title: How to detect if AWS has sufficient capacity to launch r4 instances
body: <p>We keep running into this insufficient capacity way too often when we launch our cloudformation to create test environments. I've not found a way to proactively check if AWS can provide capacity to launch the number of instances of the specific type that we want. Is there really no way to check early instead of waiting each time for cloudformation to fail and resorting to using r3 type instances (besides adding more availability zones, i.e. not specifying them?)</p>
  
  <p>Error:</p>
  
  <pre><code>2018-01-15T03:45:24.202064 2018-01-15 03:44:34.868000+00:00 | CREATE_FAILED | AWS::EC2::Instance | SlaveNode1 | We currently do not have sufficient r4.xlarge capacity in the Availability Zone you requested (ap-northeast-1c). Our system will be working on provisioning additional capacity. You can currently get r4.xlarge capacity by not specifying an Availability Zone in your request or choosing , ap-northeast-1a.
  </code></pre>