[CentOS] Cemtos 7 : Systemd alternatives ?

[Rainer Duffner]

Am 12.07.2014 um 17:08 schrieb Lamar Owen <lowen at pari.edu>:

> [I wasn't going to reply; but after thinking about it for quite a while, 
> there are a few points here that deserve just a bit of level-headed 
> attention.]
> 
> On 07/11/2014 10:53 AM, David G. Miller wrote:
>> Les Mikesell <lesmikesell at ...> writes:
>> 
>>> Or, if you want things to respawn, the original init handled that 
>>> very nicely via inittab.
> 
> Replying to Les' comment:  the original inittab respawn method is 
> completely brain-dead, blindly respawning without any thought for what 
> conditions might need to be checked, etc.



That’s probably true.

But still, I believe that much of the complexity of systemd (that it apparently has) comes from the fact that it’s most intended to provide a „smooth“ desktop experience.

Now, it looks like almost everything is a „service“.

Can I pick an example?

[root at ipa ~]# systemctl list-unit-files |grep ssh
sshd-keygen.service                         static  
sshd.service                                enabled 
sshd at .service                               static  
sshd.socket                                 disabled


What is the difference between sshd.service and sshd at .service?
Am I right in assuming that the sshd-keygen.service is responsible for creating the initial host-keys?

I may be wrong, but sshd works nice on my 100+ servers without a special service for this. In fact, I loathed the Solaris-behavior, where you had to „refresh“ the service for this (or something to this effect)
On FreeBSD, if I want to create new keys, I delete the old ones and restart the service.
I very rarely need that, so I just assume it’s the same on RHEL. 

Can anyone give an example from a stock RHEL7 install that could not have been done with a traditional SysV-init?