[CentOS] Cemtos 7 : Systemd alternatives ?

Tue Jul 8 15:58:45 UTC 2014
Lamar Owen <lowen at pari.edu>

On 07/08/2014 11:37 AM, Always Learning wrote:
> Please see the link above. I used it to find the 'stateless' item, and
> after selecting it clicked on
>
> http://0pointer.de/blog/projects/stateless.html
There are many use cases involving servers where such a capability would 
be highly desirable.  Most are cloud-oriented, where you want to spin up 
an instance rapidly (to deal with increased load, perhaps) and then spin 
it down, and having dynamically loaded /etc and /var content allows this 
in a smooth manner.  Static servers have their uses, of course, but at 
least in my data center I find actual server load to be very dynamic, 
but power load to be rather static; why *shouldn't* the power used be 
proportional to the work load?

The real promise of 'cloud' technology is for us in in-house servers 
that can spin up only when needed, saving power and cooling costs in the 
process.  Stateless is not the only way to go, of course, and nothing in 
the blog post to which you link is 'never again honor anything in /etc 
and /var' to be found, but rather, much like /etc serves as a fall-back 
for many programs who look first in a dot-file in ~, the content in /usr 
serves as an OS-default fallback to the per-system (or per-instance) 
configuration and state in /etc and /var.

It is a different way of looking at things, for sure, but I can 
definitely see a server use-case for this sort of thing, especially 
since there is significant budget pressure to reduce power costs.

And dynamic spinup of servers to handle increased load is a use case for 
systemd's rapid bootup.  They go hand-in-hand.

The Unix philosophy unfortunately sometimes misses the forest for all of 
the trees.   Sometimes tools need to actually be designed to work 
together, and sometimes a Swiss Army Knife is the right thing to have.

(And I'm an old Unix hack, too, having used Unix of several flavors 
since before Linux was even a gleam in Linus' eyes).