truefoundry-volumes

name	truefoundry-volumes
description	Creates and manages persistent volumes on TrueFoundry. Handles creation, listing, mounting, storage class selection, and static volume attachment.
license	MIT
compatibility	Requires Bash, curl, and access to a TrueFoundry instance
allowed-tools	Bash(*/tfy-api.sh *)

Routing note: For ambiguous user intents, use the shared clarification templates in references/intent-clarification.md.

Volumes

Create and manage persistent volumes on TrueFoundry. Volumes provide shared, low-latency disk storage that persists across container restarts and can be mounted by multiple pods.

When to Use

Create, list, or mount persistent volumes on TrueFoundry, including dynamic provisioning, static PV attachment, storage class selection, and Volume Browser setup.

When NOT to Use

• User needs large archival storage or global access -> suggest blob storage (S3/GCS) instead
• User wants ephemeral scratch space -> use ephemeral_storage in resource config
• User wants to deploy an app -> prefer deploy skill; ask if the user wants another valid path
• User wants to manage secrets -> prefer secrets skill; ask if the user wants another valid path

Volumes vs Blob Storage

Help the user choose the right storage type:

Aspect	Volumes	Blob Storage (S3/GCS)
Access method	Standard file system APIs (open, read, write)	SDK clients (boto3, gcsfs)
Speed	Faster (local-disk latency)	Slower (network round-trips)
Durability	High	Extremely high (11 nines)
Cost	Higher per GB	Lower per GB
Scope	Region/cluster limited	Global access
Best for	Shared model weights, training checkpoints, low-latency reads	Large archives, datasets accessed infrequently, cross-region data

Choose volumes when:

• Multiple pods need concurrent file system access to the same data
• You need file system semantics (locking, renaming, directory listing)
• Low-latency access to frequently-read data (model weights, config files)
• ML training checkpointing where write speed matters

Choose blob storage when:

• Data is larger than a few hundred GB
• Global or cross-region access is needed
• Data is written once and read occasionally
• Cost is the primary concern

Warning: Do not write to the same file path from multiple pods simultaneously -- this can cause data corruption. Coordinate writes across pods or use separate paths.

Prerequisites

Always verify before deploying:

1. Credentials -- TFY_BASE_URL and TFY_API_KEY must be set (env or .env)
2. Workspace -- TFY_WORKSPACE_FQN required. Never auto-pick. Ask the user if missing. Volumes are workspace-scoped: a volume created in one workspace can only be used by applications in that same workspace.
3. Cluster storage class -- The target cluster must have a storage provisioner configured for the desired storage class.

For credential check commands and .env setup, see references/prerequisites.md.

Volume Types

Dynamic Volumes (Create New)

TrueFoundry provisions a new Kubernetes PersistentVolumeClaim (PVC). You specify size and storage class; the cluster allocator handles the rest.

Key properties:

• Size is expandable after creation but cannot be reduced
• Access mode is ReadWriteMany (multiple pods can mount simultaneously)
• Reclaim policy is Retain (data persists even if the volume resource is deleted from TrueFoundry)

Static Volumes (Use Existing)

Mount a pre-existing Kubernetes PersistentVolume by name. Use this for:

• AWS EFS -- Elastic File System via efs.csi.aws.com driver
• AWS S3 -- S3 buckets via s3.csi.aws.com driver
• GCP Filestore / GCS -- via gcsfuse.csi.storage.gke.io driver
• Azure Files / Azure Blob -- via file.csi.azure.com or blob.csi.azure.com drivers

Static volumes require the PersistentVolume to already exist in the Kubernetes cluster. See the "Static Volume Setup" section below.

Storage Classes by Cloud Provider

For storage class tables by cloud provider (AWS, GCP, Azure) and discovery commands, see references/volume-storage-classes.md.

Creating a Volume

When using direct API, set TFY_API_SH to the full path of this skill's scripts/tfy-api.sh. See references/tfy-api-setup.md for paths per agent.

Before Creating

ALWAYS ask the user these questions in order:

1. Volume type -- "Do you want to create a new volume or use an existing Kubernetes PersistentVolume?"
   • Create new → proceed with dynamic volume questions below
   • Use existing → ask for the PersistentVolume name in Kubernetes, then skip to workspace
2. Volume name -- What should the volume be called?
3. Size -- How much storage? (integer in GB, e.g. 50). Cannot be reduced later.
4. Storage class -- Which storage class? Present available options from the cluster.
5. Workspace -- Which workspace? Volumes are workspace-scoped.
6. Volume Browser -- "Do you want to enable Volume Browser? It provides a web UI to browse and manage files in your volume without SSH." (Optional)
   • If yes, ask for:
     • Endpoint host -- The hostname where the browser will be accessible (e.g. my-cluster.example.truefoundry.com). Present available hosts from the cluster's base domain.
     • Endpoint path -- URL path prefix (optional, defaults to /)
     • Username -- Login username for the browser (optional, defaults to admin)
     • Password secret -- FQN of a TrueFoundry secret containing the browser password. If user doesn't have one, help them create it using the secrets skill first.

Present a summary and ask for confirmation:

Volume to create:
  Type:          Create new (dynamic)
  Name:          training-data
  Size:          100 GB
  Storage class: efs-sc
  Workspace:     my-cluster:my-workspace
  Volume Browser: Enabled
    Endpoint:    https://my-cluster.example.truefoundry.com/training-data/
    Username:    admin
    Password:    (secret: my-cluster:my-workspace:vol-browser-pw)

Note: Size can be expanded later but not reduced.
Proceed?

For volumes without Volume Browser:

Volume to create:
  Type:          Create new (dynamic)
  Name:          training-data
  Size:          100 GB
  Storage class: efs-sc
  Workspace:     my-cluster:my-workspace
  Volume Browser: Disabled

Note: Size can be expanded later but not reduced.
Proceed?

Via Tool Call

tfy_applications_create_deployment(
    manifest={"type": "volume", "name": "my-volume", "config": {"type": "dynamic", "size": 100, "storage_class": "efs-sc"}},
    options={"workspace_id": "ws-id-here"}
)

For Volume Browser fields and static volume tool-call examples, use the same fields as the Direct API examples below.

Via Direct API

Create new volume (without Volume Browser):

$TFY_API_SH PUT /api/svc/v1/apps '{
  "manifest": {
    "type": "volume",
    "name": "my-volume",
    "config": {
      "type": "dynamic",
      "size": 100,
      "storage_class": "efs-sc"
    }
  },
  "workspaceId": "ws-id-here"
}'

Create new volume (with Volume Browser):

$TFY_API_SH PUT /api/svc/v1/apps '{
  "manifest": {
    "type": "volume",
    "name": "my-volume",
    "config": {
      "type": "dynamic",
      "size": 100,
      "storage_class": "efs-sc"
    },
    "volume_browser": {
      "username": "admin",
      "password_secret_fqn": "my-cluster:my-workspace:vol-browser-pw",
      "endpoint": {
        "host": "my-cluster.example.truefoundry.com",
        "path": "/my-volume/"
      }
    }
  },
  "workspaceId": "ws-id-here"
}'

Using an Existing Kubernetes PersistentVolume

$TFY_API_SH PUT /api/svc/v1/apps '{
  "manifest": {
    "type": "volume",
    "name": "my-existing-vol",
    "config": {
      "type": "static",
      "persistent_volume_name": "pv-name-in-k8s"
    }
  },
  "workspaceId": "ws-id-here"
}'

Listing Volumes

Via Tool Call

tfy_applications_list(filters={"workspace_fqn": "my-cluster:my-workspace", "application_type": "volume"})

Via Direct API

# List volumes in a workspace
$TFY_API_SH GET '/api/svc/v1/apps?workspaceFqn=my-cluster:my-workspace&applicationType=volume'

# Get a specific volume by ID
$TFY_API_SH GET /api/svc/v1/apps/VOLUME_APP_ID

Presenting Volumes

Volumes in my-cluster:my-workspace:
| Name           | Size   | Storage Class | Status   | Created            |
|----------------|--------|---------------|----------|--------------------|
| training-data  | 100Gi  | efs-sc        | RUNNING  | 2026-02-10 14:30   |
| model-cache    | 50Gi   | premium-rwx   | RUNNING  | 2026-02-08 09:15   |

Attaching Volumes to Services and Jobs

Volumes are mounted into containers at a specified path. The volume must be in the same workspace as the application.

SDK (in deploy.py)

from truefoundry.deploy import Service, VolumeMount

service = Service(
    name="my-service",
    # ... image, ports, resources ...
    mounts=[
        VolumeMount(
            mount_path="/data",
            volume_fqn="my-cluster:my-workspace:my-volume",
        ),
    ],
)

API Manifest (Service)

{
  "manifest": {
    "kind": "Service",
    "name": "my-service",
    "image": {"type": "image", "image_uri": "my-image:latest"},
    "mounts": [
      {
        "type": "volume",
        "mount_path": "/data",
        "volume_fqn": "my-cluster:my-workspace:my-volume"
      }
    ],
    "resources": {
      "cpu_request": 0.5, "cpu_limit": 1.0,
      "memory_request": 512, "memory_limit": 1024
    }
  },
  "workspaceId": "ws-id-here"
}

API Manifest (Job)

{
  "manifest": {
    "kind": "Job",
    "name": "my-training-job",
    "image": {"type": "image", "image_uri": "my-training:latest"},
    "mounts": [
      {
        "type": "volume",
        "mount_path": "/data",
        "volume_fqn": "my-cluster:my-workspace:training-data"
      },
      {
        "type": "volume",
        "mount_path": "/checkpoints",
        "volume_fqn": "my-cluster:my-workspace:checkpoint-vol"
      }
    ],
    "resources": {
      "cpu_request": 4.0, "cpu_limit": 8.0,
      "memory_request": 16384, "memory_limit": 32768
    }
  },
  "workspaceId": "ws-id-here"
}

Volume FQN Format

The volume FQN follows the pattern: {cluster}:{workspace}:{volume-name}

Example: my-cluster:my-workspace:training-data

LLM Cache Volumes

For LLM deployments, TrueFoundry supports a cache_volume shorthand that creates a volume for model weight caching. This avoids re-downloading large models on every pod restart. See the llm-deploy skill for details.

# In LLM deployment manifest
cache_volume:
  cache_size: 50
  storage_class: efs-sc

Volume Sizing Guidelines

Use Case	Recommended Size	Notes
Small model cache (< 7B params)	20-50 Gi	2x the model size in FP16
Large model cache (7B-70B params)	50-200 Gi	2x the model size; account for multiple formats
Shared training dataset	50-500 Gi	Depends on dataset size; leave 20% headroom
Checkpointing	20-100 Gi	Depends on checkpoint frequency and model size
General shared storage	10-50 Gi	Start small, expand as needed

Sizing tips:

• Always add 20% headroom above your expected data size
• Volume size can be expanded later but never reduced -- start conservatively if unsure
• For model caching, use 2x the model's disk size to account for download + extraction
• Monitor volume usage after deployment and expand proactively before hitting limits

Static Volume Setup

For detailed setup instructions for AWS EFS, AWS S3, GCP GCS Fuse, and Azure Files/Blob, see references/static-volume-setup.md.

Volume Browser

For Volume Browser configuration fields, setup steps, and access instructions, see references/volume-browser-setup.md.

<success_criteria>

• The agent asked "create new or use existing?" before proceeding
• The agent has confirmed volume name, size, storage class, and workspace with the user before creating
• The agent asked whether to enable Volume Browser and collected endpoint/password details if yes
• The volume was successfully created and is in RUNNING status
• The user can list all volumes in their target workspace
• The user can attach the volume to a service or job using the correct volume FQN
• The agent has advised on appropriate sizing based on the user's use case
• The user understands the difference between volumes and blob storage for their scenario

</success_criteria>

Composability

• Before deploying with volumes: Use workspaces skill to get workspace FQN, then create the volume in the same workspace
• With secrets skill: Create a password secret before enabling Volume Browser (password_secret_fqn is required)
• With deploy skill: After creating a volume, add VolumeMount to the service's deploy.py to attach it
• With llm-deploy skill: Use cache_volume in LLM deployment manifests for model weight caching
• With jobs skill: Mount volumes to training jobs for checkpointing and shared data access
• With applications skill: List volumes alongside other application types to see what storage exists
• After creating: Use applications skill to verify the volume was created successfully

Error Handling

Error	Cause	Fix
Volume not found	Wrong name or workspace	Verify FQN; volumes are workspace-scoped
Storage class not available	Cluster missing provisioner	Check GET /api/svc/v1/clusters/CLUSTER_ID for available classes
Size cannot be reduced	PVC limitation	Create new smaller volume and migrate data
Workspace mismatch	Volume in different workspace	Create volume in same workspace as the app
Permission denied	API key lacks access	Check API key permissions for this workspace
PV not found (static)	K8s PV doesn't exist	Verify with kubectl get pv <pv-name>
Data corruption	Multiple pods writing same path	Use per-pod sub-directories (e.g., /data/pod-{POD_NAME}/)