Setup galera slaves one by one instead of parallel

Closes-Bug:#PROD-18441

Change-Id: I183ea5f9d0de8016a164139b13eb301ad6e5f142
diff --git a/tcp_tests/templates/virtual-mcp-pike-dvr-ceph-rgw/common-services.yaml b/tcp_tests/templates/virtual-mcp-pike-dvr-ceph-rgw/common-services.yaml
index 72f2c9d..4017f70 100644
--- a/tcp_tests/templates/virtual-mcp-pike-dvr-ceph-rgw/common-services.yaml
+++ b/tcp_tests/templates/virtual-mcp-pike-dvr-ceph-rgw/common-services.yaml
@@ -76,7 +76,7 @@
 
 - description: Install Galera on other servers
   cmd: salt --hard-crash --state-output=mixed --state-verbose=False
-    -C 'I@galera:slave' state.sls galera
+    -C 'I@galera:slave' state.sls galera -b 1
   node_name: {{ HOSTNAME_CFG01 }}
   retry: {count: 1, delay: 5}
   skip_fail: false