coredns: set deploy replicas when dns autoscaler is disabled (#12387)

Allow setting deployment replicas through `coredns_replicas` when
`enable_dns_autoscaler` is set to false.

Signed-off-by: Seena Fallah <seenafallah@gmail.com>

roles/kubernetes-apps/ansible/defaults/main.yml

@@ -29,6 +29,8 @@ coredns_default_zone_cache_block: |
   cache 30
 
 coredns_pod_disruption_budget: false
+# when enable_dns_autoscaler is false, coredns_replicas is used to set the number of replicas
+coredns_replicas: 2
 # value for coredns pdb
 coredns_pod_disruption_budget_max_unavailable: "30%"
 deploy_coredns: true

roles/kubernetes-apps/ansible/templates/coredns-deployment.yml.j2

@@ -9,6 +9,9 @@ metadata:
     addonmanager.kubernetes.io/mode: Reconcile
     kubernetes.io/name: "coredns{{ coredns_ordinal_suffix }}"
 spec:
+{% if not enable_dns_autoscaler %}
+  replicas: {{ coredns_replicas }}
+{% endif %}
   strategy:
     type: RollingUpdate
     rollingUpdate: