Add debug doc which describe csidriver information

Signed-off-by: Humble Chirammal <hchiramm@redhat.com>

docs/csi-debug.md

@@ -0,0 +1,47 @@
+## CSI driver debug tips
+
+### Case#1: volume create/delete failed
+-
+- locate csi iscsi driver pod
+```
+kubectl get csidriver
+NAME               ATTACHREQUIRED   PODINFOONMOUNT   STORAGECAPACITY   TOKENREQUESTS   REQUIRESREPUBLISH   MODES        AGE
+iscsi.csi.k8s.io   false            false            false             <unset>         false               Persistent   22m
+```
+
+- get csi driver logs
+```
+kubectl logs -f csi-iscsi-node-klh5c -c iscsi
+I1217 14:40:55.928307       7 driver.go:48] Driver: iscsi.csi.k8s.io version: 1.0.0
+I1217 14:40:55.928339       7 driver.go:89] Enabling volume access mode: SINGLE_NODE_WRITER
+I1217 14:40:55.928347       7 driver.go:100] Enabling controller service capability: UNKNOWN
+I1217 14:40:55.929521       7 server.go:107] Listening for connections on address: &net.UnixAddr{Name:"//csi/csi.sock", Net:"unix"}
+I1217 14:40:55.956864       7 utils.go:63] GRPC call: /csi.v1.Identity/GetPluginInfo
+I1217 14:40:55.956877       7 utils.go:64] GRPC request: {}
+I1217 14:40:55.957869       7 identityserver.go:32] Using default GetPluginInfo
+I1217 14:40:55.957874       7 utils.go:69] GRPC response: {"name":"iscsi.csi.k8s.io","vendor_version":"1.0.0"}
+I1217 14:40:56.767355       7 utils.go:63] GRPC call: /csi.v1.Identity/GetPluginInfo
+I1217 14:40:56.767375       7 utils.go:64] GRPC request: {}
+I1217 14:40:56.767437       7 identityserver.go:32] Using default GetPluginInfo
+I1217 14:40:56.767445       7 utils.go:69] GRPC response: {"name":"iscsi.csi.k8s.io","vendor_version":"1.0.0"}
+```
+
+#### Update driver version quickly by editing driver deployment directly
+- update  daemonset deployment
+```console
+kubectl get ds
+NAME             DESIRED   CURRENT   READY   UP-TO-DATE   AVAILABLE   NODE SELECTOR            AGE
+csi-iscsi-node   1         1         1       1            1           kubernetes.io/os=linux   51m
+
+kubectl edit daemmonset csi-iscsi-node
+```
+change below config, e.g.
+```console
+        image: gcr.io/k8s-staging-sig-storage/iscsiplugin:canary
+        imagePullPolicy: IfNotPresent
+
+```
+
+```console
+$ kubectl logs logs -f csi-iscsi-node-klh5c -c iscsi
+```