Adding a guide for admins to set up federation

[nikhiljindal]

Supercedes #656

cc @kubernetes/sig-cluster-federation @colhom @mml

Guide with steps for admin to setup federation

[nikhiljindal]

cc @kubernetes/docs @kubernetes/docs-review-team @johndmulhausen @lavalamp

[nikhiljindal]

Also updated _data/guides.yml to add a link to navigation menu on left.

[madhusudancs]

s/secret their/secret there/

[nikhiljindal]

good catch, thx!
fixed

[madhusudancs]

@nikhiljindal Few minor nits, LGTM otherwise. Feel free to apply the LGTM label after addressing the comments.

[jamiehannaford]

Adding my comments from #656:

One important thing that isn't included here is how DNS works. Right now AWS and GCE are supported, but the docs don't mention how/why DNS is used, or how users can add their own DNS provider.

Another thing that isn't clear is whether resources - like pods or services - can exist at the federation level, i.e. in the federation-cluster context. The use case would be: I want a pod to exist at the top level which intercepts and parses a request, finds a region value, then passes it on to the relevant cluster. If this is not possible, each cluster will need to run that pod and forward on accordingly after the federation load balancer stage.

[jamiehannaford]

What does the client-cidr refer to here?

If I have a cluster from another region I want to add (with its own load balancer), where would I find the CIDR?

[nikhiljindal]

added some explanation.
If you have a globally accessible IP address for that cluster, then you can just set the CIDR to "0.0.0.0/0"

[johndmulhausen]

@nikhiljindal ping

[nikhiljindal]

Updated code as per comments, PTAL

[jamiehannaford]

@nikhiljindal Hey, would you also mind addressing my comment above?

[johndmulhausen]

KUBERNETES_PROVIDER (backticks) -- this goes for all the env vars, just mentioning it once here

[nikhiljindal]

done

[nikhiljindal]

Apologies @jamiehannaford for missing your comment earlier.

One important thing that isn't included here is how DNS works. Right now AWS and GCE are supported, but the docs don't mention how/why DNS is used, or how users can add their own DNS provider.

Have added some info on how/why DNS is used with explanation for FEDERATION_DNS_PROVIDER env var.

Another thing that isn't clear is whether resources - like pods or services - can exist at the federation level, i.e. in the federation-cluster context. The use case would be: I want a pod to exist at the top level which intercepts and parses a request, finds a region value, then passes it on to the relevant cluster. If this is not possible, each cluster will need to run that pod and forward on accordingly after the federation load balancer stage.

IIUC, this is like a federated ingress object that is backed by pods from all clusters?
It is on our roadmap but may or may not make it in 1.4.

[johndmulhausen]

with a federation

[nikhiljindal]

well its not just a federation. Its the federation that we are setting up.

[johndmulhausen]

You could also say "with the federation" if you like that better. Just not "with federation" which is not grammatically correct. :)

[nikhiljindal]

Fixed

[nikhiljindal]

Thanks @johndmulhausen
Updated code as per comments

[mml]

We need to fix federation/manifests/federation-apiserver-deployment.yaml before telling customers to bring up a cluster this way, since as of right now the federation etcd is not backed by persistent storage.

[nikhiljindal]

As discussed have added a note to say so.

[nikhiljindal]

Updated the code as per comments

[johndmulhausen]

Thanks, @nikhiljindal ! Merging based on previous LGTMs from tech reviewers here