Spring boot java Docker connecting mongoDB in K8s - spring-boot

Question

I am struggling to connect mongodb using spring boot docket application, Below are the further details.
a) Created a mongoDB cluster in minikube.
b) Exposed an external service which connects to the mongodb. The service exposed was through Nodeport. Below is the code snippet.
mongo-service
---------------
`apiVersion: v1
kind: Service
metadata:
name: mongodb-external-service
spec:
selector:
app: mongodb
type: NodePort
ports:
- port: 27017
protocol: TCP
targetPort: 27017
nodePort: 32000
c) Minikube exposed the service with IP 192.168.49.2
d) I was able to connect mongodb using 192.168.49.2:2000 from my localhost using mongodb compass.
e) Created simple spring boot application which was able to connect the mongodb service using Ip and port.
So far no problems things were moving as expected. Next my objective was to containerize my spring boot application and execute in in the Minikube. Before i execute it as pod in minikube i wanted to test the container using the docker-compose. Below is my docker-compose and Dockerfile code snippets
Dockerfile
FROM adoptopenjdk:11-jre-hotspot as builder
ARG JAR_FILE=target/\*.jar
COPY ${JAR_FILE} tradeprocessor.jar
RUN java -Djarmode=layertools -jar tradeprocessor.jar extract
FROM adoptopenjdk:11-jre-hotspot
COPY --from=builder dependencies/ ./
COPY --from=builder snapshot-dependencies/ ./
COPY --from=builder spring-boot-loader/ ./
COPY --from=builder application/ ./
ENTRYPOINT \["java", "org.springframework.boot.loader.JarLauncher"\]
docker-compose
---------------
`version: '3.7'
services:
trdprocess:
build:
context: .
dockerfile: Dockerfile
image: tradeprocess:latest
ports:
- 8088:8088
extra_hosts:
- dockerhost:192.168.49.2
environment:
- spring_data_mongodb_authentication_database=admin
- spring_data_mongodb_username=mongouser
- spring_data_mongodb_password=mongopassword
- spring_data_mongodb_database=transactions
- spring_data_mongodb_port=32000
- spring_data_mongodb_host=192.168.49.2`
however Upon executing the above step, application is spinning up but it is throwing SocketTimeoutException.
Exception:
`Started TradeprocessingApplication in 2.09 seconds (JVM running for 2.973)`
2023-01-04 20:16:13.529 INFO 1 --- [.168.49.2:32000] o.m.d.cluster : Exception in monitor thread while connecting to server 192.168.49.2:32000
com.mongodb.MongoSocketOpenException: Exception opening socket
at com.mongodb.internal.connection.SocketStream.open(SocketStream.java:70) ~[mongodb-driver-core-4.6.1.jar:?]
at com.mongodb.internal.connection.InternalStreamConnection.open(InternalStreamConnection.java:180) ~[mongodb-driver-core-4.6.1.jar:?]
at com.mongodb.internal.connection.DefaultServerMonitor$ServerMonitorRunnable.lookupServerDescription(DefaultServerMonitor.java:193) ~[mongodb-driver-core-4.6.1.jar:?]
at com.mongodb.internal.connection.DefaultServerMonitor$ServerMonitorRunnable.run(DefaultServerMonitor.java:157) ~[mongodb-driver-core-4.6.1.jar:?]
at java.lang.Thread.run(Unknown Source) ~[?:?]
Caused by: java.net.SocketTimeoutException: connect timed out
at java.net.PlainSocketImpl.socketConnect(Native Method) ~[?:?]
at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source) ~[?:?]
at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source) ~[?:?]
at java.net.AbstractPlainSocketImpl.connect(Unknown Source) ~[?:?]
at java.net.SocksSocketImpl.connect(Unknown Source) ~[?:?]
at java.net.Socket.connect(Unknown Source) ~[?:?]
at com.mongodb.internal.connection.SocketStreamHelper.initialize(SocketStreamHelper.java:107) ~[mongodb-driver-core-4.6.1.jar:?]
It looks like it has to do with network setting but not sure how to correct it. Any help is highly appreciated
Tried to change few option with docker-compose such as extra_hosts port mappings etc but no luck

Answer 1

I finally was able to solve my own problem. A bit of learning curve. Hear are the details.
My entire setup is running on Ubuntu workstation with minikube cluster.
Minikube started with command minikube start --driver=docker. Which means minikube itself is running as container within docker runtime environment.
docker network ls
docker network ls clearly shows that both my custom build application and the minikube are running as containers. Therefore i had to link these containers network. A small change in the docker-compose did the trick. Below is the code:
networks:
default :
external :
name : minikube