What is the minimum knowledge that a Linux System Administrator should have?

Question

linux

What is the minimum knowledge required for an entry-level Linux System Administrator?
Every employer asks about LA, top, lvm and "What was the hardest thing you did in Linux?" . What is there difficult to do without being tied to applications, subds, etc. ??

Answer 1

The assigned tasks must be solved. They are different everywhere.

Answer 2

In general, there are a lot of things and immediately breaking into admins without experience is a so-so idea. Try to start with those. support. If this is your element, then in a year or two you will already be working with real tasks, understanding how to solve them and thinking about the position of an administrator.
Understanding the basics is when you have no questions about where to look at the logs; how to restart the service; how to get the data in the right view, process it and feed it to the right program; how to fix errors in applications and prevent them from happening again for the same reason; how to diagnose hardware, network, DNS; set up monitoring, understand where all the space has gone or which application is leaking memory, etc. etc. When the basics are in place, a methodology for solving problems will begin to be developed. But this takes a lot of practice. Reading the documentation over time will give you an understanding of how the system works as a whole, the pieces of the puzzle will begin to add up to the picture. Well, PS: Do not neglect to use programming languages ​​and use them to automate routine actions.

Answer 3

What is there difficult to do without being tied to applications, subds, etc. ??

What's simple?
Read about the OSI and TCP / IP models, read the history of linux, for which it was created. Read about the core of the system. Read about netfilter. Read about file systems and utilities for working with them. Familiarize yourself with the location of configuration files, processes, devices, home directories. Check out utilities for configuring/testing/monitoring network/hardware/processes. Read about bash, about scripts, about the cron scheduler. Familiarize yourself with the location and contents of configuration files for the most common applications. Familiarize yourself with the location and content of the configuration files of the applications specified in the vacancy. Search Google for the main tasks of system administration, figure out how it is solved on linux. I think this is enough to start, but everything is at the discretion of the employer

Answer 4

Lots of things to do. The issue of assessing the complexity here is not easy in itself, because in fact EVERYTHING is in the documentation, and the only question is the amount of time you spent setting up different things.
Knowledge of bash at an adequate level. Without a discount that there are all sorts of python / go / js, etc., but because bash is a shell and knowledge of bash without understanding the many nuances of posix systems will be like knowing a programming language without standard libraries.
Raise and configure a monitoring system from scratch that will monitor all critical resources and display them in an adequate readable form.
Raise and configure ldap instead of AD for LAN
Raise vpn for remote employees with access to office resources
If you need to deploy and maintain a lot of Linux, be able to work with an orchestrator, such as ansible Troubleshooting
, services, working with logs.
Mail, DNS to work, and not immediately to the spam list.
And so - it is clear that everything should be tied to applications and subds, at least to the most popular ones.

Answer 5

yes, in general, no, be able to press enikey the main thing and read books)

Answer 6

On the one hand, without reference to applications, it is probably difficult.
But let's take a simple desktop under Linux in a zombie corporation:
- configure user authentication in LDAP / AD
- configure groups via LDAP / AD
- do authorization via KERBEROS
- drive logs to a dedicated server
- enable auto-mounting of homs via NFS / SMB
- configure SELINUX
- configure printing
- set up a proxy with authorization
- set up backups
- set up work with multiple monitors
- automate the deployment of applications
- automate the launch of distributed tasks
All this without being tied to applications on servers!
Now let's go to the server am - everything is the same, but also pick up and configure all this from the side of the servers, plus:
- distributed storage
- mail, telegraph, phone
- some tool for tracking notes
-
file washer - virtual machine factory (yes, now everything soar in the clouds)
- backups to the neighboring territory
- updates of this entire economy
- monitoring of this disgrace, with notifications immediately to the brain
- and also all sorts of DNS / DHCP / Freeradius and preferably via LDAP
And so on.
And also for this business to deal with a network with vlan, 802.1x authorization, dhcp-proxy, monitoring ....

Answer 7

Does it right. Can you restore volume settings with a backup of your lvm config? (The volume has not changed, only the metadata has flown, now the volume is recognized as unallocated)
This is why I ask about LVM. You need to be able and know what is needed to solve problems in this particular place. Depending on the volume of the office, only the general and the Lord God can be above the linux admin - and here what? There will even be no one to blame :)