IP addresses of docker containers not being identified or registered by VMware tools on a Virtual Machine running Docker

Products

• VMware vSphere ESXi

Issue/Introduction

This article provides steps to resolve this issue, and to allow for network connectivity to be established to the underlying docker containers that are being managed by a VM.

Symptoms:

• Docker container IPs running on a Virtual Machine are not being picked up or identified by VMware tools.
• Connectivity to the VM managing the docker containers can be established; however, the docker containers themselves cannot be reached over the network.
• Regardless of the guest OS of the managing VM (linux, windows, macOS, FreeBSD, etc..), IP detection and network access to the docker containers cannot be established.

 

Cause

• By default, recent versions of VMware tools are set to mask the docker network interfaces from being detected on a Virtual Machine. 
  • This is due to the fact that, at present, VMware tools does not detect or report containers to the vSphere environment.

Resolution

• To override the default setting that masks docker network interfaces, changes must be made to the tools.conf file of the guest-OS that is running the docker containers
  • To see the default location for tools.conf on various guest OSes, please refer to the following article:
    • https://techdocs.broadcom.com/us/en/vmware-cis/vsphere/tools/11-0-0/vmware-tools-administration-11-0-0/configuring-vmware-tools-components/using-vmware-tools-configuration-file.html
  • Note: If the tools.conf file does not exist on your VM, it must be manually created in the correct directory (seen in above reference article)

 

• Even if tools.conf does not yet exist on your VM, VMware tools is loaded with the following configuration in place:

[guestinfo]
exclude-nics=veth*,docker*,virbr*
 

• Add the above lines to the new or existing tools.conf file, but then remove the "docker*" from the "exclude-nics" parameter.
  • For example: 
    • exclude-nics=veth*,virbr*
  • To remove all network interface detection masking, leave exclude-nics blank, such as:
    • exclude-nics=

 

• Save the file, and then restart the VMware tools service (or reboot the guest OS). 
  • The underlying docker containers should now be accessible over the network.
  • The docker IPs should now be detected and listed under "IP Addresses:" on the summary tab of the VM that is managing the docker containers. 

Additional Information

Review the following VMware article for a more detailed description of the "exclude-nics" parameter that disables certain types of network adapters from detection by VMware tools, by default

https://techdocs.broadcom.com/us/en/vmware-cis/vsphere/tools/11-0-0/vmware-tools-administration-11-0-0/configuring-vmware-tools-components/configure-network-interface-information.html
A 3rd party article also discusses vNIC exclusion, and vNIC priority re-ordering, in greater detail:

https://www.virtuallyghetto.com/2017/12/vmware-tools-10-2-0-enables-virtual-machine-vnic-exclusion-and-priority-re-ordering.html