diff --git a/ci/docker/ubuntu-20.04-cpp.dockerfile b/ci/docker/ubuntu-20.04-cpp.dockerfile
index 022fc3ee22c..c75c013799a 100644
--- a/ci/docker/ubuntu-20.04-cpp.dockerfile
+++ b/ci/docker/ubuntu-20.04-cpp.dockerfile
@@ -129,8 +129,10 @@ ENV ARROW_BUILD_TESTS=ON \
     ARROW_WITH_ZSTD=ON \
     AWSSDK_SOURCE=BUNDLED \
     GTest_SOURCE=BUNDLED \
+    gRPC_SOURCE=BUNDLED \
     ORC_SOURCE=BUNDLED \
     PARQUET_BUILD_EXAMPLES=ON \
     PARQUET_BUILD_EXECUTABLES=ON \
     PATH=/usr/lib/ccache/:$PATH \
+    Protobuf_SOURCE=BUNDLED \
     PYTHON=python3
diff --git a/dev/tasks/tasks.yml b/dev/tasks/tasks.yml
index ca21496b913..23ff18d6dec 100644
--- a/dev/tasks/tasks.yml
+++ b/dev/tasks/tasks.yml
@@ -949,6 +949,12 @@ tasks:
         UBUNTU: "20.10"
       run: ubuntu-docs
 
+  test-ubuntu-default-docs:
+    ci: azure
+    template: docker-tests/azure.linux.yml
+    params:
+      run: ubuntu-docs
+
   ############################## vcpkg tests ##################################
 
   test-build-vcpkg-win: