Oleksandr A.Private profile: Upwork shows its earnings only to signed-in members, so we check it every few weeks, not daily. MRR here is a rough estimate (Upwork's six-month earnings ÷ months active). Last read Nov 5, 2026.

Senior Engineer with more than 6 years of commercial experience in the industry. Notable skills are low-level debugging of applications and infrastructure, network optimization, performance testing, CI/ CD configuration. Demonstrated DevOps, SRE and Developer skills. Thanks to the last, confident in debugging of most complex problems in Linux kernel. Experience with the clouds and especially AWS, including microservises-oriented setups (service discovery, ECS/EKS, load balancing, etc.) * Development: Linux API (network subsystem/userspace), middleware (Kubernetes CNI). GTK3, POSIX, threading, ... * CI Solutions: TeamCity, Jenkins/Pipeline, GitlabCI. * Monitoring: ELK stack, Prometheus, Datadog, Nagios/OMD, Pakiti. Background in tuning ELK stack for high throughput & indexing speed. * Networking: ECMP, NetNS, PBR, tc. BPF syntax. ip/nftables + ipset (advanced). Snort, Suricata, nDPI. Network stack tuning for specific purposes. * Orchestration: Terraform, CloudFormation, Ansible, Octopus Deploy, Puppet (+Hiera), Spacewalk (+CentOS Errata). * Advanced experience with LEMP stack, WAFs, L3-L7 AntiDDoS (custom builds, headers inspection, ratelimit zones, secure cookie). * Complex debugging using ftrace, strace, sysdig, gdb. Background in debugging .NET software using Procmon & CLR profiler.