Kustomize Shared Configuration Across Multiple resources with

General Discussions
1

I’m switching from ansible to kustomize for deployments into k8s. I’ve created some basic deployments into different environments using overlays and it works pretty well but I’m having difficulties when it comes to keeping my code DRY.

For example I have a lot of repeated code in my overlays mostly around the configuration of container environment variables using envFrom and env. The same values are used in 3 different deployments, the main web app, a background job work and an ancillary app along with 1 job used for DB migrations. The envFrom: config isn’t a big issue as it’s just one config. But the number of variables configure under env:, both hard coded and referencing secrets already in the cluster is 30+.

For example

...
          envFrom:
            - configMapRef:
                name: dev-app-cm
                optional: false
          env:
            - name: POSTGRESQL_PASSWORD
              valueFrom:
                secretKeyRef:
                  name: dev-app-scrt
                  key: db-password
            - name: POSTGRESQL_DATABASE
              valueFrom:
                secretKeyRef:
                  name: dev-app-scrt
                  key: db-name
            - name: REDIS_URL
              valueFrom:
                secretKeyRef:
                  name: dev-app-scrt
                  key: redis-url
            - name: NODE_NAME
              valueFrom:
                fieldRef:
                  fieldPath: spec.nodeName
            - name: POD_NAME
              valueFrom:
                fieldRef:
                  fieldPath: metadata.name
            - name: COMPONENT
              valueFrom:
                fieldRef:
                  fieldPath: metadata.labels['component']
            - name: APPLICATION_NAME
              value: app1
            - name: APP_ENV
              value: dev
            - name: APP_ENVIRONMENT
              value: development
            - name: BACKEND_SERVICE_HOSTNAME
              value: backend-k8s-svc.default.svc.cluster.local
            - name: BACKEND_SERVICE_PORT
              value: '8080'
...

What’s the best way to reuse these across 4 different resources? I’ve tried replacements, components and vars. Replacements and components didn’t quote work the way I expected it too and vars is due to be deprecated.