
Xenia Fischer engineered robust upgrade, deployment, and lifecycle management features across the StackableTech ecosystem, focusing on operator reliability and platform consistency. In repositories such as stackabletech/stackable-cockpit and stackabletech/docker-images, she automated Helm-based upgrades, streamlined OCI registry adoption, and enhanced monitoring for components like ZooKeeper and Trino. Her work leveraged Rust and Kubernetes operator development, integrating CI/CD pipelines and configuration management to reduce manual intervention and improve reproducibility. By modernizing documentation and aligning test infrastructure, Xenia addressed security, compatibility, and onboarding challenges. The depth of her contributions is reflected in cross-repo coordination and the maintainability of complex distributed systems.

October 2025 performance summary for Stackable ecosystem focusing on Zookeeper-driven stability, testing, and observability. It emphasizes business value through alignment with latest stable releases, lifecycle management capabilities, and improved developer experience across platforms.
October 2025 performance summary for Stackable ecosystem focusing on Zookeeper-driven stability, testing, and observability. It emphasizes business value through alignment with latest stable releases, lifecycle management capabilities, and improved developer experience across platforms.
September 2025 – Focused on release readiness for 25.11.0, security hardening, and platform-wide upgrades across the Stackable Tech portfolio. Delivered test infra and configuration updates, security patches (CVE fixes), and consistent Vector/OPA/Druid/Hive/Docker image upgrades across 15+ repos, while cleaning up code and improving TLS deployment flexibility.
September 2025 – Focused on release readiness for 25.11.0, security hardening, and platform-wide upgrades across the Stackable Tech portfolio. Delivered test infra and configuration updates, security patches (CVE fixes), and consistent Vector/OPA/Druid/Hive/Docker image upgrades across 15+ repos, while cleaning up code and improving TLS deployment flexibility.
August 2025 focused on broad compatibility enhancements for legacy Bitnami image sources, strengthening onboarding and test reliability across Stackable’s Kubernetes Operators and demos. The work standardized the use of bitnamilegacy images in tests, docs, and Helm charts, reduced deployment friction for legacy deployments, and improved monitoring and resource-management patterns.
August 2025 focused on broad compatibility enhancements for legacy Bitnami image sources, strengthening onboarding and test reliability across Stackable’s Kubernetes Operators and demos. The work standardized the use of bitnamilegacy images in tests, docs, and Helm charts, reduced deployment friction for legacy deployments, and improved monitoring and resource-management patterns.
July 2025 performance summary focused on improving developer experience, reliability, and maintenance across four repositories. Delivered targeted documentation enhancements for the Listener Operator, introduced OpenShift-aware NiFi metrics endpoint verification, streamlined contribution and installation processes, and realigned the UI with the latest components to ensure consistency. These efforts reduce onboarding time, improve metrics observability in Kubernetes clusters, accelerate PR reviews and deployments, and maintain alignment across documentation and UI dependencies.
July 2025 performance summary focused on improving developer experience, reliability, and maintenance across four repositories. Delivered targeted documentation enhancements for the Listener Operator, introduced OpenShift-aware NiFi metrics endpoint verification, streamlined contribution and installation processes, and realigned the UI with the latest components to ensure consistency. These efforts reduce onboarding time, improve metrics observability in Kubernetes clusters, accelerate PR reviews and deployments, and maintain alignment across documentation and UI dependencies.
June 2025 performance summary across Stackable projects highlighting business value and technical delivery. Delivered robust upgrade and deployment improvements, deprecation cleanup, enhanced observability, and strengthened monitoring coverage for critical components, enabling faster customer onboarding, reduced maintenance costs, and improved reliability.
June 2025 performance summary across Stackable projects highlighting business value and technical delivery. Delivered robust upgrade and deployment improvements, deprecation cleanup, enhanced observability, and strengthened monitoring coverage for critical components, enabling faster customer onboarding, reduced maintenance costs, and improved reliability.
May 2025 monthly summary for stackable-cockpit: Delivered the Stackablectl release upgrade subcommand to automate operator upgrades. The change streamlines upgrade flows by handling uninstallation, CRD updates, and reinstallation, with options to include or exclude specific products. This reduces manual steps, minimizes downtime, and improves reliability of operator upgrades.
May 2025 monthly summary for stackable-cockpit: Delivered the Stackablectl release upgrade subcommand to automate operator upgrades. The change streamlines upgrade flows by handling uninstallation, CRD updates, and reinstallation, with options to include or exclude specific products. This reduces manual steps, minimizes downtime, and improves reliability of operator upgrades.
April 2025 highlights across Stackable’s operator ecosystem focused on reproducibility, reliability, and streamlined distribution. The team delivered reproducible builds, modernized CI/CD with OCI publishing, introduced NiFi 2.x rolling upgrades, and broadly migrated to OCI-based installation and testing workflows. These changes reduce build drift, simplify release management, accelerate onboarding, and improve consistency across environments. Key outcomes: - Reproducible Docker image builds: Added cargo install --locked flag across Dockerfiles in stackabletech/docker-images to prevent dependency drift; CHANGELOG updated. (Commits include: fix: Add `--locked` flag to cargo install commands) - CI/CD modernization: Removed Nexus references, consolidated image publishing to OCI registry (oci.stackable.tech), and retired the deprecated release workflow to streamline builds and releases. (Commit: ci: Remove Nexus from workflows (#1056)) - NiFi 2.x rolling upgrade: Implemented rolling upgrade support for NiFi 2.x clusters with updated upgrade procedures, docs, and integration tests. (Commit: feat: add rolling upgrade support for nifi 2.x (#771)) - OCI-based installation and testing workflow adoption: Aligned testing and installation flows to OCI references across 10+ operators (e.g., nifi-operator, superset-operator, airflow-operator, opa-operator, spark-k8s-operator, trino-operator, hive-operator, hbase-operator, hdfs-operator, zookeeper-operator, kafka-operator, listener-operator) with corresponding docs updates. - OCI-based image distribution modernization: Standardized on OCI registries for operator templating/distribution; Makefile changes to reflect OCI hostnames and removal of Nexus/Docker Hub usage; demos publishing moved to OCI; includes fixes to test environment image references. (Commits: fd6aa6eba0; 9db03b4349; eafd1a708a5e0e8d2ddd0b6313fdbc7078d39b6b)
April 2025 highlights across Stackable’s operator ecosystem focused on reproducibility, reliability, and streamlined distribution. The team delivered reproducible builds, modernized CI/CD with OCI publishing, introduced NiFi 2.x rolling upgrades, and broadly migrated to OCI-based installation and testing workflows. These changes reduce build drift, simplify release management, accelerate onboarding, and improve consistency across environments. Key outcomes: - Reproducible Docker image builds: Added cargo install --locked flag across Dockerfiles in stackabletech/docker-images to prevent dependency drift; CHANGELOG updated. (Commits include: fix: Add `--locked` flag to cargo install commands) - CI/CD modernization: Removed Nexus references, consolidated image publishing to OCI registry (oci.stackable.tech), and retired the deprecated release workflow to streamline builds and releases. (Commit: ci: Remove Nexus from workflows (#1056)) - NiFi 2.x rolling upgrade: Implemented rolling upgrade support for NiFi 2.x clusters with updated upgrade procedures, docs, and integration tests. (Commit: feat: add rolling upgrade support for nifi 2.x (#771)) - OCI-based installation and testing workflow adoption: Aligned testing and installation flows to OCI references across 10+ operators (e.g., nifi-operator, superset-operator, airflow-operator, opa-operator, spark-k8s-operator, trino-operator, hive-operator, hbase-operator, hdfs-operator, zookeeper-operator, kafka-operator, listener-operator) with corresponding docs updates. - OCI-based image distribution modernization: Standardized on OCI registries for operator templating/distribution; Makefile changes to reflect OCI hostnames and removal of Nexus/Docker Hub usage; demos publishing moved to OCI; includes fixes to test environment image references. (Commits: fd6aa6eba0; 9db03b4349; eafd1a708a5e0e8d2ddd0b6313fdbc7078d39b6b)
March 2025 monthly summary: Delivered targeted feature work and reliability improvements across Stackable operators with emphasis on OCI registry migration readiness, granular access-control configuration, and CRD/versioning upgrades to improve upgrade paths and stability. Key outcomes include updated OCI registry docs, new access-control.properties overrides in the Trino Operator, expanded test coverage for OPA authorization across all Trino versions, and CRD versioning/dependency upgrades for the Zookeeper Operator. These efforts reduce deployment risk, reinforce security, and enable smoother upgrades for customers.
March 2025 monthly summary: Delivered targeted feature work and reliability improvements across Stackable operators with emphasis on OCI registry migration readiness, granular access-control configuration, and CRD/versioning upgrades to improve upgrade paths and stability. Key outcomes include updated OCI registry docs, new access-control.properties overrides in the Trino Operator, expanded test coverage for OPA authorization across all Trino versions, and CRD versioning/dependency upgrades for the Zookeeper Operator. These efforts reduce deployment risk, reinforce security, and enable smoother upgrades for customers.
February 2025 Monthly Summary: Delivered key standardization and versioning improvements across stackable-cockpit, docker-images, and zookeeper-operator, focusing on OCI registry references, repository consistency, and CRD evolution to support platform scalability. Key outcomes include updating OCI registry references to pull from oci.stackable.tech to align with updated infrastructure naming conventions, standardizing image references and the default organization to improve deployment reliability, and introducing versioned CRDs with a dedicated module to enable future CRD schema evolution. These changes reduce deployment drift, simplify maintenance, and lay groundwork for scalable deployments. Implemented via targeted commits across three repos (31cc9ddb4fe25e5f617fcd271fa5a1f377688673; ff3038ff70eb2dd1dba86b596d26f13d48976619; b84bcf4fff0239f85eb21a7d1e6393597eb746eb).
February 2025 Monthly Summary: Delivered key standardization and versioning improvements across stackable-cockpit, docker-images, and zookeeper-operator, focusing on OCI registry references, repository consistency, and CRD evolution to support platform scalability. Key outcomes include updating OCI registry references to pull from oci.stackable.tech to align with updated infrastructure naming conventions, standardizing image references and the default organization to improve deployment reliability, and introducing versioned CRDs with a dedicated module to enable future CRD schema evolution. These changes reduce deployment drift, simplify maintenance, and lay groundwork for scalable deployments. Implemented via targeted commits across three repos (31cc9ddb4fe25e5f617fcd271fa5a1f377688673; ff3038ff70eb2dd1dba86b596d26f13d48976619; b84bcf4fff0239f85eb21a7d1e6393597eb746eb).
January 2025 summary focused on standardizing OCI-based image references across Stackable's operator ecosystem, modernizing deployment tooling, and improving governance and observability. Delivered OCI-centric image reference migrations across seven operator repositories, updated relevant dependencies, and refreshed changelogs to reflect the OCI migration. Additionally, deployment tooling in airflow-operator was modernized (PostgreSQL Helm chart upgrade and OCI references across operator components), and demo projects were aligned to OCI registries. Enhanced observability with a StatsD exporter upgrade across the docker-images repository, boosting metrics reliability and maintainability. The combined effort reduces Docker Hub dependency surface, improves deployment portability across environments, and strengthens governance around image sources.
January 2025 summary focused on standardizing OCI-based image references across Stackable's operator ecosystem, modernizing deployment tooling, and improving governance and observability. Delivered OCI-centric image reference migrations across seven operator repositories, updated relevant dependencies, and refreshed changelogs to reflect the OCI migration. Additionally, deployment tooling in airflow-operator was modernized (PostgreSQL Helm chart upgrade and OCI references across operator components), and demo projects were aligned to OCI registries. Enhanced observability with a StatsD exporter upgrade across the docker-images repository, boosting metrics reliability and maintainability. The combined effort reduces Docker Hub dependency surface, improves deployment portability across environments, and strengthens governance around image sources.
December 2024 performance summary: Delivered across 13 repositories with a focus on dependency modernization, build stability, and developer experience improvements. Key outcomes include cross-repo upgrades of stackable-operator to 0.83.0 with corresponding cargo.lock/cargo.nix refreshes, enhancing compatibility with latest libraries and security patches. Per-repo dependency upgrades were performed to latest stable versions (Cargo.lock/Nix updates) across hbase-operator, kafka-operator, druid-operator, nifi-operator, spark-k8s-operator, and related crates, reducing drift and improving resilience. Documentation and UX improvements were delivered to align with the current release cadence: stackable-cockpit docs now reference stackablectl 24.11.1 and direct users to correct downloads; quickstart docs updated to newest stackablectl download links; tutorials corrected to remove duplicate operators and add OpenPolicyAgent. A build correctness fix was implemented in docker-images to activate include-hadoop for NiFi 2.x+, aligning builds with Hadoop expectations. In opa-operator, dependency modernization included replacing derivative with educe and bumping to 0.83.0; this complemented a broader stackable-operator upgrade strategy across the operator suite. The cumulative effect is improved stability, security, and faster deployment cycles, with better alignment to the latest libraries and a clearer, more reliable onboarding experience.
December 2024 performance summary: Delivered across 13 repositories with a focus on dependency modernization, build stability, and developer experience improvements. Key outcomes include cross-repo upgrades of stackable-operator to 0.83.0 with corresponding cargo.lock/cargo.nix refreshes, enhancing compatibility with latest libraries and security patches. Per-repo dependency upgrades were performed to latest stable versions (Cargo.lock/Nix updates) across hbase-operator, kafka-operator, druid-operator, nifi-operator, spark-k8s-operator, and related crates, reducing drift and improving resilience. Documentation and UX improvements were delivered to align with the current release cadence: stackable-cockpit docs now reference stackablectl 24.11.1 and direct users to correct downloads; quickstart docs updated to newest stackablectl download links; tutorials corrected to remove duplicate operators and add OpenPolicyAgent. A build correctness fix was implemented in docker-images to activate include-hadoop for NiFi 2.x+, aligning builds with Hadoop expectations. In opa-operator, dependency modernization included replacing derivative with educe and bumping to 0.83.0; this complemented a broader stackable-operator upgrade strategy across the operator suite. The cumulative effect is improved stability, security, and faster deployment cycles, with better alignment to the latest libraries and a clearer, more reliable onboarding experience.
Concise monthly summary for stackabletech/demos (Month: 2024-11). Focused on release readiness for 24.11 and the security demo. Delivered version alignment across configurations and documentation improvements for end-to-end security demos, enabling faster releases and clearer security guidance for customers.
Concise monthly summary for stackabletech/demos (Month: 2024-11). Focused on release readiness for 24.11 and the security demo. Delivered version alignment across configurations and documentation improvements for end-to-end security demos, enabling faster releases and clearer security guidance for customers.
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