linkerd: Allow user to specify the controller count

In the HA mode user can specify the number of controllers that should be
created using a variable `controller_replicas`.

**Caution**: If the number of linkerd controller count is more than the
available worker nodes then some pods may stay in `Pending` state.

Signed-off-by: Suraj Deshmukh <suraj@kinvolk.io>

pkg/components/linkerd/component.go

@@ -37,14 +37,17 @@ func init() {
 }
 
 type component struct {
-	CA     string
-	Cert   string
-	Key    string
-	Expiry string
+	CA                 string
+	Cert               string
+	Key                string
+	Expiry             string
+	ControllerReplicas int `hcl:"controller_replicas,optional"`
 }
 
 func newComponent() *component {
-	return &component{}
+	return &component{
+		ControllerReplicas: 1,
+	}
 }
 
 func (c *component) LoadConfig(configBody *hcl.Body, evalContext *hcl.EvalContext) hcl.Diagnostics {

pkg/components/linkerd/manifest.go

@@ -41,7 +41,7 @@ identity:
 enablePodAntiAffinity: true
 
 # controller configuration
-controllerReplicas: 3
+controllerReplicas: {{.ControllerReplicas}}
 controllerResources: &controller_resources
   cpu: &controller_resources_cpu
     limit: "1"