[chef] Re: RE: Re: Chef Server for HA

["Julian C. Dunn" < >]

On Tue, Apr 8, 2014 at 9:03 AM, Sachin Kumar 
<
 >
 wrote:

> My aim is to install chef server for high availability in different AZ's
> in AWS.  So that if one AZ goes down, my chef server will be running in
> different availability zone.
>
> I am ok, if I have to use Enterprise chef server.

So just to clarify some terminology then:

* Hosted Enterprise Chef == the Enterprise Chef installation we run at
manage.opscode.com. As it's "hosted", you don't need to set up a
server at all.
* Private Enterprise Chef == an on-premise Enterprise Chef server that
you would run in your own infrastructure (be that AWS or a data
center)

I am assuming that you are talking about the latter.

The current deployment scenario for Private Enterprise Chef does not
support AWS. In particular, the HA scenario is incompatible with AWS
because the shared DRBD volume requires a low-latency link between the
two back-end machines for fast failover.

That said, if you want to experiment outside of the bounds of what's
supported, here is the scenario with which I would deploy Private
Enterprise Chef into AWS. Disclaimer: no warranty express or implied,
my employer doesn't officially support this, etc. :)

* Use a VPC. Put the FE boxes in a public subnet, the BE box in a private one.
* Set up N frontends, as many as you need, behind an ELB.
* Set up an autoscaling group for 1 backend. If it dies, Autoscaling
will bring up another one. Set up DHCP options so that this new
instance always gets the same IP.
* Store Chef's data in a separate EBS volume that you can reattach
automatically to a reborn backend instance. Snapshot the EBS
regularly.
* Store the generated keys from the bootstrap procedure in S3 or
somewhere that you can retrieve them if the backend dies.
* Optionally, store the cookbooks in S3.
* Use CloudFormation to orchestrate this entire setup.

If you want to hit me up off-list to talk about this, I'm happy to,
since this probably isn't of much interest to folks who aren't
purchasing Private Enterprise Chef.

- Julian

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[ Julian C. Dunn 
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