Linux system administrator skills

Life as a Linux system administrator

Linux system administration is a job. It can be fun, frustrating, mentally challenging, tedious, and often a great source of accomplishment and an equally great source of burnout. That is to say, it’s a job like any other with good days and with bad. Like most system administrators, I have found a balance that works for me. I perform my regular duties with varying levels of automation and manual manipulation and I also do a fair amount of research, which usually ends up as articles. There are two questions I’m going to answer for you in this article. The first is, «How does one become a system administrator?,» and second, «What does a Linux system administrator do?».

Becoming a system administrator

Since there’s no Linux system administrator college major and no real learning track for Linux system administrators, how does one become a Linux system administrator? Most Linux system administrators (SAs) entered the field by accident. No, seriously. Just ask one. Some SAs took up Linux as a sideline, to their duties as Unix SAs, as interest and adoption grew in the late 1990s. As Linux became a data center standard and the various Unix «flavors» waned in popularity, those who’d dabbled in it were converted to Linux administrators out of need.

Career advice

For new Linux administrators, many enter the job from their interests as home enthusiasts, gamers, or clandestine administrators of college servers. This is how it happened for me. As soon as I saw Linux for the first time in 1995, I was hooked. By January of 1996, I had started the local Linux User’s Group (LUG) here in Tulsa, Oklahoma, much to the chagrin of the Unix Special Interest Group (Unix SIG).

My beginnings with Linux were rocky. I first ran across Linux in a magazine where I could purchase a 2 CD set in early 1995 when I worked at WorldCom (Yes, that WorldCom). I installed a group FTP/download server for my desktop support group coworkers. A few weeks later, I was told by one of the «gurus» in another group, «We don’t allow Lye-nix on our network.» I wasn’t convinced of course that it mattered what was allowed and what was not, so I kept the server but installed Samba on it and changed daemon header information to make it look like my little system was a Windows server.

After I left the Desktop support group, I moved on to Windows domain administration. I installed a Red Hat Linux 4.0 system that I also hid under my desk from prying eyes. I also installed Samba on it to fool network probes and my annoying team leader who once asked, «What is that Linux server doing for us?» My answer was, «It isn’t doing anything for us, but it’s doing a lot for me. I use it for research.» I kept the Red Hat Linux system until I moved to a different group. Linux was still not allowed on the network. I still didn’t care. Yes, I was defiant and terrible but I was also not going to sit around messing with Windows 3.11 and Windows 95 while the rest of the world embraced Linux.

Even getting the LUG started was difficult. I had only about eight people who were interested and it was very frustrating. After almost a year of being too frustrated to continue, I passed the LUG torch to another group member. The Tulsa Linux User’s Group is still going today and meets once a month on the University of Tulsa campus. They still have install fests and lots of activities. And, believe it or not, Linux is now the major *nix operating system in that chilly data center that once didn’t allow it. It’s no longer WorldCom but some iteration of Verizon. The same people work there and none have ever apologized for their behavior nor have they said, «Hey, Ken, you were right about Linux.» I’m not going to hold my breath waiting either.

Other than sneaking into Linux system administration by some circuitous path, the more direct and recommended route is to still learn on your own but take some formalized Linux classes to prove your learning milestones. Being self-taught is great, but you’ll always just be an enthusiast or hobbyist unless you can formalize your knowledge with certifications or some other proof of knowledge. Self-education is commendable but you’ll have significant gaps in your learning. You should set certification knowledge as your goal, whether you become certified or choose not to do so. For a good start, check out Professor Messer’s videos on YouTube.

Also, use free resources such as Opensource.com and Enable Sysadmin to enhance your knowledge and to expand your network of learning opportunities.

What a Linux System Administrator does

A Linux system administrator wears many hats and the smaller your environment, the more hats you will wear. Linux administration covers backups, file restores, disaster recovery, new system builds, hardware maintenance, automation, user maintenance, filesystem housekeeping, application installation and configuration, system security management, and storage management. System administration covers just about every aspect of hardware and software management for both physical and virtual systems.

Oddly enough, you also need a broad knowledge base of network configuration, virtualization, interoperability, and yes, even Windows operating systems. A Linux system administrator needs to have some technical knowledge of network security, firewalls, databases, and all aspects of a working network. The reason is that, while you’re primarily a Linux SA, you’re also part of a larger support team that often must work together to solve complex problems. Security, in some form or another, is often at the root of issues confronting a support team. A user might not have proper access or too much access. A daemon might not have the correct permissions to write to a log directory. A firewall exception hasn’t been saved into the running configuration of a network appliance. There are hundreds of fail points in a network and your job is to help locate and resolve failures.

Linux system administration also requires that you stay on top of best practices, learn new software, maintain patches, read and comply with security notifications, and apply hardware updates. An SA’s day is very full. In fact, you never really finish, but you have to pick a point in time to abandon your activities. Being an SA is a 24x7x365 job, which does take its toll on you physically and mentally. You’ll hear a lot about burnout in this field. We, at Enable Sysadmin, have written several articles on the topic.

The hardest part of the job

Doing the technical stuff is relatively easy. It’s dealing with people that makes the job really hard. That sounds terrible but it’s true. On one side, you deal with your management, which is not always easy. You are the person who gets blamed when things go wrong and when things go right, it’s «just part of your job.» It’s a tough place to be.

Coworkers don’t seem to make life better for the SA. They should, but they often don’t. You’ll deal with lazy, unmotivated coworkers so often that you’ll feel that you’re carrying all the weight of the job yourself. Not all coworkers are bad. Some are helpful, diligent, proactive types and I’ve never had the pleasure of working with too many of them. It’s hard to do your work and then take on the dubious responsibility of making sure everyone else does theirs as well.

And then there are users. Oh the bane of every SA’s life, the end user. An SA friend of mine once said, «You know, this would be a great job if I just didn’t have to interface with users.» Agreed. But then again, with no users, there’s probably also not a job. Dealing with computers is easy. Dealing with people is hard. Learn to breathe, smile, and comply if you want to survive and maintain your sanity.

Being a Linux system administrator is a rewarding job. It carries with it a great deal of responsibility. It is sometimes unpleasant. It is sometimes really fun. It’s a job. Linux SAs come from a variety of backgrounds. They are among IT’s most creative and interesting people as well. I’ve known SAs who were visual artists, chefs, brewers, filmmakers, writers, furniture makers, sword fighters, martial artists, and a dozen other oddball hobbies. System administration isn’t easy nor is it for the thin-skinned. It’s for those who want to solve complex problems and improve the computing experience for everyone on their network. It’s a good job and a good career. Explore it.

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10 skills every Linux system administrator should have

Linux system administrators often morph into people who wear many hats. Sometimes you have to be a network administrator, desktop support tech, and end-user advocate. Yet, you always have to be a Linux sysadmin. To that end, I’ve devised a list of ten essential Linux system administrator skills that you should possess. These are in no particular order of importance.

User account management

Career advice

User account management is a primary responsibility of a Linux system administrator (SA). It is also one of the responsibilities generally handed to junior-level SAs. Junior-level SAs have this task because it is time-consuming and considered to be a «lower-level» activity. That designation is not meant to be insulting toward anyone, but user account management is not a critical function such as backup and recovery, troubleshooting, or patching, for example. If you need a user account management refresher, search Enable Sysadmin for posts on the topic.

Structured Query Language (SQL)

SQL isn’t a standard SA job requirement, but I’d suggest you learn it. It’s a good skill to know for a variety of reasons, not the least of which is to dispell assumptions that whatever problem is going on with a database server is infrastructure-related. Stepping outside your typical SA duties to extend yourself is generally a good idea to further your own career and to increase your value to a company. Learning something new is always positive. Check out Enable Sysadmin’s poll covering this topic.

Network traffic packet capture

One of Enable Sysadmin’s authors, Anthony Critelli, recently wrote the article Packet sniffer basics for network troubleshooting, in which he describes the use of tcpdump as an essential SA skill. But regardless of the packet capture tool you use ( tcpdump , Wireshark, etc.), capturing, interpreting, and analyzing network traffic is an important skill because of the security implications of the data you receive from it. Network traffic can alert you to multiple types of attacks in real-time and help you troubleshoot other network problems.

The vi editor

More Linux resources

As ancient and as «old school» as it is, the vi (ViM) editor is still the editor of choice for thousands of Linux SAs. This editor is easy to use, it’s installed by default, and every SA should know how to use it. If you’re unfamiliar with vi , check out my introductory article on using vi . The vi editor is the gold standard text editor and has been for more than 40 years.

Backup and restore

There are a variety of applications and techniques that SAs can use to back up files and directories as well as restore them. Backup, restore, and other disaster recovery activities are essential SA skills. You have to know how to back up and restore files for your users. If you or a member of your team perform backups, you need to audit the backups by periodically restoring a few files to check your backup and restore process.

Hardware setup and troubleshooting

Every SA needs to know how to set up, maintain, and troubleshoot hardware systems. You need to know how to deal with hardware failures that include disks, memory, NICs, ports, peripherals, and the rare CPU that goes belly up. Even if your infrastructure is entirely hosted or cloud-based, you should be familiar with the underlying hardware and its configurations, limitations, and vulnerabilities so that you can ensure that your hosting company or provider stays on top of security.

Network routers and firewalls

It’s important to know a little something about your network’s inner workings. Get familiar with your network’s routers and firewalls. You should examine your system configurations to decide if they’re consistent with Linux system security practices, which means you should be running host-based firewalls. You need to know what, if any, firewall exceptions have been configured and which systems and their ports are exposed to the internet. If you don’t have access, request a read-only account with access to all network hardware so that you can query and track configurations and changes.

Network switches

As a system administrator, your servers are directly connected to network switches, and you should know configuration details such as your VLAN configurations and who has access to change those configurations. Request read-only access so that you can perform queries against all network switches and switch stacks. And because your systems all have direct connections to network switches, you need to be apprised of maintenance activities and vulnerabilities associated with switch hardware and operating systems.

SIEMs and monitoring systems

Security information and event management (SIEM) and monitoring systems are absolutely essential skills to know. Sure, the security folks want to maintain a tight grip on access, but you need access to be able to keep a watchful eye on your systems. No one will ever care as much about the security of your systems as you do. You need to be able to query those systems, to have your own dashboard, and to adjust thresholds as needed. You also need to be able to set up specific monitoring for your systems that send notifications to you personally, or to a group account or device for on-call rotation purposes.

If neither a SIEM nor a monitoring solution already exists in your network, I suggest exploring some open source or free software options before plunking down thousands (or tens of thousands) on commercial software that has a lot of functionality that you probably don’t need.

Interviewing and other interpersonal skills

I know what you’re saying. You’re saying, «Oh, great, someone else telling me that I need soft skills.» Yes, that’s what I’m telling you. Honing your interviewing skills can not only determine if you get a particular job, it can also be a major factor in the salary you get. It’s true. Let’s say, for example, that the salary range for a mid-level SA job is $56k to $85k per year. You might be fully qualified for the top of the range, but the company offers you $70k instead and mentions some nonsense about growth potential or they tell you that they’ll bring you along when the time is right.

You need to practice answering questions. Answer the question that’s asked. Don’t give so much information that you see eyes glazing over, but giving answers that are too short will make you appear arrogant or flippant. Give enough examples of your work to let the interviewer(s) know that you know what you’re talking about. They can ask for more details if they want to.

You have to learn to watch other people’s behaviors. Are they listening to you? Are they focused on you and the interview? Do they look as though you haven’t said enough when you pause to allow them to speak or ask another question? Watch and learn. Practice with other system administrators in your group. Do mock interviews with the group. I know it might sound silly, but it’s important to be able to speak to other people about what you do. This practice can also be good for you in speaking with managers. Don’t get too deep into the weeds with non-technical people. Keep your answers concise and friendly, and offer examples to illustrate your points.

Wrapping up

As you can see from this list of ten essential sysadmin skills, being a system administrator isn’t «just one thing.» System administration covers a lot of ground and encompasses many diverse tasks. The bottom line is that you need to learn as much as you can about everything that you can. Specializing these days is not what you want to do. Additionally, being able to speak to a variety of professionals will make you even more valuable when the job market tightens up.

Want to evaluate your own sysadmin skills? Take this handy skills assessment.

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