Sergei is available for hire

Sergei Kolodeznykh

Verified Expert in Engineering

Systems Engineer and Developer

Location

Novi Sad, Vojvodina, Serbia

Toptal Member Since

March 21, 2024

Sergei is an infrastructure and operations engineer with 14 years of experience supporting high-load, Unix-based services running in virtual infrastructure and bare metal servers. He worked with open-source clustered DBMS like Percona, storage services like NFS and GlusterFS, propriety storages like Acronis and NetApp, and HPC clusters like Bright Cluster Manager, UGE, and Slurm. With 25 years of systems administration experience, Sergei also builds and supports Linux and Windows-based LANs.

System Administration Linux Bash Linux RHEL/CentOS Programming Windows Server Windows Unix MySQL Red Hat Linux VMware Jira Confluence OpenVPN NGINX SUSE Fiber Optics Cisco IOS Cacti KVM Virtualization

Portfolio

EPAM Systems

HPCC Systems, Chef, Cluster Management, Univa Grid Engine (UGE)...

Acronis

Linux CentOS 7, Bash, NetApp, Grafana, Prometheus, KVM, PXE, OpenVPN...

Litres

Percona, MySQL, NFS, GlusterFS, Apache2, NGINX, VMware ESXi, BIND9...

Experience

Linux - 20 years Bash - 20 years System Administration - 20 years Networks - 20 years Red Hat Linux - 15 years VMware vSphere - 13 years Ubuntu - 8 years Ansible - 5 years

Availability

Full-time

Preferred Environment

Linux, Bash, Python, Ansible, Jenkins, HPCC Systems, Networks

The most amazing...

...thing I've developed is an automatic process for replacing failed drives in Acronis storage clusters.

Work Experience

Systems Engineer

2021 - 2024

EPAM Systems

Wrote scripts for high-performance file system (HPFS) snapshot management and automatic snapshot rotation.
Refactored from Puppet to Ansible code, configuring compute node images for various roles.
Supported and improved a system for provisioning Linux scientific workstations using Chef, Cobbler, and Kickstart.
Participated in all standard level 3 data center operation activities, including dispatches, on-calls, issue investigation, and planned or urgent maintenance.
Interacted with vendors like Dell, HPE, and Mellanox to support customers' server hardware.

Technologies: HPCC Systems, Chef, Cluster Management, Univa Grid Engine (UGE), Slurm Workload Manager, NFS, InfiniBand, Bitbucket, Cobbler, Jenkins, ServiceNow, Zabbix, Linux RHEL/CentOS, VMware vSphere, GPFS, Ansible, Puppet, Splunk, Jira, Confluence, Bash, Networking, Unix, VMware, Red Hat Linux, Networks, Python, Git, Programming, Grafana

Senior Systems Engineer

2016 - 2021

Acronis

Created and organized a system for automatic hard drives replacement across all major storage clusters worldwide.
Built tools and systems for automatic storage cluster provisioning, configuration, and deployment for bare metal servers and thousands of hard drives.
Developed tools for everyday storage cluster management used by a team of system administrators.
Designed tools and wrote code for configuring and supporting internal VPN services. Supported these services for internal cloud and storage teams.
Engaged in all standard level 3 operations activities, including monitoring, on-calls, fixing issues, solving tasks from customers and internal teams, software or hardware maintenance and updates, and interacting with network and developer teams.
Supported all server hardware, interacting with vendors and multiple data center on-site teams.

Technologies: Linux CentOS 7, Bash, NetApp, Grafana, Prometheus, KVM, PXE, OpenVPN, Acronis Cloud Storage, PagerDuty, Jira, Confluence, Bitbucket, Git, Keepalived, IPMI, HAProxy, Networking, Unix, VMware, Red Hat Linux, Networks, Python, Cobbler, Zabbix, Programming

System Administrator

2010 - 2018

Litres

Supported the website infrastructure of three data centers and 80 blade and single servers. Handled the Percona database, Apache/mod_perl, nginx/FreeBSD/CARP, network switches, DNS in BIND9, NFS storages with GlusterFS, and ESXi.
Handled BGP and OSPF routing with Quagga, three network uplinks, and my autonomous system.
Developed and supported a configuration management system for automatic server deployment based on Puppet.
Maintained all servers and network hardware, assembled Supermicro Twin Blade systems from components, and installed and configured 1-2 racks of data center presence points from scratch, including all cabling and managing electrical equipment.
Sustained all office infrastructure for around 80 employees, including a rack of servers and VoIP/PBX systems, physical LAN cabling, WiFi access points, and 1 – 2 floors of Windows and Mac workstations.
Administrated the Google Apps system for office employees' email system.

Technologies: Percona, MySQL, NFS, GlusterFS, Apache2, NGINX, VMware ESXi, BIND9, Border Gateway Protocol (BGP), Open Shortest Path First (OSPF), FreeBSD, Ubuntu, Fiber Optics, Samba, VoIP, Cacti, Nagios, Puppet, Bash, Perl, Subversion (SVN), OpenLDAP, Postfix, Dovecot, Quagga, Heartbeat, OpenVZ, Squid, CARP, DNS, ProFTPD, Xen, Debian, SUSE, Networking, Unix, VMware, Windows, Networks, Windows Server, Zabbix, Programming, Cisco IOS

Experience

Workflow for Automatic Failed HDD Replacement on Storage Clusters

Mostly Bash-based scripts—100 kilobytes of code—with Python, Jenkins, and Jira integrations. This enabled the automatic replacement of failed HDD on Acronis storage clusters, from the alert in PagerDuty to the ticket in the data center support system and drive replacement, assigning a new drive back to the cluster. The entire process is also logged in the Jira ticket.

Education

1992 - 1995

Partially Completed Degree in Mathematics and Computer Science

Moscow State University - Moscow, Russia

Skills

Libraries/APIs

OpenLDAP

Tools

Bitbucket, VMware vSphere, Ansible, Jira, Confluence, OpenVPN, NGINX, Postfix, VMware, Chef, Jenkins, Zabbix, Puppet, Splunk, Grafana, Git, Keepalived, Cacti, Nagios, Subversion (SVN), Quagga, Squid

Platforms

Linux, Linux RHEL/CentOS, Linux CentOS 7, Percona, Ubuntu, Windows Server, Windows, Red Hat Linux, Unix, KVM, PagerDuty, Apache2, FreeBSD, Xen, Debian

Languages

Bash, Perl, Python, Groovy

Storage

Acronis Cloud Storage, MySQL, GPFS, NetApp, GlusterFS, SUSE

Paradigms

Samba

Other

System Administration, Programming, HPCC Systems, BIND9, DNS, Computer Science, Networking, Cluster Management, Univa Grid Engine (UGE), Slurm Workload Manager, NFS, InfiniBand, Cobbler, ServiceNow, Prometheus, PXE, IPMI, HAProxy, VMware ESXi, Border Gateway Protocol (BGP), Open Shortest Path First (OSPF), Fiber Optics, VoIP, Dovecot, Heartbeat, OpenVZ, CARP, ProFTPD, Mathematics, Networks, Cisco IOS

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