Fibre Channel Storage Integration

Fibre Channel (FC) is a high-speed network technology primarily used for storage area networks (SANs). In Kubernetes, Fibre Channel provides high-performance block storage connectivity, typically used in enterprise environments where maximum performance and reliability are critical requirements.

What is Fibre Channel?

Fibre Channel is a high-speed network technology (1Gbps to 128Gbps) designed for storage area networks. It uses a dedicated network fabric (separate from IP networks) to connect servers to storage systems, providing low latency and high throughput for block storage access.

graph LR A[Kubernetes Node] --> B[Fibre Channel HBA] B --> C[FC Fabric] C --> D[Storage Array] D --> E[Block Storage LUNs] style A fill:#e1f5ff style B fill:#fff4e1 style C fill:#e8f5e9 style D fill:#f3e5f5 style E fill:#ffe1e1

Key characteristics:

Dedicated network - Separate FC fabric (not IP network)
High performance - Very low latency, high throughput
Enterprise-grade - Designed for mission-critical applications
Block storage - Provides block-level access (like local disks)
Cost - More expensive than iSCSI or NFS

Fibre Channel in Kubernetes

Kubernetes supports Fibre Channel volumes through:

In-tree FC volume plugin - Built-in support (deprecated but functional)
CSI FC drivers - Vendor-specific CSI drivers (recommended)

In-Tree Fibre Channel Plugin

The in-tree plugin requires manual configuration of FC volumes:

apiVersion: v1
kind: PersistentVolume
metadata:
  name: fc-pv
spec:
  capacity:
    storage: 100Gi
  accessModes:
    - ReadWriteOnce
  fc:
    targetWWNs: ["500a048200000000", "500a048300000000"]  # World Wide Names
    lun: 0
    fsType: ext4
    readOnly: false

Key fields:

targetWWNs - Array of World Wide Names (WWNs) of FC target ports
lun - Logical Unit Number (LUN) identifier
wwids - Alternative to targetWWNs/lun (World Wide Identifiers)
fsType - Filesystem type (ext4, xfs, etc.)

CSI Fibre Channel Drivers

Vendor-specific CSI drivers provide better integration. Examples include:

Storage vendor CSI drivers (Dell EMC, NetApp, IBM, HPE, etc.)
These drivers handle FC connectivity and volume provisioning

Example using vendor CSI driver:

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: fc-storage
provisioner: vendor.csi.storage.k8s.io  # Vendor-specific
parameters:
  storagePool: "production-pool"
  # Vendor-specific parameters

Fibre Channel Components

Host Bus Adapter (HBA)

Kubernetes nodes need Fibre Channel HBAs installed:

Physical FC HBA cards in nodes
FC HBA drivers installed on nodes
FC connectivity to storage fabric

World Wide Names (WWNs)

FC uses WWNs to identify devices:

Port WWN (pWWN) - Unique identifier for each FC port
Node WWN (nWWN) - Unique identifier for the device/node
WWNs are like MAC addresses for FC devices

Logical Unit Number (LUN)

A LUN represents a logical block storage device presented by the storage array:

Storage arrays can present multiple LUNs
Each LUN appears as a block device to the host
LUNs are identified by LUN numbers

Static Provisioning Example

Here’s a complete example using static provisioning:

apiVersion: v1
kind: PersistentVolume
metadata:
  name: fc-pv
spec:
  capacity:
    storage: 200Gi
  accessModes:
    - ReadWriteOnce
  persistentVolumeReclaimPolicy: Retain
  fc:
    targetWWNs:
      - "500a048200000000"
      - "500a048300000000"
    lun: 1
    fsType: ext4
    readOnly: false
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: fc-pvc
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 200Gi
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: database
spec:
  serviceName: database
  replicas: 1
  template:
    spec:
      containers:
      - name: db
        image: postgres:14
        volumeMounts:
        - name: data
          mountPath: /var/lib/postgresql/data
  volumeClaimTemplates:
  - metadata:
      name: data
    spec:
      accessModes:
        - ReadWriteOnce
      resources:
        requests:
          storage: 200Gi

Using WWIDs

Instead of specifying targetWWNs and LUN, you can use WWIDs (World Wide Identifiers):

apiVersion: v1
kind: PersistentVolume
metadata:
  name: fc-pv-wwid
spec:
  capacity:
    storage: 100Gi
  accessModes:
    - ReadWriteOnce
  fc:
    wwids:
      - "3600508b400105e210000900000490000"
    fsType: ext4

WWIDs provide better portability and are preferred when available.

Zoning and Security

FC uses zoning to control which initiators (hosts) can access which targets (storage):

Zoning - Logical grouping of FC devices for access control
WWPN zoning - Zone based on port WWNs
LUN masking - Further restrict which LUNs initiators can access

Zoning is configured on FC switches and storage arrays, not in Kubernetes.

Use Cases

Fibre Channel is ideal for:

High-performance databases - Maximum I/O performance requirements
Mission-critical applications - Applications requiring highest reliability
Enterprise SAN environments - Existing FC infrastructure
Low-latency requirements - Applications sensitive to storage latency
Large-scale deployments - Enterprise environments with FC investments

Advantages

High performance - Lowest latency, highest throughput
Dedicated network - Separate from IP network, no interference
Enterprise reliability - Designed for mission-critical applications
Mature technology - Well-established, proven technology
Block storage - Direct block device access

Limitations

Cost - Expensive infrastructure (HBAs, switches, storage arrays)
Complexity - Requires FC expertise and infrastructure
Limited to block storage - Only supports block volumes (ReadWriteOnce)
Vendor-specific - Often requires vendor-specific CSI drivers
Infrastructure requirements - Needs dedicated FC fabric

Best Practices

Use CSI drivers - Prefer vendor CSI drivers over in-tree plugin
Proper zoning - Configure FC zoning correctly for security and isolation
LUN masking - Use LUN masking for additional access control
Multi-path - Configure multi-path I/O for high availability
Document WWNs - Document WWNs and LUN assignments
Test failover - Test FC path failover scenarios
Monitor performance - Monitor FC fabric performance and utilization
Work with storage team - Coordinate with storage administrators

Multi-Path I/O

For high availability, configure multi-path I/O (MPIO) so nodes can access storage through multiple FC paths:

apiVersion: v1
kind: PersistentVolume
metadata:
  name: fc-pv-multipath
spec:
  capacity:
    storage: 100Gi
  accessModes:
    - ReadWriteOnce
  fc:
    wwids:
      - "3600508b400105e210000900000490000"
    fsType: ext4

MPIO is typically configured at the OS level on nodes, not in Kubernetes manifests.

Troubleshooting

Volume Not Discovered

If FC volumes are not discovered:

Verify HBA is installed and recognized: lspci | grep Fibre
Check FC link status: cat /sys/class/fc_host/host*/port_state
Verify zoning configuration on FC switches
Check LUN masking on storage array
Review node system logs: dmesg | grep -i fibre

Performance Issues

If experiencing performance issues:

Check FC link speed: cat /sys/class/fc_host/host*/speed
Verify multi-path configuration
Review storage array performance metrics
Check FC fabric utilization
Verify proper zoning (avoid oversubscription)

Connection Failures

If FC connections fail:

Verify physical FC cable connections
Check FC switch port status
Verify HBA driver is loaded: lsmod | grep -i fc
Review FC fabric zoning configuration
Check storage array port status