Recommended AWS AMI + Instance types for Centos

[#1]

I would like to use Centos7x, at least for gateway hosts. With Director 1.5, I never had any luck with Centos or multiple templates in one cluster, so I ended up using a sub-optimal instance type. I would like to use r3 series for gateways.

Director 2.x supports Centos 7x and Centos 7x for cdh5.7 and later; does it matter to Director which kind of hypervisor is used? r3 series is HVM. 

I see that the faq recommends finding AMIs with:

aws ec2 describe-images \
  --output table \
  --query 'Images[*].[VirtualizationType,Name,ImageId]' \
  --owners 309956199498 \
  --filters \
    Name=root-device-type,Values=ebs \
    Name=image-type,Values=machine \
    Name=is-public,Values=true \
    Name=hypervisor,Values=xen \
    Name=architecture,Values=x86_64 

but this specifies xen and RH. Does that mean only xen is supported? Presumably there is an equivalent AMI search command for centos7x. 

Is it okay to generate a cluster from multiple templates? 

Thanks!

[#2]

I'll answer your last question now, and get back to you with an answer to your questions about AMIs and hypervisors.

Each instance group in a cluster has an associated instance type, and it is common for different groups to use different instance types. For example, the instance type for a gateway will likely differ from the instance type for a master node.

[#3 · Accepted solution]

Director itself doesn't care whether the AMI uses HVM or PV, but EC2 instance types are often only compatible with a single virtualization type. As you say, Amazon recommends HVM for the R3 instance type.

Here's a pretty good blog post on virtualization types:

http://cloudacademy.com/blog/aws-ami-hvm-vs-pv-paravirtual-amazon/

That describe-images command is just an example, and you can change the parameters to suit the particular AMI details you are looking for.