VM Details – Xen Test

This test monitors the amount of the physical server's resources that each guest on an XenServer is taking up. Using the metrics reported by this test, administrators can determine which virtual guest is taking up most CPU, which guest is generating the most network traffic, which guest is taking up the maximum memory utilization, which guest has the maximum disk activity, etc. Note that the amount of resources taken up by a virtual guest will be limited by the resource allocations that have been made by administrators. For example, an administrator could cap the amount of memory that a specific guest may take. Also, virtual guests can be organized into resource pools, and allocation of resources can be made at the resource-pool level. In this case, virtual guests allocated to the same resource pool contend for the resources allocated to the resource pool.

Target of the test : A XenServer host

Agent deploying the test : An internal/remote agent

Outputs of the test : One set of results for each guest configured on the XenServer host

Configurable parameters for the test
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 - To enable the eG agent to connect to the XenServer API for collecting statistics of interest, this test should login to the XenServer 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 XenServer: Modify the target XenServer’s configuration in the eG Enterprise system. For this, follow the Infrastructure -> Components -> Add/Modify menu sequence, pick Citrix XenServer as the Component type, and click the Modify button corresponding to the target XenServer. 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. xen password - The password of the specified xen user needs to be mentioned here. confirm password - Confirm the xen password by retyping it here. ssl - By default, the Xen Server is not SSL-enabled. This indicates that by default, the eG agent communicates with the XenServer using HTTP. Accordingly, the ssl flag is set to No by default. If you configure the XenServer to use SSL, then make sure that the SSL flag is set to Yes, so that the eG agent communicates with the XenServer using HTTPS. Note that a default SSL certificate comes bundled with every XenServer installation. If you want the eG agent to use this default certificate for communicating with an SSL-enabled XenServer, 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 XenServer. In such a case, you need to explicitly follow the broad steps given below to enable the eG agent to communicate with the XenServer via HTTPS: Obtain the server-certificate for the XenServer 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 communicates with every VM remotely and extracts “inside view” metrics. Therefore, by default, the INSIDE VIEW USING flag is set to Remote connection to VM (Windows). Typically, to establish this remote connection with Windows VMs in particular, eG Enterprise requires that the eG agent be configured with domain administrator privileges. In high-security environments, where the IT staff might have reservations about exposing the credentials of their domain administrators, this approach to extracting “inside view” metrics might not be preferred. In such environments therefore, eG Enterprise provides administrators the option to deploy a piece of software called the eG VM Agent on every Windows VM; this VM agent allows the eG agent to collect “inside view” metrics from the Windows VMs without domain administrator rights. Refer to Configuring Windows Virtual Machines to Support the eG Agent’s Inside View Using the eG VM Agent for more details on the eG VM Agent. To ensure that the “inside view” of Windows VMs is obtained using the eG VM Agent, set the INSIDE VIEW USING flag to eG VM Agent (Windows). Once this is done, you can set the DOMAIN, ADMIN USER, and ADMIN PASSWORD parameters to none. DOMAIN, ADMIN USER, ADMIN PASSWORD, and CONFIRM PASSWORD - By default, this test connects to each virtual guest remotely and attempts to collect “inside view” metrics. In order to obtain a remote connection, the test must be configured with user privileges that allow remote communication with the virtual guests. The first step towards this is to specify the DOMAIN within which the virtual guests reside. The ADMIN USER and ADMIN PASSWORD will change according to the DOMAIN specification. Discussed below are the different values that the DOMAIN parameter can take, and how they impact the ADMIN USER and ADMIN PASSWORD specifications: If the VMs belong to a single domain : If the guests belong to a specific domain, then specify the name of that domain against the DOMAIN parameter. In this case, any administrative user in that domain will have remote access to all the virtual guests. Therefore, an administrator account in the given domain can be provided in the ADMIN USER field and the corresponding password in the ADMIN PASSWORD field. Confirm the password by retyping it in the CONFIRM PASSWORD text box. If the guests do not belong to any domain (as in the case of Linux guests) : In this case, specify "none" in the DOMAIN field, and specify a local administrator account name in the ADMIN USER below. Prior to this, you need to ensure that the same local administrator account is available or is explicitly created on each of the virtual machines to be monitored. Then, proceed to provide the password of the ADMIN USER against ADMIN PASSWORD, and confirm the password by retyping it in the CONFIRM PASSWORD text box. If key-based authentication is implemented between the eG agent and the SSH daemon of a Linux guest, then, in the ADMIN USER text box, enter the name of the user whose <USER_HOME_DIR> (on that Linux guest) contains a .ssh directory with the public key file named authorized_keys. The ADMIN PASSWORD in this case will be the passphrase of the public key; the default public key file that is bundled with the eG agent takes the password eginnovations. Specify this as the ADMIN PASSWORD if you are using the default private/public key pair that is bundled with the eG agent to implement key-based authentication. On the other hand, if you are generating a new public/private key pair for this purpose, then use the passphrase that you provide while generating the pair. For the detailed procedure on Implementing Key-based Authentication refer to Troubleshooting the Failure of the eG Remote Agent to Connect to or Report Measures for Linux Guests. If the guests belong to different domains - In this case, you might want to provide multiple domain names. If this is done, then, to access the guests in every configured domain, the test should be configured with the required user privileges; this implies that along with multiple DOMAIN names, multiple ADMIN USER names and ADMIN PASSWORDs would also have to be provided. To help administrators provide these user details quickly and easily, the eG administrative interface embeds a special configuration page. To access this page, simply click on the Click here hyperlink that appears just above the parameters of this test in the test configuration page. To know how to use the special page, refer to Configuring Users for VM Monitoring. If the INSIDE VIEW USING flag is set to ‘eG VM Agent (Windows)’ - In this case, the inside view can be obtained without domain administrator privileges. Therefore, set the domain, admin user, and admin password parameters to none. 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 XenServer 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. REPORT BY USER - While monitoring a Citrix XenServer, the REPORT BY USER flag is set to No by default, indicating that by default, the guest operating systems on the XenServer are identified using the hostname specified in the operating system. On the other hand, while monitoring a Citrix XenServer - VDI, this flag is set to Yes by default; this implies that in case of the XenServer 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 POWERED ON - You can set the REPORT POWERED ON status to Yes, so that the test reports an additional measure, Is VM powered on?, revealing whether a guest OS is currently running or not. The default status of this flag is set to Yes for a Citrix XenServer. For a Citrix XenServer – VDI component on the other hand, this flag is set to No by default. This is because, in such environments, the virtual desktops will be in the powered-off state most of the time. webport - By default, in most virtualized environments, the XenServer listens on port 80 (if not SSL-enabled) or on port 443 (if SSL-enabled). This implies that while monitoring an SSL-enabled XenServer, the eG agent, by default, connects to port 443 of the server to pull out metrics, and while monitoring a non-SSL-enabled XenServer, 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 XenServer in your environment listens so that the eG agent communicates with that port. 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

Is VM powered on? :

Whether the virtual machine is currently running on the XenServer host or no.

While the test reports a wide variety of other metrics too for virtual machines that are alive, only the powered on status is indicated for virtual machines that are currently not available.

The value Yes for this measure indicates that the guest is up and running. The value No could indicate that the guest has been powered-off; it could also indicate that XenMotion has moved the guest to a different server.

The numeric values that correspond to each of the powered-on states discussed above are listed in the table below:

State	Value
Yes	1
No	0

Note:

By default, this measure reports Yes or No to indicate VM status. The graph of this measure however, represents the status of a VM using the numeric equivalents - 0 or 1.

Physical CPU usage:

Indicates the percentage of physical CPU used by the guest.

Percent

A high value for this measure indicates a virtual machine that is using a lot of the processor - possibly because one or more processes on this VM are taking a lot of CPU.

Free physical memory:

Indicates the amount of memory available for use with the guest.

Ideally, this value should be high. A low or consistent decrease in this value denotes that the application(s) executing on the guest are consuming memory excessively. You might want to consider increasing the memory allocated to the guest. XenServer Enterprise and XenServer Standard allow that a Linux/Windows VM can use up to 32GB of memory. Moreover, Xen has implemented a balloon driver concept for each domain, enabled independently, that allows the operating system to adjust its current memory allocation up to the maximum limit configured. This allows “unused” allocation to be consumed in other areas, potentially allowing for stable over-commitment of memory resources. Because of this constantly changing memory allocation, memory is allocated and freed dynamically at a granularity of the page-level.

Total physical memory allocated:

Indicates the amount of physical memory currently allocated to the guest.

Used physical memory:

Indicates the amount of memory used by the guest.

Usage of allocated memory:

Indicates the percentage of allocated memory that is being used by the guest.

Percent

High memory consumption over long periods can deplete the free memory on the guest, causing prolonged delays in the execution of the application(s) hosted by the guests.

Disk capacity:

Indicates the total allocated disk space of the guest.

Disk read rate:

Indicates the rate at which the guest read from the disk.

Kbytes/Sec

Disk write rate:

Indicates the rate at which the guest wrote data to the disk.

Kbytes/Sec

Network data received:

Indicates the network I/O reads performed by the guest.

Mbps

Network data transmitted:

Indicates the network I/O writes performed by the guest.

Mbps

Virtual CPU utilization:

Indicates the percentage of allocated CPU resources that this VM is currently using.

Percent

Comparing the value of this measure across VMs will enable you to accurately identify the VMs on which CPU-intensive applications are executing.

Virtual CPUs:

Indicates the number of virtual CPU cores allocated to this VM.

Number

Disk read and write rate:

Indicates the rate at which read-write requests were processed by this VM.

Kbytes/Sec

Compare the value of this measure across VMs to know on which VM I/O activity was abnormally high.

Network data sent and received:

Indicates the rate at which network I/O is processed by this VM.

Mbps

Compare the value of this measure across VMs to know on which VM network I/O activity was abnormally high.

Total IOPS:

Indicates the rate at which I/O operations are performed by this VM.

Requests/Sec

This measure is a good indicator of the I/O processing capacity of the VM. A high value is hence desired for this measure. A consistent drop in this value could indicate a processing bottleneck. In such a situation, you can compare the value of the Read operations and Write operations measures of the corresponding VM to figure out where the bottleneck lies – in reading data from the VM? or in writing to the VM?

Read operations:

Indicates the rate at which this VM services read requests.

Requests/Sec

Ideally, the value of this measure should be high. A steady drop in this value indicates a slowdown in processing read requests. Compare the value of this measure across VMs to know which VM is the slowest in responding to read requests.

Write operations:

Indicates the rate at which this VM services write requests.

Requests/Sec

Ideally, the value of this measure should be high. A steady drop in this value indicates a slowdown in processing write requests. Compare the value of this measure across VMs to know which VM is the slowest in responding to write requests.

Time spent waiting for I/O:

Indicates the percentage of time the host’s CPU was waiting for this VM to complete I/O processing.

Percent

A high value for this measure indicates that the VM is taking too long to complete I/O processing. This hints at a probable processing bottleneck with the VM.

Average queue size:

Indicates the average number of I/O requests to this VM that are in queue for processing.

Number

If the value of this measure grows consistently, it indicates that the VM is unable to process requests quickly enough to clear the queue. The VM with the maximum number of queued requests could be experiencing a serious I/O processing bottleneck. To identify this VM, compare the value of this measure across VMs.

Current requests in flight:

Indicates the number of I/O requests to this VM that are currently being processed.

Number

Current sessions:

This measure is relevant only for monitoring of virtual desktops (i.e., for Citrix XenServer - VDI servers). When reporting metrics for specific users, this metric indicates the number of sessions that each user has currently logged into; this measure will be available only if the test reports measures per currently logged in user.

Number

This is a good indicator of how busy the user is. The detailed diagnosis of this measure, if enabled, reveals the guests to which the user is currently logged on to.

Virtual CPUs full run:

Indicates the percentage of the time that the vCPUs were running on this VM.

Percentage

A high value for this measure indicates that the vCPUs are using a lot of the physical CPU resources for prolonged duration.

Virtual CPUs partial run:

Indicates the percentage of time that some of the total vCPUs were running, and others were blocked on this VM.

Percentage

Virtual CPUs idle:

Indicates the percentage of time that the vCPUs were blocked or offline on this VM.

Percentage

Virtual CPUs concurrency hazard:

Indicates the percentage of time that some of the total vCPUs were running, and other vCPUs were waiting for the physical CPU.

Percentage

Virtual CPUs full contention:

Indicates the percentage of time that the vCPUs on this VM were waiting for the physical CPU.

Percentage

Virtual CPUs partial contention:

Indicates the percentage of time that some of the total vCPUs were waiting for the physical CPU, and others were blocked.

Percentage