Actor:

OpenShift Administrator

Description:

As an OpenShift administrator, I want to increase the size of the /var/lib/kubelet/ directory after the OpenShift cluster has been installed and is operational. This enhancement is crucial for accommodating the growing storage demands of the kubelet, which manages pod and container operations on each node.

Preconditions:

• An OpenShift cluster is already installed and operational.
• The administrator has root or equivalent access to the cluster nodes.
• There is a clear understanding of the current storage utilization and future requirements.

Main Flow:

1. Assessment of Current Storage Utilization: The administrator evaluates the current storage usage of /var/lib/kubelet/ to determine the required increase.
2. Planning and Scheduling Downtime (if necessary): Depending on the approach and the cluster setup, the administrator plans for potential downtime, notifying relevant stakeholders.
3. Executing Storage Expansion:
   • If using a cloud provider or virtualized environment, the administrator increases the disk size through the respective management console or API.
   • For physical servers, this might involve adding new storage hardware or adjusting partitions.
4. Filesystem Resizing: The administrator resizes the filesystem to utilize the newly allocated space.
5. Verifying the Changes: Post-expansion, the administrator verifies that the kubelet and other cluster components are functioning correctly and that the new storage capacity is recognized.
6. Documentation and Reporting: Document the changes made and report back to relevant stakeholders about the upgrade.

Postconditions:

• The /var/lib/kubelet/ directory has increased storage capacity.
• The OpenShift cluster continues to function without any degradation in performance.
• Monitoring and alerts are updated to reflect the new storage thresholds.

Pain Points and Rationale for the Feature:

• Insufficient Initial Allocation: Initially, the storage allocated to /var/lib/kubelet/ might have been underestimated, leading to space issues as the cluster scales.
• Growing Workloads: As the number of pods and containers increases, the kubelet requires more space to manage these resources effectively.
• Performance Degradation: Limited storage can lead to performance issues, impacting the reliability and efficiency of the cluster.
• Operational Complexity: Expanding storage post-installation can be complex and risky, especially in production environments, necessitating a straightforward and safe method to do so.
• Data Integrity: Ensuring data integrity during the expansion process is critical, as loss of data can lead to significant disruptions.