Use Kubernetes labels to store ScaleIO sdc-guid value

[vladimirvivien]

The current version of the ScaleIO Kubernetes volume plugin relies on the presence drv_cfg binary being installed on ScaleIO SDC nodes for the simple reason of retrieving the machine's SDC guid to ultimately get the instance ID. This can be an issue if the binary has been moved or installed in non-standard location.

Label Nodes with SDC GUID

This proposal is to forego the need to use the drv_cfg binary to get the value of the SDC GUID. Instead, it relies on the Kubernetes resource labeling facility to store the SDC GUID.

The following label will be used to store the instance ID of a node:

scaleio.sdcGuid=<instance-id-value>

For instance, the following attaches the scaleio.instance_guid label to node foo:

kubectl label node fooNode scaleio.sdcGuid=ABCD-EFG-HIJKLMN-OPQRSTU

How it works

• Each SDC node in the cluster must be labeled with the proper (and correct) SDC GUID value.
• A badly labeled instance ID value will cause the storage operation failures on that node.
• If the node is not labeled, the code will attempt to use the drv_cfg binary as a best effort.
• If the binary is not installed and there is no scaleio.instance_guid label provided, storage operations will fail.

[vladimirvivien]

Done!