If a volume-claiming alloc stops and the CSI Node plugin that serves
that alloc's volumes is missing, there's no way for the allocrunner
hook to send the `NodeUnpublish` and `NodeUnstage` RPCs.
This changeset addresses this issue with a redesign of the client-side
for CSI. Rather than unmounting in the alloc runner hook, the alloc
runner hook will simply exit. When the server gets the
`Node.UpdateAlloc` for the terminal allocation that had a volume claim,
it creates a volume claim GC job. This job will made client RPCs to a
new node plugin RPC endpoint, and only once that succeeds, move on to
making the client RPCs to the controller plugin. If the node plugin is
unavailable, the GC job will fail and be requeued.
* nomad/structs/structs: new NodeEventSubsystemCSI
* client/client: pass triggerNodeEvent in the CSIConfig
* client/pluginmanager/csimanager/instance: add eventer to instanceManager
* client/pluginmanager/csimanager/manager: pass triggerNodeEvent
* client/pluginmanager/csimanager/volume: node event on [un]mount
* nomad/structs/structs: use storage, not CSI
* client/pluginmanager/csimanager/volume: use storage, not CSI
* client/pluginmanager/csimanager/volume_test: eventer
* client/pluginmanager/csimanager/volume: event on error
* client/pluginmanager/csimanager/volume_test: check event on error
* command/node_status: remove an extra space in event detail format
* client/pluginmanager/csimanager/volume: use snake_case for details
* client/pluginmanager/csimanager/volume_test: snake_case details
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
In order to correctly fingerprint dynamic plugins on client restarts,
we need to persist a handle to the plugin (that is, connection info)
to the client state store.
The dynamic registry will sync automatically to the client state
whenever it receives a register/deregister call.
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.
Tim Gross