Tcp Traffic - OS Test

Since most popular applications rely on the TCP protocol for their proper functioning, traffic monitoring at the TCP protocol layer can provide good indicators of the performance seen by the applications that use TCP. The most critical metric at the TCP protocol layer is the percentage of retransmissions. Since TCP uses an exponential back-off algorithm for its retransmissions, any retransmission of packets over the network (due to network congestion, noise, data link errors, etc.) can have a significant impact on the throughput seen by applications that use TCP. This test monitors the TCP protocol traffic to and from a guest, and particularly monitors retransmissions.

Target of the test : A Proxmox Hypervisor

Agent deploying the test : An internal/remote agent

Outputs of the test : One set of results for each powered-on VM on the Proxmox Hypervisor being monitored

Configurable parameters for the test
Parameter Description

Test period

How often should the test be executed.

Host

The IP address of the host for which this test is to be configured.

Port

The port at which the specified host listens. By default, this will be NULL.

Proxmox Node Name

Specify the name of the Proxmox node that you wish to monitor in this text box. By default, this parameter is set to none indicating that the test monitor all the nodes in the target hypervisor.

Ignore VMs Inside View

Administrators of some high security Proxmox 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, yourIgnore 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 Proxmox Hypervisor 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.

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.

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.

Domain, Admin User, Admin Password, and Confirm Password

By default, this test connects to each virtual VM 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 VMs. The first step towards this is to specify the Domain within which the virtual VMs 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 VMs 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 VMs. 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 VMs do not belong to any domain (as in the case of Linux VMs) : 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 VM, then, in the Admin User text box, enter the name of the user whose <USER_HOME_DIR> (on that Linux VM) 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 VMs belong to different domains - In this case, you might want to provide multiple domain names. If this is done, then, to access the VMs 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 icon adjacent to the Admin User text box. 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.

Report By User

While monitoring a Proxmox Hypervisor, the Report By User flag is set to No by default, indicating that by default, the VM operating systems on the target hypervisor are identified using the hostname specified in the operating system. On the other hand, if you want the desktops to be identified using the login of the user who is accessing them, set this flag to Yes. 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 this 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 VMs 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. 

Segments Sent Min

Specify the minimum threshold for the number of segments sent/transmitted over the network. The default value is 10; in this case, the test will compute/report the Retransmit ratio from VM measure only if more than 10 segments are sent over the network – i.e., if the value of the Segments sent by VM measure crosses the value 10. On the other hand, if the Segments sent by VM measure reports a value less than 10, then the test will not compute/report the Retransmit ratio from VM measure. This is done to ensure that no false alerts are generated by the eG Enterprise system for the Retransmit ratio from VM measure. You can change this minimum threshold to any value of your choice.

DD Frequency

Refers to the frequency with which detailed diagnosis measures are to be generated for this test. The default is 1:1. This indicates that, by default, detailed measures will be generated every time this test runs, and also every time the test detects a problem. You can modify this frequency, if you so desire. Also, if you intend to disable the detailed diagnosis capability for this test, you can do so by specifying none against DD frequency.

Detailed Diagnosis

To make diagnosis more efficient and accurate, the eG Enterprise 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

Segments received by VM

Indicates the rate at which segments are received by the guest.

Segments/Sec

 

Segments sent by VM

Indicates the rate at which segments are sent to clients
or other guests

Segments/Sec

 

Retransmits by VM

Indicates the rate at which segments are being retransmitted by the guest

Segments/Sec

 

Retransmit ratio from VM

Indicates the ratio of the rate of data retransmissions to the rate of data being sent by the guest

Percent

Ideally, the retransmission ratio should be low (< 5%). Most often retransmissions at the TCP layer have   significant impact on application performance. Very often a large number of retransmissions are caused by a congested network link, bottlenecks at a router causing buffer/queue overflows, or by lousy network links due to poor physical layer characteristics (e.g., low signal to noise ratio). By tracking the percentage of retransmissions at a guest, an administrator can quickly be alerted to problem situations in the network link(s) to the guest that may be impacting the service performance.