The CSI hook for each allocation that claims a volume runs concurrently. If a
call to `MountVolume` happens at the same time as a call to `UnmountVolume` for
the same volume, it's possible for the second alloc to detect the volume has
already been staged, then for the original alloc to unpublish and unstage it,
only for the second alloc to then attempt to publish a volume that's been
unstaged.
The usage tracker on the volume manager was intended to prevent this behavior
but the call to claim the volume was made only after staging and publishing was
complete. Move the call to claim the volume for the usage tracker to the top of
the `MountVolume` workflow to prevent it from being unstaged until all consuming
allocations have called `UnmountVolume`.
Fixes: https://github.com/hashicorp/nomad/issues/20424
CSI volumes are namespaced. But the client does not include the namespace in the
staging mount path. This causes CSI volumes with the same volume ID but
different namespace to collide if they happen to be placed on the same host. The
per-allocation paths don't need to be namespaced, because an allocation can only
mount volumes from its job's own namespace.
Rework the CSI hook tests to have more fine-grained control over the mock
on-disk state. Add tests covering upgrades from staging paths missing
namespaces.
Fixes: https://github.com/hashicorp/nomad/issues/18741
following ControllerExpandVolume
in c6dbba7cde,
which expands the disk at e.g. a cloud vendor,
the controller plugin may say that we also need
to issue NodeExpandVolume for the node plugin to
make the new disk space available to task(s) that
have claims on the volume by e.g. expanding
the filesystem on the node.
csi spec:
https://github.com/container-storage-interface/spec/blob/c918b7f/spec.md#nodeexpandvolume
When claiming a CSI volume, we need to ensure the CSI node plugin is running
before we send any CSI RPCs. This extends even to the controller publish RPC
because it requires the storage provider's "external node ID" for the
client. This primarily impacts client restarts but also is a problem if the node
plugin exits (and fingerprints) while the allocation that needs a CSI volume
claim is being placed.
Unfortunately there's no mapping of volume to plugin ID available in the
jobspec, so we don't have enough information to wait on plugins until we either
get the volume from the server or retrieve the plugin ID from data we've
persisted on the client.
If we always require getting the volume from the server before making the claim,
a client restart for disconnected clients will cause all the allocations that
need CSI volumes to fail. Even while connected, checking in with the server to
verify the volume's plugin before trying to make a claim RPC is inherently racy,
so we'll leave that case as-is and it will fail the claim if the node plugin
needed to support a newly-placed allocation is flapping such that the node
fingerprint is changing.
This changeset persists a minimum subset of data about the volume and its plugin
in the client state DB, and retrieves that data during the CSI hook's prerun to
avoid re-claiming and remounting the volume unnecessarily.
This changeset also updates the RPC handler to use the external node ID from the
claim whenever it is available.
Fixes: #13028
When an allocation stops, the `csi_hook` makes an unpublish RPC to the
servers to unpublish via the CSI RPCs: first to the node plugins and
then the controller plugins. The controller RPCs must happen after the
node RPCs so that the node has had a chance to unmount the volume
before the controller tries to detach the associated device.
But the client has local access to the node plugins and can
independently determine if it's safe to send unpublish RPC to those
plugins. This will allow the server to treat the node plugin as
abandoned if a client is disconnected and `stop_on_client_disconnect`
is set. This will let the server try to send unpublish RPCs to the
controller plugins, under the assumption that the client will be
trying to unmount the volume on its end first.
Note that the CSI `NodeUnpublishVolume`/`NodeUnstageVolume` RPCs can
return ignorable errors in the case where the volume has already been
unmounted from the node. Handle all other errors by retrying until we
get success so as to give operators the opportunity to reschedule a
failed node plugin (ex. in the case where they accidentally drained a
node without `-ignore-system`). Fan-out the work for each volume into
its own goroutine so that we can release a subset of volumes if only
one is stuck.
Include the VolumeCapability.MountVolume data in
ControllerPublishVolume, CreateVolume, and ValidateVolumeCapabilities
RPCs sent to the CSI controller. The previous behavior was to only
include the MountVolume capability in the NodeStageVolume request, which
on some CSI implementations would be rejected since the Volume was not
originally provisioned with the specific mount capabilities requested.
Registration of Nomad volumes previously allowed for a single volume
capability (access mode + attachment mode pair). The recent `volume create`
command requires that we pass a list of requested capabilities, but the
existing workflow for claiming volumes and attaching them on the client
assumed that the volume's single capability was correct and unchanging.
Add `AccessMode` and `AttachmentMode` to `CSIVolumeClaim`, use these fields to
set the initial claim value, and add backwards compatibility logic to handle
the existing volumes that already have claims without these fields.
When the client-side actions of a CSI client RPC succeed but we get
disconnected during the RPC or we fail to checkpoint the claim state, we want
to be able to retry the client RPC without getting blocked by the client-side
state (ex. mount points) already having been cleaned up in previous calls.
The NodePublish workflow currently creates the target path and its parent
directory. However, the CSI specification says that the CO shall ensure the
parent directory of the target path exists, and that the SP shall place the
block device or mounted directory at the target path. Much of our testing has
been with CSI plugins that are more forgiving, but our behavior breaks
spec-compliant CSI plugins.
This changeset ensures we only create the parent directory.
In #7957 we added support for passing a volume context to the controller RPCs.
This is an opaque map that's created by `CreateVolume` or, in Nomad's case,
in the volume registration spec.
However, we missed passing this field to the `NodeStage` and `NodePublish` RPC,
which prevents certain plugins (such as MooseFS) from making node RPCs.
The CSI plugins RPCs require the use of the storage provider's volume
ID, rather than the user-defined volume ID. Although changing the RPCs
to use the field name `ExternalID` risks breaking backwards
compatibility, we can use the `ExternalID` name internally for the
client and only use `VolumeID` at the RPC boundaries.
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.
The CSI plugins uses the external volume ID for all operations, but
the Client CSI RPCs uses the Nomad volume ID (human-friendly) for the
mount paths. Pass the External ID as an arg in the RPC call so that
the unpublish workflows have it without calling back to the server to
find the external ID.
The controller CSI plugins need the CSI node ID (or in other words,
the storage provider's view of node ID like the EC2 instance ID), not
the Nomad node ID, to determine how to detach the external volume.
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
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.
Add mount_options to both the volume definition on registration and to the volume block in the group where the volume is requested. If both are specified, the options provided in the request replace the options defined in the volume. They get passed to the NodePublishVolume, which causes the node plugin to actually mount the volume on the host.
Individual tasks just mount bind into the host mounted volume (unchanged behavior). An operator can mount the same volume with different options by specifying it twice in the group context.
closes#7007
* nomad/structs/volumes: add MountOptions to volume request
* jobspec/test-fixtures/basic.hcl: add mount_options to volume block
* jobspec/parse_test: add expected MountOptions
* api/tasks: add mount_options
* jobspec/parse_group: use hcl decode not mapstructure, mount_options
* client/allocrunner/csi_hook: pass MountOptions through
client/allocrunner/csi_hook: add a VolumeMountOptions
client/allocrunner/csi_hook: drop Options
client/allocrunner/csi_hook: use the structs options
* client/pluginmanager/csimanager/interface: UsageOptions.MountOptions
* client/pluginmanager/csimanager/volume: pass MountOptions in capabilities
* plugins/csi/plugin: remove todo 7007 comment
* nomad/structs/csi: MountOptions
* api/csi: add options to the api for parsing, match structs
* plugins/csi/plugin: move VolumeMountOptions to structs
* api/csi: use specific type for mount_options
* client/allocrunner/csi_hook: merge MountOptions here
* rename CSIOptions to CSIMountOptions
* client/allocrunner/csi_hook
* client/pluginmanager/csimanager/volume
* nomad/structs/csi
* plugins/csi/fake/client: add PrevVolumeCapability
* plugins/csi/plugin
* client/pluginmanager/csimanager/volume_test: remove debugging
* client/pluginmanager/csimanager/volume: fix odd merging logic
* api: rename CSIOptions -> CSIMountOptions
* nomad/csi_endpoint: remove a 7007 comment
* command/alloc_status: show mount options in the volume list
* nomad/structs/csi: include MountOptions in the volume stub
* api/csi: add MountOptions to stub
* command/volume_status_csi: clean up csiVolMountOption, add it
* command/alloc_status: csiVolMountOption lives in volume_csi_status
* command/node_status: display mount flags
* nomad/structs/volumes: npe
* plugins/csi/plugin: npe in ToCSIRepresentation
* jobspec/parse_test: expand volume parse test cases
* command/agent/job_endpoint: ApiTgToStructsTG needs MountOptions
* command/volume_status_csi: copy paste error
* jobspec/test-fixtures/basic: hclfmt
* command/volume_status_csi: clean up csiVolMountOption
* nomad/structs/csi: new RemoteID() uses the ExternalID if set
* nomad/csi_endpoint: pass RemoteID to volume request types
* client/pluginmanager/csimanager/volume: pass RemoteID to NodePublishVolume
This commit is the initial implementation of claiming volumes from the
server and passes through any publishContext information as appropriate.
There's nothing too fancy here.
The CSI Spec requires us to attach and stage volumes based on different
types of usage information when it may effect how they are bound. Here
we pass through some basic usage options in the CSI Hook (specifically
the volume aliases ReadOnly field), and the attachment/access mode from
the volume. We pass the attachment/access mode seperately from the
volume as it simplifies some handling and doesn't necessarily force
every attachment to use the same mode should more be supported (I.e if
we let each `volume "foo" {}` specify an override in the future).
This commit introduces initial support for unmounting csi volumes.
It takes a relatively simplistic approach to performing
NodeUnpublishVolume calls, optimising for cleaning up any leftover state
rather than terminating early in the case of errors.
This is because it happens during an allocation's shutdown flow and may
not always have a corresponding call to `NodePublishVolume` that
succeeded.
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 commit introduces support for staging volumes when a plugin
implements the STAGE_UNSTAGE_VOLUME capability.
See the following for further reference material:
4731db0e0b/spec.md (nodestagevolume)
This commit adds helpers that create and validate the staging directory
for a given volume. It is currently missing usage options as the
interfaces are not yet in place for those.
The staging directory is only required when a volume has the
STAGE_UNSTAGE Volume capability and has to live within the plugin root
as the plugin needs to be able to create mounts inside it from within
the container.
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.
