Fedora Silverblue is a new variant of Fedora Workstation with rpm-ostree at its core to provide fully atomic upgrades.  Furthermore, Fedora Silverblue is immutable and upgrades as a whole, providing easy rollbacks from updates if something goes wrong.

Just wondering is there anything Debian based. And of course someone else already asked this (on Reddit) and other people curated a list of immutable distributions. So the answer is EndlessOS and Vanilla OS.

Silly me, I bought a laptop for my father-in-law with EndlessOS, finding it very solid!

Failed to download metadata for repo ‘appstream’: Cannot prepare internal mirrorlist: No URLs in mirrorlist – Centos 8

luckily Habibur Rhoman Joy from namespaceit.com provided an easy solution on his blog.

Habibur Rhoman Joy

FROM centos:8<br data-rich-text-line-break="true" /><br data-rich-text-line-break="true" />RUN sed -i 's/mirrorlist/#mirrorlist/g' /etc/yum.repos.d/CentOS-Linux-* &&\<br data-rich-text-line-break="true" />    sed -i 's|#baseurl=http://mirror.centos.org|baseurl=http://vault.centos.org|g' /etc/yum.repos.d/CentOS-Linux-*<br data-rich-text-line-break="true" /><br data-rich-text-line-break="true" />#docker<br data-rich-text-line-break="true" />RUN yum upgrade -y<br data-rich-text-line-break="true" /><br data-rich-text-line-break="true" />#other commands<br data-rich-text-line-break="true" />

 

On Centos 8, I have run “sudo yum update” but getting this error – 

Error: Failed to download metadata for repo 'appstream': Cannot prepare internal mirrorlist: No URLs in mirrorlist

Here I have given different solution for different situation.

Solution 1:

This error we are getting cause CentOS 8 became EOL at the end of 2021. Better if you migrate to CentOS Stream 8, CentOS 9 or Rocky Linux.

To solve current os you can run these commands –

sed -i 's/mirrorlist/#mirrorlist/g' /etc/yum.repos.d/CentOS-Linux-*

sed -i 's|#baseurl=http://mirror.centos.org|baseurl=http://vault.centos.org|g' /etc/yum.repos.d/CentOS-Linux-*

If you run these commands then dnf will work, but you will not get any updates.

If you want you can also upgrade to centos 8 stream:

 sudo dnf install centos-release-stream -y
 sudo dnf swap centos-{linux,stream}-repos -y
 sudo dnf distro-sync -y

 

Solution 2:

If you are using docker, you may face same type of problem. Hope this commands will help you –

FROM centos:8

RUN sed -i 's/mirrorlist/#mirrorlist/g' /etc/yum.repos.d/CentOS-Linux-* &&\
    sed -i 's|#baseurl=http://mirror.centos.org|baseurl=http://vault.centos.org|g' /etc/yum.repos.d/CentOS-Linux-*

#docker
RUN yum upgrade -y

#other commands

How To Upgrade From Fedora 32 To Fedora 33 [CLI & Graphical Methods] | Linux Journal

It’s so simple with the GUI, but I’m a shell guy, so

$ sudo dnf upgrade --refresh
$ sudo dnf install dnf-plugin-system-upgrade
$ sudo dnf system-upgrade download --releasever=33
$ sudo dnf system-upgrade reboot

Nope.

As I discoverede reading Gnome 3 on CentOS 7 – How I Made It Lovely and Usable a piece from 2014, you must install the package directly from Fedora packages, as in

sudo yum install http://mirror.internode.on.net/pub/fedora/linux/releases/22/Everything/x86_64/os/Packages/e/epiphany-3.16.1-1.fc22.x86_64.rpm http://mirror.internode.on.net/pub/fedora/linux/releases/22/Everything/x86_64/os/Packages/e/epiphany-runtime-3.16.1-1.fc22.x86_64.rpm

well, I felt like being cast in the 90ties. Actually I shouldn’t have done it on my work desktop.

Mind me, it is a wonderful tool. Tell me I’m old-fashioned, tell me I’m unacknowledged about the security it brings.

This after I just wanted to add a theme to my WordPress inner company blog.

SELinux kept saying something like “I don’t think so!”.

I ended up switching it off. For a while.

Yet this «CentOS 7 + SELinux + PHP + Apache – cannot write/access file no matter what» from Lysender’s Daily Log Book is a nice page to save and study.

I wish I’ve studied RHCE and related certifications a little more…

a2enmod is a debianism, on CentOS you will need to do this manually. Please refer to the Apache documentation to find out how to do this.

Life is full of surprises

yum install hugin told me that my new Centos 7 machine don’t have it. Ok, let’s search for a proper repo. Too bad there isn’t.

Ok, let’s do it the old way: recompiling it from sources.

That’s a small log of me following the path hinted at on Hugin Compiling Fedora – PanoTools.org Wiki

Note: I’ve finally renounced. Too many unmet dependencies, too many unsolved parts. CentOS is a server distribution and I won’t mess it just to use Hugin. I would rather run something more “pliable” as a virtual machine

CompilingIf you want to compile hugin yourself, just follow the instructions in the INSTALL_cmake file, you will need these development RPM packages (April 2013): libpano13-devel zlib-devel libtiff-devel libjpeg-devel libpng-devel gettext-devel wxGTK-devel boost-devel cmake desktop-file-utils OpenEXR-devel gcc-c++ exiv2-devel glew-devel freeglut-devel mesa-libGLU-devel libXmu-devel wxPython tclap-devel python-devel swig flann-devel lensfun-devel perl-podlators (needed for fedora 19 and above)

• Installing all those requirements.
• Discovering that version 2016 requires a too recent cmake. Ok, reverting to version 2014
• Oh my: no libpano13-devel and no tclap-devel packages available. It feels like using a way-outdated distro.
• Ok, looking for their sources too. I begin longing for a less “stable” distribution.
• Exif support missing, installing libexif-devel
• Not enough, installing exiv2
• No it’s not that. It may be perl-Image-ExifTool.noarch
• Mhmmm… cmake seems satisfied. But compiler found a syntax error in 2014 release. Wow. Last try: 2015 release which also require VIGRA.
• Let’s hope that vigra-devel suffice. AFAICS it should be The VIGRA Computer Vision Library.
• Error: Libvigraimpex found.  But vigraimpex seems to compiled without OpenEXR support.  OpenEXR support is required for Hugin.

Ok, enough is enough. Let’s create a “hacking” virtual box, based on something “more recent”, such as Fedora 24.

Stay tuned

Have you noticed something strange and silly in the above photo?
Right. It misses the optical drive. Actually it has only USB and Ethernet.

I felt dumb.

Dumber indeed because I cannot boot it using PXE as the DHCP is under the control of a win domain. Well, not without making a mess on the network. And I didn’t had an USB stick big enough. I’ve literally thrown away a couple hours trying to boot a minimal ISO installed on my Ext2-formatted Usb key (yes, you can format sticks with ext2!), discovering that the ISO I picked still required PXE to boot. No way. So next day I got this shiny – literally – 8Gb stick. And here I am. Centos 7 running on a “normal” Intel i3 box with 8gb of RAM which is a fairly normal spec by today’s standards, but it’s a huge jump from my previous one.

Click to view slideshow.

It feels weird after all those years to return to an RPM based distro. Everything looks alien and familiar at the same time.

And I already miss the huge package selection of Debian. WordPress? Isn’t there. Chrome. No way. Epiphany, the Gnome browser? Not available. That’s the price of stability, I suppose.

I haven’t already enjoyed intimacy with SE-Linux security layer. I half-suspect it won’t be an easy deal.

Fourty years later people using software libero still quarrel with printers. Me for example…. on the previous (Ubuntu) box I was able to smoothly use that printer. Now Centos keeps arguing that the printer has low black ink (true!) and that there’s no paper (wrong!).

The mysteries of software libero….