AWS Elasticsearch EC2 instance cannot see each other when xpack security turned on

[duc (trinh huu duc)]

Hello,
Im working on EC2 instances and deploying elasticsearch v6.8 on them. My config is as follow:

Node1:

cluster.name: <cluster_name>
node.name: <node1_name>

node.master: true
node.data: true
node.ingest: true

discovery.zen.hosts_provider: ec2
discovery.zen.ping.unicast.hosts: [<node1_private_ipv4>, <node2_private_ipv4>]

discovery.ec2.endpoint: ec2.ap-southeast-1.amazonaws.com
discovery.ec2.protocol: http

network.host: [<node1_private_ipv4>]

Node2:

cluster.name: <cluster_name>
node.name: <node2_name>

node.master: true
node.data: true
node.ingest: true

discovery.zen.hosts_provider: ec2
discovery.zen.ping.unicast.hosts: [<node1_private_ipv4>, <node2_private_ipv4>]

discovery.ec2.endpoint: ec2.ap-southeast-1.amazonaws.com
discovery.ec2.protocol: http

network.host: [<node2_private_ipv4>]

This works fine. If I add

xpack.security.enabled: true

then 2 nodes cannot find each other.
Thank you for your help

[duc (trinh huu duc)]

Ok, I resolved this problem by deploying TLS/SSL as instructed here
Any admin/mod please close this topic.

Thanks