Add [optional] explicit IAM role specification to NodeDrainer

[ivanilves]

Add [optional] explicit IAM role specification to NodeDrainer.

If you are happy kube2iam user depending on your setup you may want no AWS credentials being available on pods having no IAM role specifications. At least I believe default access is an evil thing to be avoided.

[ivanilves]

Maybe, not sure, but specifying explicit IAM role could help with #1105

[mumoshu]

@ivanilves Thanks for the fix. Yes, I began to believe we'd need to do this everywhere!

Btw, would you mind naming it iamRole.arn? So that we could enhance it to understand e.g. iamRole.create: true to let kube-aws create the role for you in the future.

[codecov-io]

Codecov Report

Merging #1123 into master will increase coverage by 0.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #1123      +/-   ##
==========================================
+ Coverage   35.23%   35.25%   +0.01%     
==========================================
  Files          63       63              
  Lines        3735     3736       +1     
==========================================
+ Hits         1316     1317       +1     
  Misses       2207     2207              
  Partials      212      212

Impacted Files	Coverage Δ
model/node_drainer.go	100% <ø> (ø)	⬆️
core/controlplane/config/config.go	61.58% <100%> (+0.04%)	⬆️

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[ivanilves]

Hey @mumoshu I've followed your advice.

Could you please re-review and comment, maybe something more needs to be changed?

[mumoshu]

@ivanilves Thanks a lot for taking your time! LGTM.

[ivanilves]

Thank you! ☺️ 👏