diff --git a/.forgejo/actions/build-push-image/action.yaml b/.forgejo/actions/build-push-image/action.yaml
index 93b2c11..4060b2e 100644
--- a/.forgejo/actions/build-push-image/action.yaml
+++ b/.forgejo/actions/build-push-image/action.yaml
@@ -30,7 +30,7 @@ runs:
       shell: bash
       run: |
         echo "Building ${{ inputs.image_name }}:${{ inputs.version }}"
-        docker build \
+        docker buildx build \
           --tag ${{ inputs.image_name }}:${{ inputs.version }} \
           --file ${{ inputs.context }}/${{ inputs.dockerfile }} \
           ${{ inputs.context }}
diff --git a/containers/nettest/Dockerfile b/containers/nettest/Dockerfile
index 30ae27c..1e18861 100644
--- a/containers/nettest/Dockerfile
+++ b/containers/nettest/Dockerfile
@@ -3,12 +3,6 @@
 # This container tests connectivity to tailnet services from various environments:
 # - Docker on indri (during CI build)
 # - Minikube pods (manual testing)
-#
-# Build:
-#   docker build -t registry.ops.eblu.me/blumeops/nettest:latest .
-#
-# Run:
-#   docker run --rm registry.ops.eblu.me/blumeops/nettest:latest
 
 FROM alpine:3.21
 
diff --git a/docs/changelog.d/fix-docker-buildx.infra.md b/docs/changelog.d/fix-docker-buildx.infra.md
new file mode 100644
index 0000000..a44eeee
--- /dev/null
+++ b/docs/changelog.d/fix-docker-buildx.infra.md
@@ -0,0 +1 @@
+Switch CI container builds from deprecated `docker build` to `docker buildx build` (BuildKit).