Uptime - OS Test

In most virtualized environments, it is essential to monitor the uptime of VMs hosting critical server applications in the infrastructure. By tracking the uptime of each of the VMs, administrators can determine what percentage of time a VM has been up. Comparing this value with service level targets, administrators can determine the most trouble-prone areas of the virtualized infrastructure.

In some environments, administrators may schedule periodic reboots of their VM. By knowing that a specific VM has been up for an unusually long time, an administrator may come to know that the scheduled reboot task is not working on a VM.

This test included in the eG agent monitors the uptime of each VM on a Citrix Hypervisor host.

Target of the test : A Citrix Hypervisor host

Agent deploying the test : An internal/remote agent

Outputs of the test : One set of results for every guest on the target hypervisor being monitored

Configurable parameters for the test
Parameter	Description
Test period	How often should the test be executed.
Host	The host for which the test is to be configured.
Port	The port at which the specified host listens. By default, this is NULL.
Xen User, Xen Password and Confirm Password	To enable the eG agent to connect to the XenServer API for collecting statistics of interest, this test should login to the target hypervisor as a root user. Provide the name of the root user in the Xen User text box. Root user privileges are mandatory when monitoring a XenServer 5.5 (or below). However, if you are monitoring XenServer 5.6 (or above) and you prefer not to expose the credentials of the root user, then, you have the option of configuring a user with pool-admin privileges as the Xen User. If you do not want to expose the credentials of a root/pool-admin user, then you can configure the tests with the credentials of a Xen User with Read-only privileges to the XenServer. However, if this is done, then the Xen Uptime test will not run, and the Xen CPU and Xen Memory tests will not be able to report metrics for the control domain descriptor. To avoid such an outcome, do the following before attempting to configure the eG tests with a Xen User who has Read-only privileges to the Citrix Hypervisor: Modify the target hypervisor's configuration in the eG Enterprise. For this, follow the Infrastructure -> Components -> Add/Modify menu sequence, pick Citrix Hypervisor as the Component type, and click the Modify button corresponding to the target hypervisor. In the MODIFY COMPONENT DETAILS page that then appears, make sure that the os is set to Xen and the Mode is set to SSH. Then, in the same page, proceed to provide the User and Password of a user who has the right to connect to the XenServer console via SSH. Then, click the Update button to save the changes. Once this is done, you can configure the eG tests with the credentials of a Xen User with Read-only privileges. The password of the specified Xen User needs to be mentioned in the Xen Password text box. Then, confirm the Xen Password by retyping it in the Confirm Password text box.
SSL	By default, the Citrix Hypervisor is not SSL-enabled. This indicates that by default, the eG agent communicates with the target hypervisor using HTTP. Accordingly, the SSL flag is set to No by default. If you configure the target hypervisor to use SSL, then make sure that the SSL flag is set to Yes, so that the eG agent communicates with the target hypervisor using HTTPS. Note that a default SSL certificate comes bundled with every Citrix Hypervisor installation. If you want the eG agent to use this default certificate for communicating with an SSL-enabled Citrix Hypervisor, then no additional configuration is required. However, if you do not want to use the default certificate, then you can generate a self-signed certificate for use by the target hypervisor. In such a case, you need to explicitly follow the broad steps given below to enable the eG agent to communicate with the target hypervisor via HTTPS: Obtain the server-certificate for the Citrix Hypervisor Import the server-certificate into the local certificate store of the eG agent For a detailed discussion on each of these steps, refer to the Troubleshooting section of this document.
Inside View Using	By default, this test obtains the “inside view” of VMs using the eG VM Agent. Accordingly, the Inside view using flag is set to eG VM Agent by default. The eG VM Agent is a piece of software, which should be installed on every VM on a hypervisor. Every time the eG agent runs this test, it uses the eG VM Agent to pull relevant 'inside view' metrics from each VM. Once the metrics are collected, the eG agent then communicates with each VM agent and pulls these metrics, without requiring administrator privileges. Refer to Configuring the Remote Agent to Obtain the Inside View of VMs for more details on the eG VM Agent.
Domain, Admin User, and Admin Password, and Confirm Password	By default, these parameters are set to none. This is because, by default, the eG agent collects 'inside view' metrics using the eG VM agent on each VM. Domain administrator privileges need not be granted to the eG agent if it uses this default approach to obtain the 'inside view' of Windows VMs.
Ignore VMs Inside View	Administrators of some high security XenServer environments might not have permissions to internally monitor one/more VMs. The eG agent can be configured to not obtain the 'inside view' of such ‘inaccessible’ VMs using the IGNORE VMS INSIDE VIEW parameter. Against this parameter, you can provide a comma-separated list of VM names, or VM name patterns, for which the inside view need not be obtained. For instance, your IGNORE VMS INSIDE VIEW specification can be: xp,lin,win,vista. Here, the * (asterisk) is used to denote leading and trailing spaces (as the case may be). By default, this parameter is set to none indicating that the eG agent obtains the inside view of all VMs on a Citrix Hypervisor host by default. Note: While performing VM discovery, the eG agent will not discover the operating system of the VMs configured in the IGNORE VMS INSIDE VIEW text box.
Exclude VMs	Administrators of some virtualized environments may not want to monitor some of their less-critical VMs - for instance, VM templates - both from 'outside' and from 'inside'. The eG agent in this case can be configured to completely exclude such VMs from its monitoring purview. To achieve this, provide a comma-separated list of VMs to be excluded from monitoring in the EXCLUDE VMS text box. Instead of VMs, VM name patterns can also be provided here in a comma-separated list. For example, your EXCLUDE VMS specification can be: xp,lin,win,vista. Here, the * (asterisk) is used to denote leading and trailing spaces (as the case may be). By default, this parameter is set to none indicating that the eG agent obtains the inside and outside views of all VMs on a virtual host by default. By providing a comma-separated list of VMs/VM name patterns in the EXCLUDE VMS text box, you can make sure the eG agent stops collecting 'inside' and 'outside' view metrics for a configured set of VMs.
Ignore Winnt	By default, the eG agent does not support the inside view for VMs executing on Windows NT operating systems. Accordingly, the IGNORE WINNT flag is set to Yes by default.
Webport	By default, in most virtualized environments, the target hypervisor listens on port 80 (if not SSL-enabled) or on port 443 (if SSL-enabled). This implies that while monitoring an SSL-enabled Citrix hypervisor, the eG agent, by default, connects to port 443 of the server to pull out metrics, and while monitoring a non-SSL-enabled Citrix hypervisor, the eG agent connects to port 80. Accordingly, the webport parameter is set to 80 or 443 depending upon the status of the ssl flag. In some environments however, the default ports 80 or 443 might not apply. In such a case, against the webport parameter, you can specify the exact port at which the target hypervisor in your environment listens so that the eG agent communicates with that port.
Report by User	While monitoring a Citrix hypervisor, the REPORT BY USER flag is set to No by default, indicating that by default, the guest operating systems on the target hypervisor are identified using the host name specified in the operating system. On the other hand, while monitoring a Citrix hypervisor-VDI, this flag is set to Yes by default; this implies that in case of the Citrix hypervisor-VDI model, by default, the desktops will be identified using the login of the user who is accessing them. In other words, in VDI environments, this test will, by default, report measures for every username_on_virtualmachinename.
Report Powered OS	This flag becomes relevant only if the report by user flag is set to ‘Yes’. If the report powered os flag is set to Yes (which is the default setting), then this test will report measures for even those VMs that do not have any users logged in currently. Such guests will be identified by their virtualmachine name and not by the username_on_virtualmachinename. On the other hand, if the report powered os flag is set to No, then this test will not report measures for those VMs to which no users are logged in currently.
Report Manager Time	By default, this flag is set to Yes, indicating that, by default, the detailed diagnosis of this test, if enabled, will report the shutdown and reboot times of the VMs in the manager’s time zone. If this flag is set to No, then the shutdown and reboot times are shown in the time zone of the system where the agent is running (i.e., the system being managed for agent-based monitoring, and the system on which the remote agent is running - for agentless monitoring).
Detailed Diagnosis	To make diagnosis more efficient and accurate, the eG suite embeds an optional detailed diagnostic capability. With this capability, the eG agents can be configured to run detailed, more elaborate tests as and when specific problems are detected. To enable the detailed diagnosis capability of this test for a particular server, choose the On option. To disable the capability, click on the Off option. The option to selectively enable/disable the detailed diagnosis capability will be available only if the following conditions are fulfilled: The eG manager license should allow the detailed diagnosis capability Both the normal and abnormal frequencies configured for the detailed diagnosis measures should not be 0.

Measurements made by the test

Measurement	Description	Measurement Unit	Interpretation
Has the VM been rebooted?:	Indicates whether the VM has been rebooted during the last measurement period or not.	Boolean	If this measure shows 1, it means that the guest was rebooted during the last measurement period. By checking the time periods when this metric changes from 0 to 1, an administrator can determine the times when this guest was rebooted.
Uptime of VM during the last measure period:	Indicates the time period that the VM has been up since the last time this test ran.	Secs	If the guest has not been rebooted during the last measurement period and the agent has been running continuously, this value will be equal to the measurement period. If the guest was rebooted during the last measurement period, this value will be less than the measurement period of the test. For example, if the measurement period is 300 secs, and if the guest was rebooted 120 secs back, this metric will report a value of 120 seconds. The accuracy of this metric is dependent on the measurement period - the smaller the measurement period, greater the accuracy.
Total uptime of the VM:	Indicates the total time that the VM has been up since its last reboot.	Mins	Administrators may wish to be alerted if a guest has been running without a reboot for a very long period. Setting a threshold for this metric allows administrators to determine such conditions.

Measurement

Description

Measurement Unit

Interpretation

Has the VM been rebooted?:

Indicates whether the VM has been rebooted during the last measurement period or not.

Boolean

If this measure shows 1, it means that the guest was rebooted during the last measurement period. By checking the time periods when this metric changes from 0 to 1, an administrator can determine the times when this guest was rebooted.

Uptime of VM during the last measure period:

Indicates the time period that the VM has been up since the last time this test ran.

Secs

If the guest has not been rebooted during the last measurement period and the agent has been running continuously, this value will be equal to the measurement period. If the guest was rebooted during the last measurement period, this value will be less than the measurement period of the test. For example, if the measurement period is 300 secs, and if the guest was rebooted 120 secs back, this metric will report a value of 120 seconds. The accuracy of this metric is dependent on the measurement period - the smaller the measurement period, greater the accuracy.

Total uptime of the VM:

Indicates the total time that the VM has been up since its last reboot.

Mins

Administrators may wish to be alerted if a guest has been running without a reboot for a very long period. Setting a threshold for this metric allows administrators to determine such conditions.

Note:

If a value less than a minute is configured as the test period of the Uptime - VM test, then, the Uptime during the last measure period measure will report the value 0 for Unix VMs (only) until the minute boundary is crossed. For instance, if you configure the Uptime - VM test to run every 10 seconds, then, for the first 5 test execution cyles (i.e., 10 x 5 = 50 seconds), the Uptime during the last measure period measure will report the value 0 for Unix VMs; however, the sixth time the test executes (i.e, when test execution touches the 1 minute boundary), this measure will report the value 60 seconds for the same VMs. Thereafter, every sixth measurement period will report 60 seconds as the uptime of the Unix VMs. This is because, Unix-based operating systems report uptime only in minutes and not in seconds.
For VMs running Windows 8 (or above), the Uptime - VM test may sometimes report incorrect values. This is because of the 'Fast Startup' feature, which is enabled by default for Windows 8 (and above) operating systems. This feature ensures that the Windows operating system is NOT SHUTDOWN COMPLETELY, when the VM is shutdown. Instead, the operating system saves the image of the Windows kernel and loaded drivers to the file, C:\hiberfil.sys, upon shutdown. When the Windows VM is later started, the operating system simply loads hiberfil.sys into memory to resume operations, instead of performing a clean start. Because of this, the Windows system will not record this event as an actual 'reboot'. As a result, the Uptime - VM test will not be able to correctly report if any reboot happened recently ; neither will it be able to accurately compute the time since the last reboot.

To avoid this, you need to disable the Fast Startup feature on VMs running Windows 8 (and above). The steps to achieve this are outlined below:
1. Login to the target Windows VM.
2. Edit the Windows Registry. Look for the following registry entry:
  
  HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Power
3. Locate the HiberbootEnabled key under the entry mentioned above.
4. Change the value of this key to 0 to turn off Fast Startup. By default, its value will be 1, as Fast Startup is enabled by default.
  
  Also, note that the Fast Startup feature does not work if the VM is “restarted”; it works only when the VM is shutdown and then started.