Add VPA FAQ

TLA FTW

vertical-pod-autoscaler/FAQ.md

@@ -0,0 +1,100 @@
+# Vertical Pod Autoscaler FAQ
+
+1. VPA restarts my pods but does not modify CPU or memory settings. Why?
+
+First check that VPA admission controller is running correctly:
+
+```$ kubectl get pod -n kube-system | grep vpa-admission-controller```
+
+```vpa-admission-controller-69645795dc-sm88s            1/1       Running   0          1m```
+
+Check the logs of admission controller:
+
+```$ kubectl logs -n kube-system vpa-admission-controller-69645795dc-sm88s```
+
+If the admission controller is up and running, but there is no indication of it
+actually processing created pods or VPA objects in the logs, the webhook is not registered correctly.
+
+Check the output of:
+
+```$ kubectl describe mutatingWebhookConfiguration vpa-webhook-config```
+
+This should be correctly configured to point to VPA admission webhook service.
+Example:
+```yaml
+Name:         vpa-webhook-config
+Namespace:    
+Labels:       <none>
+Annotations:  <none>
+API Version:  admissionregistration.k8s.io/v1beta1
+Kind:         MutatingWebhookConfiguration
+Metadata:
+  Creation Timestamp:  2019-01-18T15:44:42Z
+  Generation:          1
+  Resource Version:    1250
+  Self Link:           /apis/admissionregistration.k8s.io/v1beta1/mutatingwebhookconfigurations/vpa-webhook-config
+  UID:                 f8ccd13d-1b37-11e9-8906-42010a84002f
+Webhooks:
+  Client Config:
+    Ca Bundle: <redacted>
+    Service:
+      Name:        vpa-webhook
+      Namespace:   kube-system
+  Failure Policy:  Ignore
+  Name:            vpa.k8s.io
+  Namespace Selector:
+  Rules:
+    API Groups:
+      
+    API Versions:
+      v1
+    Operations:
+      CREATE
+    Resources:
+      pods
+    API Groups:
+      autoscaling.k8s.io
+    API Versions:
+      v1beta1
+    Operations:
+      CREATE
+      UPDATE
+    Resources:
+      verticalpodautoscalers
+```
+
+If the webhook config doesn't exist, something got wrong with webhook
+registration for admission controller. Check the logs for more info.
+
+From the above config following part defines the webhook service:
+```yaml
+Service:
+      Name:        vpa-webhook
+      Namespace:   kube-system
+```
+
+Check that the service actually exists:
+
+```$ kubectl describe -n kube-system service vpa-webhook```
+
+```yaml
+Name:              vpa-webhook
+Namespace:         kube-system
+Labels:            <none>
+Annotations:       <none>
+Selector:          app=vpa-admission-controller
+Type:              ClusterIP
+IP:                <some_ip>
+Port:              <unset>  443/TCP
+TargetPort:        8000/TCP
+Endpoints:         <some_endpoint>
+Session Affinity:  None
+Events:            <none>
+```
+
+You can also curl the service's endpoint from within the cluster to make sure it
+is serving.
+
+Note: the commands will differ if you deploy VPA in a different namespace.
+
+

vertical-pod-autoscaler/README.md

@@ -238,7 +238,8 @@ kubectl delete clusterrolebinding myname-cluster-admin-binding
 
 # Related links
 
+* [FAQ](FAQ.md)
 * [Design
   proposal](https://github.com/kubernetes/community/blob/master/contributors/design-proposals/autoscaling/vertical-pod-autoscaler.md)
 * [API
-  definition](https://github.com/kubernetes/autoscaler/blob/master/vertical-pod-autoscaler/pkg/apis/autoscaling.k8s.io/v1beta1/types.go)
+  definition](pkg/apis/autoscaling.k8s.io/v1beta1/types.go)