On 12/13/2015 04:19 AM, Timothy Murphy wrote:> Alice Wonder wrote: > >> In the server environment you almost certainly are using a virtual >> machine, and to use a virtual machine you create an image. Set up the >> image how you want and be done with it, you can then deploy it thousands >> of times and it is set up the way you need it. > > Who is "you"? > I'm running a home server under CentOS-7, > and I'm not using a virtual machine. > Why should I? > I don't want to "deploy it thousands of times".You is an author's you, kind of like author's we. I understand author's you and we are going out of style, but they are very much ingrained within me. I mean the typical server and indicated a server environment opposed to a home environment.> > It's amazing how people assume that everyone in the world > is, or should be, running things in the same way as themselves. > >> I was one of the systemd haters initially but now I don't have an issue >> with it. Yes it is different than what I learned, > > I dislike systemd because it is much more complicated than its predecessor, > and it has no advantages in my case to make up for this. > The main advantage that was originally claimed was that it boots faster. > That is not the case on my Fedora laptop. > It is no faster, and it is much harder to work out what is happening > if something goes wrong. >It's not speed that matters to me, and I would be fine with System V init. However it seemed at the end of the day, most of the arguments against systemd boiled down to "we've never done it that way before" or "It's not the UNIX way" rather than actual technical reasons why System V should be used and systemd rejected. One of the benefits of systemd is the dependency based parallel startup. The same speed can often be achieved with system V init by fine tuning when the services start but systemd does that automatically. Speed though doesn't concern me. I almost never reboot my servers or my desktop or laptop (I do sleep the laptop but only reboot after kernel update) Especially with SSDs, boot time isn't an argument for systemd - and I do not want to convince anyone that it is better. Just that it is not difficult to use, there are some advantages - how valuable those advantages are depend upon what you do (author's you again, not personal you) but it seems that these advantages have since been seen by just about every Linux distro that has any significant market share. Popular doesn't make it right, but it did make me rethink my objections to it and whether or not those objections were rational. For me, I decided that no, they weren't rational.
On Sun, December 13, 2015 8:51 am, Alice Wonder wrote:> > > On 12/13/2015 04:19 AM, Timothy Murphy wrote: >> Alice Wonder wrote: >> >>> In the server environment you almost certainly are using a virtual >>> machine, and to use a virtual machine you create an image. Set up the >>> image how you want and be done with it, you can then deploy it >>> thousands >>> of times and it is set up the way you need it. >> >> Who is "you"? >> I'm running a home server under CentOS-7, >> and I'm not using a virtual machine. >> Why should I? >> I don't want to "deploy it thousands of times". > > You is an author's you, kind of like author's we. I understand author's > you and we are going out of style, but they are very much ingrained > within me. > > I mean the typical server and indicated a server environment opposed to > a home environment.I'm joining my "you" to yours. I'm even joining the kind of what one often does for servers: virtualized stuff, even though my case is FreeBSD jails (mostly even more comparmentalized than single virtual machine: one jail per service or per group of services which need to talk to each other through UNIX sockets; still I put mu case in the same category with yours).> >> >> It's amazing how people assume that everyone in the world >> is, or should be, running things in the same way as themselves. >> >>> I was one of the systemd haters initially but now I don't have an issue >>> with it. Yes it is different than what I learned, >> >> I dislike systemd because it is much more complicated than its >> predecessor, >> and it has no advantages in my case to make up for this. >> The main advantage that was originally claimed was that it boots faster. >> That is not the case on my Fedora laptop. >> It is no faster, and it is much harder to work out what is happening >> if something goes wrong. >> > > It's not speed that matters to me, and I would be fine with System V > init. However it seemed at the end of the day, most of the arguments > against systemd boiled down to "we've never done it that way before" or > "It's not the UNIX way" rather than actual technical reasons why System > V should be used and systemd rejected.true. Pretty much as true would be: why should we (*nix admins) be like certified Windows admins: every incarnation of the system we have to learn new way to find yet the same on the low level code tools. I know systemd is not it, it is quite different architecture. But jumping to this incarnation of Linux does feel similar.> > One of the benefits of systemd is the dependency based parallel startup. > The same speed can often be achieved with system V init by fine tuning > when the services start but systemd does that automatically. > > Speed though doesn't concern me. I almost never reboot my servers or my > desktop or laptop (I do sleep the laptop but only reboot after kernel > update)Well, for last 6+ years you should: at lest once every 45 days on average (either kernel or glibc security update, - just my observation). Of course, time the machine boot takes doesn't by any measure compare to interval between reboots. Neither it does compare to the fact you have to reboot the server. The funniest thing is: for some of the server hardware initialization by BIOS, which has to happen even before system boot starts, takes longer than system V init (not talking about faster systemd boot as I only can compare with workstation systemd boot: I do not have servers running systemd based system). So all in all the best pro systemd argument - fast boot - kind of doesn't exist for me. I know, tastes differ. But if I _have_ to reboot server often, it is time to build service cluster in which case reboot of single machine doesn't matter. Neither the time the it takes to boot matters, so we are back to square one: no advantage of systemd's fast boot (just IMHO). Valeri> > Especially with SSDs, boot time isn't an argument for systemd - and I do > not want to convince anyone that it is better. Just that it is not > difficult to use, there are some advantages - how valuable those > advantages are depend upon what you do (author's you again, not personal > you) but it seems that these advantages have since been seen by just > about every Linux distro that has any significant market share. > > Popular doesn't make it right, but it did make me rethink my objections > to it and whether or not those objections were rational. For me, I > decided that no, they weren't rational. > _______________________________________________ > CentOS mailing list > CentOS at centos.org > https://lists.centos.org/mailman/listinfo/centos >++++++++++++++++++++++++++++++++++++++++ Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ++++++++++++++++++++++++++++++++++++++++
Alice Wonder wrote:> One of the benefits of systemd is the dependency based parallel startup. > The same speed can often be achieved with system V init by fine tuning > when the services start but systemd does that automatically.If it's no faster then why is it a benefit?> Just that it is not > difficult to use, there are some advantages -Why don't you say what the advantages are, instead of launching into a philosophical discussion of "market share". -- Timothy Murphy gayleard /at/ eircom.net School of Mathematics, Trinity College, Dublin
Alice Wonder wrote:> I mean the typical server and indicated a server environment opposed to > a home environment.To me, a server is a computer providing a service to other computers or electronic devices. It may be on a space-station, or it may be in someone's home - its whereabouts, or "environment" as you call it, is completely irrelevant. All that matters is what services it offers. -- Timothy Murphy gayleard /at/ eircom.net School of Mathematics, Trinity College, Dublin
On 12/13/2015 08:39 AM, Timothy Murphy wrote:> Alice Wonder wrote: > >> One of the benefits of systemd is the dependency based parallel startup. >> The same speed can often be achieved with system V init by fine tuning >> when the services start but systemd does that automatically. > > If it's no faster then why is it a benefit?Binary logs with checksums is one benefit, much harder for a hacker or malware to hide its tracks. Binary logging also makes it easier / faster to look at specific types of events in the log. And sockets can be used before the service is actually started, so services that want to log for example can start before the logger is finished coming up. And it allows services to start on demand and stop when no longer needed. I don't use that, but that is not as easy to do with system V init. It also reduces issues related to poorly scripted init scripts, and needing to sometimes change the numbers to make sure services start in the correct order. There are benefits, at least to some people. And there isn't anything I could do with System V that can't be accomplished with systemd. systemd isn't critical to use, not for me, but other than needing to do a little research and learning, it also isn't a negative.
On Sun, Dec 13, 2015 at 04:39:05PM +0000, Timothy Murphy wrote:> Alice Wonder wrote: > > Just that it is not > > difficult to use, there are some advantages - > > Why don't you say what the advantages are, > instead of launching into a philosophical discussion of "market share".So, while the parallel startup can sometimes produce a faster startup, I believe it is more a side effect from the proper management of service dependencies. In SysV init, you either had hard-coded sequential startup of some parts of the OS (in the shell script that started init and mounted all the filesystems, ran fsck, whatever) and then the increasibly difficult to manage SysV init scripts, which were ordered by the chkconfig numbers. There's no explicit dependencies, you had to basically modify those numbers if you knew they needed to start before some other number, and if the packaged init script had a number that just didn't work out, then you're stuck maintaining that script for the rest of time. Upstart tried to fix this, and it probably would have been what we're all using instead of systemd if their development process wasn't broken. But even when we had Upstart in CentOS6, no one wanted to use it, they all used SysV init scripts. As a sysadmin, I like systemd because I can finally manage the order in which services start up and keep my sanity. Don't like how the packaged unit does something? Its easy to override a setting or write your own, and you don't have to worry about the package overwriting it because its a separate file in /etc. As a packager, I like systemd because I can write one service unit file, and know that I don't have to worry about the ordering of services, and I even get some cross-distribution portability. -- Jonathan Billings <billings at negate.org>