

Virtual Bare Metal: DevStack Multi Node on EC2 - geertj
http://www.ravellosystems.com/blog/virtual-bare-metal-devstack-multi-node-ec2

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dkhenry
So can I run linux instances on this DevStack cluster that I can run VM's on
so I can host docker containers. I feel that two levels of virtualization is
not enough for me and would like three or four.

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sysexit
I guess you're being sarcastic.

What you describe is accurate. In fact, there's one level more because the
Linux instance you run is already running as a nested guest. So in your
scenario there's 3 hypervisors involved (Amazon Xen, Ravello HVX, KVM) and
then your Docker host.

More seriously, I am very bullish on Docker myself. But I see it as a
supplement rather than a replacement for virtualization.

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ewindisch
There is a Docker driver for Nova as well, so it's possible to use OpenStack's
Devstack and Nova projects to directly spawn containers. Unfortunately, it
abstracts away the Docker API, although you can use Docker-in-Docker if you
wish to maintain the ability to use other orchestration tools (which,
incidentally is the same model as running containers on VMs)

Eventually this should all be manageable by libswarm for various combinations
of containers on baremetal, containers on containers, or containers on VMs.

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sysexit
Docker on Docker is way cool.

The use case we're trying to solve here is a tad different though: it's to
provide virtual infrastructure for the "first level" i.e. in the case of
Docker the outer container host. For Docker the answer could be EC2, since
Docker itself doesn't need VT. However that precludes you from using KVM in
any layer below, which in turn means Linux only and fairly simple networking
(no multicasting even in VPC, and hence no VXLAN for example)

We very much wanted to create something to assist OpenStack developers in
developing OpenStack itself. It should be especially useful for projects such
as Nova, Neutron and Ironic.

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jlawer
I may be mistaken, but aren't the larger EC2 machines priced fairly linearly
with the improved resources? i.e. a machine with 2x the resources typically
costs 2x as much?

If this is the case then can someone let me know the use case? Is this for
better manageability? Or is it to overcommit (i.e. run 3x 4gb ram nodes on 8gb
of ram).

Other then that I can't see the advantage over dynamically spinning up & down
nodes as required directly on AWS.

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iamondemand
Hey, I'm working with the Ravello team. Happy to answer any questions.

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nonane
Hi there,

I'm struggling to understanding where OpenStack fits in and what features it
provides over a stock Ubuntu install or perhaps a CoreOS cluster? Does it
provide a consistent platform to deploy apps on?

Thanks!

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iamondemand
This is more a generic OpenStack question. But the way I look at it, OpenStack
is the "fabric" that can be used to create a large, distributed IaaS cloud
such as Amazon EC2. People are also using it to create on-premise, private
clouds. CoreOS on the other side is very much focused on Linux containers
(Docker).

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nonane
Thank you very much - this helps.

