Virtual Desktop Client’s Network Connection Test

A Virtual Desktop Infrastructure (VDI) is a shared environment in which multiple users connect to desktops hosted by virtual machines executing on an ESX host from remote terminals using the Remote Desktop Protocol (RDP). One of the key factors influencing user experience in such an environment is the latency seen by the users when connecting to a virtual desktop. High network latencies or packet losses during transmission can cause significant slow-downs in request processing by the desktop. Hence, monitoring latencies between the virtual desktop and individual client terminals is important.

The Virtual Desktop Client’s Network Connection test is executed by the eG agent on an ESX host. This test auto-discovers the virtual desktops on the ESX host, the users who are currently logged on to each of the virtual desktops, and the IP address from which they are connecting to the virtual desktops.  For each user, the test monitors the quality of the link between the client and the virtual desktop.

Using this test, an administrator can identify user sessions that are being impacted by high latencies or by excessive packet drops. In some cases, a virtual desktop may regard a user session as active, even though the network link connecting the user terminal to the virtual desktop has failed. The Virtual Desktop Client’s Network Connection test alerts administrators to such situations.

This test will work only on Windows VMs.

Target of the test : An ESX host

Agent deploying the test : An internal/remote agent

Outputs of the test : One set of outputs for every user currently connected to the virtual desktop.

Configurable parameters for the test
  1. Test period - How often should the test be executed
  2. Host - The host for which the test is to be configured.
  3. port - The port at which the specified host listens. By default, this is NULL.
  4. esx user and esx password - In order to enable the test to extract the desired metrics from a target ESX server, you need to configure the test with an ESX USER and ESX PASSWORD. The user credentials to be passed here depend upon the mechanism used by the eG agent for collecting performance statistics from the ESX server and its VMs. These monitoring methodologies and their corresponding configuration requirements have been discussed hereunder:

    • Monitoring using the web services interface of the ESX server: Starting with ESX server 3.0, a VMware ESX server offers a web service interface using which the eG agent collects metrics from the ESX server. The VMware VI SDK is used by the agent to implement the web services interface. To use this interface for monitoring, this test should be configured with an ESX USER who has “Read-only” privileges to the target ESX server. By default, the root user is authorized to execute the test. However, it is preferable that you create a new user on the target ESX host and assign the “Read-only” role to him/her. The steps for achieving this have been elaborately discussed in Creating a New User with Read-Only Privileges to the ESX Server section.

      ESX servers terminate user sessions based on timeout periods. The default timeout period is 30 mins. When you stop an agent, sessions currently in use by the agent will remain open for this timeout period until ESX times out the session. If the agent is restarted within the timeout period, it will open a new set of sessions. If you want the eG agent to close already existing sessions before it opens new sessions, then you would have to configure all the tests with the credentials of an ESX user with permissions to View and stop sessions (prior to vSphere/ESX server 4.1, this was called the View and Terminate Sessions privilege). To know how to grant this permission to an ESX user, refer to section.

    • Monitoring using the vCenter in the target environment: By default, the eG agent connects to each ESX server and collects metrics from it. While this approach scales well, it requires additional configuration for each server being monitored. For example, separate user accounts may need to be created on each server for read-only access to VM details. While monitoring large virtualized installations however, the agents can be optionally configured to monitor ESX servers using the statistics already available with different vCenter installations in the environment.

    In this case therefore, the ESX USER and ESX PASSWORD that you specify should be that of an Administrator or Virtual Machine Administrator in vCenter. However, if, owing to security constraints, you prefer not to use the credentials of such users, then, you can create a special role on vCenter with ‘Read-only’ privileges.

    Refer to Assigning the ‘Read-Only’ Role to a Local/Domain User to vCenter section of this document to know how to create a user on vCenter.

    If the ESX server for which this test is being configured had been discovered via vCenter, then the eG manager automatically populates the esx user and esx password text boxes with the vCenter user credentials using which the ESX discovery was performed.

    Like ESX servers, vCenter servers too terminate user sessions based on timeout periods. The default timeout period is 30 mins. When you stop an agent, sessions currently in use by the agent will remain open for this timeout period until vCenter times out the session. If the agent is restarted within the timeout period, it will open a new set of sessions. If you want the eG agent to close already existing sessions before it opens new sessions, then you would have to configure all the tests with the credentials of a vCenter user with permissions to View and stop sessions (prior to vCenter 4.1, this was called the View and Terminate Sessions permission). To know how to grant this permission to a user to vCenter, refer to Creating a Special Role on vCenter and Assigning the Role to a Local/Domain User section.

    When the eG agent is started/restarted, it first attempts to connect to the vCenter server and terminate all existing sessions for the user whose credentials have been provided for the tests. This is done to ensure that unnecessary sessions do not remain established in the vCenter server for the session timeout period.  Ideally, you should create a separate user account with the required credentials and use this for the test configurations. If you provide the credentials for an existing user for the test configuration, when the eG agent starts/restarts, it will close all existing sessions for this user (including sessions you may have opened using the Virtual Infrastructure client). Hence, in this case, you may notice that your VI client sessions are terminated when the eG agent starts/restarts.

  5. confirm password - Confirm the password by retyping it here.
  6. ssl - By default, the ESX server is SSL-enabled. Accordingly, the SSL flag is set to Yes by default. This indicates that the eG agent will communicate with the ESX server via HTTPS by default.

    Like the ESX sever, the vCenter is also SSL-enabled by default. If you have chosen to use the vCenter for monitoring, then you have to set the SSL flag to Yes.

  7. webport - By default, in most virtualized environments, the vSphere/ESX server and vCenter listen on port 80 (if not SSL-enabled) or on port 443 (if SSL-enabled). This implies that while monitoring an SSL-enabled vSphere/ESX server directly, the eG agent, by default, connects to port 443 of the vSphere/ESX server to pull out metrics, and while monitoring a non-SSL-enabled server, the eG agent connects to port 80. Similarly, while monitoring a vSphere/ESX server via an SSL-enabled vCenter, the eG agent connects to port 443 of vCenter to pull out the metrics, and while monitoring via a non-SSL-enabled vCenter, the eG agent connects to port 80 of vCenter. 

    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 vSphere/ESX server or vCenter in your environment listens so that the eG agent communicates with that port.

  8. VIRTUAL CENTER - If the eG manager had discovered the target ESX server by connecting to vCenter, then the IP address of the vCenter server used for discovering this ESX server would be automatically displayed against the vIRTUAL center parameter; similarly, the esx user and esx password text boxes will be automatically populated with the vCenter user credentials, using which ESX discovery was performed.

    If this ESX server has not been discovered using vCenter, but you still want to monitor the ESX server via vCenter, then select the IP address of the vCenter host that you wish to use for monitoring the ESX server from the vIRTUAL center list. By default, this list is populated with the IP address of all vCenter hosts that were added to the eG Enterprise system at the time of discovery. Upon selection, the esx user and esx password that were pre-configured for that vCenter server will be automatically displayed against the respective text boxes.

    On the other hand, if the IP address of the vCenter server of interest to you is not available in the list, then, you can add the details of the vCenter server on-the-fly, by selecting the Other option from the vIRTUAL center list. This will invoke the add vcenter server details page. Refer to Adding the Details of a vCenter Server for Guest Discovery section.

    On the other hand, if you want the eG agent to behave in the default manner -i.e., communicate with each ESX server for monitoring it - then set the VIRTUAL CENTER parameter to ‘none’. In this case, the ESX USER and ESX PASSWORD parameters can be configured with the credentials of a user who has at least ‘Read-only’ privileges to the target ESX server.

  9. 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 (Windows) 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 the eG Agent to Collect Current Hardware Status Metrics section 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.

  10. 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 domainIf 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/Solaris 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 section.

    • 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 VM Details – ESX Test section.
    • 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.
  11. 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.
  12. ignore vms inside view - Administrators of some high security VMware 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 an ESX 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.

  13. 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.
  14. REPORT BY USER - While monitoring a VMware ESX server, the REPORT BY USER flag is set to No by default, indicating that by default, the guest operating systems on the ESX server are identified using the hostname specified in the operating system. On the other hand, while monitoring VMware Desktop environments, this flag is set to YES by default; this implies that in case of VDI servers, by default, the guests will be identified using the login of the user who is accessing the guest OS. In other words, in VDI environments, this test will, by default, report measures for every username_on_virtualmachinename.
  15. 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 virtual machine 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.

  16. REPORTUNAVAILABILITY – By default, this flag is set to No. This implies that, by default, the test will not report the unavailability of network connection between a user terminal and a virtual desktop. In other words, if the Packet loss measure of this test registers the value 100% for any user, then, by default, this test will not report any measure for that user; under such circumstances, the corresponding user name will not appear as a descriptor of this test. You can set this flag to Yes, if you want the test to report and alert you to the unavailability of network connection between a user terminal and a virtual desktop.

  17. PACKETSIZE - The size of packets used for the test (in bytes)
  18. PACKETCOUNT - The number of packets exchanged between the virtual desktop and the user terminal during the test
  19. TIMEOUT - How long after transmission should a packet be deemed lost (in seconds)
  20. PACKETINTERVAL - Represents the interval (in milliseconds) between successive packet transmissions during the execution of this test.
  21. 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

Number of sessions:

Indicates the current number of sessions for a particular user

Number

The value 0 indicates that the user is not currently connected to the virtual desktop.

The detailed diagnosis of this measure lists the IP addresses of the clients from which this user connected to the virtual desktop. This will tell you if the same user launched session from multiple sessions. Moreover, if a user is unable to establish a network connection with a virtual desktop, administrators can use the detailed diagnosis to accurately identify the network connection – i.e., the connection from which client terminal to the virtual desktop - that is experiencing issues.

Average delay:

Indicates the average delay between transmission of a request by the agent on a virtual desktop and receipt of the response back from the user terminal.

Secs

Comparing the value of this measure across users will enable administrators to quickly and accurately identify users who are experiencing higher latency when connecting to a virtual desktop.

Minimum delay:

Indicates the minimum delay between transmission of a request by the agent on a virtual desktop and receipt of the response back from the user terminal.

Secs

A significant increase in the minimum round-trip time is often a sure sign of a poor link between the desktop and a user’s terminal.

Packet loss:

Indicates the percentage of packets lost during data exchange between the virtual desktop and the user terminal.

Percent

Comparing the value of this measure across users will enable administrators to quickly and accurately identify users who are experiencing slowdowns because of poor performance on the network links between their terminals and the virtual desktop.

Note:

  • If the same user is connecting to the virtual desktop from multiple client terminals, the value of the Number of sessions, Average delay, and Packet loss measures will be averaged across all the sessions of that user. The Minimum delay measure, on the other hand, will display the least value reported for Minimum delay across all the sessions of that user.
  • When a user logs out, the number of sessions will be reduced by 1. If the number of user sessions becomes 0, the corresponding entry for that user in the eG user interface will be removed after a short period of time.