add sample policy for deployments

samples/README.md

@@ -37,6 +37,7 @@ These policies provide additional best practices and are worthy of close conside
 1. [Restrict User Group](CheckUserGroup.md)
 1. [Require pods are labeled](RequireLabels.md)
 1. [Require pods have certain labels](RequireCertainLabels.md)
+1. [Require Deployments have multiple replicas](RequireDeploymentsHaveReplicas.md)
 
 ## Applying the sample policies
 

samples/RequireDeploymentsHaveReplicas.md

@@ -0,0 +1,40 @@
+# Require deployments have multiple replicas
+
+Deployments with only a single replica produce availability concerns should that single replica fail. In most cases, you would want Deployment objects to have more than one replica to ensure continued availability if not scale.
+
+This sample policy requires that Deployments have more than one replica excluding a list of system namespaces.
+
+## More Information
+
+* [Kubernetes Deployments](https://kubernetes.io/docs/concepts/workloads/controllers/deployment/)
+
+## Policy YAML
+
+[require_deployments_have_multiple_replicas.yaml](more/require_deployments_have_multiple_replicas.yaml)
+
+```yaml
+apiVersion: kyverno.io/v1
+kind: ClusterPolicy
+metadata:
+  name: deployment-has-multiple-replicas
+spec:
+  validationFailureAction: audit
+  rules:
+    - name: deployment-has-multiple-replicas
+      match:
+        resources:
+          kinds:
+            - Deployment
+      exclude:
+        resources:
+          namespaces:
+          - kyverno
+          - kube-system
+          - kube-node-lease
+          - kube-public
+      validate:
+        message: "Deployments must have more than one replica to ensure availability."
+        pattern:
+          spec:
+            replicas: ">1"
+```

samples/more/require_deployments_have_multiple_replicas.yaml

@@ -0,0 +1,24 @@
+apiVersion: kyverno.io/v1
+kind: ClusterPolicy
+metadata:
+  name: deployment-has-multiple-replicas
+spec:
+  validationFailureAction: audit
+  rules:
+    - name: deployment-has-multiple-replicas
+      match:
+        resources:
+          kinds:
+            - Deployment
+      exclude:
+        resources:
+          namespaces:
+          - kyverno
+          - kube-system
+          - kube-node-lease
+          - kube-public
+      validate:
+        message: "Deployments must have more than one replica to ensure availability."
+        pattern:
+          spec:
+            replicas: ">1"