VCAP6-DCV Deployment – Objective 3.4 – Troubleshoot a vSphere 6.x Network Implementation


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Objectives 3.4 are broke down as the following

  • Perform a vDS Health Check for teaming, MTU, mismatches, etc.
  • Configure port groups to properly isolate network traffic
  • Use command line tools to troubleshoot and identify configuration issues
  • Use command line tools to troubleshoot and identify VLAN configurations
  • Use DCUI network tool to correct network connectivity issue

Perform a vDS Health Check for teaming, MTU, mismatches, etc

Health Check can be enabled on a vDS to help identify and troubleshoot configuration errors.  Health checks run regularly, default interval 1 minute, to identify common errors for VLAN, MTU and teaming policy config problems.  To enable Web Client – Networking – vDS – Settings –  Edit Health Check.  Choose to enable the following

  • VLAN and MTU – reports the status of distributed uplink ports and VLAN ranges.
  • Teaming and Failover – checks for any configuration mismatch between the host and the physical switch used in the teaming policy.

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Once enabled it can be displayed from Web Client – Networking – vDS – Monitor – Health

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Each section either VLAN, MTU or teaming and failover can be seen in the Health status details box.  In my lab I have many warnings as its all nested

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Use command line tools to troubleshoot and identify configuration issues

I have covered these commands in previous posts but will list them again as its listed as an objective.

To view configuration information for VMKernel adapter

>esxcli network ip interface list

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To see the IP address for a specific VMKernel adapter run the following

>esxcli network ip interface ipv4 get -i vmk3

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For netstat information run the following

>esxcli network ip connection list

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To view information on configured vSS run the following

>esxcli network vswitch standard list

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To see advanced options for a vSS run the following

>escli network vswitch standard policy failover get -v vSS_name

>escli network vswitch standard policy security get -v vSS_name

>escli network vswitch standard policy shaping get -v vSS_name

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To list information relating to vDS

>esxcli network vswitch dvs list

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For a high level view vmnic configuration, if the vmnics are up or down as well as speed and duplex

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Use command line tools to troubleshoot and identify VLAN configurations

To view what VLANs are assigned to port groups via the CLI I run the following

>esxcli network vswitch standard portgroup list

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To change the VLAN ID I run the following

>esxcli network vswitch standard portgroup set -p vSS_new –vlan-id 120

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See VMware CLI reference guide here for more options


Use DCUI network tool to correct network connectivity issue

Occasionally the network setting for a host must be configured from the Direct Console User Interface (DCUI), for instance incorrect changes to the management VMKernel interface leaves the host unreachable on the network.

To check the IP configuration and which vmnic is used for management I check the IPv4 Configuration and Network Adapters under Configure Management Network

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To check the VLAN configuration Configure Management Network – VLAN (optional)

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To test the management network connectivity and any other IP address use Test Management Network – this will ping out on the adapter used for management

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Finally the DCUI has some options to restore network configuration to default.  Another option here is to restore vDS, this is handy if the management VMKernel interface resides on a vDS port group, when selected the DCUI creates a local ephemeral port and applies the VLAN and uplink configuration to the port

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