March 2026 monthly summary for scylladb/scylla-cluster-tests focusing on the key accomplishments, with emphasis on business value and technical achievements achieved this month.

December 2025 monthly summary for scylladb/scylla-cluster-tests focused on delivering safety-critical features and stabilizing multi-datacenter test configurations. Highlights include new Paxos-table filtering to prevent changes to restricted Paxos state tables, a replication-factor symmetry fix across data centers to satisfy rf_rack_valid_keyspaces constraints, and test configuration enhancements for longevity runs with proper node and availability-zone settings.

Monthly 2025-11 review for scylla-cluster-tests. Focused on robustness and reliability improvements in test harness behavior under node outages. Implemented a resilient datacenter name retrieval that no longer depends on the first node in the list, reducing flakiness when the first node is down and improving cluster management reliability.

Month: 2025-10 — Focused on stabilizing the test harness for multi-datacenter Scylla deployments and delivering a targeted fix to datacenter-aware load balancing in the cluster tests. The work reduced flaky behavior and improved reliability of cross-datacenter verification. Overall, achieved a robust fix in the test harness that ensures correct datacenter resolution and stable connections across DCs, enabling safer multi-region validation and faster feedback cycles.

September 2025: Delivered Materialized View disruption resilience enhancements in scylla-cluster-tests by centralizing MV creation and index management, and added a nemesis test to validate MV building resilience when the coordinator node is killed. Implemented a bug fix to support MV creation for a random column, improving disruption handling. These changes strengthen MV reliability and expand failure-scenario test coverage, delivering business value through more robust MV workflows and lower production risk.

June 2025 monthly summary for the scylladb/scylla-cluster-tests repository focused on stability and reliability improvements in the cluster test suite. Addressed a SIGSTOP-induced test hang during removenode operations by implementing a workaround that blocks Scylla ports before removenode when the target node is paused, preventing barriers from attempting connections to nodes marked as down.

2025-05 Monthly Summary: Strengthened upgrade reliability, CI coverage, and observability for scylla-cluster-tests. Delivered validation for LIMITED Voters post-upgrade, Jenkins-based rolling upgrade tests for vnodes across Ubuntu and cloud backends, updated audit log parsing for Scylla 2025.2, and adjusted severity for raft_topology tablets draining to reduce alert noise. These work items improve upgrade success rates, data integrity, and observability across environments.

Concise monthly summary for 2025-04 focusing on feature delivery, bug fixes, and technical impact for scylladb/scylla-cluster-tests. Highlights include IPv6 Nemesis enhancements, raft limited voters correctness fixes, and global raft error filtering improvements, with measurable impact on test stability and cluster validation.

March 2025 monthly summary for scylla-cluster-tests: Delivered key reliability improvements with a refactor of cluster status management and a raft topology restart stability patch. The status management refactor directly maps node IPs to their status dictionaries, simplifying status retrieval and increasing efficiency across get_nodetool_status, check_nodes_up_and_normal, get_nodes_up_and_normal, and get_node_status_dictionary. The raft patch adds a global workaround to ignore 'connection is closed' errors during topology changes to reduce race with gossip in longevity tests. These changes improve CI reliability, reduce test flakiness, and provide a clearer maintenance path.

February 2025 (2025-02) monthly summary for scylladb/scylla-cluster-tests focused on enhancing test determinism, expanding resilience coverage, and extending CI/CD validation. Delivered Nemesis Testing Framework Enhancements with explicit target node types and broadened disruption targeting (data, token, zero-token) along with stability improvements by adjusting wait/log timings to reduce premature failures across cloud environments. Introduced Longevity Testing Jenkins Job for Zero-Token Node Configuration to validate resilience under larger zero-token topologies (four zero-token nodes) with a YAML configuration and a Jenkinsfile to orchestrate the test. Implemented reliability fixes in Nemesis: explicit target node type setting and increased wait timeout for decommission operations. These changes raise test determinism, coverage, and CI/CD throughput, delivering faster feedback and higher confidence in cluster resilience across cloud environments. Technologies/skills demonstrated include chaos testing, Nemesis framework, Jenkins CI, YAML-based configurations, and cloud-enabled resilience validation.

January 2025: Delivered a reliability-focused bug fix in scylladb/scylla-cluster-tests to preserve topology integrity during node replacement after decommission. Ensured that a new node with the same token type is added post-decommission, preserving token distribution and node count in simulated failure scenarios. This improvement reduces test flakiness, increases resilience of failure-injection tests, and strengthens production-readiness for cluster replacement workflows.

December 2024 performance summary for the scylladbbot/scylla-cluster-tests and scylladb/scylla-cluster-tests repositories. Focused on reliability, resilience, and test stability across fault-injection scenarios and CQL operations. Achievements center on improving Raft coordination reliability, clarifying nemesis target selection, stabilizing parallel longevity tests, and introducing a robust retry policy for CQL scans. These changes reduce flaky tests, shorten feedback cycles, and increase confidence in production readiness.

November 2024 (2024-11) focused on stabilizing chaos testing and cluster-management across multi-DC environments, tightening behavior around zero-nodes, and correcting disruption flows in EKS contexts. Key outcomes include more reliable chaos tests, accurate cluster state detection, and correct zero-node handling during instance creation, enabling safer rollouts and faster validation of multi-region deployments. These changes reduce test flakiness, improve configuration correctness, and enhance overall reliability of the scylla-cluster-tests suite.

October 2024: Focused on reliability of cluster tests in scylladbbot/scylla-cluster-tests. Delivered a critical bug fix to ensure test scripts target data-carrying nodes consistently, reducing test flakiness and increasing accuracy of cluster operations. The change aligns test script node selection with actual data nodes. Commit a58de1b569d009ee316bfd83b27eee64cac780e5: fix(data_nodes): use data nodes for sct operations. This work strengthens test coverage and supports more dependable CI results.

May 2024: Focused on scalable MDC testing infrastructure in scylladb/scylla-cluster-tests. Delivered Multi-Data Center Cluster Scaling feature enabling iterative per-DC node additions to reach target cluster sizes, improving realism and speed of MDC testing. No bugs fixed in this repository this month.

August 2023 (2023-08) monthly summary for scylla-cluster-tests focused on hardening cluster stability and security by implementing a ban mechanism for removed nodes. The feature prevents removed nodes from rejoining or executing queries, significantly reducing risk of stale or rogue nodes affecting test clusters and live environments.