Jarno Rajahalme
Principal Software Engineer at Isovalent
Zurich, Zurich, Switzerland
Summary
🤩
Rockstar🎓
Top SchoolJarno Rajahalme is a Principal Software Engineer based in Zurich with 13 years of focused experience in cloud-native networking, security, and eBPF datapaths. He has deep hands-on expertise across Go, gRPC, Envoy, and C/C++ from roles at Isovalent and Nicira, where he worked on Open vSwitch and kernel datapaths. A long-time contributor to high-profile open-source projects like Envoy and Cilium, Jarno has implemented core features ranging from original-destination routing in Envoy to advanced eBPF-based policy matching in Cilium. He combines research pedigree—doctoral-level work in data communications—with practical production engineering, bridging low-level kernel work and distributed control planes. Colleagues know him for pragmatic refactors and performance-minded runtime configuration patterns that reduce friction in fast-changing cloud-native environments.
13 years of coding experience
22 years of employment as a software developer
Doctor of Science in Technology Data Communications Software, Doctor of Science in Technology Data Communications Software at Aalto UniversityMaster of Science (M.Sc.) Computer Science, Master of Science (M.Sc.) Computer Science at Teknillinen korkeakoulu-Tekniska högskolan
English
Github Skills (22)
c-language10
ebpf10
build-system10
policies10
go10
network10
cprogramming-language10
testing9
networking9
security9
c119
net9
dns9
c179
microservices8
Programming languages (15)
Github contributions (5)
cilium/cilium
May 2017 - Apr 2025
eBPF-based Networking, Security, and Observability
Role in this project:
Back-end Developer
Back-end DeveloperContributions:7 releases, 1614 reviews, 1304 PRs in 8 years
Contributions summary:Jarno primarily contributed to the core networking, security, and observability features of the Cilium project, focusing on eBPF-based network policies. They added missing policy match cases to improve policy enforcement. They also implemented features for protocol matching, allowing for enhanced control over network traffic. Furthermore, the user refactored and optimized several functions related to policy handling. They introduced, or worked with, a runtime configuration map for passing values that could change frequently to enhance the performance of the project.
bpfcontainerskerneltroubleshootingkubernetes-networking
envoyproxy/envoy
Jun 2017 - Aug 2022
Cloud-native high-performance edge/middle/service proxy
Role in this project:Back-end Developer & DevOps Engineer
Back-end Developer & DevOps EngineerContributions:15 reviews, 44 commits, 66 PRs in 5 years 3 months
Contributions summary:Jarno primarily contributed to the Envoy proxy project by implementing and modifying core features. Their work included disabling libunwind in gperftools configurations to address build failures. They also set up DNS request timeout timers and moved comments for better code clarity. The user also contributed to test code and added a new cluster type to support original destination routing.
nanoservicesmore-catsgolangcontainersproxy
Find and Hire Top DevelopersWe’ve analyzed the programming source code of over 60 million software developers on GitHub and scored them by 50,000 skills. Sign-up on Prog,AI to search for software developers.