When we try to prefix match the `nomad volume detach` node ID argument, the
node may have been already GC'd. The volume unpublish workflow gracefully
handles this case so that we can free the claim. So make a best effort to find
a node ID among the volume's claimed allocations, or otherwise just use the
node ID we've been given by the user as-is.
The CSI specification for `ValidateVolumeCapability` says that we shall
"reconcile successful capability-validation responses by comparing the
validated capabilities with those that it had originally requested" but leaves
the details of that reconcilation unspecified. This API is not implemented in
Kubernetes, so controller plugins don't have a real-world implementation to
verify their behavior against.
We have found that CSI plugins in the wild may return "successful" but
incomplete `VolumeCapability` responses, so we can't require that all
capabilities we expect have been validated, only that the ones that have been
validated match. This appears to violate the CSI specification but until
that's been resolved in upstream we have to loosen our validation
requirements. The tradeoff is that we're more likely to have runtime errors
during `NodeStageVolume` instead of at the time of volume registration.
The CSI specification allows only the `file-system` attachment mode to have
mount options. The `block-device` mode is left "intentionally empty, for now"
in the protocol. We should be validating against this problem, but our
documentation also had it backwards.
Also adds missing mount_options on group volume.
The soundness guarantees of the CSI specification leave a little to be desired
in our ability to provide a 100% reliable automated solution for managing
volumes. This changeset provides a new command to bridge this gap by providing
the operator the ability to intervene.
The command doesn't take an allocation ID so that the operator doesn't have to
keep track of alloc IDs that may have been GC'd. Handle this case in the
unpublish RPC by sending the client RPC for all the terminal/nil allocs on the
selected node.
The MVP for CSI in the 0.11.0 release of Nomad did not include support
for opaque volume parameters or volume context. This changeset adds
support for both.
This also moves args for ControllerValidateCapabilities into a struct.
The CSI plugin `ControllerValidateCapabilities` struct that we turn
into a CSI RPC is accumulating arguments, so moving it into a request
struct will reduce the churn of this internal API, make the plugin
code more readable, and make this method consistent with the other
plugin methods in that package.
CSI plugins can require credentials for some publishing and
unpublishing workflow RPCs. Secrets are configured at the time of
volume registration, stored in the volume struct, and then passed
around as an opaque map by Nomad to the plugins.
Includes:
* changes `nomad alloc status` and `nomad node status`
* changes to `volume` block in jobspec
* new `csi_plugin` block in jobspec
* new `nomad volume register/deregister/status` commands
* new `nomad plugin status` command
