dind ?

.gitea/workflows/ci.yaml

@@ -14,6 +14,12 @@ env:
 jobs:
   build-base-builder:
     runs-on: ubuntu-latest
+    services:
+      docker:
+        image: docker:dind
+        options: --privileged --shm-size=2g
+        volumes:
+          - /var/run/docker.sock:/var/run/docker.sock:ro
     timeout-minutes: 360
 
     steps:
@@ -44,6 +50,12 @@ jobs:
 
   build-cpp-builder:
     runs-on: ubuntu-latest
+    services:
+      docker:
+        image: docker:dind
+        options: --privileged --shm-size=2g
+        volumes:
+          - /var/run/docker.sock:/var/run/docker.sock:ro
     timeout-minutes: 360
     needs: build-base-builder