Standardize CI tests on Debian AMD64 and document supported image variants (#14593)

* Standardize CI tests on Debian AMD64 and document supported image variants

Reduce CI matrix to only build and test the Debian AMD64 Django image,
which is the officially supported configuration. Alpine and ARM64 images
are still built for release but are no longer tested in CI.

- Add Docker Image Variants section to installation docs
- Remove ARM64 from build and REST framework test matrices
- Exclude django-alpine from test build workflow
- Switch performance tests from alpine to debian
- Remove alpine from integration and REST framework OS matrices

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Restore ARM64 builds and unit tests, keep integration tests AMD64-only

ARM64 should still be built and unit tested in CI. Only integration,
performance, and k8s tests are restricted to AMD64. Update the
installation docs to reflect the three support tiers.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Update .github/workflows/build-docker-images-for-testing.yml

Co-authored-by: valentijnscholten <valentijnscholten@gmail.com>

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Co-authored-by: valentijnscholten <valentijnscholten@gmail.com>

Author: 3 people

.github/workflows/integration-tests.yml

@@ -76,7 +76,7 @@ jobs:
           # "tests/import_scanner_test.py",
           # "tests/zap.py",
         ]
-        os: [alpine, debian]
+        os: [debian]
         v3_feature_locations: [true, false]
         exclude:
           # standalone create endpoint page is gone in v3

.github/workflows/performance-tests.yml

@@ -23,13 +23,13 @@ jobs:
         uses: actions/download-artifact@70fc10c6e5e1ce46ad2ea6f2b72d43f7d47b13c3 # v8.0.0
         with:
           path: built-docker-image
-          pattern: built-docker-image-django-alpine-linux-amd64
+          pattern: built-docker-image-django-debian-linux-amd64
           merge-multiple: true
 
       - name: Load docker images
         timeout-minutes: 10
         run: |
-          docker load -i built-docker-image/django-alpine-linux-amd64_img
+          docker load -i built-docker-image/django-debian-linux-amd64_img
           docker images
 
       - name: Set unit-test mode
@@ -45,7 +45,7 @@ jobs:
             -f docker/docker-compose.override.performance_tests_cicd.yml \
             up -d --no-deps uwsgi
         env:
-          DJANGO_VERSION: alpine
+          DJANGO_VERSION: debian
 
       - name: Run performance tests (auto-update counts)
         timeout-minutes: 15

.github/workflows/rest-framework-tests.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ${{ inputs.platform ==  'linux/arm64' && 'ubuntu-24.04-arm' || 'ubuntu-latest' }}
     strategy:
       matrix:
-        os: [alpine, debian]
+        os: [debian]
 
     steps:
       # Replace slashes so we can use this in filenames

docs/content/get_started/open_source/installation.md

@@ -18,6 +18,23 @@ See instructions in [DOCKER.md](<https://github.com/DefectDojo/django-DefectDojo
 
 [SaaS link](https://defectdojo.com/platform)
 
+---
+## **Docker Image Variants**
+---
+
+DefectDojo publishes Docker images in multiple variants:
+
+| | AMD64 | ARM64 |
+|---|---|---|
+| **Debian** | ✅ Supported | ⚠️ Unit tested |
+| **Alpine** | ⚠️ Community | ⚠️ Community |
+
+**Debian on AMD64** is the officially supported and tested configuration. All CI tests (unit, integration, and performance) run against this combination.
+
+**Debian on ARM64** is built and covered by unit tests in CI, but integration and performance tests are not run against it.
+
+The **Alpine** variants are built and published but are not covered by any automated testing. Use them at your own risk.
+
 ---
 ## **Options for the brave (not officially supported)**
 ---