Here are 50 essential OpenShift installation notes:

1. Preparation and Requirements: Ensure your environment meets the hardware, software, and networking requirements for OpenShift v4.
2. Choose the Installation Method: Decide between Installer-Provisioned Infrastructure (IPI) or User-Provisioned Infrastructure (UPI).
3. Infrastructure Requirements: Check for compatibility with your infrastructure, whether it’s bare metal, virtualized, or cloud-based.
4. Operating System: Use a compatible Linux distribution, preferably Red Hat Enterprise Linux CoreOS (RHCOS).
5. DNS Setup: Properly configure DNS records for OpenShift cluster nodes and services.
6. Load Balancer Configuration: Set up a load balancer for the API and ingress traffic.
7. Certificate Management: Plan for necessary certificates for secure communication.
8. Persistent Storage: Determine the storage requirements and set up persistent storage solutions.
9. Networking: Plan your network topology, including subnetting and VLANs.
10. Download OpenShift Installer: Obtain the latest version of the OpenShift installer for your platform.
11. Pull Secret: Obtain a pull secret from the Red Hat OpenShift Cluster Manager site.
12. Installation Configuration File: Generate and customize the install-config.yaml file for your installation.
13. SSH Key Pair: Generate an SSH key pair for secure access to cluster nodes.
14. Run the Installer: Execute the OpenShift installer to start the deployment process.
15. Monitor Installation Progress: Use the installer’s output and OpenShift console to monitor the installation progress.
16. Validate the Installation: After installation, validate that all components are running as expected.
17. Networking Policies: Configure networking policies for pod communication.
18. Security Context Constraints: Understand and configure Security Context Constraints (SCCs) as per your workload needs.
19. User Management: Set up user authentication and authorization.
20. Project and Quota Management: Organize resources into projects and set resource quotas.
21. Logging and Monitoring: Set up and configure logging and monitoring tools.
22. Registry Configuration: Configure the integrated container image registry.
23. Image Security: Implement image scanning and security policies.
24. Cluster Updates and Upgrades: Plan for cluster updates and understand the upgrade process.
25. Backup and Disaster Recovery: Implement a backup and disaster recovery strategy.
26. Application Deployment: Understand the process of deploying applications on OpenShift.
27. Service Mesh Implementation: Consider using a service mesh for microservices communication.
28. Serverless Applications: Explore options for deploying serverless applications with OpenShift.
29. Container Security: Implement security best practices for containerized applications.
30. Node Maintenance: Plan for regular maintenance of cluster nodes.
31. Cluster Scaling: Understand how to scale your OpenShift cluster.
32. Resource Management: Utilize Resource Limits and Requests effectively.
33. Custom Resource Definitions: Use CRDs for extending Kubernetes capabilities.
34. Operators: Utilize Operators for managing complex applications on the cluster.
35. Networking Plugins: Choose and configure the right CNI plugin.
36. API Management: Consider API management solutions for your services.
37. Edge Computing Considerations: If applicable, plan for edge computing scenarios.
38. Multitenancy Considerations: Plan for multitenancy if required.
39. Compliance and Security Standards: Ensure your cluster meets necessary compliance and security standards.
40. Integration with Existing Systems: Plan how OpenShift will integrate with existing systems and infrastructure.
41. Troubleshooting Tools: Familiarize yourself with tools and techniques for troubleshooting cluster issues.
42. Documentation: Regularly consult the official OpenShift documentation for guidance.
43. Community and Support: Engage with the OpenShift community and Red Hat support for help.
44. Training and Certification: Consider training and certification for team members.
45. Cluster Autoscaling: Configure cluster autoscaler for handling workload spikes.
46. Node Feature Discovery: Use Node Feature Discovery to leverage specific hardware features.
47. Network Policies: Implement network policies for controlling pod-to-pod communication.
48. Cluster Resource Optimization: Regularly monitor and optimize resource usage.
49. CI/CD Integration: Integrate continuous integration and continuous deployment pipelines with your cluster.
50. Customization and Extensions: Explore options for customizing and extending the capabilities of your OpenShift cluster.