Uptime – Xen Test

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

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

The Uptime - Xen test included in the eG agent monitors the uptime of critical Citrix Hypervisors in a virtualized infrastructure.

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 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.
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 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 XenServer host 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.

Measurement	Description	Measurement Unit	Interpretation
Has the Xen server been rebooted?	Indicates whether the server has been rebooted during the last measurement period or not.	Boolean	If this measure shows 1, it means that the server 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 server was rebooted. The detailed diagnosis of this measure, if enabled, will provide you with the details of the last reboot of the XenServer. Such details will include the shutdown date/time, reboot date/time, the shutdown duration (in minutes), and whether the host has been configured for maintenance or not.
Uptime of the Xen server during the last measure period:	Indicates the time period that the system has been up since the last time this test ran.	Secs	If the server 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 server 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 server 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 Xen server:	Indicates the total time that the server has been up since its last reboot.	Mins	Administrators may wish to be alerted if a server 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 Xen server been rebooted?

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

Boolean

If this measure shows 1, it means that the server 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 server was rebooted.

The detailed diagnosis of this measure, if enabled, will provide you with the details of the last reboot of the XenServer. Such details will include the shutdown date/time, reboot date/time, the shutdown duration (in minutes), and whether the host has been configured for maintenance or not.

Uptime of the Xen server during the last measure period:

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

Secs

If the server 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 server 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 server 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 Xen server:

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

Mins

Administrators may wish to be alerted if a server 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 XenUptime test, then, the Uptime during the last measure period measure will report the value 0 until the minute boundary is crossed. For instance, if you configure the XenUptime test host 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 only; 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. This way, every sixth measurement period will report 60 seconds as the uptime of the host. This is because, the XenServer reports uptime only in minutes and not in seconds.