Red Hat Certified System Administrator – RHCSA EX200 – Tips and Advice for the Exam
Having finally taken and passed the Red Hat Certified System Administrator EX200 exam last week, I thought I’d share a few tips and tricks based on my experience.
I don’t think any of the below is revealing anything that isn’t already public knowledge, but these are all things I would have found helpful to know before taking the exam.
Prepare the exam USB well in advance
The RHCSA remote exam is run on a bootable live USB, not – as is the case with many other remote certification exams – an executable that you download to your system and run from the desktop.
You can test booting into this USB a few days before the exam, and I strongly recommend you do so. Whatever about having trouble with your webcam or mic, realising you can’t boot from USB a few hours before an exam (check secure boot!) is not good mental preparation!
Official guide for writing and using a bootable RHCSA exam USB is below:
Be prepared for the exam environment
As with just about all practical exams I’ve experienced, you are going to be using a incredibly cramped interface. To prepare for this, I would highly recommend restricting yourself to a single monitor when doing practice labs for the RHCSA.
On the exam, you will be running 2 RHEL VMs, two VM control interfaces (to allow VM reset, restart, console connection etc.), a web browser, and the core RHEL 8 host, all on a single screen. If at all possible, take the exam on as large a screen as possible, with at least 1080p resolution.
I also found the environment to be very laggy during my exam, despite being on a wired 100M internet connection, so be prepared for this too.
Be aware of cascading tasks
The majority of tasks on the RHCSA appear to be standalone, which you can complete in isolation from any other tasks. However, a number of them will be reliant on you completing a previous task.
For this reason, the RHCSA training I did strongly suggested that you are well versed in how to reset the root password, mount repositories from a number of different sources, and be comfortable configuring networking. It’s not hard to understand how failing to complete one of these tasks on a given system could directly impair your ability to complete additional tasks along the way. You certainly won’t be configuring an Apache web server if you don’t have a repository in place to download it from…
Be aware of the “important information” section
At the beginning of the exam, you will be presented with a pop-up browser containing quite a lot of information; how to control the VMs, the IP addresses and subnets of any live machines, the domain you are working in, default root password etc. One particular section is called “important information” (I believe, recollecting from the exam). If the tasks ever imply that you should already have a password to access something, and the default root credentials aren’t working, check here. I lost time on my exam trying to figure out why I couldn’t log into podman, only to realise the supplied credentials were in this section.
On that, note that the RHCSA website states you will not have internet access during the exam. From this you should realise that you will not be using subscription manager or podman to log into any real-life internet based accounts.
Be comfortable with all RHCSA Objectives (and the obvious questions you can glean from them)
The RHCSA objectives are listed below, and are very clearly defined. You really should be able to run down through this list and be comfortable with each point before considering taking the exam:
Taking the main headings into account, I would say it’s fair to predict that you are almost assured to see shell scripting, configuring storage, mounting storage, configuring networking, and managing persistent containers on every single RHCSA exam.
It’s always worth checking journalctl (and maybe tailing it)
All logging will be written to journalctl, and as such, it’s worth checking here if something isn’t working as expected for you. Journalctl straight up gave me the answer to an SELinux task that I had all but decided to skip.
One idea I had toyed with, although I didn’t do on the exam, is to always have a second shell open with ‘
journalctl -f‘ running, which will display live system messages as you attempt tasks. Either way, it’s worth creating persistent logging by creating
/var/log/journal/ so that journalctl retains logs between reboots.
Tips and Tricks for finding the information you need
And finally, although it’s true that you won’t have time to leisurely read man pages during the exam, there are lots of ways to get the information you need quickly, especially on subjects that you are familiar with but just can’t remember the exact command or syntax. RHCSA isn’t an open book exam, but the amount of help you have at your fingertips is considerable.
If you can’t remember the name of a command, try typing an associated word and double-tapping TAB to see what related commands are available. For example, you need to configure the hostname for a system, but you can’t remember how. Type
host and double-tap TAB, to reveal the command
hostname, but following up both commands with
--help will quickly eliminate
hostname as being relevant). Sometimes you can get lucky with this and it will jog your memory as to the correct command to use.
It should go without saying, but
--help on any command is often a lifesaver, and more concise than man. Breaking it up with
| less is sometimes required. Continuing with
hostnamectl as an example,
hostnamectl --help will quickly give you the exact command for changing the hostname of the system.
Grep for keywords in config files
Sometimes you know there is a configuration file you need to modify, but can’t remember the name or location. You can grep for anything related to the task at hand, to try and find the filename or a related keyword within the file.
For example, you might need to configure NTP, but can’t remember which file is used to specify the NTP source address. You know that
/etc generally contains configuration files, so you grep for ” ntp ” recursively to reveal
chrony.conf, the file you need to modify:
Use man -k with keywords
man -k [keyword] is incredibly useful for finding a command you can’t quite remember. -k searches the description of the man commands, not just the command names.
Even better, you can pipe the result to grep to further narrow down your search. Simple example: you need to add a new group, but can’t remember the command. Using
man -k group you get 156 results! Using
man -k group | grep create, you get a much more manageable 5 results, and from there it is obvious what your command is:
Know the basics of man
And finally, without going into too much detail here, be comfortable with the basics of man itself. Know how to use ‘/’ and ‘?’ to specify a search term (searching forward and back respectively), and ‘n/N’ to jump down/up to each match. Home and End keys are useful for jumping between the top and bottom of the man page. And remember you will need to escape special characters, so to find the string ‘/journal’ in a man page, you will need to search for