ci: run one job at a time
diff --git a/.github/workflows/ceph.yml b/.github/workflows/ceph.yml
index 93f7b64..ea5638c 100644
--- a/.github/workflows/ceph.yml
+++ b/.github/workflows/ceph.yml
@@ -37,6 +37,9 @@
         network_backend:
           - openvswitch
           - ovn
+    concurrency:
+      group: ${{ github.ref }}-${{ matrix.network_backend }}
+      cancel-in-progress: true
     steps:
       - name: Checkout project
         uses: actions/checkout@v3
@@ -81,6 +84,9 @@
         network_backend:
           - openvswitch
           - ovn
+    concurrency:
+      group: ${{ github.ref }}-${{ matrix.network_backend }}
+      cancel-in-progress: true
     steps:
       - name: Checkout project
         uses: actions/checkout@v3