Document how gcs.csi.ofek.dev/driver-ready can be used.

docs/troubleshooting.md

@@ -1,5 +1,46 @@
 # Troubleshooting
+## Warnings events from pods scheduled on newly started nodes when mounting csi-gcs volumes
 
------
+Warnings, like the one below, can be seen from pods scheduled on newly started nodes.
 
-## TODO
+```
+MountVolume.MountDevice failed for volume "xxxx" : kubernetes.io/csi: attacher.MountDevice failed to create newCsiDriverClient: driver name gcs.csi.ofek.dev not found in the list of registered CSI drivers
+```
+
+Those warnings are temporary and reflect the csi-gcs driver is still starting. Kubernetes will retry until the csi-gcs driver is ready.
+
+It's possible to avoid those warnings by adding a node selector or affinity using the node label `gcs.csi.ofek.dev/driver-ready=true`.
+
+> Adding such node selector or affinity will trade the time spend waiting for volume mounting retries against time waiting for scheduling.
+
+
+```
+apiVersion: v1
+kind: Pod
+metadata:
+    name: pod-mount-csi-gcs-volume
+spec:
+  // ...
+  nodeSelector:
+    gcs.csi.ofek.dev/driver-ready: "true"
+```
+
+```
+apiVersion: v1
+kind: Pod
+metadata:
+    name: pod-mount-csi-gcs-volume
+spec:
+  // ...
+  affinity:
+    nodeAffinity:
+      requiredDuringSchedulingIgnoredDuringExecution:
+        nodeSelectorTerms:
+        - matchExpressions:
+          - key: gcs.csi.ofek.dev/driver-ready
+            operator: In
+            values:
+            - "true"
+```
+
+You can also add an admission mutating webhook to automatically inject such node selector or affinity in all pods mounting csi-gcs volumes.