From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.comp.sysutils.supervision.general/278 Path: main.gmane.org!not-for-mail From: Charlie Brady Newsgroups: gmane.comp.sysutils.supervision.general Subject: Re: runit/dependencies Date: Mon, 12 Jan 2004 10:41:15 -0500 (EST) Message-ID: References: <20040112142913.14952.qmail@ccf32c333c9930.315fe32.mid.smarden.org> NNTP-Posting-Host: deer.gmane.org Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Trace: sea.gmane.org 1073922088 26052 80.91.224.253 (12 Jan 2004 15:41:28 GMT) X-Complaints-To: usenet@sea.gmane.org NNTP-Posting-Date: Mon, 12 Jan 2004 15:41:28 +0000 (UTC) Original-X-From: supervision-return-516-gcsg-supervision=m.gmane.org@list.skarnet.org Mon Jan 12 16:41:22 2004 Return-path: Original-Received: from antah.skarnet.org ([212.43.221.114]) by deer.gmane.org with smtp (Exim 3.35 #1 (Debian)) id 1Ag4Bu-0000Wf-00 for ; Mon, 12 Jan 2004 16:41:22 +0100 Original-Received: (qmail 25286 invoked by uid 76); 12 Jan 2004 15:41:40 -0000 Mailing-List: contact supervision-help@list.skarnet.org; run by ezmlm List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Archive: Original-Received: (qmail 25280 invoked from network); 12 Jan 2004 15:41:39 -0000 X-X-Sender: charlieb@e-smith.charlieb.ott.istop.com Original-To: supervision@list.skarnet.org In-Reply-To: <20040112142913.14952.qmail@ccf32c333c9930.315fe32.mid.smarden.org> Xref: main.gmane.org gmane.comp.sysutils.supervision.general:278 X-Report-Spam: http://spam.gmane.org/gmane.comp.sysutils.supervision.general:278 On Mon, 12 Jan 2004, Gerrit Pape wrote: > Regarding all these ``I need support for dependencies'' (I've been asked > often), and even work to provide straight dependencies with runit[0], > I've yet to see a real example that cannot be handled by runit as it is > currently. It works for me. All a service needs to do if another > service it depends on isn't available, is to fail. The key word here is "available". The exact semantics of "available" will vary from service to service. The best that runit can provide is "has been asked to start and hasn't failed yet". A service run script, OTOH, can perform arbitrary probes of the "availability" of other services on which it depends. I consider the limited semantics of the status provided by "runsvstat" to be a fatal obstacle to attempts to build dependency management into runit. All you can achieve is a slightly ordered parallel startup of multiple services, with race conditions determining whether or not services start successfully. -- Charlie