Extend linux stress to support multivm with multi stress tools

Existing linux stress was supporting single vm with single stress
tool. This commit extends that testcase to now support multiple
guests running same/different stress tools inside for given duration
Signed-off-by: NSrikanth Aithal <sraithal@linux.vnet.ibm.com>

generic/tests/cfg/linux_stress.cfg

 - linux_stress:
     only Linux
     type = linux_stress
+    stress_shell_timeout = 1200
+    stress_wait_for_timeout = 60
+    stress_duration = 10
+    variants:
+        - @default:
             stress_duration = 60
-    # Please specify below params for stress test, or use default value as shown
-    # download_url = http://people.seas.harvard.edu/~apw/stress/stress-1.0.4.tar.gz
+        - stressapptest:
+            #all vms in this variant will run stressapptest
+            stress_type = "stressapptest"
+            stress_cmds_stressapptest = "stressapptest"
+            make_cmds_stressapptest = "./configure && make && make install"
+            uninstall_cmds_stressapptest = "./configure && make && make uninstall"
+            download_url_stressapptest = "https://github.com/stressapptest/stressapptest.git"
+            download_type_stressapptest = "git"
+            stressapptest_args = "-s 100 -M 256 -m 8 -W"
+        - stress-ng:
+            #all vms in this variant will run default stress apart from vm2 which runs stress-ng
+            stress_type_vm2 = "stress-ng"
+            stress_cmds_stress-ng_vm2 = "stress-ng"
+            make_cmds_stress-ng_vm2 = "rm -rf /usr/bin/stress-ng && make && cp stress-ng /usr/bin && rm -rf /tmp/stress-*"
+            uninstall_cmds_stress-ng_vm2 = "rm -rf /usr/bin/stress-ng && make clean"
+            download_url_stress-ng_vm2 = "https://github.com/ColinIanKing/stress-ng.git"
+            download_type_stress-ng = "git"
+            stress-ng_args_vm2 = "--timer 32 --timer-freq 1000000"

generic/tests/linux_stress.py

 import time
+import logging
+
+from avocado.core import exceptions
 
 from virttest import utils_test
 
@@ -19,19 +22,47 @@ def run(test, params, env):
     :param env: Dictionary with test environment
     """
 
-    vm = env.get_vm(params['main_vm'])
-    vm.verify_alive()
-    stress = utils_test.VMStress(vm, 'stress', params)
-    stress.load_stress_tool()
-    stress_duration = int(params.get('stress_duration', 0))
+    stress_duration = int(params.get("stress_duration", "0"))
     # NOTE: stress_duration = 0 ONLY for some legacy test cases using
     # autotest stress.control as their sub test.
     # Please DO define stress_duration to make sure the clean action
     # being performed, if your case can not be controlled by time,
     # use utils_test.VMStress() directly
+    stress_type = params.get("stress_type", "stress")
+    vms = env.get_all_vms()
+    up_time = {}
+    error = False
+    stress_server = {}
+
+    for vm in vms:
+        try:
+            up_time[vm.name] = vm.uptime()
+            stress_server[vm.name] = utils_test.VMStress(vm, stress_type, params)
+            stress_server[vm.name].load_stress_tool()
+        except exceptions.TestError as err_msg:
+            error = True
+            logging.error(err_msg)
 
     if stress_duration:
         time.sleep(stress_duration)
-        stress.unload_stress()
-        stress.clean()
-        vm.verify_kernel_crash()
+
+    for vm in vms:
+        try:
+            s_ping, o_ping = utils_test.ping(vm.get_address(), count=5, timeout=20)
+            if s_ping != 0:
+                error = True
+                logging.error("%s seem to have gone out of network", vm.name)
+                continue
+            uptime = vm.uptime()
+            if up_time[vm.name] > uptime:
+                error = True
+                logging.error("%s seem to have rebooted during the stress run", vm.name)
+            stress_server[vm.name].unload_stress()
+            stress_server[vm.name].clean()
+            vm.verify_dmesg()
+        except exceptions.TestError as err_msg:
+            error = True
+            logging.error(err_msg)
+
+    if error:
+        test.fail("Run failed: see error messages above")