# Curriculum vitae / Lauri Tirkkonen ## Contact * * lotheac @ IRCnet, libera.chat, and oftc ## Languages * Native Finnish * Fluent English * Intermediate Japanese ## Education * 2008 – 2016: M.Sc. (Tech), Computer Science and Engineering at Aalto University School of Science (form. Helsinki University of Technology) ## Work * PayPay株式会社, Tokyo, Japan\ 2022-04 – present: SRE Tech Lead * Division-wide migration from New Relic to self-hosted metrics, alerting and tracing system based on Victoria Metrics, Grafana, OpenTelemetry and ClickHouse. Increased metrics resolution by 6x and improved trace reliability, while reducing yearly cost by 80% * Maintenance and redesign of logging pipelines. Reduced the number of lost logs to zero, and made the entire system significantly cheaper by simplifying its architecture * iconicchain Oy\ 2021-01 – 2022-03: Head of DevOps and Security * Building infrastructure (Hetzner cloud), supporting development (eg. creating tools to run dev workloads in hcloud), optimizing deliveries and Docker image builds, building CI/CD & improving test performance * Siili One Oy\ 2019-12 – 2020-12: Staff SRE * Consultant; technical lead on an embedded Linux system project for a customer in the telecommunications industry * Tuxera Inc.\ 2017-04 – 2019-12: Release Engineer * Development and maintenance of online build service used by customers, 400k–600k kernel module builds delivered per year * Aalto University Department of Computer Science and Engineering\ 2009-05 – 2011-05, 2011-09 – 2017-03: Systems Designer * Unix (Solaris, illumos, Linux, OpenBSD) server and workstation administration. Xen and KVM virtualization, illumos zones (containers) * Building and upgrading internal systems, migrating from legacy solutions. Examples: * LDAP authentication and name services * Puppet configuration management for workstations and servers * Redundant firewalls with pfsync and CARP * Improving processes and workflows, eg. putting everything under version control, deploying an issue tracker ## Skills / experience * Operating systems * Various GNU/Linux distributions (Debian, Ubuntu, RHEL, CentOS, Alpine, Void… you name it) * OpenBSD * illumos, Solaris 10, 11, OpenSolaris * Programming language preferences: Zig, Python, C (C99), shell * Instrumentation and debugging * bpftrace, DTrace, traditional debuggers like gdb, mdb * traditional Unix visibility tools (strace, ps, netstat, vmstat, fstat, etc.) * TCP/IP networks in depth, including IPv6 * Network security: firewalls (pf, nftables, iptables), SSL/TLS, ZTNA (Tailscale, headscale) * IAM: SSO (OIDC, SAML); Keycloak, Authentik, FreeIPA, LDAP etc. * Storage: ZFS (incl. send/receive based backup systems) * Containers: systemd-nspawn, podman, Docker, Solaris zones * Orchestration: Kubernetes (kOps, EKS, k3s) * Configuration management: Ansible, Puppet, Terraform * Observability: Victoria Metrics, Prometheus, Grafana, OpenTelemetry, New Relic * CI/CD: git, Jenkins, GitHub Actions, GitLab, sr.ht * Build systems: OpenEmbedded/Yocto, Android, GNU make, BSD make, CMake, Meson, GNU autotools * Porting, packaging, patching and contributing to open source software ## Other * Worked on a [hobby operating system](https://unleashed.31bits.net/) from 2016 to 2019