The node-driver-registrar is a sidecar container that registers the CSI driver with Kubelet using the kubelet plugin registration mechanism.
This is necessary because Kubelet is responsible for issuing CSI NodeGetInfo
,
NodeStageVolume
, NodePublishVolume
calls. The node-driver-registrar
registers
your CSI driver with Kubelet so that it knows which Unix domain socket to issue
the CSI calls on.
Latest stable release | Branch | Compatible with CSI Version | Container Image | Min K8s Version | Max K8s Version |
---|---|---|---|---|---|
node-driver-registrar v1.0.2 | release-1.0 | CSI Spec v1.0.0 | quay.io/k8scsi/csi-node-driver-registrar:v1.0.2 | 1.13 | - |
driver-registrar v0.4.2 | release-0.4 | CSI Spec v0.3.0 | quay.io/k8scsi/driver-registrar:v0.4.2 | 1.10 | - |
For release-0.4 and below, please refer to the node-registrar repository.
There are two UNIX domain sockets used by the node-driver-registrar:
-
Registration socket:
- Registers the driver with kubelet.
- Created by the
node-driver-registrar
. - Exposed on a Kubernetes node via hostpath in the Kubelet plugin registry.
(typically
/var/lib/kubelet/plugins_registry/<drivername.example.com>-reg.sock
).
-
CSI driver socket:
- Used by kubelet to interact with the CSI driver.
- Created by the CSI driver.
- Exposed on a Kubernetes node via hostpath somewhere other than the Kubelet.
plugin registry (typically
/var/lib/kubelet/plugins/<drivername.example.com>/csi.sock
). - This is the socket referenced by the
--csi-address
and--kubelet-registration-path
arguments.
--csi-address
: This is the path to the CSI driver socket (defined above) inside the pod that thenode-driver-registrar
container will use to issue CSI operations (e.g./csi/csi.sock
).--kubelet-registration-path
: This is the path to the CSI driver socket on the host node that kubelet will use to issue CSI operations (e.g. `/var/lib/kubelet/plugins/<drivername.example.com>/csi.sock). Note this is NOT the path to the registration socket.
The node-driver-registrar does not interact with the Kubernetes API, so no RBAC rules are needed.
It does, however, need to be able to mount hostPath volumes and have the file permissions to:
- Access the CSI driver socket (typically in
/var/lib/kubelet/plugins/<drivername.example.com>/
).- Used by the
node-driver-registrar
to fetch the driver name from the driver contain (via the CSIGetPluginInfo()
call).
- Used by the
- Access the registration socket (typically in
/var/lib/kubelet/plugins_registry/
).- Used by the
node-driver-registrar
to register the driver with kubelet.
- Used by the
Here is an example sidecar spec in the driver DaemonSet. <drivername.example.com>
should be replaced by
the actual driver's name.
containers:
- name: csi-driver-registrar
image: quay.io/k8scsi/csi-node-driver-registrar:v1.0.2
args:
- "--csi-address=/csi/csi.sock"
- "--kubelet-registration-path=/var/lib/kubelet/plugins/<drivername.example.com>/csi.sock"
lifecycle:
preStop:
exec:
command: ["/bin/sh", "-c", "rm -rf /registration/<plugin> /registration/<drivername.example.com>-reg.sock"]
volumeMounts:
- name: plugin-dir
mountPath: /csi
- name: registration-dir
mountPath: /registration
volumes:
- name: registration-dir
hostPath:
path: /var/lib/kubelet/plugins_registry/
type: Directory
- name: plugin-dir
hostPath:
path: /var/lib/kubelet/plugins/<drivername.example.com>/
type: DirectoryOrCreate
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