Docker Compose: Cannot connect to Redis - docker

Question

I'm following the Docker Compose tutorial here
https://docs.docker.com/get-started/part5/#recap-optional
version: "3"
services:
web:
image: example/get-started:part-1
deploy:
replicas: 10
resources:
limits:
cpus: "0.1"
memory: 50M
restart_policy:
condition: on-failure
ports:
- "80:80"
networks:
- webnet
visualizer:
image: dockersamples/visualizer:stable
ports:
- "8080:8080"
volumes:
- "/var/run/docker.sock:/var/run/docker.sock"
deploy:
placement:
constraints: [node.role == manager]
networks:
- webnet
redis:
image: redis
ports:
- "6379:6379"
volumes:
- ./data:/data
deploy:
placement:
constraints: [node.role == manager]
networks:
- webnet
driver:
build: .
links:
- redis
networks:
webnet:
and while Redis seems to be running on myvm1, the app is unable to connect to it, and gives an error.
This is the app code in case it matters:
from flask import Flask
from redis import Redis, RedisError
import os
import socket
redis = Redis(host="redis", db=0, socket_connect_timeout=0, socket_timeout=0)
app = Flask(__name__)
#app.route("/")
def hello():
try:
visits = redis.incr("counter")
except RedisError:
visits = "<i>cannot connect to redis. Counter disabled</i>"
html = "<h3>Hello {name}!</h3>" \
"<b>Hostname:</b> {hostname}<br/>" \
"<b>Visits:</b> {visits}"
return html.format(name=os.getenv("NAME", "World"), hostname=socket.gethostname(), visits=visits)
if __name__ == "__main__":
app.run(host='0.0.0.0', port=80)
VM IPs:
myvm1 - virtualbox Running tcp://192.168.99.101:2376
v17.07.0-ce
myvm2 - virtualbox Running tcp://192.168.99.102:2376
v17.07.0-ce
Redis is running without errors on VM.
Any idea? There are many similar discussions online, but none helped yet.

Answer 1

If the redis is running on the VM , the binding might not be proper . Can you please check if its binding on 0.0.0.0 or else you need to edit the redis
config to bind on 0.0.0.0 and port for external service to connect to it