diff --git a/.github/workflows/containers.yml b/.github/workflows/containers.yml
index f265609..17e7a5d 100644
--- a/.github/workflows/containers.yml
+++ b/.github/workflows/containers.yml
@@ -22,13 +22,25 @@ jobs:
           - dev
           - build
     steps:
+      - name: Check for GitHub Container Registry credentials (secrets)
+        id: ghcr-credentials
+        run: if [ ${{ secrets.GHCR_USERNAME == null || secrets.GHCR_TOKEN == null }} = true ]; then exit 1; fi
+        continue-on-error: true
       - name: Login to GitHub Container Registry
+        id: ghcr-login
+        if: ${{ steps.ghcr-credentials.outcome == 'success' }}
         uses: docker/login-action@v1
         with:
           registry: ghcr.io
           username: ${{ secrets.GHCR_USERNAME }}
           password: ${{ secrets.GHCR_TOKEN }}
+      - name: Check for Docker Hub credentials (secrets)
+        id: docker-hub-credentials
+        run: if [ ${{ secrets.DOCKER_HUB_USERNAME == null || secrets.DOCKER_HUB_TOKEN == null }} = true ]; then exit 1; fi
+        continue-on-error: true
       - name: Login to Docker Hub
+        id: docker-hub-login
+        if: ${{ steps.docker-hub-credentials.outcome == 'success' }}
         uses: docker/login-action@v1
         with:
           username: ${{ secrets.DOCKER_HUB_USERNAME }}
@@ -80,14 +92,22 @@ jobs:
           tags: |
             docker.io/${{ steps.vars.outputs.docker-hub-namespace }}/${{ steps.vars.outputs.candidate-tag }}
           cache-from: type=registry,ref=docker.io/${{ steps.vars.outputs.docker-hub-namespace }}/${{ env.cache-repository-name }}:dev
-          cache-to: type=registry,ref=docker.io/${{ steps.vars.outputs.docker-hub-namespace }}/${{ env.cache-repository-name }}:${{ matrix.target }},mode=max
-          push: true
+          cache-to: ${{ (steps.docker-hub-login.outcome == 'success') && format('type=registry,ref=docker.io/{0}/{1}:{2},mode=max', steps.vars.outputs.docker-hub-namespace, env.cache-repository-name, matrix.target) || null }}
+          push: ${{ steps.docker-hub-login.outcome == 'success' }}
       - name: Image digest
         if: ${{ !startsWith(github.ref, 'refs/tags') }}
         run: echo ${{ steps.build-push.outputs.digest }}
       - name: Release (pull candidate, tag, push)
         if: ${{ github.ref == steps.vars.outputs.tag-trigger-ref }}
         run: |
+          if [ "${{ steps.docker-hub-login.outcome }}" != "success" ]; then
+            echo "Docker Hub must be authenticated to perform a release!"
+            exit 1
+          fi
+          if [ "${{ steps.ghcr-login.outcome }}" != "success" ]; then
+            echo "GitHub Container Registry must be authenticated to perform a release!"
+            exit 1
+          fi
           docker pull docker.io/${{ steps.vars.outputs.docker-hub-namespace }}/${{ steps.vars.outputs.candidate-tag }}
           docker tag docker.io/${{ steps.vars.outputs.docker-hub-namespace }}/${{ steps.vars.outputs.candidate-tag }} docker.io/${{ steps.vars.outputs.docker-hub-namespace }}/${{ steps.vars.outputs.versions-tag }}
           docker tag docker.io/${{ steps.vars.outputs.docker-hub-namespace }}/${{ steps.vars.outputs.candidate-tag }} docker.io/${{ steps.vars.outputs.docker-hub-namespace }}/${{ steps.vars.outputs.latest-tag }}