====== Administering Linux servers skills ======


### Basic System Administration

1. **Installation and Configuration**

   - Installing Linux server distributions (e.g., Ubuntu Server, CentOS, Debian).
   - Initial system configuration: setting hostname, network settings, and updating the system.

2. **User and Group Management**

   - Commands: `useradd`, `usermod`, `userdel`, `groupadd`, `passwd`
   - Managing user permissions and groups.
   - Using `sudo` to delegate administrative rights.

3. **File System Management**

   - Mounting and unmounting file systems.
   - Commands: `mount`, `umount`, `df`, `du`
   - Managing file systems with tools like `mkfs`, `fsck`, `resize2fs`, `xfs_growfs`.

4. **Package Management**

   - Using package managers to install, update, and remove software.
   - Debian/Ubuntu: `apt`, `dpkg`
   - RedHat/CentOS: `yum`, `dnf`, `rpm`

### Networking

1. **Network Configuration**

   - Configuring network interfaces: `ifconfig`, `ip`, `nmcli`
   - Managing network services: DHCP, DNS, NTP

2. **Firewall Configuration**

   - Using `iptables`, `firewalld`, or `ufw` to configure firewall rules.
   - Ensuring security by restricting access to services.

3. **SSH and Remote Access**

   - Configuring and securing SSH: `/etc/ssh/sshd_config`
   - Setting up SSH keys for password-less login.

### Service and Process Management

1. **Systemd and Init Systems**

   - Managing services with `systemctl` (start, stop, enable, disable).
   - Creating and managing custom service units.

2. **Process Monitoring**
   - Commands: `ps`, `top`, `htop`, `kill`, `nice`, `renice`
   - Understanding and managing system load.

### Security

1. **User and Group Security**

   - Implementing best practices for user account security.
   - Configuring `sudo` for administrative tasks.

2. **Security Policies**

   - Implementing SELinux or AppArmor for mandatory access control.
   - Regularly updating the system and installed packages to patch vulnerabilities.

3. **Auditing and Logging**

   - Configuring and managing system logs: `rsyslog`, `journalctl`
   - Using tools like `auditd` for auditing system activities.

### Backup and Recovery

1. **Backup Solutions**

   - Implementing backup strategies using tools like `rsync`, `tar`, `dd`, `Bacula`, `Amanda`.

2. **Disaster Recovery**

   - Creating and restoring from backups.
   - Understanding and implementing RAID configurations for data redundancy.

### Performance Monitoring and Tuning

1. **Monitoring Tools**

   - Using tools like `top`, `htop`, `iostat`, `vmstat`, `netstat`, `dstat`, `sar` to monitor system performance.
   - Implementing monitoring solutions like Nagios, Zabbix, Prometheus.

2. **Performance Tuning**
   - Tuning system parameters for optimal performance: `sysctl`, kernel tuning.
   - Managing resource limits with `ulimit`.

### Automation and Scripting

1. **Shell Scripting**

   - Writing and debugging shell scripts to automate routine tasks.
   - Understanding `bash`, `sh`, and other shell environments.

2. **Configuration Management**

   - Using tools like Ansible, Puppet, Chef, or SaltStack for automating system configuration and management.

### Database Management

1. **Database Servers**

   - Installing and configuring database servers: MySQL, PostgreSQL, MongoDB.
   - Performing routine database administration tasks: backups, restores, user management.

### Web Server Administration

1. **Web Servers**

   - Installing, configuring, and managing web servers: Apache, Nginx.
   - Securing web servers and managing SSL/TLS certificates.

### Cloud and Virtualization

1. **Virtualization**

   - Setting up and managing virtual machines with KVM, VirtualBox, VMware.
   - Using containerization technologies like Docker.

2. **Cloud Platforms**

   - Understanding and managing instances on cloud platforms like AWS, Google Cloud, Azure.
   - Using infrastructure-as-code tools like Terraform.