdaemon and supervistor2 handle. Yu also want an application to be able to exit normally without being restarted. Jim -- Jim Fulton mailto:[EMAIL PROTECTED] Python Powered! CTO (540) 361-1714http://www.python.org Zope Corporation http://www.zope.com http://www.zope.org ___ Zope3-dev mailing list Zope3-dev@zope.org Unsub: http://mail.zope.org/mailman/options/zope3-dev/archive%40mail-archive.com
Re: [Zope3-dev] Is there an alternative to zdaemon?
On Fri, Dec 22, 2006 at 11:38:33PM +0100, Sascha Ottolski wrote: At my previous job, we used daemontools, which was OK, except we never found a solution to the problem of I want to get email notifications when the system is restarting unexpectedly, but I don't want my mail to get a DOS attack when the system can't start successfully so it keeps restarting forever. hmm, what about: let the run script touch or write some status file; the very same script would send an email on a normal restart, but may stop to do so if the status file is to new. hmm, thinking further, the script could even delay or block the restart, if desired. i guess the run script could also be written in python. Sure, but it's such a common need that ideally I'd like that to be taken care of for me :-) supervisor normally gives up after some number of restart attempts, which is fine with me. -- Paul Winkler http://www.slinkp.com ___ Zope3-dev mailing list Zope3-dev@zope.org Unsub: http://mail.zope.org/mailman/options/zope3-dev/archive%40mail-archive.com
