Leonard Cohnen
Software Engineering Technical Leader, Isovalent At Cisco
Aachen, North Rhine-Westphalia, Germany
Summary
🤩
Rockstar🎓
Top SchoolLeonard Cohnen is a software engineering technical leader with nine years of experience building secure, cloud-native networking and observability tooling from Aachen, Germany. Currently working on Tetragon at Isovalent (Cisco), he brings deep hands‑on expertise in eBPF, kernel-level networking, and secure tunneling—demonstrated by contributions to the flagship Cilium project that fixed WireGuard encryption edge cases and improved MTU/tunnel handling. His background includes security-focused engineering roles at Edgeless Systems and Akamai, plus collaborative research with ETH Zürich, reflecting a consistent focus on systems security and high-assurance networking. Leonard has also contributed to the Kata Containers project, enhancing policy tooling and test automation, which highlights his ability to bridge runtime security and developer ergonomics. He holds an MS in IT-Security from Ruhr University Bochum and pairs academic rigor with production-grade deliverables. Notably, his work often targets subtle interoperability and edge-case bugs that materially improve encryption correctness and cluster connectivity.
9 years of coding experience
5 years of employment as a software developer
Master of Science - MS, IT-Security, Master of Science - MS, IT-Security at Ruhr University Bochum
Github Skills (23)
kubernetes10
tunnel10
container10
docker10
ebpf10
testing10
kubernetes-networking10
networking10
dockers10
wireguard10
security10
automation10
go10
tunneling10
virtualization10
Programming languages (10)
Github contributions (5)
cilium/cilium
Jun 2022 - Nov 2024
eBPF-based Networking, Security, and Observability
Role in this project:
Back-end & DevOps Engineer
Back-end & DevOps EngineerContributions:12 reviews, 8 PRs, 45 comments in 2 years 4 months
Contributions summary:Leonard primarily contributes to the networking and security aspects of Cilium, particularly related to WireGuard integration and tunnel features. Their work includes fixing bugs in WireGuard encryption, specifically addressing issues related to endpoint lookups and traffic filtering. They also implemented improvements related to MTU calculations and correct handling of tunnel protocols within Cilium. Furthermore, the user contributed to the connectivity tests within cilium-cli, improving packet capture and testing node-to-node encryption.
bpfcontainerskerneltroubleshootingkubernetes-networking
kata-containers/kata-containers
Mar 2024 - Mar 2025
Kata Containers is an open source project and community working to build a standard implementation of lightweight Virtual Machines (VMs) that feel and perform like containers, but provide the workload isolation and security advantages of VMs. https://katacontainers.io/
Role in this project:Back-end & Automation Engineer
Back-end & Automation EngineerContributions:7 reviews, 7 PRs, 31 comments in 1 year
Contributions summary:Leonard primarily contributed to the `genpolicy` tool within the Kata Containers repository, focusing on enhancing its capabilities. They added features such as the ability to filter resources based on `runtimeClassName`, specify a layer cache file, and handle `binaryData` correctly within Kubernetes configuration. Furthermore, the user implemented integration tests utilizing the `kata-agent-policy` crate, demonstrating their understanding of policy enforcement and automated testing in the context of the project. The commits also involved refactoring the policy module into a separate crate and adding network namespace checks.
firecrackervirtualizationociworkloadvdi
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