diff --git a/roles/run-tempest-26/tasks/main.yaml b/roles/run-tempest-26/tasks/main.yaml
index 7423bfb..7ad5c99 100644
--- a/roles/run-tempest-26/tasks/main.yaml
+++ b/roles/run-tempest-26/tasks/main.yaml
@@ -17,7 +17,7 @@
 
 - name: Limit max concurrency when more than 3 vcpus are available
   set_fact:
-    default_concurrency: "{{ num_cores|int // 2 }}"
+    default_concurrency: "{{ num_cores|int - 2 }}"
   when: num_cores|int > 3
 
 - name: Override target branch
diff --git a/roles/run-tempest/tasks/main.yaml b/roles/run-tempest/tasks/main.yaml
index 3fb494f..3d78557 100644
--- a/roles/run-tempest/tasks/main.yaml
+++ b/roles/run-tempest/tasks/main.yaml
@@ -17,7 +17,7 @@
 
 - name: Limit max concurrency when more than 3 vcpus are available
   set_fact:
-    default_concurrency: "{{ num_cores|int // 2 }}"
+    default_concurrency: "{{ num_cores|int - 2 }}"
   when: num_cores|int > 3
 
 - name: Override target branch
diff --git a/tempest/scenario/test_network_basic_ops.py b/tempest/scenario/test_network_basic_ops.py
index cbe4122..7b819e0 100644
--- a/tempest/scenario/test_network_basic_ops.py
+++ b/tempest/scenario/test_network_basic_ops.py
@@ -898,10 +898,13 @@
                                        nic=spoof_nic, should_succeed=True)
         # Set a mac address by making nic down temporary
         spoof_ip_addresses = ssh_client.get_nic_ip_addresses(spoof_nic)
-        cmd = ("sudo ip link set {nic} down;"
+        dhcp_cmd = ("sudo start-stop-daemon -K -x /sbin/dhcpcd -p "
+                    "/var/run/dhcpcd/pid -o || true")
+        cmd = ("{dhcp_cmd}; sudo ip link set {nic} down;"
                "sudo ip link set dev {nic} address {mac};"
                "sudo ip link set {nic} up;"
                "sudo ip address flush dev {nic};").format(nic=spoof_nic,
+                                                          dhcp_cmd=dhcp_cmd,
                                                           mac=spoof_mac)
         for ip_address in spoof_ip_addresses:
             cmd += (