Kubernetes

This section of documentation covers use of the vanilla kubernetes orchestrator. The StorageOS installation procedure is slightly different depending on the version you have deployed, so follow the appropriate guide. Other documents in this section are version agnostic.

Kubernetes with StorageOS

Kubernetes and StorageOS communicate with each other to perform actions such as creation, deletion or mounting volumes. The standard communication procedure uses REST API calls. However, StorageOS also implements communication using CSI. By using CSI, Kubernetes and StorageOS communicate over a Unix domain socket. That socket is handled by the Kubelet in the Host.

CSI (Container Storage Interface) Note

CSI is the future standard that enables storage drivers to release on their own schedule. This allows storage vendors to upgrade, update, and enhance their drivers without the need to update Kubernetes source code, or follow Kubernetes release cycles.

CSI is available from Kubernetes 1.9 alpha. As CSI is still not GA in Kubernetes, StorageOS recommends it is only used if the user is aware of its limitations and understands that non-GA versions of an active project might contain breaking changes.

Check out the status of the CSI release cycle in relation with Kubernetes in the CSI project page.

StorageOS leverages labels in PVCs to apply features to StorageOS volumes. However, StorageOS doesn’t have these labels set when using CSI. Therefore, default feature labels (storageos.com/*) must be defined on the Kubernetes StorageClass parameters. Multiple StorageClasses can be defined with different parameters. The StorageOS CLI can also manipulate volume labels or create rules to add/delete labels on StorageOS volumes.