Unsolved
2 Posts
0
1963
May 4th, 2020 01:00
vxflexos csi driver for kubernetes with block devices
HI,
I am trying out the csi driver for vxflexos from the github page, and according to that readme I should be able to use block devices.
// Can only be published once as read/write on a single node, at
// any given time.
SINGLE_NODE_WRITER = 1;
// Can be published as read/write at multiple nodes
// simultaneously.
MULTI_NODE_MULTI_WRITER = 5;
But when I do, I get the following error
ExitCode:128,Signal:0,Reason:ContainerCannotRun,Message:error gathering device information while adding custom device "/var/lib/kubelet/pods/8067031a-a83a-4f5e-8ac8-48c2ec89db29/volumeDevices/kubernetes.io~csi/k8s-3be9f73946": not a device node
When I check the mounts on that node, it does have the following mount
/var/lib/kubelet/plugins/kubernetes.io/csi/volumeDevices/k8s-3be9f73946/dev/8067031a-a83a-4f5e-8ac8-48c2ec89db29 type ext4 (rw,relatime,seclabel,stripe=64,data=ordered)
I am using the following helm template for the pvc.
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: {{ include "fullname" . }}
labels:
{{- include "labels" . | nindent 4 }}
spec:
storageClassName: vxflexos
accessModes:
- ReadWriteMany
volumeMode: Block
resources:
requests:
storage: 8Gi
Another error that I encountered is when deleting the pod. It keeps spamming the following messages
csi_util.go:78] kubernetes.io/csi: loading volume data file [/var/lib/kubelet/plugins/kubernetes.io/csi/volumeDevices/k8s-3be9f73946/data/vol_data.json]
csi_plugin.go:676] kubernetes.io/csi: setting up block unmapper for [Spec=k8s-3be9f73946, podUID=8067031a-a83a-4f5e-8ac8-48c2ec89db29]Until I manually unmount the volume on that node myself then it continues and finally it is unmapped successfully.
operation_generator.go:1257] UnmapDevice succeeded for volume "k8s-3be9f73946" (UniqueName: "kubernetes.io/csi/csi-vxflexos.dellemc.com^bf8715ec0000000c")
No Events found!
gashof
46 Posts
0
May 5th, 2020 15:00
Hi,
ReadWriteMany is not supported according to the Production Guide:
https://github.com/dell/csi-vxflexos
And this link:
https://www.dell.com/community/Containers/Capabilities-of-the-Dell-CSI-drivers/td-p/7539641
Can you use ReadWriteOnce? Also, were you able to run the tests in the Production Guide successfully?
Thanks,
Frank
Joris5
2 Posts
0
May 6th, 2020 02:00
Hi,
ReadWriteOnce with volumeMode: Filesystem does work like the test in the guide, but there are no tests/examples with the other modes.
Can you explain me how I should configure the following modes?
Supports the following access modes:
single-node-writer
single-node-reader-only
multi-node-reader-only
multi-node-single-writer
bmcfeeters
1 Rookie
•
72 Posts
1
May 6th, 2020 11:00
Although there are five access modes for volumes defined in the CSI spec...
https://github.com/container-storage-interface/spec/blob/master/spec.md
// Specify how a volume can be accessed.
message AccessMode {
enum Mode {
UNKNOWN = 0;
// Can only be published once as read/write on a single node, at
// any given time.
SINGLE_NODE_WRITER = 1;
// Can only be published once as readonly on a single node, at
// any given time.
SINGLE_NODE_READER_ONLY = 2;
// Can be published as readonly at multiple nodes simultaneously.
MULTI_NODE_READER_ONLY = 3;
// Can be published at multiple nodes simultaneously. Only one of
// the node can be used as read/write. The rest will be readonly.
MULTI_NODE_SINGLE_WRITER = 4;
// Can be published as read/write at multiple nodes
// simultaneously.
MULTI_NODE_MULTI_WRITER = 5;
}
It appears in the Kubernetes documentation that only three are supported/available right now for PV/PVC
https://kubernetes.io/docs/concepts/storage/persistent-volumes/#access-modes
I believe that ReadWriteOnce maps to SINGLE_NODE_WRITER, ReadOnlyMany maps to MULTI_NODE_READER_ONLY, and ReadWriteMany maps to MULTI_NODE_MULTI_WRITER.
gashof
46 Posts
0
May 11th, 2020 15:00
Hi,
Looking at this link, the driver does not yet support block. I reached out by private message to get further details.
https://www.dell.com/community/Containers/Capabilities-of-the-Dell-CSI-drivers/td-p/7539641/jump-to/first-unread-message
Thanks,
Frank