On Fri, 2003-05-09 at 20:55, Tom Allison wrote:
I'm a Lurker from Debian.
And I'm a Red Hat refugee that just put SuSE and Debian head-to-head for a couple weeks, and settled on SuSE.
Two problems that comes up is if I am looking at a highly customized configuration to over-ride a YAST configuration option (eg: 3 network cards was something that was just impossible under Suse v6) or if I want to have something that is outside of the currently available packages.
You can just install whatever package you wish, either from source, or from RPM. (Someone has even made apt systems for SuSE, but I haven't checked it out. I like RPM just fine.) If you install a non-SuSE RPM, it gets marked specially in the RPM database and Yast never touches it. I did this with VMware, and it's just what you want it to do.
For the first option, I am assuming that I can edit the network configuration files. I might even be able to do something with the YAST master file. But what happens when I run the YAST GUI? Does it know not to mess with my manual entries in the master file? What about the end network configuration file? (Debian has no Master config file and 'diffs' the two for you, with the option to 'vi' the config file)
You can edit the files directly if you wish. That's just normal Linux. However, you are correct, Yast has a "meta-config" capability. Since we're talking about email, let's take postfix for example. Now, I've got my postfix fairly tweaked out, but Yast's sysconfig file editor was able to accomodate all the changes I wanted. (Or you can edit the sysconfig file by hand - they are extensively documented.) When you run `SuSEconfig --module postfix', Yast reads /etc/sysconfig/postfix and generates /etc/postfix/main.cf and master.cf. The beauty of this system is that *your* changes are in /etc/sysconfig. When you go to install an update, Yast -- at least has the capability -- to preserve what you want to happen, as well as allow new config changes based on the new RPM, and keep it all working together. Whether this will actually work in practice, I don't know. I'm still only 3 weeks into SuSE myself, but I like the _idea_ better than working through a diff. On both Red Hat and Debian, I simply put the new configs in place and rehacked them. I'm just anal-retentive enough to care about cruft like that. With SuSE's system, updated RPM's can drop new configs into place, and Yast will pick up those changes and merge them with my config automatically. At least on paper. The other option is that you can just toggle Yast to not mess with a particular package, like postfix or apache, and it won't munge the configs for you. So far, I haven't made a config Yast couldn't handle, so I've opted for working within their system.
For the second option, how do you tell the system that you are using program XXX for a function (like SMTP) and not to worry about any dependencies for email servers? (Under Debian you can install a DUMMY package to act as a dependency placeholder to always return "true" for many of these packages)
Taking email again, how does email get interacted with? It's invoked through port 25 (or 465 over SSL). Yeah, lots of stuff after that might be different, but that's the interface. If you want a different email server, there's nothing to stop you. Just shut off postfix. Then start qmail. It will have it's server programs to take up port 25. You already know all of this. Postfix (my fave), sendmail, and exim are all on the discs. All "provide" (in the RPM sense of the word) "smtp_daemon", and this is what other packages are looking for. So, though I'm no expert, I think there's sort of the same thing going on here as on Debian. The "smtp_daemon" is the generic placeholder that will satisfy, say, here on my workstation, mailx, cron, fetchmail, and mutt. So if you want to run qmail, the way I see it is that you could either leave postfix (the default) installed, but shut off, and install your own from source. Or you could build qmail, then make an RPM of it and install that, making sure that it advertised that it provided "smtp_daemon". I've never done such a thing, so I'm not sure of the level of effort there, though I've recompiled existing source RPM's with changes, and that's not too bad. I would still probably choose the former option though. Just like every other Linux distro, someone else has probably already done this, but I personally don't like using other people's RPM's (or DEB's). If you were installing from scratch and wanted to use one of the other two email servers, you'd just rearrange it then. If you wanted to install and change later, I don't think there's a way to do it through RPM at the command line. However, Yast seems to think it's got all dependencies satisfied if I mark postfix for removal and exim for installation, so it looks like that would work. (If anyone reading this knows how to do both things in one fell swoop at the command line, I'm all ears!) But, BTW, Yast has the same featureset running under curses that it has under X, which is nice, because I just leave X off my servers. I guess I'm curious, though, after all of this: what does qmail offer that exim, sendmail, or postfix doesn't? HTH, dk