Distrbuted network – 1800 branches. Two thousand physical servers (VMware ESXi 5.1-6.7), more than four thousand virtual (Win2003/2008/2012/2016/2019, Linux OEL/RHEL/Centos/Debian/Ubuntu, AIX, FreeBSD etc), appropriate amount of network equipment (routers, switches, IP-telephony, Wi-Fi). vCenter 6.7 is used for managing virtual servers.Active Directory, databases, network storage, mail servers Exchange 2019, Zimbra and Sendmail, proxies, fileservers etc.All branches are connected in a single network by VPN and dynamic routingMain responsibilities (at different times):- setting up new ESXi servers, creating new virtual servers in main data center and in braches.- remote server support – updates, migrations, recovery, anything necessary.- migrations of services and data from obsolete servers to new.- Zimbra mail server – installation and configuration, support, user migration.- Zabbix monitoring system – configuration, support, implementing new functions, reports creating.- monitoring and ensuring uninterrupted Internet access for all branches – remote setup, recoverySome significant projects:- implementation of Zimbra mail server - installation and configuration, making scripts for creating and removing different classes of users, for backup and purging of database; migrating 4000 users from several Sendmail servers.- implementation of Docker on branch servers – containerizing all services from many virtual machines and placing them on one; writing scripts for simple migration of each branch.- implementation of Ansible – for managing all virtual machines on branch servers – updating, file distributions, configuring, gathering data etc. - implementation of Synapse - Kubernetes based corporate messenger service

Administration of entire IT- infrastructure of company. Active Directory, e-mail, internet access, IT-security, fileservers, web-site, financial software and databases, specialized industrial software etc. Analysis and design of new servers and services. Providing desktop, phone and remote support for users.