[CentOS] What are the differences between systemd and non-systemd Linux distros?

[Japheth Cleaver]

On 10/16/2018 10:27 AM, Jonathan Billings wrote:
> On Tue, Oct 16, 2018 at 09:25:15AM -0500, Valeri Galtsev wrote:
>
>> Also, it is likely that at some point
>> systemd-free Linux distribution(s) may fade away.
> There was already a move away from SysV init before systemd was
> introduced, heck RHEL6/CentOS6 used Upstart instead of SysV.  There
> are always going to be projects with a diverse set of tools, it just
> depends on how many people care about it.  Turns out, not that many
> people care about maintaining a SysV init (or other init) distro.
>

I'm not sure that that necessarily follows. Among RH-ecosystem 
distributions, and specifically RHEL derivatives, there's a barrier to 
the usefulness of smaller projects given that a large chunk of the users 
need binary-compatible commercial equivalents, or at least vaguely 
commercially supported ecosystems. We're long past the days where WBEL 
and other hobbyist projects can probably gain traction. Those RHEL 
alternatives that do exist either have a long history (CentOS, even 
before the RH deal), or are supported by large entities: the government 
(SL, before it became more or less congruent with CentOS), a multi 
billion dollar company (OEL), or a trillion dollar company (AWS). SuSE 
Enterprise might be the best counter example here.

Also, while EL6 did move from original init to upstart, that's somewhat 
beside the point. Almost none of the advanced features from upstart were 
used, and - crucially - the startup sequence was still handled with 
grokkable, imperative scripts. The jump from EL6->EL7 was night and day 
compared to EL5->EL6.

-jc