4.4 Config Map and Ambassador Changes

Setup configmaps

Configmaps play a vital role in the migration process by storing configuration data for applications running in Kubernetes clusters. It is necessary to set up the required configmaps to ensure a smooth transition of the application to the AWS environment.

• Separate Configurations for Primary and DR Environments
  If you have different configurations for your primary and DR environments, follow these steps:

  1. Open your values.yml file in a text editor.
  2. Locate the section where config maps are defined.
  3. Create a single config under env_vars with name: "only", as shown below or refer:

  env_vars:
    - name: "primary"
      configs:
        INSTANCE: "primary"
        DB_HOST: "mongo1-dnt.abc-db-mongo1-dnt.svc.cluster.local"
        API_ENDPOINT: "https://dummy-api.netapp.com"
    - name: "dr"
      configs:
        INSTANCE: "dr"
        DB_HOST: "mongo1-dnt.abc-db-mongo1-dnt.svc.cluster.local"
        API_ENDPOINT: "https://dummy-api-dr.netapp.com"

  4. Create a file named - configmap.yaml under templates folder and copy the below contents.

  {{- if .Values.env_vars }}
  {{- range $configmaps := .Values.env_vars }}
  ---
  apiVersion: v1
  kind: ConfigMap
  metadata:
    name: {{ printf "%s-%s" (include "app.fullname" $) ( $configmaps.name ) | quote }}
    labels:
      {{- include "app.labels" $ | nindent 4 }}
  data: 
  {{- range $key, $val := $configmaps.configs }}
  {{ $key | quote | indent 4}}: {{ $val | quote }}
  {{- end }}
  {{- end }}
  {{- end }}

  5. Add the primary config map referance in deployment.yaml - refer

  envFrom:
  {{- if .Values.env_vars }}
    - configMapRef:
        name: {{ include "app.fullname" . }}-primary
  {{- end }}

• Config Map if there are no Changes during DR Transition
  If you do not have any configuration changes during the DR transition and want to reuse the same config map, follow these steps:

  1. Open your values.yml file in a text editor.
  2. Locate the section where config maps are defined.
  3. Create a single config under env_vars with name: "only", as shown below:

  env_vars:
    - name: "only"
      configs:
        INSTANCE: "primary"
        DB_HOST: "mongo1-dnt.abc-db-mongo1-dnt.svc.cluster.local"

Make Ambassador Changes

Update the Ambassador configurations to allow both primary and DR URLs for services. By allowing multiple URLs for each service, including DR URLs, you can test services during the DR validation state before the final cutover. This step enhances the resilience and reliability of the application.

1. Replace your ambassador.yaml file with the code in this link

2. Add both primary and dr URLs in your values.hostspace/values/values.workspace.yml files - refer

ingressEndpoints:
- # Dynamically Generate URL
  internal:
    enabled: true
    mappings:
    - prefix: "/"
      rewrite: "/"
  external:
    enabled: true
    mappings:
    - prefix: "/"
      rewrite: "/"
- host: nodejs.netapp.com
  internal:
    enabled: true
    mappings:
    - prefix: "/nodejs"
      rewrite: "/"
  external:
    enabled: true
    mappings:
    - prefix: "/nodejs"
      rewrite: "/"
- host: nodejs-dr.netapp.com
  internal:
    enabled: true
    mappings:
    - prefix: "/nodejs"
      rewrite: "/"
  external:
    enabled: true
    mappings:
    - prefix: "/nodejs"
      rewrite: "/"