

Ask HN: Why use lxc/Docker/Puppet? - hardwaresofton

What are the actual use cases for these things? I have a raspberri pi which I use as a testing environment for applications I&#x27;m developing, and I generally worry about setup once, and then never again...<p>Though I understand the low level benefits and lightness over traditional virtualization, I just don&#x27;t know what I would even use this for, concretely.<p>At this point, the only use case I can imagine is during the development of an app (let&#x27;s say a Flask app), deploying something like Docker to create a container for an apache + redis + *sql + flask environment preloaded with the app that will start running immediately and give me a network address at which I can look at changes&#x2F;test the webapp.<p>I don&#x27;t see how much more beneficial this is compared to doing some setup on the rpi, and just updating the files stored therein and managing the server from over SSH
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wmf
DevOps in general is about speed and repeatability of provisioning. It tends
to kick in when you need, say, 5 Apaches, 7 Redises, and perhaps 3 *SQL slaves
to handle your traffic.

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hardwaresofton
Thanks for the response - So here's more questions if you wouldn't mind
answering.

I know much less about DevOps (mostly because I don't manage large production
servers) -- If you have 5 Apaches on one machine, where is the benefit vs one
apache?

What I'm assuming is, 5 apaches on one machine mean you can load balance to
the different apaches (assuming you have some system in place to handle
replication of the site html/css/js/etc to all these instances) -- and you can
have only sections go down? Or is it to just make the failure more
predictable?

In the case of system failure, all the containers go down, so I don't know
that I see the benefit there.

Also, if you have some literature on general devops things (I feel like this
is stuff I should at least know already), feel free to drop some links, I'll
click through.

EDIT - I DDG'd, have some stuff I am reading now, but feel free to answer
whatever you feel like answering

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wmf
I mean you'd have 5 Apaches on different servers because one server couldn't
handle the load. You want those servers to be identical, so your deployment
needs to be repeatable.

I don't know any links offhand that are better than what you can probably find
by searching, so I'll leave it at that.

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makerops
In addition to this, consider if your rasberry pi breaks, or you decide to add
a second one, rather than have to set it up from scratch again, you just apply
a manifest/cookbook/etc. I guess that falls into the repeatable part of the
statement, now that I read it aloud.

