* Allow specification of CSI staging and publishing directory path
* Add website documentation for stage_publish_dir
* Replace erroneous reference to csi_plugin.mount_config with csi_plugin.mount_dir
* Avoid requiring CSI plugins to be redeployed after introducing StagePublishDir
We enforce exactly one plugin supervisor loop by checking whether
`running` is set and returning early. This works but is fairly
subtle. It can briefly result in two goroutines where one quickly
exits before doing any work. Clarify the intent by using
`sync.Once`. The goroutine we've spawned only exits when the entire
task runner is being torn down, and not when the task driver restarts
the workload, so it should never be re-run.
The task runner hook `Prestart` response object includes a `Done`
field that's intended to tell the client not to run the hook
again. The plugin supervisor creates mount points for the task during
prestart and saves these mounts in the hook resources. But if a client
restarts the hook resources will not be populated. If the plugin task
restarts at any time after the client restarts, it will fail to have
the correct mounts and crash loop until restart attempts run out.
Fix this by not returning `Done` in the response, just as we do for
the `volume_mount_hook`.
* Use unix:// prefix for CSI_ENDPOINT variable by default
* Some plugins have strict validation over the format of the
`CSI_ENDPOINT` variable, and unfortunately not all plugins
agree. Allow the user to override the `CSI_ENDPOINT` to workaround
those cases.
* Update all demos and tests with CSI_ENDPOINT
The Prestart hook for task runner hooks doesn't get called when we
restore a task, because the task is already running. The Postrun hook
for CSI plugin supervisors needs the socket path to have been
populated so that the client has a valid path.
The dynamic plugin registry assumes that plugins are singletons, which
matches the behavior of other Nomad plugins. But because dynamic
plugins like CSI are implemented by allocations, we need to handle the
possibility of multiple allocations for a given plugin type + ID, as
well as behaviors around interleaved allocation starts and stops.
Update the data structure for the dynamic registry so that more recent
allocations take over as the instance manager singleton, but we still
preserve the previous running allocations so that restores work
without racing.
Multiple allocations can run on a client for the same plugin, even if
only during updates. Provide each plugin task a unique path for the
control socket so that the tasks don't interfere with each other.
Nomad communicates with CSI plugin tasks via gRPC. The plugin
supervisor hook uses this to ping the plugin for health checks which
it emits as task events. After the first successful health check the
plugin supervisor registers the plugin in the client's dynamic plugin
registry, which in turn creates a CSI plugin manager instance that has
its own gRPC client for fingerprinting the plugin and sending mount
requests.
If the plugin manager instance fails to connect to the plugin on its
first attempt, it exits. The plugin supervisor hook is unaware that
connection failed so long as its own pings continue to work. A
transient failure during plugin startup may mislead the plugin
supervisor hook into thinking the plugin is up (so there's no need to
restart the allocation) but no fingerprinter is started.
* Refactors the gRPC client to connect on first use. This provides the
plugin manager instance the ability to retry the gRPC client
connection until success.
* Add a 30s timeout to the plugin supervisor so that we don't poll
forever waiting for a plugin that will never come back up.
Minor improvements:
* The plugin supervisor hook creates a new gRPC client for every probe
and then throws it away. Instead, reuse the client as we do for the
plugin manager.
* The gRPC client constructor has a 1 second timeout. Clarify that this
timeout applies to the connection and not the rest of the client
lifetime.
The CSI specification says:
> The CO SHALL provide the listen-address for the Plugin by way of the
`CSI_ENDPOINT` environment variable.
Note that plugins without filesystem isolation won't have the plugin
dir bind-mounted to their alloc dir, but we can provide a path to the
socket anyways.
Refactor to use opts struct for plugin supervisor hook config.
The parameter list for configuring the plugin supervisor hook has
grown enough where is makes sense to use an options struct similiar to
many of the other task runner hooks (ex. template).
The plugin supervisor lazily connects to plugins, but this means we
only get "Unavailable" back from the gRPC call in cases where the
plugin can never be reached (for example, if the Nomad client has the
wrong permissions for the socket).
This changeset improves the operator experience by switching to a
blocking `DialWithContext`. It eagerly connects so that we can
validate the connection is real and get a "failed to open" error in
case where Nomad can't establish the initial connection.
Allow for faster updates to plugin status when allocations become
terminal by listening for register/deregister events from the dynamic
plugin registry (which in turn are triggered by the plugin supervisor
hook).
The deregistration function closures that we pass up to the CSI plugin
manager don't properly close over the name and type of the
registration, causing monolith-type plugins to deregister only one of
their two plugins on alloc shutdown. Rebind plugin supervisor
deregistration targets to fix that.
Includes log message and comment improvements
Fix some docstring typos and fix noisy log message during client restarts.
A log for the common case where the plugin socket isn't ready yet
isn't actionable by the operator so having it at info is just noise.
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.
* structs: CSIInfo include AllocID, CSIPlugins no Jobs
* state_store: eliminate plugin Jobs, delete an empty plugin
* nomad/structs/csi: detect empty plugins correctly
* client/allocrunner/taskrunner/plugin_supervisor_hook: option AllocID
* client/pluginmanager/csimanager/instance: allocID
* client/pluginmanager/csimanager/fingerprint: set AllocID
* client/node_updater: split controller and node plugins
* api/csi: remove Jobs
The CSI Plugin API will map plugins to allocations, which allows
plugins to be defined by jobs in many configurations. In particular,
multiple plugins can be defined in the same job, and multiple jobs can
be used to define a single plugin.
Because we now map the allocation context directly from the node, it's
no longer necessary to track the jobs associated with a plugin
directly.
* nomad/csi_endpoint_test: CreateTestPlugin & register via fingerprint
* client/dynamicplugins: lift AllocID into the struct from Options
* api/csi_test: remove Jobs test
* nomad/structs/csi: CSIPlugins has an array of allocs
* nomad/state/state_store: implement CSIPluginDenormalize
* nomad/state/state_store: CSIPluginDenormalize npe on missing alloc
* nomad/csi_endpoint_test: defer deleteNodes for clarity
* api/csi_test: disable this test awaiting mocks:
https://github.com/hashicorp/nomad/issues/7123
CSI Plugins that manage devices need not just access to the CSI
directory, but also to manage devices inside `/dev`.
This commit introduces a `/dev:/dev` mount to the container so that they
may do so.
When providing paths to plugins, the path needs to be in the scope of
the plugins container, rather than that of the host.
Here we enable that by providing the mount point through the plugin
registration and then use it when constructing request target paths.
This changeset is some pre-requisite boilerplate that is required for
introducing CSI volume management for client nodes.
It extracts out fingerprinting logic from the csi instance manager.
This change is to facilitate reusing the csimanager to also manage the
node-local CSI functionality, as it is the easiest place for us to
guaruntee health checking and to provide additional visibility into the
running operations through the fingerprinter mechanism and goroutine.
It also introduces the VolumeMounter interface that will be used to
manage staging/publishing unstaging/unpublishing of volumes on the host.
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.
