Re: [PATCH v2 8/9] devconfig: add automatic APT mirror fallback for Debian testing

[Daniel Gomez <da.gomez@kernel.org>]

On 30/07/2025 08.01, Luis Chamberlain wrote:
> Debian testing (trixie) VMs can fail to provision when configured APT
> mirrors become unavailable or unresponsive. This is particularly common
> with local or regional mirrors that may have intermittent connectivity
> issues.
> 
> This fix adds automatic mirror health checking specifically for Debian
> testing systems. The implementation:
> 
> 1. Extracts the currently configured APT mirror hostname
> 2. Tests connectivity to the mirror on port 80 with a 10 second timeout
> 3. Falls back to official Debian mirrors if the test fails
> 4. Backs up the original sources.list before making changes
> 5. Updates the APT cache after switching mirrors
> 6. Provides clear user notification about the fallback
> 
> The check only runs on Debian testing systems where devconfig_debian_testing
> is set to true, avoiding any impact on stable Debian or other distributions.
> 
> This ensures that Debian testing VMs can successfully provision even when
> the initially configured mirror is unavailable, improving reliability for
> development and testing workflows.
> 
> Generated-by: Claude AI
> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> ---
>  .../devconfig/tasks/check-apt-mirrors.yml     | 63 +++++++++++++++++++
>  playbooks/roles/devconfig/tasks/main.yml      |  8 +++
>  .../debian-testing-fallback-sources.list      | 10 +++
>  3 files changed, 81 insertions(+)
>  create mode 100644 playbooks/roles/devconfig/tasks/check-apt-mirrors.yml
>  create mode 100644 playbooks/roles/devconfig/templates/debian-testing-fallback-sources.list
> 
> diff --git a/playbooks/roles/devconfig/tasks/check-apt-mirrors.yml b/playbooks/roles/devconfig/tasks/check-apt-mirrors.yml
> new file mode 100644
> index 00000000..02e0c800
> --- /dev/null
> +++ b/playbooks/roles/devconfig/tasks/check-apt-mirrors.yml
> @@ -0,0 +1,63 @@
> +---
> +# Only run mirror checks for Debian testing (trixie) where mirror issues are common
> +- name: Extract current APT mirror hostname
> +  shell: |
> +    grep -E "^deb\s+http" /etc/apt/sources.list | head -1 | awk '{print $2}' | sed 's|http://||' | cut -d'/' -f1
> +  register: apt_mirror_host
> +  changed_when: false
> +  ignore_errors: yes
> +
> +- name: Check connectivity to current APT mirror
> +  wait_for:
> +    host: "{{ apt_mirror_host.stdout }}"
> +    port: 80
> +    timeout: 10
> +  register: mirror_connectivity
> +  ignore_errors: yes
> +  when: apt_mirror_host.stdout != ""
> +
> +- name: Display mirror check results
> +  debug:
> +    msg: |
> +      Current APT mirror: {{ apt_mirror_host.stdout | default('Not found') }}
> +      Mirror connectivity: {{ 'OK' if mirror_connectivity is not failed else 'FAILED' }}
> +  when: apt_mirror_host.stdout != ""
> +
> +- name: Fall back to official Debian mirrors if current mirror fails
> +  block:
> +    - name: Backup current sources.list
> +      copy:
> +        src: /etc/apt/sources.list
> +        dest: /etc/apt/sources.list.backup
> +        remote_src: yes
> +      become: yes
> +
> +    - name: Apply Debian testing fallback sources
> +      template:
> +        src: debian-testing-fallback-sources.list
> +        dest: /etc/apt/sources.list
> +        owner: root
> +        group: root
> +        mode: '0644'
> +      become: yes
> +
> +    - name: Update APT cache after mirror change
> +      apt:
> +        update_cache: yes
> +        cache_valid_time: 0
> +      become: yes
> +
> +    - name: Inform user about mirror fallback
> +      debug:
> +        msg: |
> +          WARNING: The configured APT mirror '{{ apt_mirror_host.stdout }}' is not accessible.
> +          Falling back to official Debian testing mirrors:
> +          - deb.debian.org for main packages
> +          - security.debian.org for security updates
> +
> +          This may result in slower package downloads depending on your location.
> +          Consider configuring a local mirror for better performance.
> +
> +  when:
> +    - apt_mirror_host.stdout != ""
> +    - mirror_connectivity is failed
> diff --git a/playbooks/roles/devconfig/tasks/main.yml b/playbooks/roles/devconfig/tasks/main.yml
> index 656d5389..ceb0f2e8 100644
> --- a/playbooks/roles/devconfig/tasks/main.yml
> +++ b/playbooks/roles/devconfig/tasks/main.yml
> @@ -30,6 +30,14 @@
>    tags: hostname
>  
>  # Distro specific
> +
> +# Check and fix APT mirrors for Debian testing before installing dependencies
> +- name: Check and fix APT mirrors for Debian testing
> +  include_tasks: check-apt-mirrors.yml
> +  when:
> +    - devconfig_debian_testing is defined
> +    - devconfig_debian_testing | bool
> +
>  - name: Install dependencies
>    ansible.builtin.include_tasks: install-deps/main.yml
>    tags: ['vars', 'vars_simple']
> diff --git a/playbooks/roles/devconfig/templates/debian-testing-fallback-sources.list b/playbooks/roles/devconfig/templates/debian-testing-fallback-sources.list
> new file mode 100644
> index 00000000..456ed60f
> --- /dev/null
> +++ b/playbooks/roles/devconfig/templates/debian-testing-fallback-sources.list
> @@ -0,0 +1,10 @@
> +deb http://deb.debian.org/debian testing main contrib non-free non-free-firmware
> +deb-src http://deb.debian.org/debian testing main contrib non-free non-free-firmware
> +
> +# Security updates
> +deb http://security.debian.org/debian-security testing-security main contrib non-free non-free-firmware
> +deb-src http://security.debian.org/debian-security testing-security main contrib non-free non-free-firmware
> +
> +# Updates (if available for testing)
> +deb http://deb.debian.org/debian testing-updates main contrib non-free non-free-firmware
> +deb-src http://deb.debian.org/debian testing-updates main contrib non-free non-free-firmware
> \ No newline at end of file

Debian has switched to a new sources format [1]. They have also provided a
manual conversion for users with "apt modernize-sources". So it makes sense to
start using the new format directly here.

[1] https://wiki.debian.org/SourcesList