The instructions for installing Mesosphere DC/OS on AWS use a CloudFormation template where the minimum configuration indicates:
You have the option of 1 or 3 Mesos master nodes. 5 private Mesos agent nodes is the default. 1 public Mesos agent node is the default.
For our POC, as not to incur too much up-front cost, is it possible to do this all with two nodes? One for DC/OS and the other containterized with ElasticSearch and Kafka?
If not, what would be a good configuration for this type of architecture?
DC/OS does not run on Docker Swarm or Kubernetes. But you can run a development docker-in-docker local deployment on linux (or in a VM on mac/windows): dcos-docker
You could then install ElasticSearch and Kafka on top of DC/OS.
You could also use dcos-vagrant to run a multiple VM DC/OS local dev cluster.
Warning: the current vagrant v1.9.1 has a crippling centos network bug, if you need a VM. dcos-vagrant has a monkey patch workaround included, dcos-docker does not.