Why is dockerized config client unable to connect to dockerized config server - ssl

Question

I'm out of ideas on this and appreciate any suggestions. I have a handful of dockerized springboot microservices which include a config server. Here are the characteristics:
Springboot version 2.3.0-RELEASE
Standard Springboot config server with basic auth turned on.
3 Springboot microservices that are also config clients to config server.
-- I use a simple Dockerfile model for microservices and springboot maven plugin with default docker layers capabilities.
SSL is enabled for all including the config server.
-- For dev and testing, I use a self signed cert.
All microservices use a JKS to sign JWTs
Docker image for java is openjdk8 alpine.
Docker compose is used to orchestrate container launch and settings.
The docker container for config server runs perfectly fine. I can even query for config via a browser following the HTTPS URL: https://app-dev.localhost.com:8443/config-server/shopping-svc/dev.
The Problem
I cannot manage to successfully start container 'shopping-svc'. It fails with this error.
2023-01-25T23:44:12.375221300Z
2023-01-25 23:44:12.575 INFO 1 --- [ main] c.c.c.ConfigServicePropertySourceLocator : Fetching config from server at : https://app-dev.localhost.com:8443/config-server
2023-01-25 23:44:12.829 INFO 1 --- [ main] c.c.c.ConfigServicePropertySourceLocator : Connect Timeout Exception on Url - https://app-dev.localhost.com:8443/config-server. Will be trying the next url if available
2023-01-25 23:44:12.836 ERROR 1 --- [ main] o.s.boot.SpringApplication : Application run failed
2023-01-25T23:44:12.837487100Z
java.lang.IllegalStateException: Could not locate PropertySource and the fail fast property is set, failing
at org.springframework.cloud.config.client.ConfigServicePropertySourceLocator.locate(ConfigServicePropertySourceLocator.java:155) ~[spring-cloud-config-client-2.2.8.RELEASE.jar:2.2.8.RELEASE]
at org.springframework.cloud.bootstrap.config.PropertySourceLocator.locateCollection(PropertySourceLocator.java:52) ~[spring-cloud-context-2.2.9.RELEASE.jar:2.2.9.RELEASE]
at org.springframework.cloud.config.client.ConfigServicePropertySourceLocator.locateCollection(ConfigServicePropertySourceLocator.java:170) ~[spring-cloud-config-client-2.2.8.RELEASE.jar:2.2.8.RELEASE]
at org.springframework.cloud.bootstrap.config.PropertySourceBootstrapConfiguration.initialize(PropertySourceBootstrapConfiguration.java:98) ~[spring-cloud-context-2.2.9.RELEASE.jar:2.2.9.RELEASE]
at org.springframework.boot.SpringApplication.applyInitializers(SpringApplication.java:626) [spring-boot-2.3.0.RELEASE.jar:2.3.0.RELEASE]
at org.springframework.boot.SpringApplication.prepareContext(SpringApplication.java:370) [spring-boot-2.3.0.RELEASE.jar:2.3.0.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:314) [spring-boot-2.3.0.RELEASE.jar:2.3.0.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1237) [spring-boot-2.3.0.RELEASE.jar:2.3.0.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) [spring-boot-2.3.0.RELEASE.jar:2.3.0.RELEASE]
at com.shopping.app.ShoppingApplication.main(ShoppingApplication.java:35) [classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_212]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_212]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_212]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_212]
at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:49) [application/:na]
at org.springframework.boot.loader.Launcher.launch(Launcher.java:109) [application/:na]
at org.springframework.boot.loader.Launcher.launch(Launcher.java:58) [application/:na]
at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:88) [application/:na]
Caused by: org.springframework.web.client.ResourceAccessException: I/O error on GET request for "https://app-dev.localhost.com:8443/config-server/shopping-app/dev": Connection refused (Connection refused); nested exception is java.net.ConnectException: Connection refused (Connection refused)
at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:748) ~[spring-web-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:674) ~[spring-web-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at org.springframework.web.client.RestTemplate.exchange(RestTemplate.java:583) ~[spring-web-5.2.6.RELEASE.jar:5.2.6.RELEASE]
Investigations
At first, I thought perhaps the port 8443 is blocked somehow by my OS firewall but that's not it. Clearing the port makes no difference
Then I thought, perhaps it's a cert issue so I tried supplying the cert differently with the JAVA_TOOL_OPTIONS argument with the override populated: -Djavax.net.ssl.trustStore=/path/to/cert, etc... No dice.
I read several posts and articles suggesting services inside docker containers should refer to others via service name. While this poses a bit of confusion for me since my certs are generated against a hostname, I tried swapping the URL of config server in shopping-app YML to something like: https://config-server:8443/config-server/ or the same without https to see if at least successful connection would be made.
Last thing I tried was to change the compose network driver to 'host' instead of 'bridge' so the containers would use the host machine network config. The rationale was that at least, it's obvious it's all on same network.
I am not sure what or where to look anymore
References
=====
Docker compose file:
version: "3"
networks:
default:
driver: bridge
frontend:
driver: bridge
backend:
driver: bridge
services:
config-server:
image: config-server
env_file: .env
hostname: app-dev.localhost.com # Not sure this is necessary I add this because the self signed cert was generated with this domain name
volumes: #I'm developping on windows, hence the backslash "\"
- shoppingapp:/var/opt
- shoppingapp\certs\server.jks:/etc/certs/server.jks
- shoppingapp\certs\ssl/app-dev.localhost.com.p12:/etc/certs/ssl/app-dev.localhost.com.p12
ports:
- "8443:8443"
networks:
- backend
shopping-svc:
image: shopping-svc
env_file: .env
hostname: app-dev.localhost.com # Not sure this is necessary I add this because the self signed cert was generated with this domain name
volumes:
- shoppingapp:/var/opt
- shoppingapp\certs\server.jks:/etc/certs/server.jks
- shoppingapp\certs\ssl\app-dev.localhost.com.p12:/etc/certs/ssl/app-dev.localhost.com.p12
ports:
- "8444:8444"
depends_on:
config-server:
condition: service_started
networks:
- backend