On Saturday 14 November 2009 19:36:06 Alex Schuster wrote: > Alan McKinnon wrote: > > clusterssh will let you log into many machines at once and run emerge > > -avuND world everywhere > > This is way cool. I just started using it on eight Fedora servers I am > administrating. Nice, now this is an improvement over my 'for $h in > $HOSTS; do ssh $h "yum install foo"; done' approach.
I feel your pain :-) We used to have the same problem adding new admins to 87 machines. Now we have a bespoke provisioner that does it all. > What do you guys think about using Gentoo for servers? At the institute I > partially work we chose Fedora. There is no special reason for that - we > already had some Fedora machines, the setup seemed to work, the reputation > was good, so we kept it. That was okay for me, why choose many different > environments and learn everything again. I mentioned Gentoo, but did not > really suggest to actually use it. Maybe I should have. I'm a huge fan of Gentoo and all my personal machines (except the new netbook) have run it for the last 5 years. But I will never install Gentoo on a production server at work. Why? Because it is too time consuming, because no two machines are set up the same, because I can't trust that other admins used the flags they should have. So updates become a case of logging into 80+ machines individually and doing emerge world by hand. Gentoo allows you to customize things to the nth degree - that is it's strength - so people WILL use this one discriminating factor. If OTOH I had a server farm of 80+ machines, all identical, I'd put Gentoo on them in a flash. But I don't have that > These 8 servers I mentioned are basically clones of the one I installed > manually. Instead of doing this again, I boot a live-cd on a new one, > create partitions, and extract tar files of the first server's partitions. > Then I do some extra configuration, like hostname and network setup. Done. > > My plan for updating them is to take the first server down, and upgrade > the installation (if that works - I had some trouble with that before, so > maybe it will be better to reinstall from scratch). Then I will create a > snapshot of the new setup, transfer that to the other hosts, and unpack it > in new logical volumes. I plan to script this so I do not have to do it > manually every time - but that was before I knew ClusterSSH. When all is > done and there is some time to take the servers down, I will reboot into > the new system. > > Now I am thinking about a Gentoo installation instead. > > Pros: > - Continuous updates, no downtime for upgrading, only when I decide to > install a new kernel. This is really really cool. I fear the upgrade from > Fedora 10 to 12 which has to be done soon. Do not upgrade, especially not with a version jump of 2 or more. If you have a lot of machines, I assume you are a decent shop, and that you have some form of formal process for upgrades and changes. What you do instead is a formal migration - copy the data off, reinstall, restore data. If you can't afford to do that every six or twleve months, then I have to ask - what the hell is the organization doing using a distro that is unsupported after 12 months? > - Some improvement in speed. Those machines do A LOT of numbercrunching, > which jobs often lasting for days, so even small improvements would be > nice. Don't fool yourself. Unless you need what Google needs, there is very little speed difference between Gentoo and Fedora. I/O improvements you need can be easily gotten by fiddling the kernel tuning knobs. > - Easier debugging. When things do not work, I think it's easier to dig > into the problem. No fancy, but sometimes buggy GUIs hiding basic > functionality. Errrrrrrrrrrrrrrrmmmmmmmmmmmmmm, Fedora does not require a GUI :-) > - Heck, Gentoo is _cooler_ than typical distributions. And emerging with > distcc on about 8*4 cores would be fun :) Can't argue with that. But that is your ego talking and the machines do not belong to you but to the institute. Your ego has no place in that. > - I am probably the only one who can administrate them. This is not a benefit. It is a severe liability. Where I work, I get fired for trying that :-( > Cons: > - If something will not work with this not so common (meta)distribution, > people will say "always trouble with your Gentoo Schmentoo, it works fine > in Fedora". Fedora is more mainstream, if something does not work there, > then it's okay for the people to accept it. Those same people are likely to say the same about linux vs windows. > - I fear that big packages like Matlab are made for and tested on the > typical distributions, and may have problems with the not-so-common > Gentoo. I think someone here just had such a problem with Mathematica > (which we do currently not use). One or two persons had problems. Many many more replied that they had no problems at all. In Fedora-land, the ratio is the same. > - I am probably the only one who can administrate them. I think Gentoo is > easier to maintain in the long run, but only when you take the time to > learn it. With Fedora, you do not need much more than the 'yum install' > command. There is no need to read complicated X.org upgrade guides and > such. > > I think I already made my decision, but I am still interested in your > opinions, maybe some of you are in a similar position and like to share > your experiences. Whether I will be allowed to use Gentoo is another > question, I guess my boss will not like my idea at first, and I am not > even sure if he is right. But maybe I can test-install Gentoo on one > machine in a chroot, and see if things work fine. Depends how critical these machines are. If you want to change them just because you feel like it, then I do not see how that can possibly be a valid reason. Remember, the institute's needs and desires trump yours every time -- alan dot mckinnon at gmail dot com
