Most Nomad upsert RPCs accept a single object with the notable exception of
CSI. But in CSI we don't actually expose this to users except through the Go
API. It deeply complicates how we present errors to users, especially once
Sentinel policy enforcement enters the mix.
Refactor the `HostVolume.Create` and `HostVolume.Register` RPCs to take a single
volume instead of a slice of volumes.
Add a stub function for Enterprise policy enforcement. This requires splitting
out placement from the `createVolume` function so that we can ensure we've
completed placement before trying to enforce policy.
Ref: https://github.com/hashicorp/nomad/pull/24479
When making a request to create a dynamic host volumes, users can pass a node
pool and constraints instead of a specific node ID.
This changeset implements a node scheduling logic by instantiating a filter by
node pool and constraint checker borrowed from the scheduler package. Because
host volumes with the same name can't land on the same host, we don't need to
support `distinct_hosts`/`distinct_property`; this would be challenging anyways
without building out a much larger node iteration mechanism to keep track of
usage across multiple hosts.
Ref: https://github.com/hashicorp/nomad/pull/24479
Add several validation steps in the create/register RPCs for dynamic host
volumes. We first check that submitted volumes are self-consistent (ex. max
capacity is more than min capacity), then that any updates we've made are
valid. And we validate against state: preventing claimed volumes from being
updated and preventing placement requests for nodes that don't exist.
Ref: https://github.com/hashicorp/nomad/issues/15489
This changeset implements the HTTP API endpoints for Dynamic Host Volumes.
The `GET /v1/volumes` endpoint is shared between CSI and DHV with a query
parameter for the type. In the interest of getting some working handlers
available for use in development (and minimizing the size of the diff to
review), this changeset doesn't do any sort of refactoring of how the existing
List Volumes CSI endpoint works. That will come in a later PR, as will the
corresponding `api` package updates we need to support the CLI.
Ref: https://hashicorp.atlassian.net/browse/NET-11549
