Hello. I would like to see and practice in VM with Linux servers, like Windows Server 2016 which I did learn a lot in VM. I already have Ubuntu but I don't know if this works or I have to install a package? Thank you P.S: I did a search on the internet search engines using "site:howtoforge.com new Linux user install server" but I did not find any question-related.
Ubuntu is a distribution, so it will install the whole OS; you may need to install additional packages, depending on what you have installed and what you end up needing.
You can install Linux in a virtual machine. Debian is my favorite for server OS. If your current virtualization system does not support Linux, I suggest Proxmox Virtual Environment. https://proxmox.com/en/proxmox-ve Howtoforge has installation instructions for Linux server, Ubuntu, CentOS and Debian. For example https://www.howtoforge.com/tutorial/debian-10-buster-minimal-server/
Ahem.. Err.. Erm... CentOS, free but not quite. Why CentOS, well while Ubuntu, Debian in fact pretty virtually all Distros have a vast community of enthusiast behind them, not many are backed with Enterprise level support. CentOS is one such Distro that is. That support is not free of course, its enterprise level. BUT.. if you are running critical services and you are not sure what you are doing or you cannot spare the downtime its going to be indispensable for you to have that support in place. The alternative is searching the web looking for a solution and implementing it yourself or hiring somebody else to do it, either way, it costs, time or money. I will give you an example from my early days. apt package manager broke on my 12.10 install I think it was, could have been 12.04, not sure. Anyway I digress. I didnt know if it could be fixed or how to fix it. I had to use another computer to look up the problem and then implement it because the machine had a broken wifi module and I didnt have a cable long enough to reach the router in the next room. That took time. Do you have the time or would your time be better spent elsewhere? things you should ask yourself before deciding which way to go.
Other distros like Ubuntu also have enterprise level of support but that level of support is not neccesarily needed by many server administrators.
You should also be aware of the changes at CentOS stemming from the takeover of Red Hat by IBM. Red Hat are the creators of what CentOS distributes (debranded). RH have summarily forced the ending CentOS 8 support this December which has shot a whole industry in the foot. CentOS 8 is the stable version equivelent to Red Hat's RHEL 8. Instead CentOS will now distribute CentOS Stream - which is a less stable development version which in effect is there to debug the software that will become Enterprise. Stability in a server, unlike desktops, is usually the most prized attribute. Hence many CentOS users are bailing fast. Some, because of the short notice and integration into the RH world cannot easily switch away. Hence a number of forks of RHEL 8 with different organisational models have appeared offering seamless migration. Which will succeed has yet to be seen. It also questions the future of Red Hat derivatives and policies as RH/IBM are solely concerned with maximising benefit for their shareholders at the expense of other users of the software. Those that have time and resources are evaluating moves to Debian or its derivatives. Debian is there unlike Red Hat, and solely there, to write, collate and distribute a free Linux distribution. They also act as the leading upstream provider to Ubuntu, Linux Mint and many other distros. Ubuntu, in particular, through its owner Canonical provides enterprise server level support for those who need it. Disclosure: I was a CentOS user and, for other reasons, migrated to Debian five years ago. Now, with the upheaval at CentOS - glad I did. I've never need support for either CentOS or Debian beyond the Linux forums - which is probably the norm if you are reasonably technically competent and in a small controllable environment.
Well then i take back my recommendation. Seems there is a lot of take overs in the industry at the moment.