tests/limit - Add a test verifying we can reach the new VIF limit of 16

Currently the test verifies that interfaces have been created correctly
(that there were enough grant frames to allocate all the queues), and
simply prints performance metrics. This should be integrated with
whatever database we are going to use for performance monitoring in the
future.

Signed-off-by: Andrii Sultanov <[email protected]>

Author: last-genius

tests/limits/__init__.py

@@ -0,0 +1,93 @@
+from pkgfixtures import host_with_saved_yum_state
+import ipaddress
+import logging
+import os
+import pytest
+import tempfile
+
+# Requirements:
+# - one XCP-ng host (--host) >= 8.2
+# - a VM (--vm)
+# - the first network on the host can be used to reach the host
+
+vif_limit = 16
+interface_name = "enX"
+vcpus = '8'
+
+# There is a ResourceWarning due to background=True on an ssh call
+# We do ensure the processes are killed
+@pytest.mark.filterwarnings("ignore::ResourceWarning")
+@pytest.mark.debian_uefi_vm
+class TestVIFLimit:
+    def test_vif_limit(self, host_with_saved_yum_state, imported_vm):
+        host = host_with_saved_yum_state
+        vm = imported_vm
+        if (vm.is_running()):
+            logging.info("VM already running, shutting it down first")
+            vm.shutdown(verify=True)
+
+        network_uuid = vm.vifs()[0].param_get('network-uuid')
+        existing_vifs = len(vm.vifs())
+
+        logging.info(f'Get {vcpus} vCPUs for the VM')
+        vm.param_set('VCPUs-max', vcpus)
+        vm.param_set('VCPUs-at-startup', vcpus)
+
+        logging.info('Create VIFs before starting the VM')
+        for i in range(existing_vifs, vif_limit):
+            vm.create_vif(i, network_uuid=network_uuid)
+
+        vm.start()
+        vm.wait_for_os_booted()
+
+        logging.info('Verify the interfaces exist in the guest')
+        for i in range(0, vif_limit):
+            if vm.ssh_with_result([f'test -d /sys/class/net/{interface_name}{i}']).returncode != 0:
+                guest_error = vm.ssh_with_result(['dmesg | grep -B1 -A3 xen_netfront']).stdout
+                logging.error("dmesg:\n%s", guest_error)
+                assert False, "The interface does not exist in the guest, check dmesg output above for errors"
+
+        logging.info('Configure interfaces')
+        config = '\n'.join([f'iface {interface_name}{i} inet dhcp\n'
+                            f'auto {interface_name}{i}'
+                            for i in range(existing_vifs, vif_limit)])
+        vm.ssh([f'echo "{config}" >> /etc/network/interfaces'])
+
+        logging.info('Install iperf3 on VM and host')
+        if vm.ssh_with_result(['apt install iperf3 --assume-yes']).returncode != 0:
+            assert False, "Failed to install iperf3 on the VM"
+        host.yum_install(['iperf3'])
+
+        logging.info('Reconfigure VM networking')
+        if vm.ssh_with_result(['systemctl restart networking']).returncode != 0:
+            assert False, "Failed to configure networking"
+
+        # Test iperf on all interfaces in parallel
+        # Clean up on exceptions
+        try:
+            logging.info('Create separate iperf servers on the host')
+            with tempfile.NamedTemporaryFile('w') as host_script:
+                iperf_configs = [f'iperf3 -s -p {5100+i} &'
+                                 for i in range(0, vif_limit)]
+                host_script.write('\n'.join(iperf_configs))
+                host_script.flush()
+                host.scp(host_script.name, host_script.name)
+                host.ssh([f'nohup bash -c "bash {host_script.name}" < /dev/null &>/dev/null &'],
+                         background=True)
+
+            logging.info('Start multiple iperfs on separate interfaces on the VM')
+            with tempfile.NamedTemporaryFile('w') as vm_script:
+                iperf_configs = [f'iperf3 --no-delay -c {host.hostname_or_ip} '
+                                 f'-p {5100+i} --bind-dev {interface_name}{i} '
+                                 f'--interval 0 --parallel 1 --time 30 &'
+                                 for i in range(0, vif_limit)]
+                vm_script.write('\n'.join(iperf_configs))
+                vm_script.flush()
+                vm.scp(vm_script.name, vm_script.name)
+                stdout = vm.ssh([f'bash {vm_script.name}'])
+
+            # TODO: log this into some performance time series DB
+            logging.info(stdout)
+        finally:
+            vm.ssh(['pkill iperf3 || true'])
+            host.ssh('killall iperf3')