Systemd equivalent to dhclient exit-hooks script
Hi, I configure a dhcp interface using systemd-networkd. When a new lease is acquired I need to reload some services. How can I do that? In other words: I'm looking for a systemd equivalent to dhclient exit hooks script. I'm on Debian 9. -- John Doe
Re: systemd equivalent
On Fri, Jun 12, 2015 at 05:53:52PM -0400, Bob Bernstein wrote: I need to steel myself to using systemd commands. What would be the systemd-correct form of this: $ ps ax | grep ssh I use that to check for the existence (or, as the case may be) demise) of an ssh tunnel I use for VNC. What should I use? Not directly answering your question here, but some alternative ways to ask your system the question Is there an 'ssh' process running?: $ ps ax | grep [s]sh# Avoids the grep process showing up $ pgrep ssh # Returns the PID of any 'ssh' processes Thanks all, -- For more information, please reread. signature.asc Description: Digital signature
Re: systemd equivalent
On 20150612_1753-0400, Bob Bernstein wrote: I need to steel myself to using systemd commands. What would be the systemd-correct form of this: $ ps ax | grep ssh I use that to check for the existence (or, as the case may be) demise) of an ssh tunnel I use for VNC. What should I use? Thanks all, Bob, and other posters on this thread; In another thread, Bob made reference to the Debian social contract. Here Bob is trying to discover some experiment that he can do to test, yes or no, whether his expectation about the answer to a simple query is still valid under systemd. He could have worded the question as: Does '$ ps ax | grep ssh' still work under systemd, and does it give results in same way, or a different way? But I don't think my suggested rewording is any better than his orginal wording, just different, with more words, which might have slowed some readers enough for their minds to keep up with there eyeballs, so they apprehend what the question really is. Everyone has expectations. All expectations are pre-conceptions. No one can know another person's expectations without a conversation. The flame wars over systemd have muddied the waters about systemd, as has been recently mentioned by another Bob in another thread on this list. HTH ;-) -- Paul E Condon pecon...@mesanetworks.net -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org Archive: https://lists.debian.org/20150615160931.gb15...@big.lan.gnu
Re: systemd equivalent
Bob Bernstein b...@fanatick.org writes: My initial question was _meant_ to be, simply: can this (ps ax|grep ssh) be done, or approximated to, using sysctl? No, systemd is not supposed to replace standard system utilities. (Also sysctl is a completely unrelated tool to configure kernel parameters; the systemd utility is systemctl.) However if you configure your ssh tunnel as a service that systemd manages, then you can query systemd about its state via systemctl or directly via systemd's DBus interface: Is the service running? systemctl is-active my-tunnel What is the services main process' PID? systemctl -pMainPID show my-tunnel Note that there is also a per-user instance of systemd to allow regular users to use systemd to manage their own services if they choose to do so. Not everything has to be a system service. Ansgar -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org Archive: https://lists.debian.org/87twuawrdh@deep-thought.43-1.org
Re: systemd equivalent
On Sun 14 Jun 2015 at 05:14:53 -0400, Bob Bernstein wrote: On Sun, 14 Jun 2015, Frederic Marchal wrote: Why do you think systemd has a way of doing everything other tools are designed for? That's not a thought I have ever harbored or expressed. My initial question was _meant_ to be, simply: can this (ps ax|grep ssh) be done, or approximated to, using sysctl? The first respondent seemed to be saying oh yes certainly and here is how to do that. No one but me took note that he was, regrettably, wrong. There is no need for any speculation aimed at getting at what I might be thinking about systemd or ps or anything else for that matter. If a question arises as to what I am thinking beyond what I have typed in an email, just ask me. I don't bite. I think everyone is trying to point out you have encountered the age-old Square Peg in a Round Hole conundrum. The Ancient Egyptians were puzzled by it when building the pyramids and it went on to stump Euclid. Recent research indicates it is related to the Barking up the Wrong Tree problem. -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org Archive: https://lists.debian.org/20150614111930.gk24...@copernicus.demon.co.uk
Re: systemd equivalent
On Sun, 14 Jun 2015, Frederic Marchal wrote: Why do you think systemd has a way of doing everything other tools are designed for? That's not a thought I have ever harbored or expressed. My initial question was _meant_ to be, simply: can this (ps ax|grep ssh) be done, or approximated to, using sysctl? The first respondent seemed to be saying oh yes certainly and here is how to do that. No one but me took note that he was, regrettably, wrong. There is no need for any speculation aimed at getting at what I might be thinking about systemd or ps or anything else for that matter. If a question arises as to what I am thinking beyond what I have typed in an email, just ask me. I don't bite. But when you indicate that you believe you know what Brian is thinking, well, all I can imagine is that he must be a struggling relative of yours, or something, in order to have earned that level of dedicated support on your part, although perhaps I do you both a disservice with such observations, and if that is the case please allow me to make haste to apologize. Thank you for your reply which was kind and well-intentioned. I will pursue my studies of systemd with heightened caution and circumspection. These are troubled waters indeed, yes? -- These are not the droids you are looking for. -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org Archive: https://lists.debian.org/nycvar.QRO.7.75.3.1506140441440.4342@arjgebyy.ybpnyqbznva
Re: systemd equivalent
On Sat, 2015-06-13 at 16:35 -0400, Bob Bernstein wrote: But it turns out I haven't yet found a way to do that, that is, replicate (more or less) the output of 'ps ax| grep ssh' using sysctl commands. They don't seem to register, as it were, my ssh tunnel. But systemd manages services (daemons) like sshd, but you set up the ssh tunnel using the client, ssh right? -- Cheers, Sven Arvidsson http://www.whiz.se PGP Key ID 6FAB5CD5 signature.asc Description: This is a digitally signed message part
Re: systemd equivalent
On Sun 14 Jun 2015 at 13:51:47 -0400, Bob Bernstein wrote: On Sun, Jun 14, 2015 at 12:19:30PM +0100, Brian wrote: I think everyone is trying to point out you have encountered the age-old Square Peg in a Round Hole conundrum. I knew you wouldn't let me down. *plonk* The objective is not to disappoint. -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org Archive: https://lists.debian.org/14062015192429.8481c2ebb...@desktop.copernicus.demon.co.uk
Re: systemd equivalent
On Sun, Jun 14, 2015 at 12:19:30PM +0100, Brian wrote: I think everyone is trying to point out you have encountered the age-old Square Peg in a Round Hole conundrum. I knew you wouldn't let me down. *plonk* -- Bob Bernstein -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org Archive: https://lists.debian.org/20150614175147.ga7...@sixtiessurvivor.org
Re: systemd equivalent
On Sun, 14 Jun 2015, Ansgar Burchardt wrote: No, systemd is not supposed to replace standard system utilities. I have never believed nor claimed that it was thus supposed to be anything of the sort. I framed a query about it, and various subscribers read into that what they wished. (Also sysctl is a completely unrelated tool to configure kernel parameters; the systemd utility is systemctl.) Ah. My bad. Thank you. However if you configure your ssh tunnel as a service that systemd manages, then you can query systemd about its state via systemctl or directly via systemd's DBus interface: Is the service running? systemctl is-active my-tunnel What is the services main process' PID? systemctl -pMainPID show my-tunnel Thank you. Note that there is also a per-user instance of systemd to allow regular users to use systemd to manage their own services if they choose to do so. Not everything has to be a system service. Thank you again. How I love simple facts. I have suspected all along that my destination was very likely configuring my tunnel via systemd, and perhaps even building in thereby some stay-alive capacity for said tunnel. -- These are not the droids you are looking for. -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org Archive: https://lists.debian.org/nycvar.QRO.7.75.3.1506141352400.4342@arjgebyy.ybpnyqbznva
Re: systemd equivalent
On Sun, Jun 14, 2015 at 07:25:36PM +0100, Brian wrote: On Sun 14 Jun 2015 at 13:51:47 -0400, Bob Bernstein wrote: On Sun, Jun 14, 2015 at 12:19:30PM +0100, Brian wrote: I think everyone is trying to point out you have encountered the age-old Square Peg in a Round Hole conundrum. I knew you wouldn't let me down. *plonk* The objective is not to disappoint. Otherwise stated as we aim to please. -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org Archive: https://lists.debian.org/14062015192429.8481c2ebb...@desktop.copernicus.demon.co.uk -- Bob Holtzman A fair fight is the result of poor planning. -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org Archive: https://lists.debian.org/20150614225950.ga23...@cox.net
Re: systemd equivalent
On Sat, 13 Jun 2015, Brian wrote: You don't mean that, do you? After all, you do use its functionality for booting. :) Thanks for that. You may be right. BUT...hrrrmmm...just to show that I can be as reasonable as the next fellow, allow me to ask if perhaps there was something actually helpful you wanted to mention here. I know how under the pressure of composing a post to a list things can slip one's mind. -- These are not the droids you are looking for. -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org Archive: https://lists.debian.org/nycvar.QRO.7.75.3.1506132246560.4342@arjgebyy.ybpnyqbznva
Re: systemd equivalent
On Saturday 13 June 2015 22:52:22 Bob Bernstein wrote: On Sat, 13 Jun 2015, Brian wrote: You don't mean that, do you? After all, you do use its functionality for booting. :) Thanks for that. You may be right. BUT...hrrrmmm...just to show that I can be as reasonable as the next fellow, allow me to ask if perhaps there was something actually helpful you wanted to mention here. I know how under the pressure of composing a post to a list things can slip one's mind. I'm thinking the same thing as Brian when I read your posts. I may be able to formulate his point of view differently. Why do you thing systemd has a way of doing everything other tools are designed for? In that instance, ps is designed to report active tasks. And that's just what your ssh tunnel is. It is a child process started by the ssh service started by systemd. Even if the top ssh service was started by systemd, it doesn't mean systemd has to provide every possible tool to keep track of everything the service might do (thankfully for that I would add!). You may be lured by the fact that systemd is responsible for the system journal. As a consequence, it does provide the tool to show the system log but every child process isn't registered in the log (or it might with the proper output level if the service support it but that's not the point here). Hope it helps, Frederic
Re: systemd equivalent
On Fri, 2015-06-12 at 17:53 -0400, Bob Bernstein wrote: I need to steel myself to using systemd commands. What would be the systemd-correct form of this: $ ps ax | grep ssh I use that to check for the existence (or, as the case may be) demise) of an ssh tunnel I use for VNC. What should I use? Not sure I follow, why would you use a different way to list processes just because you're using systemd? -- Cheers, Sven Arvidsson http://www.whiz.se PGP Key ID 6FAB5CD5 signature.asc Description: This is a digitally signed message part
Re: systemd equivalent
On Sat, 13 Jun 2015, Sven Arvidsson wrote: Not sure I follow, why would you use a different way to list processes just because you're using systemd? Well, the thing is, I am so gunshy about systemd that I am _not_ using its functionality for anything right now! SO, I thought I might coax myself into using it by finding substitutes for tried-and-true unix commands, such as 'ps ax|grep [something]. But it turns out I haven't yet found a way to do that, that is, replicate (more or less) the output of 'ps ax| grep ssh' using sysctl commands. They don't seem to register, as it were, my ssh tunnel. I wonder if this is a problem with ownership, i.e if by default sysctl will not consider processes started by non-system users, i.e. what we used to call ordinary users. I start my ssh tunnels as such a user, not as root or anything else fancy-schmancy. But then on my system it appears only root can launch sysctl. Hrrr. Thanks. I'm sorry if I seem all over the place here. -- These are not the droids you are looking for. -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org Archive: https://lists.debian.org/nycvar.QRO.7.75.3.1506131623240.4342@arjgebyy.ybpnyqbznva
Re: systemd equivalent
On Sat 13 Jun 2015 at 16:35:39 -0400, Bob Bernstein wrote: On Sat, 13 Jun 2015, Sven Arvidsson wrote: Not sure I follow, why would you use a different way to list processes just because you're using systemd? Well, the thing is, I am so gunshy about systemd that I am _not_ using its functionality for anything right now! You don't mean that, do you? After all, you do use its functionality for booting. :) SO, I thought I might coax myself into using it by finding substitutes for tried-and-true unix commands, such as 'ps ax|grep [something]. But it turns out I haven't yet found a way to do that, that is, replicate (more or less) the output of 'ps ax| grep ssh' using sysctl commands. They don't seem to register, as it were, my ssh tunnel. systemctl is about *control* of the system. ps is about giving a *report* on the current pocesses. Coercing either one into doing the job of the other seems doomed to failure. I wonder if this is a problem with ownership, i.e if by default sysctl will not consider processes started by non-system users, i.e. what we used to call ordinary users. I start my ssh tunnels as such a user, not as root or anything else fancy-schmancy. The problem lies outside the province of the software. But then on my system it appears only root can launch sysctl. Hrrr. If the command 'systemctl' gives no output you have a system problem. -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org Archive: https://lists.debian.org/20150613224353.gj24...@copernicus.demon.co.uk
systemd equivalent
I need to steel myself to using systemd commands. What would be the systemd-correct form of this: $ ps ax | grep ssh I use that to check for the existence (or, as the case may be) demise) of an ssh tunnel I use for VNC. What should I use? Thanks all, -- These are not the droids you are looking for. -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org Archive: https://lists.debian.org/nycvar.QRO.7.75.3.1506121750100.917@arjgebyy.ybpnyqbznva
Re: systemd equivalent
On Friday 2015-06-12 15:53, Bob Bernstein wrote: Date: Fri, 12 Jun 2015 15:53:52 From: Bob Bernstein poo...@ruptured-duck.com To: Debian User List debian-user@lists.debian.org Subject: systemd equivalent I need to steel myself to using systemd commands. What would be the systemd-correct form of this: $ ps ax | grep ssh I use that to check for the existence (or, as the case may be) demise) of an ssh tunnel I use for VNC. What should I use? My usual approach is to look for the name of the service, like so: systemctl -a|grep ssh On my Debian/Jessie box, I get: ssh.service loadedactive running OpenBSD Secure Shell server Then you can check status, like so: systemctl status ssh.service Assuming it's running, the output should include a listing of the sshd processes running. I still find systemd to be excessively complicated and the tools (especially systemadm) primitive, but at least now I have some idea as to how to work the system. --| John L. Ries | Salford Systems | Phone: (619)543-8880 x107 | or (435)867-8885 | --| Thanks all, -- These are not the droids you are looking for. -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org Archive: https://lists.debian.org/nycvar.QRO.7.75.3.1506121750100.917@arjgebyy.ybpnyqbznva -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org Archive: https://lists.debian.org/alpine.LSU.2.11.1506121627210.30769@snypbe.evrfraunhf.ybpny
Re: systemd equivalent
On Fri, 12 Jun 2015, John L. Ries wrote: Then you can check status, like so: systemctl status ssh.service The output of this command (above) doesn't change after a tunnel is started. My old clunky ps command tells me the tunnel is there: # ps ax |grep ssh 458 ?Ss 0:00 /usr/sbin/sshd -D 904 ?Ss 0:00 /usr/bin/ssh-agent /bin/bash /home/bob/.xsession 3503 pts/1S+ 0:00 ssh b...@fanatick.org 3613 ?S 0:00 ssh -N -T -L 4900:localhost:5901 sixtiessurvivor.org 3624 pts/3S+ 0:00 grep ssh But systemd tells me only: # systemctl status ssh.service ● ssh.service - OpenBSD Secure Shell server Loaded: loaded (/lib/systemd/system/ssh.service; enabled) Active: active (running) since Tue 2015-06-09 21:12:58 EDT; 2 days ago Main PID: 458 (sshd) CGroup: /system.slice/ssh.service └─458 /usr/sbin/sshd -D Jun 09 21:13:02 newtroll sshd[458]: Server listening on 0.0.0.0 port 22. Jun 09 21:13:02 newtroll sshd[458]: Server listening on :: port 22. Hrrrmmm -- These are not the droids you are looking for.
