Kibana can't reach elasticsearch - docker

Question

Using docker-compose v3 and deploying to a swarm:
version: '3'
services:
elasticsearch:
image: docker.elastic.co/elasticsearch/elasticsearch:5.4.1
deploy:
replicas: 1
ports:
- "9200:9200"
tty: true
kibana:
image: docker.elastic.co/kibana/kibana:5.4.1
deploy:
mode: global
ports:
- "5601:5601"
depends_on:
- elasticsearch
tty: true
I see this in the kibana service log:
Unable to revive connection: http://elasticsearch:9200/
Elasticsearch service is running and can be reached.
Swarm consists of 3 nodes.
What am I missing?
Update:
I turns out that if I try to access kibana on the same swarm node where elasticsearch is running, it works. All other nodes either have a network problem or cannot resolve the elasticsearch name.

Answer 1

I found the reason, and the solution.
My swarm is running on AWS - All nodes are placed in the same security group and I assumed all ports were open internally in that security group. That's not the case.
I explicitly configured the security group to allow inbound traffic as per dockers routing mesh specs here: https://docs.docker.com/engine/swarm/ingress/

Answer 2

Docker-compose by default generates a network and puts all services within it. But I do not know if it changes in docker swarm. To define it you can do this.
version: '3'
services:
elasticsearch:
image: docker.elastic.co/elasticsearch/elasticsearch:5.4.1
deploy:
replicas: 1
ports:
- "9200:9200"
tty: true
networks:
- some-name
kibana:
image: docker.elastic.co/kibana/kibana:5.4.1
deploy:
mode: global
ports:
- "5601:5601"
links:
- elasticsearch
depends_on:
- elasticsearch
tty: true
networks:
- some-name
networks:
some-name:
driver: overlay
I hope it serves you, I will wait for news.