Linux :Debian / Ubuntu, Red Hat / CentOS, FreeBSD
DevOps, CI/CD, IaC :Ansible, Gitlab, Docker, Kubernetes, Terraform, Puppet, Chef
Cloud :Cloudflare, AWS, GCP, Azure, Scaleway, OVH
Web server :Nginx, Apache, Lighttpd, Tomcat, Caddy
Database :Mysql / Mariadb, Postgresql, Sqlite
High availability :Squid, Haproxy, Keepalived
Monitoring and metrics :Zabbix, Prometheus, Grafana, Munin, Mon, Nagios
Virtualization :Lxc, Kvm, Proxmox, Xen, Virtualbox, Vmware
Programming / Scripting :Bash, Php, Html, Perl, Python, Javascript, Ruby
Security :Fail2ban, Rkhunter, Zed Attack Proxy, Greenbone Security Manager
Firewall :Unifi, pfSense / OPNSense, Zyxel, Iptables, Shorewall, Ufw, Palo Alto
Diagnostics :Strace, Syslog, Top, Netstat, Lsof
Backup :Rsync, Snapshot, Rsnapshot, Bacula, Backup-manager, Cp
Remote control :Ssh, Vnc, Telnet, Nx, Rdp
High performance :Openmpi, Numa, Slurm, Munge
Network :TCP/IP, Lan, Vlan, Dhcp, Pxe, Tcpdump, Loadbalance
Server :Ftp, Dns, Smtp, Imap, Pop