How can I use the port of a server running on localhost in kubernetes running spring boot app - spring-boot

Question

I am new to Kubernetes and kubectl. I am basically running a GRPC server in my localhost. I would like to use this endpoint in a spring boot app running on kubernetes using kubectl on my mac. If I set the following config in application.yml and run in kubernetes, it doesn't work. The same config works if I run in IDE.
grpc:
client:
local-server:
address: static://localhost:6565
negotiationType: PLAINTEXT
I see some people suggesting port-forward, but it's the other way round (It works when I want to use a port that is already in kubernetes from localhost just like the tomcat server running in kubernetes from a browser on localhost)
apiVersion: apps/v1
kind: Deployment
metadata:
name: testspringconfigvol
labels:
app: testspring
spec:
replicas: 1
selector:
matchLabels:
app: testspringconfigvol
template:
metadata:
labels:
app: testspringconfigvol
spec:
initContainers:
# taken from https://gist.github.com/tallclair/849601a16cebeee581ef2be50c351841
# This container clones the desired git repo to the EmptyDir volume.
- name: git-config
image: alpine/git # Any image with git will do
args:
- clone
- --single-branch
- --
- https://github.com/username/fakeconfig
- /repo # Put it in the volume
securityContext:
runAsUser: 1 # Any non-root user will do. Match to the workload.
allowPrivilegeEscalation: false
readOnlyRootFilesystem: true
volumeMounts:
- mountPath: /repo
name: git-config
containers:
- name: testspringconfigvol-cont
image: username/testspring
ports:
- containerPort: 8080
volumeMounts:
- mountPath: /usr/local/lib/config/
name: git-config
volumes:
- name: git-config
emptyDir: {}
What I need in simple terms:
Ports having some server in my localhost:
localhost:6565, localhost:6566, I need to access these ports some how in my kubernetes. Then what should I set it in application.yml config? Will it be the same localhost:6565, localhost:6566 or how-to-get-this-ip:6565, how-to-get-this-ip:6566.

Answer 1

We can get the vmware host ip using minikube with this command minikube ssh "route -n | grep ^0.0.0.0 | awk '{ print \$2 }'". For me it's 10.0.2.2 on Mac. If using Kubernetes on Docker for mac, it's host.docker.internal.
By using these commands, I managed to connect to the services running on host machine from kubernetes.

Answer 2

1) Inside your application.properties define
server.port=8000
2) Create Dockerfile
# Start with a base image containing Java runtime (mine java 8)
FROM openjdk:8u212-jdk-slim
# Add Maintainer Info
LABEL maintainer="vaquar.khan#gmail.com"
# Add a volume pointing to /tmp
VOLUME /tmp
# Make port 8080 available to the world outside this container
EXPOSE 8080
# The application's jar file (when packaged)
ARG JAR_FILE=target/codestatebkend-0.0.1-SNAPSHOT.jar
# Add the application's jar to the container
ADD ${JAR_FILE} codestatebkend.jar
# Run the jar file
ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom","-jar","/codestatebkend.jar"]
3) Make sure docker is working fine
docker run --rm -p 8080:8080
4)
https://kubernetes.io/docs/tasks/access-application-cluster/port-forward-access-application-cluster/
use following command to find the pod name
kubectl get pods
then
kubectl port-forward <pod-name> 8080:8080
Useful links :
https://kubernetes.io/docs/tasks/access-application-cluster/port-forward-access-application-cluster/#forward-a-local-port-to-a-port-on-the-pod
https://kubernetes.io/docs/tasks/administer-cluster/access-cluster-services/#manually-constructing-apiserver-proxy-urls
https://kubernetes.io/docs/tasks/access-application-cluster/port-forward-access-application-cluster/
https://developer.okta.com/blog/2019/05/22/java-microservices-spring-boot-spring-cloud