Linux Tools Apt-Mirror And Systemd-nspawn Are Super Effective
April 25, 2024 Leave a comment
Alright, let’s explore two specific tools for productivity elevation. Namely, systemd-nspawn1 and apt-mirror2.
I can show you the brief interactions I have had with these in recent times and how beneficial those could be in the general sense.
Apt-mirror is to create a local mirror of the upstream mirror
What does that mean? Simple, something hosted remotely and publicly available that can be brought down to your local machine for your inspection and improvements et.al.
Okay, a little demo won’t hurt much đ , here are some ways:
Installation
Oh, you are supposed to get it by the debian package manager and it’s darn simple.
apt-get install apt-mirror
Now, it brings down a few files with it, especially two files that should interest us for the usability of this tool. Which are /etc/apt/mirror.list and /etc/cron.d/apt-mirror . And we will tweak a little to fulfill our needs.
############# config ################## # set base_path /home/bhaskar/apt-mirrors # # set mirror_path $base_path/mirror # set skel_path $base_path/skel # set var_path $base_path/var # set cleanscript $var_path/clean.sh # set defaultarch <running host architecture> # set postmirror_script $var_path/postmirror.sh # set run_postmirror 0 set nthreads 20 set _tilde 0 # ############# end config ############## # deb http://ftp.us.debian.org/debian bookworm main contrib non-free # deb-src http://ftp.us.debian.org/debian bookworm main contrib non-free # mirror additional architectures #deb-alpha http://ftp.us.debian.org/debian unstable main contrib non-free deb-amd64 http://ftp.us.debian.org/debian unstable main contrib non-free #deb-armel http://ftp.us.debian.org/debian unstable main contrib non-free #deb-hppa http://ftp.us.debian.org/debian unstable main contrib non-free #deb-i386 http://ftp.us.debian.org/debian unstable main contrib non-free #deb-ia64 http://ftp.us.debian.org/debian unstable main contrib non-free #deb-m68k http://ftp.us.debian.org/debian unstable main contrib non-free #deb-mips http://ftp.us.debian.org/debian unstable main contrib non-free #deb-mipsel http://ftp.us.debian.org/debian unstable main contrib non-free #deb-powerpc http://ftp.us.debian.org/debian unstable main contrib non-free #deb-s390 http://ftp.us.debian.org/debian unstable main contrib non-free #deb-sparc http://ftp.us.debian.org/debian unstable main contrib non-free clean http://ftp.us.debian.org/debian
You see, I have changed three things in the above file. First, I created a directory under my home directory called apt-mirrors and fixed the base_path variable with it. Heads up! You are supposed to create the directory in places where some hefty amount of free space is available. This operation needs a placeholder big in some hundreds of Gibs, otherwise you might not accommodate it.
Then I commented on the two lines right after the end config marker. You might keep that if you want to. Because those are defaults and it will certainly pull from there.
Next, I uncommented one line specifically some architecture-specific i.e. an amd64-related line, so it pulls from that source.
Once you made changes to the mirror.list file then you are supposed to run this command as a superuser, as the manual said to get a sync.
sudo apt-mirror -c apt-mirror
Well, we are now all set. Let’s see how it goes âŚ
See! It is quite big, a whooping 143 gig, but that is okay to get the entire repo.
And the last thing about this is that, once you get the content down to your local machine you probably want to have it frequently after certain intervals with the updates. Here comes the importance of having a cron file attached to it. This software brings along a file with it and it looks like this :
# # Regular cron jobs for the apt-mirror package # #0 4 * * * apt-mirror /usr/bin/apt-mirror > /var/spool/apt-mirror/var/cron.log
You can change the value of this cron entry at your convenience, so you don’t have to do it by hand when you need it.
Systemd-nspawn is a more popular tool in the modern era
How so? Because distributions running(whether in enterprise or person) Systemd should take advantage of this tool. In crux, this is a modern way of doing chroot in systemd specific systems.
There are various use cases to use this tool and on top of my head, I could be using it to test some new stuff about some arcane thing in the restricted environment. So, it isolates the host system from getting banged by some experimentation done in the confined area of your machine. (aka containerized way of doing things).
Here I am showing you the abject ordinary thing this tool can help by running two different Linux distributions in a confined area of the machine. I am sitting on Debian3,i.e. the host system, and going to try our latest version of fedora404 and openSUSE Tumbleweed5 , which is installed in different physical partitions in the same machine.
First, take openSUSE Tumbleweed, and this is how boots with the help of this tool :
#!/usr/bin/env bash if test $UID -ne 0;then echo you are suppose to run this as superuser exit 1 fi if test ! -d /OpenSuseTW;then mkdir -p /OpenSuseTW fi echo Mounting..... /bin/mount /dev/nvme0n1p8 /OpenSuseTW systemd-nspawn -bD /OpenSuseTW
Pretty simple! Right. I said in the above vignette that this particular distribution is already installed in other physical partitions. Just created a directory to hold the mounted partition and boot from it to provide the login prompt and you can use the normal login credential, which you probably created when installed it.
The -b flag is for the booting and
The -D flag is for providing the shell.
Likewise, using this same tool i.e. systemd-nspawn ,I can spin up a minimal fedora version in a quick time. The system-nspawn man page clearly states how to do it.
Prerequisite :
You are supposed to install dnf beforehand to make things easy to do this kind of stuff. Again the manual clearly states that.
Here is how I put all those in an ordinary script to do the job for me:
#!/usr/bin/env bash # To get the cloud image # machinectl pull-raw --verify=no https://download.fedoraproject.org/pub/fedora/linux/releases/38/Cloud/x86_64/images/Fedora-Cloud-Base-38-1.6.x86_64.raw.xz fedora38 # systemd-nspawn -M fedora38 # Another way of getting minimal stuff # if test $(which dnf) == "";then # pkg_install dnf # fi # dnf -y --releasever=40 --installroot=/srv/fedora40 --disablerepo='*' --enablerepo=fedora --enablerepo=updates install systemd util-linux iputils passwd dnf fedora-release vim-minimal # systemd-nspawn -D /srv/fedora40 ----> to set the root password # if test $UID -ne 0;then echo you are suppose to run this as superuser exit 1 fi if test ! -d /srv/fedora40;then mkdir -p /srv/fedora40 fi unlink /srv/fedora40/etc/resolv.conf cp /etc/resolv.conf /srv/fedora40/etc/resolv.conf systemd-nspawn -bD /srv/fedora40
I have commented on the DNF-related lines because I had it before I made the script. Oh, that pkg_install is nothing but a wrapper over the underlying package manager used by the host distributions. I have made a few steps explicit because it was hindering smooth operation, although you could ignore the unlink and cp steps. Those are ugly workarounds in my convoluted environment. In your case, those are not necessary.
Last, if you are the kind of person, who are getting excited by seeing in a different form than this writing, then I have at least a video about apt-mirror on YouTube.
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