Hello there, I am Sergey, and I am finding my footing as a system administrator. I am intensely intrigued by managing and hosting web resources.

For nearly a year, both in the professional and personal context, I have been experimenting with Linux. Setting up my own web server with nginx and apache2, I've been earnestly trying to comprehend the nuances of their configuration.

I'm curious about understanding how hosting providers organize the hierarchy of web servers. In my eagerness to learn, I have delved into a lot of dоcumentation, eager to absorb as much as I can.

I am curious about the core competencies that one must master to excel as a system administrator. If you could outline the essential areas of knowledge, I'd be profoundly appreciative.

From my journey so far, I've learned that having a good grasp of networking fundamentals, understanding the Linux operating system, database management, and scripting languages like Python or Bash are integral. Moreover, mastering cloud platforms like AWS, Azure, or Google Cloud can significantly bolster your skills as a system administrator.

Hello Sergey,

It sounds like you've already made substantial progress in your journey to becoming a system administrator. Your grasp of several foundational competencies is impressive. There aren't many hard and fast rules about what you need to know, as responsibilities can vary widely based on the specifics of your job. However, you are definitely on the right track.

Let's add some more topics to your existing foundational areas, and group these skills across few broad categories. Here's what could comprise of an approximate "core competency" map for an experienced system administrator:

**Operating System Knowledge:**

1. **Linux**: You've already noted this. It's the most common server OS, and many sysadmin jobs will require it. You should know how to administer users, manage files and processes, troubleshoot and diagnose issues, understand and manage system security, work with software packages, and more. In addition, understanding SystemD and tutorialing services is highly useful.

2. **Windows Server**: Depending upon your role, you may need to understand Windows environment too. Especially, Active Directory is a common technology you'll encounter.

**Networking:**

1. **TCP/IP** is a core protocol that you'll need to understand. Be sure to also learn about how DNS, DHCP, SMPT, and HTTP(S) work, among other protocols.

2. **Subnetting** and **routing** are essential for understanding how networks are organized and how traffic flows between them.

3. **Firewalls** and **security** protocols are important for protecting an organization's data.

4. **VPN** and **remote access** knowledge are integral for enabling remote work and secure communication with the network.

**Web Servers & Databases:**

1. Proficiency in setting up, configuring and managing web servers such as Apache, Nginix, and Tomcat.

2. Understanding databases like MySQL, MongoDB, or PostgreSQL is vital, as a lot of data handled by the servers is managed by databases.

**Cloud Platforms & Virtualization:**

1. **Virtualization** with Hyper-V, VMware, and similar software is a must today.

2. Being able to work with **container technologies** like Docker and orchestration platforms such as Kubernetes is becoming increasingly important.

3. Familiarity with **cloud platforms**, like you mentioned AWS, GCP, or Azure. Knowing how to work with these platforms' corresponding APIs is also valuable.

**Languages & Tools:**

1. **Scripting languages** like Python, Ruby, Perl, or Bash are fundamental. PowerShell is also useful, especially in a Windows environment.

2. Mastering various **devops tools** like Jenkins, Ansible, Terraform, Puppet or Chef are also desired skills.

**Troubleshooting & Monitoring:**

1. **Monitoring** different systems for performance, errors, and anomalies using tools like Nagios or Zabbix is required.

2. **Troubleshooting** skills - knowing how to analyze and respond to issues that arise, often persistently and methodically.

**Security & Compliance:**

1. Understanding **security concepts** and methods associated with networks, databases, and servers. This can range from understanding access control to understanding how to protect assets from attacks and intrusions.

2. Knowledge of **compliance standards** like PCI-DSS, GDPR, HIPAA etc, based on the nature of the organization you are working for.

Remember, you don't need to master these all at once, and there's value to specializing in specific areas based on your interests and the needs of the company you're working for. That said, a broad understanding of these areas should set you on the path to becoming an effective system administrator.

Here are some additional essential aspects to consider, and areas for you to deepen your knowledge and skills:

Configuration Management:

Being able to manage and track your systems is crucial - especially as you scale up the number of servers you're administering. Configuration management tools like Puppet, Ansible, Chef, or SaltStack can help you manage system configuration, ensuring that systems are in their desired state, and make large scale changes more manageable.

Backup & Recovery:

A system administrator should be proficient in configuring and managing backup systems to avoid data loss and to recover from a catastrophic failure if necessary. In addition to understanding local backup methodologies, you should also be familiar with cloud-based backup solutions.

Performance Tuning:

Learning how to tune your systems to optimise their performance can be incredibly beneficial. This can be done at many levels, from tuning a specific service, to optimising a database, to adjusting kernel parameters.

Load Balancing:

You'll often need to balance workloads across multiple servers, especially in a web hosting environment. Technologies like HAProxy or Nginx can distribute the load, while tools like Keepalived can help with failover and high availability.

System Design and Architecture:

Designing how various parts of the infrastructure work together is a crucial part of many sysadmin roles. This might involve designing a backup and recovery plan, architecting how new services will be deployed, or planning out network structure and security.

Additional Tools:

Apart from the mentioned tools, familiarity with additional tools such as Git (for version control), Jira (for ticketing system), and Grafana (for metrics visualization) will be beneficial.

Soft Skills:

Soft skills such as excellent problem-solving abilities, communications skills, and the capacity to work well under pressure are essential for a system administrator. Understanding businesses needs and aligning your strategy accordingly is also a critical part of being successful in this role.

Continual Learning:

Finally, always remember that technology evolves quickly. What's relevant today might not be in a few years. To stay marketable and effective as a sysadmin, it's important to stay curious about new technologies, and to take the initiative in learning and experimenting with them.

Operating Systems

Remember, understanding different operating systems is not just about knowing how to use their interfaces. It's about understanding the underlying principles, and how to effectively use the command line interface (CLI).

Learning about the file systems (like ext4 for Linux, NTFS for Windows), process management, system calls, and init systems (like systemd, upstart) will be beneficial. You should also understand how to manage services, the boot process, and package management systems (like rpm, yum, apk, apt, etc).

Networking

Networking is broad and can go very deep. The OSI model would be a good place to start, understanding how the different layers work and how they interact with each other (protocols at each layer, the concept of encapsulation and more). Beyond this, diving deeper into IP addressing, learning how VLANs work, understanding the details of DNS, DHCP, NAT and VPN technologies will be very useful.

Web Servers & Databases

Web servers like Apache and Nginx typically work in very similar ways. Understanding the HTTP protocol thoroughly can help you better understand these tools. It's also useful to know about load balancing, SSL/TLS, virtual hosts, reverse proxies, etc.

And when it comes to databases, focus on SQL first. Understand how SQL works, how to make queries, how indexes work, and so on. You should also understand the concept of ACID properties in databases.

Systems Troubleshooting

You can learn a lot about this from experience, but you can also try to seek out resources or training materials that specifically focus on troubleshooting. Understanding log files, network diagnostics tools (like ping, traceroute, netstat, etc.), and basic debugging can go a long way.

Scripting

A good system administrator should ideally be comfortable with at least one scripting language. Bash is almost universal, and Python is becoming more and more common due to its readability and versatility.

These can save you immense amounts of time by automating routine tasks. You should also understand how to use the shell effectively, making use of tools like grep, awk, sed, and the many others that are available.

Certifications

While it's not a "knowledge area," earning relevant certifications can also be very helpful. Certifications not only provide structured learning paths that help ensure you aren't missing important topics, they also demonstrate to employers that you have a certain level of knowledge and capability. Some respected certifications in the sysadmin world include CompTIA's A+ and Network+, several Cisco certifications (like the CCNA), various Linux certifications (like those from Red Hat or the Linux Professional Institute), and many more.

Apache, Nginx, MySQL, PHP, PostgreSQL, Redis, Node - these are the fundamental technologies. Understanding HA, CDN, routing, the workings of firewalls, and the concept of virtualization is also key. Familiarize yourself with 3-4 popular hypervisors helps. Practicing and gaining experience is crucial.

Hosting covers an array of tasks - from network management, server administration, security measures, to the planning of architecture and development - it's difficult to detail all. Monitoring is also an essential part of the job, among several other things. The easiest way in is to take an entry-level role at a hosting company and learn firsthand.

While technical skills are vital, soft skills such as communication and problem-solving can greatly enhance your effectiveness in hosting roles. Different situations may call for out-of-the-box thinking and the ability to articulate technical information clearly to clients. Remember, hands-on experience is your best teacher.

It's still crucial, quite frequently, to have an understanding of various hosting panels, such as cPanel, Plesk, ISPmanager, DirectAdmin, and others.

Knowing how to navigate and interact with these panels can greatly facilitate your work in web hosting environments.

Equally important is having knowledge of popular Content Management Systems (CMS) like WordPress, Joomla, Bitrix, and more.

Being equipped to resolve basic issues with these systems is a sought-after skill, saving you from potential downtime and providing an overall smoother site management experience.

Understanding control panels and CMS tools not only helps in troubleshooting but also allows you to customize your website, enhancing its functionality and user experience.