Advanced Cluster Management

Red Hat Advanced Cluster Management for Kubernetes (ACM) extends OpenShift's capabilities with multi-cluster management, policy-based governance, and application lifecycle management.

Prerequisites

Before deploying ACM, ensure you have:

• An operational OpenShift cluster
• Valid Red Hat subscription
• Sufficient cluster resources:
  • 3+ worker nodes
  • 8GB RAM per worker
  • 4 vCPUs per worker

Installation

Configuration Parameters

Configure ACM installation parameters:

# Set ACM channel version
drpcli profiles set demo param openshift/acm-channel to "release-2.11"

# Configure namespace
drpcli profiles set demo param openshift/acm-namespace to "open-cluster-management"

# Adjust installation timeouts if needed
drpcli profiles set demo param openshift/acm-install-timeout to "1800"
drpcli profiles set demo param openshift/acm-install-mcm-timeout to "3600"

Deploy ACM

To deploy ACM, first get your cluster's UUID:

# Get cluster UUID
CLUSTER_UUID=$(drpcli clusters show demo | jq -r .Uuid)

# Create work order to run ACM installation blueprint
drpcli clusters work_order on $CLUSTER_UUID
drpcli clusters work_order add $CLUSTER_UUID openshift-cluster-acm-install

Usage Guide

Accessing ACM Features

Access ACM through the OpenShift console:

1. Log into the OpenShift web console
2. Navigate to "Home" → "Multicluster"
3. Access features through the console interface:
   • Cluster management
   • Application management
   • Policy enforcement
   • Risk and compliance

Managing Clusters

Importing Existing Clusters

Follow these steps to import clusters:

1. In the OpenShift console:

   • Navigate to Home → Multicluster → Infrastructure → Clusters
   • Click "Import cluster"
   • Follow the guided process

2. On the target cluster:

   # Apply the generated import command
   oc apply -f import.yaml
   
   # Verify registration
   oc get managedclusters
   

Troubleshooting

Common Issues

Monitor ACM health and diagnose issues:

# Check MultiClusterHub status
oc get mch -n open-cluster-management

# Review operator status
oc get csv -n open-cluster-management

# Check pod health
oc get pods -n open-cluster-management

Collecting Diagnostics

Gather ACM-specific logs:

# Use must-gather for ACM
oc adm must-gather --image=registry.redhat.io/rhacm2/acm-must-gather-rhel8:v2.11 --dest-dir=acm-logs

Best Practices

Consider these guidelines for ACM usage:

1. Hub Cluster Sizing

   • Monitor resource usage regularly
   • Scale worker nodes based on managed cluster count
   • Consider dedicated nodes for ACM workloads

2. Policy Management

   • Test policies in inform mode before enforcement
   • Use hierarchical policies for complex requirements
   • Document policy decisions and exceptions

3. Cluster Lifecycle

   • Implement consistent naming conventions
   • Use placement rules effectively
   • Maintain backup procedures for ACM configurations