Is there any way to deploy lagom projects on kubernetes in different environments (ie. dev,stage,prod) such that I can use one image with multiple configuration overrides?
For example, let's say I have an environment variable, foo=bar-{{env}}. I want to build and publish one image and override configurations so that in dev foo=bar-dev and in prod foo=bar-prod.
Currently, my understanding is that the application.conf is tied to the image and cannot be overridden. If this is correct, is there a way to work around this so that I do not need to create multiple images, one for each environment?
Alternatively, you can set typesafe config system property variable to override application.conf file
application.conf: default conf file use in development
foo: bar-dev
application.prod.conf:
include "application.conf" foo: bar-prod
Set dockerfile system variable:
ENTRYPOINT java -Dconfig.resource="$CONFIG_FILE"In kubernetes yml
env:
- name: CONFIG_FILE
value: "application.prod.conf"You can do this in a few ways:
Static:
You can create 3 deployments in 3 namespaces and add the env variable to each deployment. You can manage these variables manually for each deployment:
apiVersion: v1
kind: Pod
metadata:
namespace: dev
name: envar-demo
labels:
purpose: demonstrate-envars
spec:
containers:
- name: java-demo-container
image: my-super-java-app
env:
- name: foo
value: "bar-dev"
- name: JAVA_HOME
value: "/opt/java/jdk1.7.0_05/bin/java"Helm:
You can make helm chart and use 3 files with variables to deploy your application. To develop charts, you could read the official documentation or find some examples in official Kubernetes repo