# Classes

| Class | Description |
|-|-|
| [`flyteplugins.union.errors.VolumeCommandError`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.errors/volumecommanderror/page.md) |A backend CLI invocation (e. |
| [`flyteplugins.union.errors.VolumeCommitError`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.errors/volumecommiterror/page.md) |A keep-alive checkpoint could not be made durable: the writeback staging. |
| [`flyteplugins.union.errors.VolumeError`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.errors/volumeerror/page.md) |Base for Volume *system* failures — infra/runtime problems the caller. |
| [`flyteplugins.union.errors.VolumeMigrateNoop`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.errors/volumemigratenoop/page.md) |Metadata-store migration was requested to the store type already in use. |
| [`flyteplugins.union.errors.VolumeMountError`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.errors/volumemounterror/page.md) |The volume could not be mounted — the client exited prematurely, the. |
| [`flyteplugins.union.errors.VolumeMountTimeout`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.errors/volumemounttimeout/page.md) |The mount did not become a FUSE mountpoint within the timeout. |
| [`flyteplugins.union.errors.VolumeNoIndex`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.errors/volumenoindex/page.md) |An operation needs a published index, but the Volume has none. |
| [`flyteplugins.union.errors.VolumeNotForkable`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.errors/volumenotforkable/page.md) |Fork was requested on a Volume that is neither mounted nor has an index. |
| [`flyteplugins.union.errors.VolumeNotMounted`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.errors/volumenotmounted/page.md) |An operation that needs a live mount was called on an unmounted Volume. |
| [`flyteplugins.union.errors.VolumeStoreTypeNotSet`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.errors/volumestoretypenotset/page.md) |The Volume's ``metadata_store_type`` is unset and couldn't be resolved. |
| [`flyteplugins.union.errors.VolumeUnmountError`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.errors/volumeunmounterror/page.md) |The volume could not be unmounted (``fusermount`` kept returning EBUSY). |
| [`flyteplugins.union.errors.VolumeUsageError`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.errors/volumeusageerror/page.md) |Base for Volume *user* errors — caller misuse the caller can fix. |
| [`flyteplugins.union.io.ActionRef`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.io/actionref/page.md) |Provenance: the action (one task execution within a run) that. |
| [`flyteplugins.union.io.ROVolume`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.io/rovolume/page.md) |Immutable, versioned volume — PRD §Core Concepts. |
| [`flyteplugins.union.io.RWVolume`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.io/rwvolume/page.md) |Mutable working copy — PRD §Core Concepts. |
| [`flyteplugins.union.io.Volume`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.io/volume/page.md) |A persistent volume identified by its metadata index. |
| [`flyteplugins.union.remote.ApiKey`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.remote/apikey/page.md) |Represents a Union API Key (OAuth Application). |
| [`flyteplugins.union.remote.Assignment`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.remote/assignment/page.md) |Represents role/policy assignments for an identity. |
| [`flyteplugins.union.remote.Cluster`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.remote/cluster/page.md) |Represents a Union cluster. |
| [`flyteplugins.union.remote.ClusterPool`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.remote/clusterpool/page.md) |Represents a Union cluster pool — the configuration shared by its member clusters. |
| [`flyteplugins.union.remote.Member`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.remote/member/page.md) |Represents a Union organization member (user or application). |
| [`flyteplugins.union.remote.Policy`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.remote/policy/page.md) |Represents a Union RBAC Policy. |
| [`flyteplugins.union.remote.Queue`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.remote/queue/page.md) |Represents a Union scheduling queue. |
| [`flyteplugins.union.remote.Role`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.remote/role/page.md) |Represents a Union RBAC Role. |
| [`flyteplugins.union.remote.User`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.remote/user/page.md) |Represents a Union user. |
| [`flyteplugins.union.remote.VolumeExplore`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.remote/volumeexplore/page.md) |A resolved :class:`Volume` plus the IO to inspect and walk its lineage. |
| [`flyteplugins.union.remote.VolumeResolveError`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.remote/volumeresolveerror/page.md) |No (or ambiguous) Volume-typed value could be resolved on an action. |
| [`flyteplugins.union.utils.auth.AppClientCredentials`](https://www.union.ai/docs/v2/union/api-reference/union-plugin/packages/flyteplugins.union.utils.auth/appclientcredentials/page.md) |Application client credentials for API key. |

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**Source**: https://github.com/unionai/unionai-docs/blob/main/content/api-reference/union-plugin/classes/_index.md
**HTML**: https://www.union.ai/docs/v2/union/api-reference/union-plugin/classes/