Date: Sat, 7 Apr 2001 01:37:01 +0200 (CEST) From: Bert Driehuis <driehuis@playbeing.org> To: freebsd-stable@FreeBSD.ORG Subject: Re: Cluster Solution for FreeBSD Message-ID: <Pine.BSI.4.21.0104070122180.10470-100000@c1111.nl.compuware.com> In-Reply-To: <200104062317.f36NHJW48955@earth.backplane.com>
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On Fri, 6 Apr 2001, Matt Dillon wrote: > The quick and dirty thing to do is simply setup a DNS round robin > for the domain name used to access the servers. [snip] > That leaves just dealing with downed servers. That depends on your service. It won't fly if you use something that has a concept of session. This is where Eddie comes in, except I too found Eddie to be too complex to want to rely on unless you can afford to plow significant time into learning -- anyone who is not willing to learn the programming language it is written in should probably not want to depend on it at this stage). As an alternative (or supplement) to round robin DNS, one could consider IP takeover. Web servers are paired, and if one detects the other to go down, it assigns the other IP address as a secondary of its own. I'm not aware of ready made daemons for FreeBSD that do this, but finding out and writing one if necessary is on my to do list (sigh -- so is getting Cricket 1.0.3 out the door and rewriting the OS interface of net-snmp :-) As a third alternative, one could hack up lbnamed (a set of perl tools that implement a DNS server that can handle load balancing and dead host detection). I started on this, but the requirement to get it running sort of faded over time so I never got round to finishing it). The hard part (the DNS bits) are done and don't need touching. There's a link on www.isc.org to it someplace. The easy bit that needs finishing is writing a simple tool that updates a plaintext file that the DNS uses to determine where to redirect a client. This would implement the bits from Eddie I need most without requiring me (or my colleagues who might need to service it in an emergency) to learn a new language. I recommend downloading lbnamed even if you don't plan to run it because it contains a quite lucid description of some of the DNS issues and how to deal with them. Cheers, -- Bert -- Bert Driehuis -- driehuis@playbeing.org -- +31-20-3116119 If the only tool you've got is an axe, every problem looks like fun! To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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