Module 5: Storage Configuration for OpenShift 4.18/4.19

Storage Overview for OpenShift 4.18/4.19

Storage Architecture in OpenShift

OpenShift Container Platform 4.18/4.19 provides comprehensive storage capabilities through multiple storage solutions:

Storage Requirements for OpenShift 4.18/4.19

Before configuring storage, understand the requirements:

OpenShift Data Foundation (ODF) Setup

What is OpenShift Data Foundation?https://docs.redhat.com/en/documentation/openshift_container_platform/4.19/html/storage/configuring-persistent-storage#persistent-storage-using-azure

OpenShift Data Foundation is Red Hat’s software-defined storage solution that provides:

  • Block Storage: High-performance block storage using Ceph RBD

  • File Storage: Shared file storage using CephFS

  • Object Storage: S3-compatible object storage using Ceph RADOS Gateway

  • Multi-Cloud Gateway: Unified object storage across multiple clouds

ODF Architecture Components

  • Ceph Storage Cluster: Distributed storage backend

  • Rook Operator: Kubernetes-native storage orchestration

  • NooBaa: Multi-cloud object gateway

  • CSI Drivers: Container Storage Interface drivers for dynamic provisioning

Prerequisites for ODF Installation

Before installing ODF, ensure:

  • Hardware Requirements: Minimum 3 worker nodes with local storage

  • Storage Devices: Raw block devices or local disks on each storage node

  • Network Requirements: High-bandwidth, low-latency network between storage nodes

  • Node Labels: Proper node labeling for storage node identification

Step-by-Step ODF Installation

Step 1: Install OpenShift Data Foundation Operator

  1. Access the OpenShift web console

  2. Navigate to Operators → OperatorHub

  3. Search for "OpenShift Data Foundation"

  4. Click Install and follow the installation wizard

  5. Wait for the operator to be installed successfully

Step 2: Prepare Storage Nodes

Label nodes that will provide storage:

# Label storage nodes
oc label nodes worker-1 cluster.ocs.openshift.io/openshift-storage=""
oc label nodes worker-2 cluster.ocs.openshift.io/openshift-storage=""
oc label nodes worker-3 cluster.ocs.openshift.io/openshift-storage=""

Step 3: Create Storage Cluster

  1. Navigate to Operators → Installed Operators → OpenShift Data Foundation

  2. Click "Create StorageSystem"

  3. Select deployment type (Internal or External)

  4. Configure storage devices and capacity

  5. Review and create the storage cluster

Local Storage Operator Configuration

What is the Local Storage Operator?

The Local Storage Operator enables the use of local storage devices for persistent volumes in OpenShift 4.18/4.19.

Local Storage Use Cases

  • High-performance workloads: Applications requiring low-latency storage access

  • Database workloads: Databases that benefit from direct storage access

  • Edge computing: Environments where external storage is not available

  • Cost optimization: Utilizing existing local storage resources

Installing the Local Storage Operator

Step 1: Install the Operator

# Create namespace for local storage operator
oc create namespace openshift-local-storage

# Install the operator via OperatorHub or CLI
oc apply -f - <<EOF
apiVersion: operators.coreos.com/v1alpha1
kind: Subscription
metadata:
  name: local-storage-operator
  namespace: openshift-local-storage
spec:
  channel: stable
  name: local-storage-operator
  source: redhat-operators
  sourceNamespace: openshift-marketplace
EOF

Step 2: Discover Local Storage Devices

# Create LocalVolumeDiscovery to discover available devices
oc apply -f - <<EOF
apiVersion: local.storage.openshift.io/v1alpha1
kind: LocalVolumeDiscovery
metadata:
  name: auto-discover-devices
  namespace: openshift-local-storage
spec:
  nodeSelector:
    nodeSelectorTerms:
    - matchExpressions:
      - key: kubernetes.io/os
        operator: In
        values:
        - linux
EOF

Step 3: Create LocalVolumeSet

# Create LocalVolumeSet for automatic PV creation
oc apply -f - <<EOF
apiVersion: local.storage.openshift.io/v1alpha1
kind: LocalVolumeSet
metadata:
  name: local-block
  namespace: openshift-local-storage
spec:
  nodeSelector:
    nodeSelectorTerms:
    - matchExpressions:
      - key: kubernetes.io/os
        operator: In
        values:
        - linux
  storageClassName: local-block
  volumeMode: Block
  fsType: ext4
  maxDeviceCount: 10
  deviceInclusionSpec:
    deviceTypes:
    - disk
    - part
    minSize: 100Gi
EOF

External Storage Integration

Supported External Storage Types

OpenShift 4.18/4.19 supports various external storage systems:

Block Storage Providers

File Storage Providers

Object Storage Providers

  • S3-compatible storage: Amazon S3 and compatible systems

  • OpenStack Swift: OpenStack object storage

  • Ceph RADOS Gateway: Ceph object storage interface

Configuring External Storage

Creating Storage Classes

# Example NFS storage class
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: nfs-storage
provisioner: nfs.csi.k8s.io
parameters:
  server: nfs-server.example.com
  share: /exports/nfs
reclaimPolicy: Delete
volumeBindingMode: Immediate

Persistent Volume Management

Container Image Registry Configuration

Configuring the Internal Registry

The OpenShift internal registry requires persistent storage for production use:

Configure Registry Storage with ODF

# Configure image registry to use ODF storage
oc patch configs.imageregistry.operator.openshift.io cluster --type merge --patch '{"spec":{"storage":{"pvc":{"claim":""}}}}'

# Verify registry configuration
oc get configs.imageregistry.operator.openshift.io cluster -o yaml

Configure Registry Storage with NFS

# Configure image registry with NFS storage
apiVersion: imageregistry.operator.openshift.io/v1
kind: Config
metadata:
  name: cluster
spec:
  storage:
    pvc:
      claim: registry-storage
  managementState: Managed

Registry Security and Access Control

Volume Snapshots and Backup

Configuring Volume Snapshots

OpenShift 4.18/4.19 provides comprehensive snapshot capabilities:

Install Volume Snapshot Components

# Volume snapshot components are included by default
# Verify snapshot CRDs are available
oc get crd | grep snapshot

# Check volume snapshot controller
oc get pods -n openshift-cluster-storage-operator

Create Volume Snapshot Classes

# Example volume snapshot class for ODF
apiVersion: snapshot.storage.k8s.io/v1
kind: VolumeSnapshotClass
metadata:
  name: ocs-storagecluster-rbdplugin-snapclass
driver: openshift-storage.rbd.csi.ceph.com
deletionPolicy: Delete

Creating and Managing Snapshots

# Create a volume snapshot
apiVersion: snapshot.storage.k8s.io/v1
kind: VolumeSnapshot
metadata:
  name: my-app-snapshot
spec:
  volumeSnapshotClassName: ocs-storagecluster-rbdplugin-snapclass
  source:
    persistentVolumeClaimName: my-app-data

Backup and Disaster Recovery

Implement comprehensive backup strategies:

Storage Monitoring and Performance

Storage Metrics and Monitoring

Monitor storage performance and capacity:

Key Storage Metrics

  • Capacity Utilization: Available vs. used storage capacity

  • IOPS Performance: Input/output operations per second

  • Latency Metrics: Storage response times

  • Throughput: Data transfer rates

Monitoring Tools

  • Prometheus Monitoring: Built-in metrics collection

  • Grafana Dashboards: Visual storage performance dashboards

  • ODF Monitoring: Specialized monitoring for OpenShift Data Foundation

  • Storage Alerts: Automated alerting for storage issues

Performance Optimization

Optimize storage performance for different workloads:

  • Storage Class Parameters: Tune storage class settings for performance

  • Node Affinity: Place storage-intensive workloads on appropriate nodes

  • Resource Limits: Configure appropriate CPU and memory limits

  • Network Optimization: Optimize network configuration for storage traffic

Storage Best Practices for OpenShift 4.18/4.19

Design Principles

  • Redundancy: Implement storage redundancy across failure domains

  • Performance: Choose appropriate storage types for workload requirements

  • Scalability: Plan for storage growth and expansion

  • Security: Implement encryption at rest and in transit

Operational Best Practices

  • Capacity Planning: Monitor and plan for storage capacity growth

  • Backup Strategy: Implement regular backup and disaster recovery procedures

  • Performance Monitoring: Continuously monitor storage performance metrics

  • Security Updates: Keep storage components updated with security patches

Cost Optimization

  • Storage Tiering: Use appropriate storage tiers for different data types

  • Lifecycle Management: Implement data lifecycle policies

  • Resource Optimization: Right-size storage allocations

  • Monitoring and Alerting: Implement cost monitoring and alerting

Documentation References

For detailed storage configuration information, refer to:

Next Steps

Ready to configure advanced networking with Nmstate? Continue to Module 6: Network Configuration using Nmstate.