Package manager

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Hi don't know if i put in the correct product name. I have REHL(developer subscription) on an external HD and Fedora on my main Hard Drive. This question is related to booth because they are the same family. The disros i have used before are Opensuse, Arch, Manjaro,CentOS and Kubuntu. They had only one package manager Opensuse uses ZYpp(Think SLES uses another not sure) Manjaro and Arch uses Pacman and Kubuntu uses APT like all Debian based distros but REHL, CentOS and Fedora uses two Yum and DNF why? I can booth type for example sudo yum install gparted or sudo dnf install gparted which one to use YUM or DNF. Sorry mabye stupid question but i am quite new to linux in general yes i used Linux in the early 2000s but i was young than and than you had like mostly 3 distros Red Hat, Suse and Mandrake before Ubuntu. Red Hat was my very first disro than Suse.

Responses

Hi Daniel, I'm going to break this down hopefully into categories.

==Your questions:

  • (Daniel Ostrowski) - I have REHL(developer subscription) on an external HD and Fedora on my main Hard Drive. This question is related to both because they are the same family. Possible Answer: From your post above, it seems you might be well served by using virtualization to host all your virtual systems. My next post will have some virtualization options.

  • (Daniel Ostrowski) -The disros i have used before are Opensuse, Arch, Manjaro,CentOS and Kubuntu. Answer: This is the Red Hat Discussion Forum, we generally focus our discussion against Red Hat itself. The other distros are just fine, but this forum happens to center around Red Hat because it's part of access.redhat.com. It's good to know you have some background in other distributions. Linux admins have to support various distributions on occasion

  • (Daniel Ostrowski) -They had only one package manager Opensuse uses ZYpp(Think SLES uses another not sure) Manjaro and Arch uses Pacman and Kubuntu uses APT like all Debian based distros but REHL, CentOS and Fedora uses two Yum and DNF why? Answer: WHY DNF - I'm glad you asked, see this link and also this link too, but wait, there's more, see this link which shows changes in dnf cli compared to yum
  • (Daniel Ostrowski) -I can booth type for example sudo yum install gparted or sudo dnf install gparted which one to use YUM or DNF. Answer: Sometimes I forget about the use of dnf and stick to yum commands, and so far it's worked for me. My pal here in the discussion forum named Christian Labisch makes enough reminders for me to remember to try dnf. Sometimes change does not come easy, and it is certainly an unknown to those who have not seen dnf such as in Fedora where it has been around for a while now.
  • (Daniel Ostrowski) -Sorry mabye stupid question but i am quite new to linux in general yes i used Linux in the early 2000s but i was young than and than you had like mostly 3 distros Red Hat, Suse and Mandrake before Ubuntu. Answer: It's great you have had this experience with various distributions.
  • (Daniel Ostrowski) -Red Hat was my very first disro than Suse. Answer: I used SuSE as well. They at least have rpms. However, I haven't used SuSE in years.

Is there something else we can help you with here?

Kind Regards

RJ

Hi RJ,

Thanks for putting this together ! I'll give you (and Daniel of course) an example for why it's better to get used to
use dnf instead of yum in RHEL 8 : if you need to clear the cache, by running sudo rm -r /var/cache/yum, nothing
will happen. Why ? Simply because the folder doesn't exist - to clear the cache /var/cache/dnf has to be deleted.
It is kind of the Red Hat developers to provide the symlink to yum, but sooner or later we'd get used to use dnf. :)

Regards,
Christian

Daniel,

Virtualization of your numerous operating systems may be easier than dealing with the issues of hardware, external drives etc.

Some options:

  • KVM which is a poor and insufficient name for the standard virtualization that comes standard with Red Hat/CentOS and Fedora. KVM here stands for "Kernel Virtualization Machine". I use it for a tiny lab at work on a decently powered system.
  • Ovirt: I personally have not tried Ovirt, but someone I know uses it https://www.ovirt.org/download/.
  • Virtual Box which is useful for a workstation that is robust enough to host a number of systems. https://www.virtualbox.org/ free from Oracle (they acquired it from Sun Microsystems when they were bought out.
  • VMware ESXI which gives you pretty much a fully functioning VMware instance. https://www.vmware.com/products/esxi-and-esx.html. You can use it alone as a free product. VMware will try to urge you to buy a paid product, but you can get away with using ESXI.

Why virtualize your operating systems? Virtualization is useful when you need to have multiple systems and yet you have limited hardware. Instead of juggling multiple internal/external drives, or swapping drives with OS loads, you can virtualize your system using one of these methods and create systems. Make sure to have a decent enough amount of RAM. You can probably run a couple or few light virtual "machines" with 8G of RAM and a 500G drive (I make small Linux systems with 30GB or so virtual hard drive space) - You do not have to partition the drive for each virtual system. These "hypervisors" or virtual operating system methods allow you to build multiple systems on one computer. I have a higher powered workstation with a lot of RAM and hard drive space, and I can create multiple systems and have them running concurrently. Now I only have a couple of network interfaces, so in some cases you might be limited to network operations to some degree for high-intensity network functions. That being said, I personally have not had many issues. - You might want to consider virtualizing your systems.

Regards

RJ

Hi RJ,

Cannot agree more ... making use of virtualization capabilities is way more efficient than dealing with multiple
boot setups. Those were relevant in days when virtualization solutions were not perfectly "production-ready".
Me personally (as you know RJ) can definitely recommend to make use of (RHEL built-in) KVM/libvirt/qemu.
I'm using it for years and I can only say, everything just works. You may want to consider trying it out Daniel. :)

Regards,
Christian

Hi Daniel,

I assume that this thread is a follow-up on the other discussion you have started. My "buddy" RJ has provided you with a lot of
excellent general information already. I will sum up the main technical background regarding your question about the software
package managers on CentOS, Fedora, and RHEL. First of all, DNF and YUM are not different - dnf is the successor of yum. :)

DNF : main package management tool used in CentOS 8 and RHEL 8 (yum is just a symlink to dnf, provided for convenience.)
YUM : main package management tool used in CentOS 7 and RHEL 7 (fedora already replaced yum with dnf many years ago.)
PackageKit : an additional tool (running alongside dnf/yum) to feed the graphical applications Cockpit and GNOME Software.

Regards,
Christian

Note that in RHEL 7.6+, you can install DNF (the package name is something like "nextgen-yum4") in addition to the legacy yum 3.x packages. In that case, "yum" and "dnf" are not entirely interchangeable, since they each use a different & incompatible set of databases (in particular, the "yum history" and "dnf history" commands will return different results - and thus things like rolling back previous updates may become very difficult).

In RHEL 8.x, there is only one version (dnf/yum 4.x); the alias "yum" for "dnf" exists mostly so that those of us who have been using "yum" commands for the last 12 years or so won't storm Red Hat headquarters with torches and pitchforks for changing such a fundamental system management command that our fingers are well-trained to type :-)

Hi Jim,

Thanks for providing this additional information. I know ... I have tested YUM 4 (DNF preview) on
RHEL 7 some time ago, but skipped the test soon. Both of them running side-by-side generated
some "strange issues" and hence I recommend to stick with standard YUM there. It doesn't make
much sense to run two package managers side-by-side that are doing the exactly same thing. :)

Regards,
Christian

Ok thanks for the answer :) from what i understand correct me if i am wrong dnf is an uppdated version of yum with less risk of dependency hell and the yum is there only for users that are used to typing yum.

You're welcome, Daniel ! Yes, you understood it correctly : DNF has replaced YUM in RHEL 8. :)

Regards,
Christian