Build XCP-ng ISO - issue at create-installimg

[Vagrantin]

Hi everyone,

I'm playing around with the build of the XCP-ng ISO to add a custom RPM in it.
Also, I'm facing an issue where I can't find my way out.

This is the create-installimg.sh step where setup_yum_repos ( from misc.sh ) doesn't manage to access the yum config.

What is weird is that just before this function is called I manage with a simple cat command to access it.
And as per my understanding at reading the script the TPMDIR is set by misc.sh so I don't have control over it.

This is the output of my tests currently.

sudo docker run --rm -it -v "$(pwd)/create-install-image:/create-install-image:ro" -v "$(pwd):/output" b292e8a21068 /bin/bash
[root@85b20fccb0e7 /]# /create-install-image/scripts/create-installimg.sh --output /output/install-8.3.img 8.3
-----Set REPOS-----
YUMCONF: //tmpdir-VcYHGW/yum-171swX.conf
YUMREPOSD: //tmpdir-VcYHGW/yum-repos-eg1dEe.d
YUMCONF_TPML: /create-install-image/configs/8.3/yum.conf.tmpl
ROOTFS: //tmpdir-VcYHGW/rootfs-1RKWIe
YUMFLAGS: --config=//tmpdir-VcYHGW/yum-171swX.conf --installroot=//tmpdir-VcYHGW/rootfs-1RKWIe -q
ls REPOSD
cat YUMCONF
[main]
keepcache=1
debuglevel=2
reposdir=//tmpdir-VcYHGW/yum-repos-eg1dEe.d
logfile=/var/log/yum.log
retries=20
obsoletes=1
gpgcheck=1
assumeyes=1
syslog_ident=mock
syslog_device=
metadata_expire=0
mdpolicy=group:primary
best=1
protected_packages=
skip_missing_names_on_install=0
tsflags=nodocs
--- ISSUE happens here *setup_yum_repos* ----
CRITICAL:yum.cli:Config error: Error accessing file for config file:////tmpdir-VcYHGW/yum-171swX.conf

This is the docker image I'm using.

sudo docker images
                                                                                                                                                                                           i Info →   U  In Use
IMAGE                                 ID             DISK USAGE   CONTENT SIZE   EXTRA
ghcr.io/xcp-ng/xcp-ng-build-env:8.3   b292e8a21068        543MB             0B        

I have been building this from the xcp-ng build env repo:
https://github.com/xcp-ng/create-install-image/tree/master

I'm puzzle and can't find what I'm doing wrong here.

Any hint will be much welcome !

[poddingue]

Hi Vagrantin,

If I'm reading this right, the four-slash path is the tell. I can't confirm without seeing your exact Docker invocation, but this pattern points pretty clearly at one thing.

misc.sh builds its temp dir from $PWD; something like $PWD/tmpdir-XXXXXX. If Docker is running your build from /, that expands to //tmpdir-XXXXXX. Linux is fine with that. Yum is not. It turns the config path into a file:// URI, and ////tmpdir-VcYHGW/yum-171swX.conf is not a URI anything wants to parse.

One other thing worth knowing: a :ro read-only mount on your repo directory causes the same symptom. mktemp fails silently, TMPDIR ends up empty, and you get the same mangled path. Different cause, same four-slash result.

Two things to try. The faster diagnostic is just cd into your repo before calling the script: if the build completes, that was it. The cleaner fix for scripted runs is passing -w /path/to/your/repo to your docker run command, which sets the working directory explicitly.

Before you do either, this will tell you what you're actually dealing with:

echo $PWD && ls -la $TMPDIR

That's my best guess, at least. I'm curious what those two commands show.

[Vagrantin]

@poddingue thank you that was it !

I had the feeling that the issue was around the path with the 4 slashes but couldn't figure out why, what and where.

So essentially, after setting the working directory to /tmp for my docker run it worked.

Here is the extract of the working build step for install.img

      - name: Build install.img
        run: |
          XCPNG_VER="${{ github.event.inputs.xcpng_version }}"
          docker run --rm \
            --user root -w /tmp \
            -v "$(pwd)/create-install-image:/create-install-image:ro" \
            -v "/tmp/RPM-GPG-KEY-xcp-ng-ce:/etc/pki/rpm-gpg/RPM-GPG-KEY-xcp-ng-ce" \
            -v "$(pwd):/output" \
            xcp-ng-build-ready \
            bash -ce "
              rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-xcpng 
              rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-xcp-ng-ce 

              /create-install-image/scripts/create-installimg.sh \
                --output /output/install-${XCPNG_VER}.img \
                --define-repo base!https://updates.xcp-ng.org/8/${XCPNG_VER}/base \
                --define-repo updates!https://updates.xcp-ng.org/8/${XCPNG_VER}/updates \
                ${XCPNG_VER}
            echo 'install.img built'

Regarding the output you wanted to see, here is it when it fails, first the way I trigger the container for context.

sudo docker run --rm -it -v "$(pwd)/create-install-image:/create-install-image:ro" -v "$(pwd):/output" b292e8a21068 /bin/bash

./create-install-image/scripts/create-installimg.sh --output /output/instal.img 8.3
-----Set REPOS-----
--- PWD var and TMPDIR content----
/
total 20
drwx------ 4 root root 4096 Apr 16 00:54 .
drwxr-xr-x 1 root root 4096 Apr 16 00:54 ..
drwx------ 2 root root 4096 Apr 16 00:54 rootfs-FJWbFM
-rw------- 1 root root  295 Apr 16 00:54 yum-HRyIb1.conf
drwx------ 2 root root 4096 Apr 16 00:54 yum-repos-1FbWwV.d
--- ISSUE happens here *setup_yum_repos* ----
CRITICAL:yum.cli:Config error: Error accessing file for config file:////tmpdir-sApL80/yum-HRyIb1.conf

As soon as I'm moving to different directory other than the root / then this issue goes away.

Now going through the ISO build.
With kind regards.

[poddingue]

Thank you so much for your feedback, @Vagrantin !