def test_check_timedrift_stress(self):
        '''
        :avocado: tags=test_check_timedrift_stress
        After 120 seconds stress test, if the average drift time over 1
        seconds, we are considering it as fail.
        polarion_id: RHEL7-110673
        '''
        utils_lib.run_cmd(self,
                          r"sudo cat /etc/redhat-release",
                          expect_ret=0,
                          cancel_kw="release 7,release 6",
                          msg="Only run in RHEL7 and RHEL6")

        utils_lib.run_cmd(self, "sudo systemctl stop ntpd")
        utils_lib.run_cmd(self, "sudo systemctl disable ntpd")
        utils_lib.run_cmd(self, "sudo systemctl stop chronyd")
        utils_lib.run_cmd(self, "sudo systemctl disable chronyd")
        utils_lib.run_cmd(self, "sudo timedatectl set-ntp 0")
        offset1 = aws.get_drift(self)
        stress_url = self.params.get('stress_url')
        aws.install_pkgs(self.session, stress_url)
        cpu_count = utils_lib.run_cmd(
            self, 'cat /proc/cpuinfo |grep -i "model name"|wc -l')
        utils_lib.run_cmd(self, "stress -c %s -t 120" % cpu_count, timeout=160)
        offset2 = aws.get_drift(self)

        x = decimal.Decimal(offset2) - decimal.Decimal(offset1)
        drift = math.fabs(x) * 10
        self.assertLess(drift, 10, msg="Drift is over 1 seconds")
        self.log.info("Average drift is less than 1 seconfs. %d/10" % drift)
    def test_check_timedrift_reboot(self):
        '''
        :avocado: tags=test_check_timedrift_reboot
        After 3 times reboot, if the average drift time over 1 seconds,
        we are considering it as fail.
        polarion_id: RHEL7-110672
        '''
        utils_lib.run_cmd(self,
                          "sudo cat /etc/redhat-release",
                          expect_ret=0,
                          cancel_kw="release 7,release 6",
                          msg="Only run in RHEL7 and RHEL6")
        utils_lib.run_cmd(self, "sudo systemctl stop ntpd")
        utils_lib.run_cmd(self, "sudo systemctl disable ntpd")
        utils_lib.run_cmd(self, "sudo systemctl stop chronyd")
        utils_lib.run_cmd(self, "sudo systemctl disable chronyd")
        utils_lib.run_cmd(self, "sudo timedatectl set-ntp 0")

        offset1 = aws.get_drift(self)
        self.vm.reboot()
        self.session.connect(timeout=self.ssh_wait_timeout)
        offset2 = aws.get_drift(self)
        self.vm.reboot()
        self.session.connect(timeout=self.ssh_wait_timeout)
        offset3 = aws.get_drift(self)
        self.vm.reboot()
        self.session.connect(timeout=self.ssh_wait_timeout)
        offset4 = aws.get_drift(self)
        x = decimal.Decimal(offset2) - decimal.Decimal(offset1)
        y = decimal.Decimal(offset3) - decimal.Decimal(offset1)
        z = decimal.Decimal(offset4) - decimal.Decimal(offset1)
        drift = math.fabs(x) * 10 + math.fabs(y) * 10 + math.fabs(z) * 10
        self.assertLess(drift, 30, msg="Drift is over 1 seconds")
        self.log.info("Average drift is less than 1 seconds. %d/30" % drift)