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.
Several of the CSI `VolumeCapability` methods return pointers, which
we were then comparing to pointers in the request rather than
dereferencing them and comparing their contents.
This changeset does a more fine-grained comparison of the request vs
the capabilities, and adds better error messaging.
This changeset corrects handling of the `ValidationVolumeCapabilities`
response:
* The CSI spec for the `ValidationVolumeCapabilities` requires that
plugins only set the `Confirmed` field if they've validated all
capabilities. The Nomad client improperly assumes that the lack of a
`Confirmed` field should be treated as a failure. This breaks the
Azure and Linode block storage plugins, which don't set this
optional field.
* The CSI spec also requires that the orchestrator check the validation
responses to guard against older versions of a plugin reporting
"valid" for newer fields it doesn't understand.
The CSI Specification defines various gRPC Errors and how they may be retried. After auditing all our CSI RPC calls in #6863, this changeset:
* adds retries and backoffs to the where they were needed but not implemented
* annotates those CSI RPCs that do not need retries so that we don't wonder whether it's been left off accidentally
* added a timeout and cancellation context to the `Probe` call, which didn't have one.
Derive a provider name and version for plugins (and the volumes that
use them) from the CSI identity API `GetPluginInfo`. Expose the vendor
name as `Provider` in the API and CLI commands.
This changeset implements the minimal structs on the client-side we
need to compile the work-in-progress implementation of the
server-to-controller RPCs. It doesn't include implementing the
`ClientCSI.DettachVolume` RPC on the client.
This changeset implements the initial registration and fingerprinting
of CSI Plugins as part of #5378. At a high level, it introduces the
following:
* A `csi_plugin` stanza as part of a Nomad task configuration, to
allow a task to expose that it is a plugin.
* A new task runner hook: `csi_plugin_supervisor`. This hook does two
things. When the `csi_plugin` stanza is detected, it will
automatically configure the plugin task to receive bidirectional
mounts to the CSI intermediary directory. At runtime, it will then
perform an initial heartbeat of the plugin and handle submitting it to
the new `dynamicplugins.Registry` for further use by the client, and
then run a lightweight heartbeat loop that will emit task events
when health changes.
* The `dynamicplugins.Registry` for handling plugins that run
as Nomad tasks, in contrast to the existing catalog that requires
`go-plugin` type plugins and to know the plugin configuration in
advance.
* The `csimanager` which fingerprints CSI plugins, in a similar way to
`drivermanager` and `devicemanager`. It currently only fingerprints
the NodeID from the plugin, and assumes that all plugins are
monolithic.
Missing features
* We do not use the live updates of the `dynamicplugin` registry in
the `csimanager` yet.
* We do not deregister the plugins from the client when they shutdown
yet, they just become indefinitely marked as unhealthy. This is
deliberate until we figure out how we should manage deploying new
versions of plugins/transitioning them.
