VM Connectivity Test

Sometimes, a VM could be in a powered-on state, but the failure of the VM operating system or any fatal error in VM operations could have rendered the VM inaccessible to users. In order to enable administrators to promptly detect such ‘hidden’ anomalies, the eG agent periodically runs a connectivity check on each VM using this test, and reports whether the VM is accessible over the network or not.

Target of the test : A KVM server

Agent deploying the test : An internal/remote agent

Outputs of the test : One set of results for each VM configured on the KVM server host 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 is NULL.

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 the Remote Agent to Obtain the Inside View of Windows VMs, 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).

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 VMstext box, you can make sure the eG agent stops collecting 'inside' and 'outside' view metrics for a configured set of VMs.

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 a KVM server 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.

Packetsize

The size of packets used for the test (in bytes).

Packetcount

The number of packets to be transmitted during the test.

Timeout

How long after transmission should a packet be deemed lost (in seconds).

PacketInterval

Represents the interval (in milliseconds) between successive packet transmissions during the execution of the network test for a specific target.

ReportUnavailability

By default, this flag is set to No. This implies that, by default, the test will not report the unavailability of network connection to any VM. In other words, if the Network availability measure of this test registers the value 0 for any VM, then, by default, this test will not report any measure for that VM; under such circumstances, the corresponding VM 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 the network connection to a VM. 

Measurements made by the test

Measurement Description Measurement Unit Interpretation

Avg network delay:

Indicates the average delay between transmission of packet to a VM and receipt of the response to the packet at the source.

Secs

An increase in the value of this measure is a cause for concern. Given below are some common reasons for such an anomaly:

  • The network between the VM and the eG external agent is congested. When there is an increase in traffic on the interconnecting network, data transmission can slow down, thereby increasing communication latency.

  • The quality of the network connection between the eG external agent and the VM is sub-par. Poor signal quality, faulty transmission lines, etc. can result in an increase in packet loss and/or network latency.

  • The VM is overloaded. If the VM is very busy, it takes longer to respond to requests, and this will result in an increase in latency.

  • There are problems with network routingbetween the VM and the eG external agent. A faulty network router, routing loops, etc., can increase network latency. Check the detailed diagnosis of this test to track latency on the first three hops between the agent and the VM. The latency to each hop can be used to determine which hop the problem lies in.

Min network delay:

The minimum time between transmission of a packet and receipt of the response back.

Secs

A significant increase in the minimum round-trip time is often a sure sign of network congestion.

Packet loss:

Indicates the percentage of packets lost during transmission from source to target and back.

Percent

A value close to 100% for this measure is a cause for concern. Given below are some common reasons for such an anomaly:

  • The network between the VM and the eG external agent is congested. When there is an increase in traffic on the interconnecting network, packets may be dropped.

  • The quality of the network connection between the eG external agent and the VM is sub-par. Poor signal quality, faulty transmission lines, etc. can result in an increase in packet loss and/or network latency.

  • The VM is overloaded. If the VM is very busy, it takes longer to respond to requests, and this will result in packet drops.

  • There are problems with network routingbetween the VM and the eG external agent. A faulty network router, routing loops, etc., can increase packet loss. Check the detailed diagnosis of this test to know the hops that are on the path from the external agent to target VM, and the packet loss on each hop. This information can be used to diagnose the hop(s) that could be causing excessive packet loss.

Network availability of VM:

Indicates whether the network connection is available or not.

Percent

A value of 100 indicates that the VM is connected. The value 0 indicates that the VM is not connected.

Typically, the value 100 corresponds to a Packet loss of 0.

The value 0 for this measure could mean that the target VM is either down or too busy, or the interconnecting network is down.