Hire the Best Unix System Administrators
in Ukraine

⭐️ Top Rated Plus - Top 3% Expert on Upwork 🕒 9000+ Working Hours ✅ 20+ Years of Expertise ✅ 100% Job Success ✅ 300+ Successful Projects Finished ✅ 5 Star Rating Hello, I'm Oleksandr. As a seasoned Linux System Administrator and DevOps Engineer with over 20 years of experience I specialize in delivering robust IT solutions that enhance operational efficiency and security. My expertise spans across various domains, including: ▪ DevOps & Automation: Successfully implemented automated provisioning using Ansible, streamlining deployment processes and reducing manual intervention. ▪ Linux & FreeBSD Maintenance: Managed and optimized server environments on CentOS, Debian, Ubuntu, RHEL, and FreeBSD, ensuring high availability and performance. ▪ Cloud Hosting: Deployed and maintained scalable cloud solutions on AWS, Azure, and DigitalOcean, enhancing infrastructure reliability and scalability. ▪ Virtualization: Utilized Docker, VirtualBox, and OpenVZ to create flexible and efficient virtual environments, supporting diverse application needs. ▪ Web & Database Servers: Configured and maintained Apache, Nginx, MySQL, PostgreSQL, and MongoDB servers, ensuring secure and efficient data handling. ▪ Networking & Security: Implemented secure networking solutions, including VPNs and firewalls, to protect sensitive data and maintain network integrity. I am committed to continuous improvement and staying abreast of the latest industry trends. My approach is rooted in ITIL best practices, ensuring incident management and business continuity planning are at the forefront of my work. Let's collaborate to drive your IT projects to success with innovative solutions and expert guidance.

More than 15+ year previous experience in Linux/Sysadmin/Hosting Design of High Availability/High-Performance services and architectures Ability to work flexible hours My primary experience (daily tasks) Server Setup/Migration/Transfer, Server Configuration, Server Optimization, Server Troubleshooting, Domain Registration, Domain Transfer, Domain Nameservers, Domain DNS Website Transfer, Website Migration SSL Install, SSL Renew, SSL Certificate Signing Request (CSR), SSL Let's Encrypt & Certbot Mail Transfer/Migration, Mail Delivery (SPF/DKIM/DMARC) Solid working knowledge of RPM/DEB based Linux Distributions: RHEL, CentOS, AlmaLinux, Rocky Linux, Oracle Linux, Fedora, Debian, Ubuntu, ArchLinux Experience with AWS EC2, AWS Lightsail, AWS RDS, AWS ROUTE53, AWS S3 Experience with RackSpace, DigitalOcean, Singlehop, Hetzner Dedicated, Hetzner Cloud, OVH, Godaddy Experience with Shared Hosting : JustHost, BlueHost, Hostgator, Godaddy, a2hosting, fatcow Experience with Control Panels: cPanel & WHM, Plesk, DirectAdmin, Virtualmin/Webmin, CWP (Control Web Panel) Software: Apache, Nginx, PHP-FPM, BIND, DHCP, Dovecot, Exim, Postfix, MySQL, iptables, ufw, CSF

Based on my 30 years of experience in the field of IT, i am able to complete complex tasks of high difficulty. Working in international corporations allowed me to have a practice with productive and expensive systems. Contracts in the banking sector has taught confidentiality and responsibility and the importance of trust. My main qualification is in system administration. From the direct assembly of the server to the configuration of the operating system. Therefore i have expert knowledge of operation systems Windows\UNIX. Server OS: Microsoft Windows server, RedHat, Ubuntu, CentOS, PopOS, Debian, other Linux.. Cloud: Amazon Web Services AWS, Google cloud GCP, Oracle cloud, Microsoft Azure, IBM cloud.. Hosters: Digital Ocean, Hetzner.. Virtualization: Hyper-V, VMWare, VirtualBox, KVM, Proxmox.. Emergency problem resolving. Web, VPN, VPS, Cloud, Virtualization. Hardware troubleshoting and repair. Security networking. Infrastructure protection. BIOS\FW recovering, updating.

I'm experienced UNIX systems administrator and software developer. Have deep knowledge in GNU/Linux and BSD operating systems. Gentoo Linux power user and contributor, package maintainer. Author of Linux kernel patch for Terminus terminal font support. Started from 2004 worked in many software companies as C and C++ developer. Participated in various commercial projects for Windows and GNU/Linux distributions. Have understanding of such programming paradigms like OOP, C++ templates, functional, imperative programming, scripting. • Developing software in C, C++ according to customer needs • Writing shell scripts in Bash to perform administrative routines • Configuring Linux netfilter firewalls using iptables, IP routing • Deploying and configuring Apache HTTP Server, Postfix MTA, VPNs, SSH • Deploying business apps on various VPS providers like Hetzner, AWS • Resolving Linux issues like kernel panics, boot failures etc. • Maintaining legacy setups and environments, writing documentation • Consulting customers how to implement their business requirements • Consulting customers how to keep Linux environment secure and up to date

I am skilled network/system administrator with more than 10 years of experience. If you need: - Install and configure backup and monitoring system - Install and configure fast and reliable web-server - Configure your network equipment - Install and configure Mail System for the Email Marketing purposes or any other server side work, please feel free to contact me.

I focus on building reliable systems and enjoy digging into complex issues — performance tuning, disaster recovery, root cause analysis, and solving problems that aren't always straightforward. With 20+ years in system administration and infrastructure engineering, I work with both legacy systems and modern environments — from bare metal servers to virtualized and containerized setups. 🚀 Key areas I work with: • Infrastructure setup and migrations (bare metal ↔ VM ↔ cloud) • Troubleshooting and performance tuning (high CPU/load, slow systems, bottlenecks) • Email deliverability (SPF, DKIM, DMARC, spam issues, warmup, mail server reputation restoration) • Virtualization and containerization (VMware, Proxmox, KVM, Docker) • Networking and VPN solutions • Disaster recovery, backup strategies, malware cleaning, and finding the point of intrusion. • Long-term systems support and maintenance 🛠 Legacy Systems & Industrial Equipment Support • Migration and virtualization of legacy systems (DOS, Windows 3.x/9x/NT/2000) • Running outdated software on modern hardware via virtualization • Recovery systems from old working HDD to VM, if native hardware fails. Including industrial PCs. 🔧 Core Expertise • OS: FreeBSD, Linux (CentOS, AlmaLinux, Rocky, RHEL, Ubuntu, Debian, Gentoo), Windows, Windows Server • Virtualization: VMware vSphere, ESXi, Proxmox, KVM, oVirt, VMware Workstation, VirtualBox • Containers & Automation: Docker, Docker Compose, Jenkins, Ansible • Web: Nginx, Apache, LiteSpeed, Tomcat, Lighttpd, Caddy • Databases: MySQL, MariaDB, PostgreSQL, MongoDB • Mail systems: Postfix, Dovecot, Courier Cyrus, Rspamd, Postgrey, PostfixAdmin, SquirrelMail, Roundcube, SPF, DKIM, DMARC, MTA-STS, AWS SES, Mailgun, Sendy • Control panels: WHM/cPanel, VestaCP, Virtualmin, Cyberpanel, and so on 🔐 Networking & VPN • WireGuard, AmneziaWG, OpenVPN, StrongSwan, tinc, mpd5, IPSec, L2TP, IKEv2 • BGP (quagga), Squid (including LDAP and Kerberos auth), DNS (BIND), DHCP, TFTP • Fail2ban, iptables, ipfw, pf, csf 💾 Storage & Backup • TrueNAS Core/Scale, FreeNAS, SAN (iSCSI), ZFS, AWS S3, Backblaze, Wasabi • Veeam Backup & Replication, XSI Backup, rsync, rsnapshot, rclone ⚙️ Other • Samba3 + LDAP, Samba4 (NT4 and AD domains analog, LDAP, domains up to 500 users, GPO, roaming profiles) • Monitoring: Zabbix, Prometheus, Grafana • Services: Memcache, Redis, OpenLDAP, NFS, SVN, Git, GitLab (self-hosted), FTP, SFTP • Platforms: Moodle, Nextcloud, OnlyOffice, BigBlueButton, DAViCal, WordPress, Magento • Remote management: AnyDesk, TeamViewer, Radmin, Ammyy Admin, RustDesk, MeshCentral • Hardware: Dell, HP, Supermicro servers, Dell PowerVault storages • Networking equipment: HP, Dell, 3Com switches • Embedded/firmware: DD-WRT, OpenWRT (including software cross-compiling for ARM) • Scripting: Shell scripting, Python, PHP Have an interesting or unusual problem? That's exactly what I enjoy — feel free to reach out. I value long-term collaboration and quality over quick fixes.