rbd: provide host-path for rbd-nbd logging

Problem:
--------
1. rbd-nbd by default logs to /var/log/ceph/ceph-client.admin.log,
Unfortunately, container doesn't have /var/log/ceph directory hence
rbd-nbd is not logging now.
2. Rbd-nbd logs are not persistent across nodeplugin restarts.

Solution:
--------
Provide a host path so that log directory is made available, and the
logs persist on the hostnode across container restarts.

Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com>

charts/ceph-csi-rbd/templates/nodeplugin-daemonset.yaml

@@ -124,6 +124,8 @@ spec:
               mountPropagation: "Bidirectional"
             - name: keys-tmp-dir
               mountPath: /tmp/csi/keys
+            - name: ceph-logdir
+              mountPath: /var/log/ceph
           resources:
 {{ toYaml .Values.nodeplugin.plugin.resources | indent 12 }}
 {{- if .Values.nodeplugin.httpMetrics.enabled }}
@@ -169,6 +171,10 @@ spec:
           hostPath:
             path: {{ .Values.kubeletDir }}/pods
             type: DirectoryOrCreate
+        - name: ceph-logdir
+          hostPath:
+            path: /var/log/ceph
+            type: DirectoryOrCreate
         - name: host-dev
           hostPath:
             path: /dev

charts/ceph-csi-rbd/templates/nodeplugin-psp.yaml

@@ -42,6 +42,8 @@ spec:
       readOnly: true
     - pathPrefix: '/lib/modules'
       readOnly: true
+    - pathPrefix: '/var/log/ceph'
+      readOnly: false
     - pathPrefix: '{{ .Values.kubeletDir }}'
       readOnly: false
 {{- end }}

deploy/rbd/kubernetes/csi-nodeplugin-psp.yaml

@@ -38,6 +38,8 @@ spec:
       readOnly: true
     - pathPrefix: '/var/lib/kubelet/pods'
       readOnly: false
+    - pathPrefix: '/var/log/ceph'
+      readOnly: false
     - pathPrefix: '/var/lib/kubelet/plugins/rbd.csi.ceph.com'
       readOnly: false
     - pathPrefix: '/var/lib/kubelet/plugins_registry'

deploy/rbd/kubernetes/csi-rbdplugin.yaml

@@ -111,6 +111,8 @@ spec:
               mountPropagation: "Bidirectional"
             - name: keys-tmp-dir
               mountPath: /tmp/csi/keys
+            - name: ceph-logdir
+              mountPath: /var/log/ceph
         - name: liveness-prometheus
           securityContext:
             privileged: true
@@ -146,6 +148,10 @@ spec:
           hostPath:
             path: /var/lib/kubelet/pods
             type: DirectoryOrCreate
+        - name: ceph-logdir
+          hostPath:
+            path: /var/log/ceph
+            type: DirectoryOrCreate
         - name: registration-dir
           hostPath:
             path: /var/lib/kubelet/plugins_registry/