Advantages of systemd over sysVinit

[dos2unix]

From CoPilot.

Let’s explore the advantages of systemd over SysVinit:

1. Parallelization and Faster Boot Times:
   • systemd aggressively parallelizes service startup, leading to faster boot times. It manages services concurrently, whereas in SysVinit, achieving parallelism requires manual effort12.
   • Automatic dependency handling in systemd contributes to efficient startup, whereas SysVinit lacks this feature2.
2. Dependency Resolution:
   • systemd automatically resolves dependencies between services. When a service depends on another, systemd ensures the correct order of startup.
   • In contrast, SysVinit relies on manual configuration for dependency management.
3. Monitoring and Service Restart:
   • systemd monitors started services and can automatically restart crashed services. This self-healing behavior enhances system reliability.
   • SysVinit lacks built-in monitoring and automatic restart capabilities.
4. Cgroups and Process Tracking:
   • systemd organizes daemons into their own Linux control groups (cgroups). This isolation allows better resource management and tracking of processes.
   • SysVinit does not provide native cgroup support.
5. Service Management with systemctl:
   • systemctl is the primary tool for managing systemd services. It allows users to start, stop, enable, disable, reload, and verify services.
   • In SysVinit, service management relies on traditional bash scripts, whereas systemd uses .service files.
6. Snapshotting and State Restoration:
   • systemd supports snapshotting and restoring the system state, which can be useful for system maintenance and troubleshooting.
   • SysVinit lacks such features.

In summary, systemd offers improved performance, dependency handling, monitoring, and modern features compared to the traditional SysVinit

 

[atanere]

Just joking around!

From CoPilot.

Let’s delve into some of the risks and downsides associated with using systemd:

1. Complexity and Bloat:
   • Systemd is not just an init system; it’s a collection of tightly integrated components that handle various aspects of system management.
   • Critics argue that this complexity can be seen as bloat and overreach, especially when compared to the Unix philosophy of “doing one thing and doing it well” 1.
2. Monoculture Concerns:
   • Systemd is widely adopted across modern Linux distributions. While standardization can be beneficial, there are concerns about relying on a single system for critical functions.
   • A monoculture increases the risk of widespread vulnerabilities if a security flaw is discovered in systemd 1.
3. Security Implications:
   • Systemd moves more logic into binaries and relies on a complex and poorly documented configuration.
   • While it provides security features, any bugs or misconfigurations can have significant security implications 2.
4. Dependency on Privileges:
   • Ironically, security often requires privileges. For example, services may need root privileges to set up custom mount namespaces or open low-numbered ports.
   • While the service manager (like systemd) runs with high privileges, services themselves shouldn’t. The hardening setup often necessitates elevated privileges 3.
5. Resistance from Traditionalists:
   • Some Linux users and administrators prefer the simplicity and predictability of older init systems like SysVinit.
   • The shift to systemd has faced resistance due to its departure from established practices 4.

In summary, while systemd offers powerful features and benefits, it’s essential to weigh these against the potential risks and consider alternatives based on specific use cases and preferences.

 

[ML_113]

The xz back door and Systemd

What we know about the xz Utils backdoor that almost infected the world

Malicious updates made to a ubiquitous tool were a few weeks away from going mainstream.

arstechnica.com

 

[ron.alan]

It boggles my mind that so many distros out there adopted systemd when there is also openRC and runit to choose from. Also, there is nothing wrong with systemv to begin with (that's what I still use).

 

[MikeWalsh]

From what I understand, it was more or less admitted - by whichever of the idiots at RedHat was responsible for it (Poettering, I believe?) - that systemd was a step further along the path toward the long-term goal of amalgamating all mainstream distros into one 'LinuxOS'.....and taking-on Microsoft at their own game.

I could be wrong, of course, but that's what I heard.....somewhere.

Mike.

 

[wizardfromoz]

In my stable of distros (80+) I have mostly systemd, a number of sysvinit, and also an openRC which runs Calculate Linux (Gentoo-based).

I like them all, and performance-wise cannot detect much if any, differences.

I am no expert in this regard.

Wizard

 

[ML_113]

I like them all, and performance-wise cannot detect much if any, differences.

On weak systems like mine 2G, 4G RAM DDR2, systemd slowness is markely shown.

 

[f33dm3bits]

The xz back door and Systemd

Not all Distributions the backdoor would work with systemd, since I read somewhere that the ssh server had to be compiled to with liblzma

Security Alert: Potential SSH Backdoor Via Liblzma

In breaking news that dropped just after our weekly security column went live, a backdoor has been discovered in the xz package, that could potentially compromise SSH logins on Linux systems. The m…

hackaday.com

 

[osprey]

Without having a preference one way or the other on the SysVinit versus systemd issue, there are a few issues that are significantly commented on here:

The Biggest Myths

Posts and writings by Lennart Poettering

0pointer.net

Another point worth noting is that a systemd system can run SysVinit scripts but the reverse is not the case. Systemd has a generator which wraps SysVinit scripts into systemd units, so users can write SysVinit scripts to the /etc/init.d/ and /etc/rc.# directories of a systemd system in perfect SysVinit formats and they'll run flawlessly. An inspection of systemd systems will usually show that the /etc directories that SysVinit traditionally uses still hold a number of scripts in current systemd installations, but it's systemd that runs them.

SysVinit can be made very minimal in a system in a way that systemd would find it hard to match. The systemd package has over 900 files and an installed size of over 11MB, and that's a basic installation without a number of other services. Not all services may be used, but the package itself is far in excess of a minimal collection of SysVinit executable scripts that would still be able to bring up a system effectively.

 

[CaffeineAddict]

Can somebody please list disadvantages?
There are people who complain about systemd but I never understood them...

 

[f33dm3bits]

Can somebody please list disadvantages?

One disadvantage is that it makes Linux software with systemd dependencies incompatible with other Unix-like systems such as the different BSD distributions.

 

[MikeWalsh]

Can somebody please list disadvantages?
There are people who complain about systemd but I never understood them...

I'll just say this; trying to explain the pros and cons of the various init systems to a fairly recent Linux convert would be like trying to describe the color blue to someone born blind. They've only ever known systemd.....so there's NO WAY they could possibly understand (since systemd will be all they've used).

Poettering's just a prat.....and a very self-centered one at that.


Mike.

 

[kc1di]

One disadvantage is that it makes Linux software with systemd dependencies incompatible with other Unix-like systems such as the different BSD distributions.

That may be the very Idea in the first place. Just a thought fedora/redhat/IBM would like to be the only Linux in the game.

 

[f33dm3bits]

That may be the very Idea in the first place. Just a thought fedora/redhat/IBM would like to be the only Linux in the game.

I haven't seen any evidence that Redhat/IBM wants to extinguish BSD. Sure such things happen but it's better not to overthink things. From what I've see systemd has brough more standardization to Linux when it comes to init systems, I wouldn't look for more behind it.

 

[f33dm3bits]

Sure such things happen but it's better not to overthink things

Just like I'm not when I come across people with red hair, I don't directly think. Hmm the planet Mars is red, so people with red hair must be Martians from Mars and not human beings.

 

[KGIII]

Let's remember to be civil, including to people who aren't forum members. Thanks!

That said, I don't mind systemd. When faced with using it, I learned a few new commands and moved on. The naysayers kind of crack me up, actually.

 

[f33dm3bits]

Let's remember to be civil, including to people who aren't forum members. Thanks!

I was just giving give an example as to why there isn't more to everything and not everything should be over thought, because Mars is red the only comparison I could think of is people with red hair being martians.

 

[dos2unix]

I posted 3 threads on the same day.
I got a little response about wayland, but not a lot.
I got hardly anything about pipewire.
But systemd... boy, that one seems to have struck a nerve somewhere.

the idiots at RedHat was responsible for it

Why Linux’s systemd Is Still Divisive After All These Years

systemd is 10 years old, but feelings about it in the Linux community haven’t mellowed—it’s as divisive now as it ever was. Although it’s used by many major Linux distributions, the hardcore opposition hasn’t relented.

www.howtogeek.com

fedora was the first distro to use it, so yeah, I guess you could say so.
But knowing some of these people personally, I don't think it had much to do with "monopolizing"
a standard. I think they genuinely felt it was better. Not everyone agrees of course.

Personally, I like the uniqueness of the mainstream distro's.
If you like a distro that uses sysV, great. If you like systemd, that's great too.
If you like dnf/rpm, use that. If you like deb/apt, use that.

But I have to wonder... what makes a particular technology received by most everyone, and another not?

Why do almost all mainstream distro's use systemd now? They didn't have to.
Why are almost all mainstream distro's going over to wayland? They don't have to.
Why did almost all mainstream distro's go to pipewire?
It seems all mainstream distro's have switched from networkd to NetworkManager for quite a while now.
( I suppose we can blame redhat/fedora for most of these ).

But yet, for package management, we still have pacman/yast2/dnf/apt.. pick your favorite flavor.
Then you have the default filesystems, some use xfs by default, some use btrfs by default, and still others use ext4
by default. Some distro's seem to like flatpack or snap, or appImage,
Some distro's prefer docker, other's use podman by default.

Why wasn't there a universal acceptance of these things? I don't know, but it gives us the freedom to choose
what we want to use.

 

[KGIII]

But systemd... boy, that one seems to have struck a nerve somewhere.

Post about Snap applications and watch that thread.

 

[kc1di]

But systemd... boy, that one seems to have struck a nerve somewhere.

I think the reason Systemd strikes such a nerve is the way it was introduced in the first place. I have no real problem with it. It works fine on the Ditros I've used that use it.