Elasticsearch auto discovery with AWS - elasticsearch

Question

Hi running Elasticsearch 1.6.0 and AWS plugin 2.6.0 on Windows 2008 in Amazon.
I have AWS plgin setup, I don't get any Exception in the logs but the nodes can't seem to dicover each other.
bootstrap.mlockall: true
cluster.name: my-cluster
node.name: "ES MASTER 01"
node.data: false
node.master: true
plugin.mandatory: "cloud-aws"
cloud.aws.access_key: "AK...Z7Q"
cloud.aws.secret_key: "gKW...nAO"
cloud.aws.region: "us-east"
discovery.zen.minimum_master_nodes: 1
discovery.type: "ec2"
discovery.ec2.groups: "Elastic Search"
discovery.ec2.ping_timeout: "30s"
discovery.ec2.availability_zones: "us-east-1a"
discovery.zen.ping.multicast.enabled: false
Logs:
[2015-07-13 15:02:19,346][INFO ][node ] [ES MASTER 01] version[1.6.0], pid[2532], build[cdd3ac4/2015-06-09T13:36:34Z]
[2015-07-13 15:02:19,346][INFO ][node ] [ES MASTER 01] initializing ...
[2015-07-13 15:02:19,378][INFO ][plugins ] [ES MASTER 01] loaded [cloud-aws], sites []
[2015-07-13 15:02:19,440][INFO ][env ] [ES MASTER 01] using [1] data paths, mounts [[(C:)]], net usable_space [6.8gb], net total_space [29.9gb], types [NTFS]
[2015-07-13 15:02:26,461][INFO ][node ] [ES MASTER 01] initialized
[2015-07-13 15:02:26,461][INFO ][node ] [ES MASTER 01] starting ...
[2015-07-13 15:02:26,851][INFO ][transport ] [ES MASTER 01] bound_address {inet[/0:0:0:0:0:0:0:0:9300]}, publish_address {inet[/172.30.0.123:9300]}
[2015-07-13 15:02:26,866][INFO ][discovery ] [ES MASTER 01] my-cluster/SwhSDhiDQzq4pM8jkhIuzw
[2015-07-13 15:02:56,884][WARN ][discovery ] [ES MASTER 01] waited for 30s and no initial state was set by the discovery
[2015-07-13 15:02:56,962][INFO ][http ] [ES MASTER 01] bound_address {inet[/0:0:0:0:0:0:0:0:9200]}, publish_address {inet[/172.30.0.123:9200]}
[2015-07-13 15:02:56,962][INFO ][node ] [ES MASTER 01] started
[2015-07-13 15:03:13,455][INFO ][cluster.service ] [ES MASTER 01] new_master [ES MASTER 01][SwhSDhiDQzq4pM8jkhIuzw][WIN-3Q4EH3B8H1O][inet[/172.30.0.123:9300]]{data=false, master=true}, reason: zen-disco-join (elected_as_master)
[2015-07-13 15:03:13,517][INFO ][gateway ] [ES MASTER 01] recovered [0] indices into cluster_state

Answer 1

It can surely work with private IP, if and only if your node instances are able to access ec2 information on the same VPC in order to find out about the Cluster it should join.
you can set this Discovery Permission as a policy as the following and apply it to your IAM role:
{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "whatever",
"Effect": "Allow",
"Action": [
"s3:GetObject",
"ec2:DescribeAvailabilityZones",
"ec2:DescribeInstances",
"ec2:DescribeRegions",
"ec2:DescribeSecurityGroups",
"ec2:DescribeTags"
],
"Resource": [
"*"
]
}
]
}