Tags help you to label NSX objects so that you can quickly search or filter objects, troubleshoot and trace, and do other related tasks.

You can create tags using both the UI and APIs. Each tag has the following two attributes:
  • Tag (refers to the tag name. It is required, must be unique and case-sensitive.)
  • Scope (optional)
Tag scope is analogous to a key and tag name is analogous to a value. For example, let us say, you want to label all virtual machines based on their operating system (Windows, Mac, Linux). You can create three tags, such as Windows, Linux, and Mac, and set the scope of each tag to OS. Other examples of tag scope can be tenant, owner, name, and so on.

After you save a tag, you cannot update the name and scope. However, you can unassign or remove tags from objects.

For information about the maximum number of tags supported in NSX objects, see the VMware Configuration Maximums tool at https://configmax.vmware.com/home.

Following are some of the operations that you can do with tags:
  • Assign or unassign tags to an object.
  • Assign or unassign a single tag to multiple objects simultaneously (supported only for VMs).
  • View a list of all tags in the inventory.
  • Filter the list of tags by tag name, tag source, and tag scope.
  • View a list of objects that are assigned a specific tag.
Note: When a VM disappears from the VMware vCenter inventory for more than 30 minutes, tags on the VM are lost. If the same VM reappears in the VMware vCenter inventory after 30 minutes, NSX treats it as a new VM, and you must add the tags again on the VM. This behavior is expected and as per design. For example, this behavior is seen when using array-based replication with VMware Site Recovery Manager™.

Use Cases of Tags

The following table describes some use cases of using tags.
Use Case Description
Manageability
  • Simplify searching of objects in a large-scale inventory management.
  • Provide more information to differentiate objects that share similar or unclear names.
Third-party sharing and context sharing
  • Annotate objects with custom information.
  • Allow third-party non-NSX systems to add metadata information in an automated fashion. For example, metadata from partners, container platforms, and so on.
  • Capture attributes or properties and relationships that are learned using NSX discovery agent, inventory collection, Guest Introspection, VM Tools, and so on.
Security
  • Create grouping membership criteria.
  • Specify the firewall source and destination.
Troubleshooting (Traceability)
  • Trace a firewall rule into the logs (Rule tags)
  • Trace and correlate objects back to an OpenStack network.

System Tags

System tags are tags that are system-defined, and you cannot add, edit, or delete them.

Table 4. System Tags in Other NSX Objects
Objects System Tags
Group
  • autoPlumbing
  • abstractionPath
  • NLB-VIP_ID
  • NLB-Lb-ID
  • NLB-Pool_ID
Segment
  • subnet-cidr

IP Address Pool

IP Address Block
  • abstractionPath

Discovered Tags

NSX can discover and synchronize tags from the following:

  • Amazon Web Services
  • Microsoft Azure
  • Kubernetes container clusters with NSX Container Plugin (NCP)
  • Kubernetes container clusters with Antrea network plug-in
  • OpenShift container clusters with NCP

Discovered tags are displayed for workload VMs and container cluster objects. You cannot edit discovered tags in the NSX UI.

For example:
  • Tags that are added to container cluster objects in the Kubernetes container clusters with NCP CNI or Antrea CNI, and OpenShift container clusters with NCP CNI.
Tag Prefix Meaning
dis:aws Tags discovered from Amazon Web Services (AWS).
dis:azure Tags discovered from Microsoft Azure.
dis:k8s Tags discovered from Kubernetes container clusters with NCP CNI, Antrea CNI, and OpenShift container clusters with NCP CNI.

You can enable or disable the discovery of AWS tags at the time of adding the AWS account. Similarly, you can enable or disable Microsoft Azure tags at the time of adding the Microsoft Azure subscription.