Planning a Tanzu GemFire Upgrade on Kubernetes

Products

VMware Tanzu Gemfire

Issue/Introduction

Upgrading a VMware Tanzu GemFire cluster deployed on Kubernetes requires careful planning to ensure a smooth and reliable process. A lack of preparation can result in inconsistencies, region data loss, and cluster instability—especially when dealing with persistent regions, tombstones, or partitioned regions without redundancy.

This article outlines what to check and prepare before initiating a GemFire upgrade in a Kubernetes environment. It is designed to help operators prevent common pitfalls and ensure a seamless upgrade experience.

Cause

Upgrading a distributed data system like GemFire in a dynamic environment like Kubernetes introduces several risk factors:

Unbacked disk stores and configurations can lead to irreversible data loss.
Uncreated regions referenced in disk stores may accumulate tombstones, consuming memory.
Tombstone GC stalls and network congestion can cause threads to remain in a waiting state.
Cluster split-brain or membership loss may occur if locators are brought down ungracefully.
Inconsistent configurations can arise if configuration files or Cluster Configuration Service states are not synchronized.

Resolution

To mitigate the above risks, follow this Pre-Upgrade checklist before performing a GemFire upgrade:

Backups
- Take full backups of
  - Disk stores using gfsh> backup disk-store
  - Persistent Volumes (PVCs) in Kubernetes.
  - Server-side code, custom JARs, and all configuration files.
- Stop application traffic briefly, if necessary , to capture consistent state.

Validate Cluster State

- Ensure all GemFire pods are healthy: kubectl get pods
- Verify all expected members are present: gfsh> list members
- Check for any warnings/alerts/errors in logs and make sure that everything looks good.

Backup Configuration

- Export current configuration: gfsh> export cluster-configuration

Confirm Version Compatibility
- Ensure all system components meet the software and hardware requirements for the new version.
- Major versions must match across all cluster components.
- Minor version mismatches are allowed temporarily during rolling upgrades.

Application Awareness
- Confirm all client applications are compatible with the target GemFire version.
- Validate that locators are discoverable post-upgrade by clients.
- Review for deprecated APIs or settings in use.

Clean unnecessary Disk Stores & Regions

- Remove or initialize uncreated regions that may bloat memory or tombstone usage.
- Unused regions mentioned in disk stores may trigger: "These uncreated regions will consume memory and should either be created or removed from the disk store."

Kubernetes Environment Checks

- Review Kubernetes deployment setup:
  - Helm/YAML compatibility with new GemFire versions
  - StatefulSets, PVCs, and Services configuration
- Validate:
  - Readiness/liveness probes
  - ConfigMaps and RBAC policies
  - Auto-restart settings

Additional Information

References: