I'm deploying a Spring Boot app in minikube that connects to a database running on the host. Following the 12 factor app recommendations I use environment variables for the necessary configuration:
SPRING_DATASOURCE_DRIVER_CLASS_NAME=org.postgresql.Driver
SPRING_DATASOURCE_PASSWORD=...
SPRING_DATASOURCE_URL=jdbc:postgresql://<HOST_IP_FROM_K8S>:5432/myservice
SPRING_DATASOURCE_USERNAME=...The kubernetes docs only show how to set environment variables in the service and deployment .yaml files which I don't want to do. Is there a way to pass environment variables on the command line for minikube or kubectl when I create the deployment? (In Docker I do this with -e.)
Note that the environment variables have to be set before starting the app or it crashes.
We have no direct option with create subcommand in kubectl to pass the environmental variables.
You may use Helm to customize deployment.
(Example: https://docs.bitnami.com/kubernetes/how-to/deploy-java-application-kubernetes-helm/)
Following Ansil's comment above I used configmap and secret to pass the configuration like this:
kubectl create secret generic springdatasourcepassword --from-literal=SPRING_DATASOURCE_PASSWORD=postgres
kubectl create secret generic springdatasourceusername --from-literal=SPRING_DATASOURCE_USERNAME=postgres
kubectl create configmap springdatasourcedriverclassname --from-literal=SPRING_DATASOURCE_DRIVER_CLASS_NAME=org.postgresql.Driver
kubectl create configmap springdatasourceurl --from-literal=SPRING_DATASOURCE_URL=jdbc:postgresql://172.18.0.1:5432/bookserviceThese are referenced in the deployment.yaml file like this:
env:
- name: GET_HOSTS_FROM
value: dns
- name: SPRING_DATASOURCE_DRIVER_CLASS_NAME
valueFrom:
configMapKeyRef:
name: springdatasourcedriverclassname
key: SPRING_DATASOURCE_DRIVER_CLASS_NAME
- name: SPRING_DATASOURCE_URL
valueFrom:
configMapKeyRef:
name: springdatasourceurl
key: SPRING_DATASOURCE_URL
- name: SPRING_DATASOURCE_PASSWORD
valueFrom:
secretKeyRef:
name: springdatasourcepassword
key: SPRING_DATASOURCE_PASSWORD
- name: SPRING_DATASOURCE_USERNAME
valueFrom:
secretKeyRef:
name: springdatasourceusername
key: SPRING_DATASOURCE_USERNAMEA full explanation can be found here.