Re: [DNG] Felker Init: was without-systemd.org not working
>> On 21 May 2020, at 17:31, Steve Litt wrote: >> >> On Thu, 21 May 2020 05:13:52 +0100 >> tux...@sapo.pt wrote: >> >> Citando Steve Litt : >>> This whole discussion balances on the definition of "shell aware". >>> What is "shell aware?" >>> SteveT >> Have you tried to write shell script code into the execution command >> of a systemd unit file? >> it doesn't work right?! >> Why do you think it doesn't work? > > Because it's a configuration file, not a script. I think they mean the specific “ExecStart=” line in the unit file that references the executable file and it’s arguments to run when the service is started. https://www.freedesktop.org/software/systemd/man/systemd.service.html Ref: § Command Lines - - -8<- - - This syntax is inspired by shell syntax, but only the meta-characters and expansions described in the following paragraphs are understood, and the expansion of variables is different. Specifically, redirection using "<", "<<", ">", and ">>", pipes using "|", running programs in the background using "&", and other elements of shell syntax are not supported. - - -8<- - -___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] Felker Init: was without-systemd.org not working
On Thu, 21 May 2020 05:13:52 +0100 tux...@sapo.pt wrote: > Citando Steve Litt : > > > This whole discussion balances on the definition of "shell aware". > > What is "shell aware?" > > > > SteveT > > > > > > Have you tried to write shell script code into the execution command > of a systemd unit file? > it doesn't work right?! > Why do you think it doesn't work? Because it's a configuration file, not a script. > > For it to work you need 2 files, ... the service unit , and also a > shell script, You mean the service unit and a binary executable that is the daemon, right? > But SysVInit only needs a script, no service unit required.. so its > more optimized, only a file to control something.. s6 operates the same way as sysvinit, only s6 run scripts are MUCH less complex than sysvinit init scripts. > > Why in hell would you need to create several files to control the > same thing? Its stupid.. In s6 you don't, unless you have a finish script to define what happens when the daemon terminates. [snip stuff I don't understand] > The Linux Stadard Base, > have defines the LSB Headers, as a way to control the services.. Yeah, meaningful comments: What could *possibly* go wrong? With s6 and runit, if you want runlevels (and I don't), you achieve them with directories that can be symlinked. > > And their definition was in the same file as the daemon is.. > So we expect only 1 file.. Huh? One other thing: Although I prefer sysvinit to systemd (by a wide margin), I'm not against using multiple files to do something. Truth be told, with sysvinit I'd rather they have multiple files for start, stop, restart and the like, than the typical 100+ line behemoths exhibited by sysvinit and OpenRC. I have a suggestion. The Obarun distro comes stock with the s6 init, together with some helper software called "66". I suggest you install Obarun somewhere, and add a couple daemons of your own. You'll see exactly what files are necessary, and exactly what the supervisor part of s6 does, and you can let us all know. Thanks, SteveT Steve Litt May 2020 featured book: Troubleshooting Techniques of the Successful Technologist http://www.troubleshooters.com/techniques ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] Felker Init: was without-systemd.org not working
Citando Steve Litt : This whole discussion balances on the definition of "shell aware". What is "shell aware?" SteveT Have you tried to write shell script code into the execution command of a systemd unit file? it doesn't work right?! Why do you think it doesn't work? For it to work you need 2 files, ... the service unit , and also a shell script, But SysVInit only needs a script, no service unit required.. so its more optimized, only a file to control something.. Why in hell would you need to create several files to control the same thing? Its stupid.. Now in relation to s6, I need yet to read about it, maybe there are improvements.. Does s6 do the same mistake as systemd, with having 2 files for the same thing? The Linux Stadard Base, have defines the LSB Headers, as a way to control the services.. And their definition was in the same file as the daemon is.. So we expect only 1 file.. ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] Felker Init: was without-systemd.org not working
On Tue, 19 May 2020 04:14:05 +0100 tux...@sapo.pt wrote: > The problem is that this init systems are not shell aware. I don't know what "shell aware" means. The minute a file begins with: #!/bin/sh the rest of the text executes according to the grammar/syntax/capabilities of /bin/sh. > yes they can fork and exec a shell script, What more would anyone want? > but does the service files > or daemon files are shell based? I don't understand the preceding sentence. > No they are not, they are in a intermediate language that for example > in systemd, is not even Turing Feature complete( I am speaking about > the unit files language ).. That's systemd's problem, but a s6 run or finish script can be written in /bin/sh, or even in compiled C++ if somebody wanted a difficult life. > > I don't know much about systemd, or s6 to be honest, only a bit.. > But the s6 creator told in the devuan conference that s6 is not shell > aware, and I believe he told, there is not simple way to turn it > shell aware.. This whole discussion balances on the definition of "shell aware". What is "shell aware?" SteveT Steve Litt May 2020 featured book: Troubleshooting Techniques of the Successful Technologist http://www.troubleshooters.com/techniques ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] Felker Init: was without-systemd.org not working
I believe I didn't expressed myself well, and so was badly understood.. Citando Steve Litt : On Sat, 16 May 2020 22:04:51 +0100 tux...@sapo.pt wrote: Hello, Citando Steve Litt : It's such a shame. Runit and s6 were both there, waiting to be picked up and used. Both were 10 times easier than sysvinit. But n. All init systems that want to be taken seriously, need to accept also the system language.. As I understand, and was also recognized by s6 creator at devuan conference, s6 *cannot* run a script made in shell script( the systems language.. ) Yes it can. I've created s6 run scripts programmed in /bin/sh. Laurent Bercot *discourages* using /bin/sh in favor of the execline language (http://www.troubleshooters.com/linux/execline.htm), but s6 run scripts can be created in almost any language, including /bin/sh. Maybe you think at it like been a superfluous thing, Not at all: I'd consider it almost a showstopper. Fortunately, s6 enables you to program run scripts (and finish scripts) in /bin/sh. Anything can fork what is given.. The problem is that this init systems are not shell aware. yes they can fork and exec a shell script, but does the service files or daemon files are shell based? No they are not, they are in a intermediate language that for example in systemd, is not even Turing Feature complete( I am speaking about the unit files language ).. I don't know much about systemd, or s6 to be honest, only a bit.. But the s6 creator told in the devuan conference that s6 is not shell aware, and I believe he told, there is not simple way to turn it shell aware.. The question was put by KatolaZ, at the last Devuan conference.. If you have a chance look at the video of the devuan conference.. The s6 creator was there invited.. Best Regards, tux ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] Felker Init: was without-systemd.org not working
hello, Citando Dimitris via Dng : On 5/17/20 12:04 AM, tux...@sapo.pt wrote: But is a major flaw, being it a init system for a operating system, and not beign able to run shell scripts( systemd has also this limitation.. ).. you're right about s6, but wrong about systemd.you can run shell scripts with that bloated beast. What I meant was that..you know.. systemd or S6 is not shell built-ins/ Environment aware. You can execute commands that are operating system available.. I believe that you can also do the same with S6, But you can't use direct shell scripting language to be executed by systemd, or by S6( the proper developer of S6 spoke about that in the Devuan conference.. ). They could had done it Shell aware, and substitute the crapy unit files with direct shell scripting, Which is a lot more natural( as it is the system language.. ), and reduce the amount of files, for the same thing.. Moreover, a "called motive" for the systemd existence, as I recall it, "terminate the amount of files or symlinks "madness" that goes on SysVInit"..??anyone remember? I do.. The result... They ended creating a ton of symlinks more, plus the need of 2 files for each service o_0..using a closer method like is used in SysVInit with symlinks to the deamon.. In fact the number of symlinks that exist in systemd is *insanely* high, a lot but a lot bigger than in SysVinit..they are hidden.. They fork and exec what is given in the command, so for systemd, the thing get even uglier.. You need to create a Service unit file, that is not shell aware, and then you need to create the REAL SHELL SCRIPT to pass to that file, to be executed, And then prepare it to run accordingly..insane! if you think that systemd is shell friendly, Test it, :) You can start by a command that could be very basic like: 'A=0;WHILE READ LINE;DO ECHO $A:$LINE;LET ++A;DONE < /ETC/FSTAB' And we doesn't even started to speak about Environment variables( and its propagation inside the same namespace ).. That is another atrocity that could had been prevented was it shell aware from the beginning, because you can set or unset variables in shell scripting when you want.. Let's take for example a SAP service, That at least will take 7 different users, several databases( at least 2 ), for several Java Installations( administration/ operators, etc ).. To Launch a service like this with systemd, is madness, the amount of environment variables are tons of them, the users are independent, will you put all environment variables in the same place( Shared )? But that will destroy completely the idea of roles separation, security reasons.. I'am not saying that it is not impossible but you will start to mix, or share things, destroying your initial goal of having all services separated and communicating only via network/shm.. So long story short, you can fork *only*, you don't have the shell awareness.. :) Ofcourse if you only have basic services running, like ntp, stmp,dhcp, etc, its peanuts, anything can do the job..but for servers were you have a complex setup the problems start to be noticed.. Its my believe that systemd, as a project, started with the desktop Idea in mind, because its not designed with servers in mind.. You can look at the last disaster "homed"... Even for desktop is terrible, you cant even run services when the keyboard is locked...crazy.. :D It has a similar behaviour as with MS Windows( no surprise, as the developers that were developing it, had not real experience with unix before, but with windows they had plenty.. ).. ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] Felker Init: was without-systemd.org not working
On Sun, 17 May 2020 13:46:28 +0200 Didier Kryn wrote: > Le 16/05/2020 à 11:30, Steve Litt a écrit : > > On Fri, 15 May 2020 14:44:06 -1000 > > Joel Roth via Dng wrote: > > > > > >> Reminds me to revisit https://ewontfix.com/14/ > >> for Felker's Broken by Design article on systemd. > > That web page changed my life. When I saw, on that page, how simple > > PID1 could really be, that was when I really started to despise > > systemd. > I just re-read this nice document, thanks for reminding it. > > It is very intresting because it immediately raises a question: > what if pid2 (called rc here) crashes? It isn't respawned by pid1. Your preceding paragraph is *precisely* the strongest stated benefit of s6 over runit: s6 supervises its equivalent to the rc file, whereas runit pretty much conforms to Felker's model. If one is worried about the rc file crashing, one should use s6. I've been using runit almost 5 years, and I don't remember a case of the rc file crashing. Keep in mind that the rc file can fork off everything it needs to fork off, doublefork the things it wants parented by PID1, and then when the rc file's work is done, it simply exits. > > rc, as the supervisor of all other daemons, is essential to > maintain the state of the system. I can think of four options when it > crashes: > > 1) respawn it, but then, why wouldn't it crash again immediately? > > 2) reboot, but this may have the same effect as opton 1 if the cause > of the crash persists. > > 3) stop the system, but why wouldn't it produce the same effect as > the two options above at next boot. > > 4) do nothing and let the admin investigate. But at least there > should be a possibility for the admin to log in on the console, which > means spawning and re-spawning getty or sulogin. > > Therefore, as it has been said already, I'm for keeping the > current sysv-init (but not sysv-rc) as is, That's exactly how I feel. It's just so easy to use sysv PID1 with a different supervisor. I think also it's necessary to keep some of the sysvinit early boot stuff. But the daemons would all be easier to do with a separate process supervisor. > instead of reducing it to > the minimalistic example of Rich Felker, despite my respect and > admiration for him. Even Rich Felker admitted a practical init would need to be more complicated than his 16 line PID1. SteveT Steve Litt May 2020 featured book: Troubleshooting Techniques of the Successful Technologist http://www.troubleshooters.com/techniques ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] Felker Init: was without-systemd.org not working
On Sat, 16 May 2020 22:04:51 +0100 tux...@sapo.pt wrote: > Hello, > > Citando Steve Litt : > > > It's such a shame. Runit and s6 were both there, waiting to be > > picked up and used. Both were 10 times easier than sysvinit. But > > n. > > All init systems that want to be taken seriously, need to accept also > the system language.. > > As I understand, and was also recognized by s6 creator at devuan > conference, s6 *cannot* run a script made in shell script( the > systems language.. ) Yes it can. I've created s6 run scripts programmed in /bin/sh. Laurent Bercot *discourages* using /bin/sh in favor of the execline language (http://www.troubleshooters.com/linux/execline.htm), but s6 run scripts can be created in almost any language, including /bin/sh. > > Maybe you think at it like been a superfluous thing, Not at all: I'd consider it almost a showstopper. Fortunately, s6 enables you to program run scripts (and finish scripts) in /bin/sh. SteveT Steve Litt May 2020 featured book: Troubleshooting Techniques of the Successful Technologist http://www.troubleshooters.com/techniques ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] Felker Init: was without-systemd.org not working
Le 16/05/2020 à 11:30, Steve Litt a écrit : On Fri, 15 May 2020 14:44:06 -1000 Joel Roth via Dng wrote: Reminds me to revisit https://ewontfix.com/14/ for Felker's Broken by Design article on systemd. That web page changed my life. When I saw, on that page, how simple PID1 could really be, that was when I really started to despise systemd. I just re-read this nice document, thanks for reminding it. It is very intresting because it immediately raises a question: what if pid2 (called rc here) crashes? It isn't respawned by pid1. rc, as the supervisor of all other daemons, is essential to maintain the state of the system. I can think of four options when it crashes: 1) respawn it, but then, why wouldn't it crash again immediately? 2) reboot, but this may have the same effect as opton 1 if the cause of the crash persists. 3) stop the system, but why wouldn't it produce the same effect as the two options above at next boot. 4) do nothing and let the admin investigate. But at least there should be a possibility for the admin to log in on the console, which means spawning and re-spawning getty or sulogin. Therefore, as it has been said already, I'm for keeping the current sysv-init (but not sysv-rc) as is, instead of reducing it to the minimalistic example of Rich Felker, despite my respect and admiration for him. Didier ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] Felker Init: was without-systemd.org not working
On 5/17/20 12:04 AM, tux...@sapo.pt wrote: > But is a major flaw, being it a init system for a operating system, and > not beign able to run shell scripts( systemd has also this limitation.. ).. you're right about s6, but wrong about systemd. you can run shell scripts with that bloated beast. signature.asc Description: OpenPGP digital signature ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] Felker Init: was without-systemd.org not working
Hello Steve, > This enraged me: > The fact that a Troubleshooting Trainer could make an init in a couple > weeks, yet the Redhat/Freedesktop/Poettering axis was telling us what a > complex thing an init was. They have in mind their own, different from yours and mine, idea of how the computers are to be used and administrated: A clueless user and magic behind the scenes, which also keeps the user clueless forever - good for business. /D ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] Felker Init: was without-systemd.org not working
Hello, Citando Steve Litt : It's such a shame. Runit and s6 were both there, waiting to be picked up and used. Both were 10 times easier than sysvinit. But n. All init systems that want to be taken seriously, need to accept also the system language.. As I understand, and was also recognized by s6 creator at devuan conference, s6 *cannot* run a script made in shell script( the systems language.. ) Maybe you think at it like been a superfluous thing, But is a major flaw, being it a init system for a operating system, and not beign able to run shell scripts( systemd has also this limitation.. ).. Best Regards, tux ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] Felker Init: was without-systemd.org not working
On Sat, 16 May 2020 11:41:29 +0200 Antony Stone wrote: > On Saturday 16 May 2020 at 11:30:03, Steve Litt wrote: > > > You know, runit's or s6's process supervisor could be used, on > > systemd systems, as a tobacco patch to wean the user off systemd, > > one process at a time. As each daemon gets moved to runit or s6, > > that daemon's unit file name gets put in a shellscript that > > disables systemd's execution of that daemon. It's very easy to do. > > Surely one of the biggest problems (or at least, one of the things > people complain most about) regarding systemd is that it is no longer > just an init system. > > It may have been sold that way in the early days, but it's now > infiltrated so many parts of the GNU / Linux system that just telling > people (or showing them) that they can use something else to manage > their daemons is no longer enough. Your two preceding paragraphs are absolutely true, which is why s6 supervisor as a patch is an excellent tactic in the strategy to one by one either/both limit systemd damage and/or replace systemd functionalities. Another benefit if s6 as a tobacco patch and later tobacco patches: The more DIY types who do these things, the more collective knowledge will be available to call bullshit on the nonsense propagated by the Redhat/Freedesktop/Poettering axis and their chatterbox repeaters. My preceding paragraph is the carrot. The stick is that if we let systemd get too far ahead of us, it will become too bubble-gummed into our systems to ever remove. Just speaking for myself, I think a great intermediate goal for Devuan would be to keep the sysvinit PID1, and use it with the process supervisor for s6. s6 is still under active development and is getting **good** features all the time, while remaining simple and logical. SteveT Steve Litt May 2020 featured book: Troubleshooting Techniques of the Successful Technologist http://www.troubleshooters.com/techniques ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] Felker Init: was without-systemd.org not working
Quoting Antony Stone (antony.st...@devuan.open.source.it): > It may have been sold that way in the early days, but it's now > infiltrated so many parts of the GNU / Linux system that just telling > people (or showing them) that they can use something else to manage > their daemons is no longer enough. Except that robust alternatives exist for all of the other major areas where systemd is touted as the One True Solution. And, as I've shown in my own modest writings, it remains a pretty easy task to swap in modular replacements, each chosen with an appropriate scope of functionality[1] rather than a figurative brass band (or in other cases, such as daemon supervision in most cases, electing to omit entirely as not needed). I mean, c'mon, this isn't the first time the right solution to scope creep and pathologically excessive integration was to say 'But I don't actually want that.' When the 'crowd pushing systemd' (to borrow Rich Felker's phrase), in early day ballyhooed how great systemd's allegedly innovative daemon supervision was, I was right then administering many hundreds of CentOS Internet servers running (selected) critical daemons under Chris McDonough's Python-based supervisord -- so, my reaction was 'What, you think you systemd guys invented process supervision? And what else, the light bulb? Toilet paper?' (To answer Rich Felker's doubt-raising, yes, supervisord is IMO robust enough, and also the others he cites.) IMO, pretty nearly the only place the systemd suite has an arguably compelling advantage is an exotic one: cgroups controller. This makes systemd irritably difficult to avoid for containerised cloud computing, and, cgroup controllers have that Highlander quality that 'There can be only one' (in a running system). The systemd implementation is crammed like much else into PID1, which has operational advantages over the better-security alternative of _not_ running it out of PID1 (as does OpenRC's implementation, https://wiki.gentoo.org/wiki/OpenRC/CGroups ). [1] E.g., I remain unconvinced I need a half-dozen different ways to refer to a device node. -- Cheers, Rick MoenDiaeresis: Keeping the cow out of co-worker since 700 AD. r...@linuxmafia.com McQ! (4x80) ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] Felker Init: was without-systemd.org not working
On Saturday 16 May 2020 at 11:30:03, Steve Litt wrote: > You know, runit's or s6's process supervisor could be used, on systemd > systems, as a tobacco patch to wean the user off systemd, one process > at a time. As each daemon gets moved to runit or s6, that daemon's unit > file name gets put in a shellscript that disables systemd's execution > of that daemon. It's very easy to do. Surely one of the biggest problems (or at least, one of the things people complain most about) regarding systemd is that it is no longer just an init system. It may have been sold that way in the early days, but it's now infiltrated so many parts of the GNU / Linux system that just telling people (or showing them) that they can use something else to manage their daemons is no longer enough. Antony. -- Most people have more than the average number of legs. Please reply to the list; please *don't* CC me. ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
