STEM · Full roadmap · ~115 min read · 33 steps
🛠️System Administrator
Own and run real infrastructure: servers, identity, virtualization, automation, and recovery
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Unit 1
Start here
Course overview
What a system administrator actually owns
You are accountable for systems, not just tickets
The Linux filesystem hierarchy
Every directory on a Linux server has a job
Users, groups, and ownership
Every file is owned by a user and a group
Permissions: chmod and chown
Read, write, execute for owner, group, and others
Unit 2
Package managers: apt and yum
Install, update, and remove software the supported way
systemd and managing services
systemd starts, stops, and supervises everything
Processes and resource use
See what is running and what it is eating
Cron and scheduled jobs
Run tasks automatically on a schedule
SSH and key authentication
Remote access done securely with keys, not passwords
Unit 3
Reading logs under /var/log
The system already told you what went wrong
Shell scripting for real tasks
Glue commands together so they run themselves
Windows Server roles and features
A Windows server becomes what you install on it
Active Directory: forest, domain, and OU design
The structure that holds your users, computers, and rules
Group Policy and GPO design
Push settings to thousands of machines from one place
Unit 4
DNS and DHCP server administration
Names to addresses, and addresses handed out automatically
FSMO roles, replication, sites and services
Domain controllers share work and special jobs
Virtualization and hypervisors
Many virtual servers on one physical box
VM lifecycle, snapshots, and resource allocation
Create, size, snapshot, and retire virtual machines
Storage: RAID, SAN, NAS, iSCSI, and LVM
How servers get reliable, expandable disk
Unit 5
Identity, access, and least privilege
Give the minimum access needed, and no more
Containers and the cloud, briefly
Lighter than VMs, and someone else's data center
Infrastructure as code and configuration management
Describe the desired state, let the tool enforce it
PowerShell and Bash automation in practice
Scripting is how a small team runs a large fleet
Patch and update management at scale
Patching a fleet on purpose, not one box at a time
Unit 6
Monitoring and observability
Know it is broken before the users tell you
Backup and disaster recovery
A backup you have not restored is a guess
Security hardening
Shrink the attack surface on every system
Documentation, runbooks, and incident response
The knowledge has to outlive your memory
Capacity planning
Solve next quarter's problem before it is a crisis
Unit 7
Common mistakes that bite sysadmins
The failures are predictable, so learn them cheap
The culture and career side: on-call, postmortems, and what comes next
How sysadmins work together, and where the job leads
Where to go next
Where to go next