Spring boot app fail to link consul in docker

Question

I am trying to use Consul as discovery service, and another two spring boot app to register with Consul; and put them into docker;

following are my codes: app:

server:
  port: 3333

spring:
  application:
    name: adder
  cloud:
    consul:
      host: consul
      port: 8500
      discovery:
        preferIpAddress: true
        healthCheckPath: /health
        healthCheckInterval: 15s
        instanceId: ${spring.application.name}:${spring.application.instance_id:${server.port}}

2 docker-compose.yml

 consul1:
  image: "progrium/consul:latest"
  container_name: "consul1"
  hostname: "consul1"
  command: "-server -bootstrap -ui-dir /ui"
 adder:
  image: wsy/adder
  ports:
   - "3333:3333"
 links:
   - consul1
 environment:
   WAIT_FOR_HOSTS: consul1:8500

There is another similar question Cannot link Consul and Spring Boot app in Docker; the answer suggests, the app should wait for consul to fully work by using depends_on, which I tried, but didn't work;

the error message is as following:

adder_1    | com.ecwid.consul.transport.TransportException: java.net.ConnectException: Connection refused
adder_1    |    at com.ecwid.consul.transport.AbstractHttpTransport.executeRequest(AbstractHttpTransport.java:80) ~[consul-api-1.1.8.jar!/:na]
adder_1    |    at com.ecwid.consul.transport.AbstractHttpTransport.makeGetRequest(AbstractHttpTransport.java:39) ~[consul-api-1.1.8.jar!/:na]

---

besides spring boot application.yml and docker-compose.yml, following is App's Dockerfile

FROM java:8

VOLUME /tmp
ADD adder-0.0.1-SNAPSHOT.jar app.jar
RUN bash -c 'touch /app.jar'
ADD start.sh start.sh
RUN bash -c 'chmod +x /start.sh'
EXPOSE 3333
ENTRYPOINT ["/start.sh", " java -Djava.security.egd=file:/dev/./urandom    -jar /app.jar"]

and the start.sh

#!/bin/bash

set -e

wait_single_host() {
  local host=$1
  shift
  local port=$1
  shift

  echo "waiting for TCP connection to $host:$port..."

  while ! nc ${host} ${port} > /dev/null 2>&1 < /dev/null
  do
    echo "TCP connection  [$host] not ready, will try again..."
    sleep 1
 done

  echo "TCP connection ready. Executing command [$host] now..."
}

 wait_all_hosts() {
  if [ ! -z "$WAIT_FOR_HOSTS" ]; then
   local separator=':'
   for _HOST in $WAIT_FOR_HOSTS ; do
      IFS="${separator}" read -ra _HOST_PARTS <<< "$_HOST"
      wait_single_host "${_HOST_PARTS[0]}" "${_HOST_PARTS[1]}"
    done
   else
     echo "IMPORTANT : Waiting for nothing because no $WAIT_FOR_HOSTS env var defined !!!"
   fi
  }

  wait_all_hosts

  exec $1

Answer 1

I can infer that your Consul configuration is located in your application.yml instead of bootstrap.yml, that's the problem.

According to this answer, bootstrap.yml is loaded before application.yml and Consul client has to check its configuration before the application itself and therefore look at the bootstrap.yml.

Example of a working bootstrap.yml :

spring:
  cloud:
    consul:
      host: consul
      port: 8500
      discovery:
        prefer-ip-address: true

1. Run Consul server and do not forget the name option to match with your configuration:

   docker run -d -p 8500:8500 --name=consul progrium/consul -server -bootstrap

2. Consul server is now running, run your application image (builded previously with your artifact) and link it to the Consul container:

   docker run -d -name=my-consul-client-app --link consul:consul acme/spring-app