diff --git a/.github/workflows/nix_integration_tests.yaml b/.github/workflows/nix_integration_tests.yaml
index e480ba62..b73fd9d2 100644
--- a/.github/workflows/nix_integration_tests.yaml
+++ b/.github/workflows/nix_integration_tests.yaml
@@ -21,6 +21,10 @@ jobs:
     steps:
     - uses: actions/checkout@v4
     - uses: cachix/install-nix-action@v27
+    - name: Setup nix to mounted disk
+      run: |
+        sudo mkdir -p /mnt/hf_cache/nix/
+        sudo ln -s /mnt/hf_cache/nix /nix
     - uses: cachix/cachix-action@v14
       with:
         name: text-generation-inference
diff --git a/integration-tests/conftest.py b/integration-tests/conftest.py
index bcc4342c..c1c992ab 100644
--- a/integration-tests/conftest.py
+++ b/integration-tests/conftest.py
@@ -370,11 +370,7 @@ def launcher(event_loop):
         if num_shard is not None:
             args.extend(["--num-shard", str(num_shard)])
         else:
-            try:
-                os.environ["WORLD_SIZE"] = 1
-                del os.environ["NUM_SHARD"]
-            except Exception:
-                pass
+            args.extend(["--sharded", "false"])
         if quantize is not None:
             args.append("--quantize")
             args.append(quantize)
@@ -457,11 +453,7 @@ def launcher(event_loop):
         if num_shard is not None:
             args.extend(["--num-shard", str(num_shard)])
         else:
-            try:
-                os.environ["WORLD_SIZE"] = 1
-                del os.environ["NUM_SHARD"]
-            except Exception:
-                pass
+            args.extend(["--sharded", "false"])
         if quantize is not None:
             args.append("--quantize")
             args.append(quantize)