Case Studies

Problem The database architecture reached its limit when a critical node stopped responding. A standby node experienced a PostgreSQL Patroni replica failure, repeatedly logging “incorrect resource manager data checksum” errors. The system stopped working because corrupted Write-Ahead Log segments completely broke the replication stream. A dangerous shortcut would involve running continuous base backups to force […]

Problem: The client needed to modernize their Zabbix v7.4.8 setup by migrating a Low-Level Discovery rule away from a static, local JSON file. They required best practices and an architectural recommendation for dynamically triggering and feeding the discovery rule from an external Windows server, while ensuring reliable and efficient updates. Process: Step 1: Architecture Review […]

Problem: During migration to Zabbix 7.4, hundreds of HTTPS health checks failed because the HTTP Host header differed from the SNI hostname used for the TLS handshake. In this environment, monitoring items connect to a load-balancer VIP using a custom Host header to reach specific virtual sites. However, the target servers detected the discrepancy between […]

Problem: A customer running Patroni-managed PostgreSQL v15.17 (Patroni 3.3.2) asked whether Commvault backups can be taken from the DR site’s Standby Leader. The DR cluster is a replicating standby of Production. The request asked specifically whether WAL file generation can be started on the DR Standby Leader and whether Commvault’s option to delete WALs after […]

Problem: On a primary Sonatype Nexus instance running version 3.29.2-02, container images stored in Docker repositories were disappearing without any recorded user DELETE calls. The operator reported unexpected removals, noted release notes referencing a prior cleanup-policy UI bug (where day values were misinterpreted as seconds), and observed that repository artifacts had been cleaned automatically. The […]

Problem: A Patroni-managed PostgreSQL cluster (PostgreSQL 15.17, Patroni 3.3.2) running asynchronous replication intermittently failed to rejoin an ex-master after a physical host reboot performed as part of high‑availability testing. Test pattern: hard shutdown of the former primary for ~5 minutes, then restart. Symptom observed on restart: the node failed to rejoin with the error “requested […]

Problem: Argo CD UI responsiveness and application sync/refresh operations experienced frequent slowness and timeouts on a bare‑metal OpenShift cluster. Symptoms included UI timeout and long sync times when running bulk refresh/sync operations against an app‑of‑apps topology: sync jobs that exceeded a 1,800s pipeline timeout would fail. The environment manages ~5,200 Argo CD applications on a […]

Problem: An official Apache NiFi Docker image (standard distribution) was scanned by a security tool and reported a high-severity finding: sonatype-2024-3350 (commons-collections version 3.2.2). The scanner identified the vulnerable class (SetUniqueList) inside the nifi-toolkit-assembly artifact (zip:bin, NiFi distribution version 2.8.0). The deployment context was a stock NiFi image pulled from the vendor registry — no […]

Problem: Seven identical Patroni-managed PostgreSQL 15.15 clusters (Patroni 3.3.2) showed divergent behaviour for the same SELECT query: clusters labelled Cust 1–5 returned results quickly while Cust 6–7 returned the same query much slower. Dataset sizes, indexes, constraints and foreign keys were reported as equivalent across clusters. One temporary mitigation (set enable_mergejoin = false) had been […]