CLI Reference for Troubleshooting NSX

Quick post documenting some useful CLI commands for troubleshooting NSX, mainly for my own reference. Other useful information can be found at NSX CLI Cheat Sheet and NSX for vSphere Command Line Interface Reference.

ESXi Hosts

Open an SSH session to an ESXi host. The SSH service can be started from the Configure, System, Security Profile page in the vSphere web client, or under Manage, Services when logging into the host UI.


  • esxcli software vib list displays installed vibs, add | grep esx to filter.
  • vmkload_mod -l | grep vd displays the loaded drivers, add | grep nsx to filter, nsx-vdl2, nsx-vdrb, and nsx-vsip kernel modules should be loaded (
  • /etc/init.d/vShield-Stateful-Firewall status displays the status of user world agent vsfwd which connects the host to NSX Manager.
  • /etc/init.d/netcpad status displays the status of user world agent netcpa which connects the host to the controller cluster.


  • tail -f /var/log/netcpa.log tails the user world agent netcpa log.
  • Note – to change the logging level for netcpa execute the following commands on the ESXi host:
    • chmod +wt /usr/lib/vmware/netcpa/etc/netcpa.xml gives write permissions to the file.
    • vi /usr/lib/vmware/netcpa/etc/netcpa.xml opens the file in an editor. Find <level>info</level>, press insert to edit the line and replace info with verbose. Press escape twice and enter :wq to save the file and quit.
    • /etc/init.d/netcpad restart restarts netcpad.


  • esxcfg-advcfg -g /UserVars/RmqIpAddress lists the IP address of the registered NSX Manager.
  • esxcli network ip connection list lists active TCP/IP connections, add | grep 5671 to filter port 5671 used to connect to NSX Manager.
  • ping ++netstack=vxlan -d -s 1572 -I vmk3 <VMK> <VTEP> can be used to ping a VTEP IP address using an increased packet size, where <VMK> is the VMkernel to use on the source host, and <VTEP> is the destination VTEP IP address to ping.
    • For example ping ++netstack=vxlan -d -s 1572 -I vmk4
    • If the ping comes back successful then we know the MTU is set correctly, since the command specifies a packet size of 1572 (there is a 28 byte overhead = 1600). If the ping drops the packet then try reducing the packet size to 1472: ping ++netstack=vxlan -d -s 1472 -I (again + 28 byte overhead = 1500). If the smaller ping packet is successful but the larger packet is dropped then we know there is an MTU mismatch.
  • pktcap-uw can be used for packet capturing, full syntax here.
  • esxtop is a useful host troubleshooting tool, type n to switch to network view.


NSX Manager Appliance

Open an SSH session to the NSX Manager. The SSH service can be started from the Summary page of the NSX Manager Virtual Appliance Management page.


  • show interface displays information for the NSX Manager management interface.
  • show ip route NSX Manager route information.
  • show filesystem NSX Manager file system capacity.
  • show log manager follow follows the NSX Manager log.


  • show controller list all displays the controller nodes status.
  • show cluster all displays vSphere clusters managed by the vCenter Server.
  • show logical-switch list all displays all logical switch information.
  • show logical-switch controller master vni 5001 connection displays the hosts connected to segment ID 5001, also replace connection with vtep mac arp.
  • show logical-router list all displays all distributed logical router information.

Deploying an NSX Load Balancer with vRA

In this post we will walk through the process of deploying an NSX Load Balancer using vRealize Automation. We will also cover high availability and post deployment scaling. In order to take advantage of the direct NSX API integration with vRA you will need to be running at least v7.3, read more about the enhancements made in vRA 7.3 from the release notes or what’s new. In the example we’ll work towards multiple web servers are provisioned with an On-Demand Load Balancer, along with app servers and a database server. The On-Demand Load Balancer deploys an NSX edge for load balancing and adds the web servers as pool members. There are a number of available customisations which we’ll cover in the configuration process below.


Adding Endpoints

The following process assumes that you have a fully deployed vRA topology with all the components required to provision virtual machines; vCenter endpoint(s), reservations, compute resources, and a published catalog with entitlements. It would also be beneficial to have an understanding of using an NSX edge for load balancing or have deployed an edge manually to see the corresponding deployment options.

The first step is to add the NSX Manager as a vRA endpoint. From the Infrastructure tab select Endpoints and Endpoints again. Click New and select Networking and Security, NSX. Enter the details for the NSX Manager. Before adding the NSX endpoint we can create an association with the registered vCenter Server. From the Associations tab, click New. Select the vCenter Server from the dropdown, the platform type will auto-populate to vSphere and the description vSphere to NSX Association. Click Test Connection and then Ok to save the configuration.


Blueprint Modifications

After NSX has been added as an endpoint navigate to Blueprints under the Design tab. From the design canvas of a new or existing blueprint select Network & Security, drag and drop the On-Demand Load Balancer onto the canvas.


Click the On-Demand Load Balancer that has been added to the canvas. When the load balancer is provisioned in NSX the servers associated with the load balancer in the blueprint are automatically added as members in the pool. This is set in the Member field, in the example below the web servers in the blueprint are added as members of the load balancer.


The network for the member servers and the network for the VIP address are configured in the appropriate fields. Leave the IP address blank to automatically assign an IP address from the associated VIP network. Under Virtual servers click New, here you can configure the protocol settings for the load balancer, and the algorithm/persistence, health check, and connection settings by selecting Customize.


Before saving the blueprint click the settings cog at the top of the page, this opens the blueprint properties. From the NSX Settings tab set the Transport zone to attach the load balancer to, this can be a local or universal transport zone. Next select the Edge and routed gateway reservation policy, this is the reservation policy (compute, storage) that will be used when provisioning the edge.


Click the Properties tab and select Custom Properties. There are a number of optional parameters we can add here.

  • NSX.Edge.ApplianceSize sets the appliance size of the edge, accepted values are compact, large, quadlarge and xlarge.
  • NSX.Edge.HighAvailability deploys the edge appliance in HA mode when the value is true. Without this property only a single appliance is deployed.
  • NSX.Edge.HighAvailability.PortGroup references the port group to use for the heartbeat network of the edge appliances deployed in HA mode.


Click Ok and Finish to save the blueprint. Make the blueprint available as a catalog item and request a test deployment. In vSphere you will see the edge and VMs being provisioned and, once complete, the virtual machines will be added as members in the load balacer pool. You can view the settings of the deployed edge in the vSphere web client under Networking & Security, NSX Edges, double click the edge and select Load Balancer.


Post Deployment

When the deployment is destroyed the edge appliances are removed along with the VMs as part of the cleanup process. If the deployment is scaled out then the new server is added as a member to the existing load balancer pool, likewise if the deployment is scaled in then the server deleted is also removed from the pool.


The scale in and scale out actions are assigned as entitled actions from within the relevant entitlement  Aswell as having the permissions to perform the scale actions the blueprint must also contain a higher number of maximum instances. In the example below 2 web servers will be deployed with an On-Demand Load Balancer, as the maximum number of instances is set to 10 the requester can scale out the number of web servers and pool members to a maximum of 10 servers.


Configuring VMware Cross-vCenter NSX

This post provides an overview of cross-vCenter NSX and walks through the configuration steps. Cross-vCenter NSX allows central management of network virtualization and security policies across multiple vCenter Server systems. Cross vCenter NSX introduces universal objects; such as universal logical switches, universal logical routers, and universal distributed firewall rules. Universal objects are able to span multiple sites or vCenter Server instances, enhancing workload mobility by allowing cross vCenter and long distance vMotion for virtual machines, whilst keeping the same network settings and firewall rules. This improves DR capabilities, overcomes scale limits of vCenter Server, and gives administrators more control over resource pooling and the separation of environments.

Cross vCenter-NSX was introduced in NSX v6.2 and requires vSphere v6.0 or later. As normal NSX Manager is deployed with vCenter server in a 1:1 pairing.  In a single site NSX deployment the NSX Manager is given the standalone role by default. When configuring cross-vCenter NSX one NSX Manager is assigned the primary role, and up to seven other NSX Managers are assigned the secondary role. NSX Managers configured for cross-vCenter NSX must all be running the same version. The primary NSX Manager is responsible for deploying the Universal Controller Cluster; forming the control plane across the NSX Managers. The Universal Controller Cluster runs in the site of the primary NSX Manager. Universal objects are created on the primary NSX Manager and automatically synchronized across the multi-site NSX environment.

Configuring Cross-vCenter NSX

The steps below assume you have already deployed and registered the NSX Managers, and have a good understanding of NSX. This post is intended as add on to the NSX Install Guide to provide an outline of the additional or different steps required for a cross-vCenter NSX install, further resources are listed at the bottom of the page. If you are using vCenter enhanced linked mode then multiple NSX Manager instances are displayed within the same interface, or single pane of glass, when managing the Network & Security section of the vSphere web client. Enhanced linked mode is not a requirement for cross-vCenter NSX however, and vCenter Server systems not in enhanced linked mode can still be configured for cross-vCenter NSX.

From the Networking & Security page of the vSphere web client select Installation, highlight the NSX Manager in the primary site, from the Actions menu select Assign Primary Role.


The secondary NSX Manager(s) synchronize with the primary using the Universal Synchronization Service. These sites do not run any NSX Controllers, although they can be redeployed easily in the event of a primary site outage. Before assigning the secondary role you should ensure there are no existing NSX Controllers deployed in the associated vCenter. If you have already assigned a segment ID pool to the NSX Managers then ensure the segment ID pools do not overlap. Select the primary NSX Manager and from the Actions menu click Add Secondary NSX Manager. Enter the secondary NSX Manager information and admin password.


Review the table of NSX Managers, the roles have now changed accordingly.


The universal controller cluster is formed by individually deploying the NSX controllers from the primary NSX Manager, the method of deploying the controllers is the same (see NSX Install Guide Part 1 – Mgmt and Control Planes for further assistance). Once the controllers are deployed you will notice placeholder controllers listed against the secondary NSX Manager, these are not connected or deployed. In the event of a site failure the configuration is synchronized between NSX Managers so you can simply re-deploy the controllers in the DR site. To see the failover process review this blog post. VMware recommend deploying 3 controllers on different hosts with anti-affinity rules.


The next part of the install process is to follow the host preparation and VXLAN configuration steps as normal (see NSX Install Guide Part 2 – Data Plane for further assistance). Create the segment ID pools for each NSX Manager, making sure they do not overlap. On the primary NSX Manager you will also assign a universal segment ID pool.

In order for us to deploy universal logical switches we need to create a universal transport zone. A universal transport zone determines which hosts a universal logical switch can reach, spanning multiple vCenters. From the Logical Network Preparation tab open Transport Zones, ensure the primary NSX Manager is selected and click the plus symbol. Select Mark this object for Universal Synchronization, and enter the configuration for the universal transport zone. All universal objects must be created on the primary NSX Manager, change the NSX Manager to the secondary site and you will see the universal transport zone has synchronized there also.


Next we will create a universal logical switch for the transit network. Local objects such as logical switches, logical routers, and Edge Services Gateways can still be deployed from each NSX Manager, although by design they are only local to the vCenter linked to that specific NSX Manager, and cannot be deployed or edited elsewhere. From the left hand navigation pane in Networking & Security select Logical Switches, ensure the primary NSX Manager is selected and click the plus symbol. Enter a name for the transit network and select the universal transport zone we created earlier.


At this stage you can also deploy another universal logical switch, connecting a couple of test VMs on a private subnet, and have them ping one another to confirm connectivity. Now that we have a transit network and test universal logical switches connected to our universal transport zone we can go ahead and create a universal DLR. In this particular environment we have already deployed an ESG in each site. For further assistance with deploying an ESG and DLR see NSX Install Guide Part 3 – Edge and DLR.

From the Networking & Security page click NSX Edges, ensure the primary NSX Manager is selected and click the plus symbol. The control VM for the DLR is deployed to the primary site, again the configuration is synchronized and this can be re-deployed to the DR site in the event of a primary site outage. Select Universal Logical Router and follow the wizard as normal, if local egress is required then check the appropriate box. Sites configured in a cross-vCenter NSX environment can use the same physical routers for egress traffic, or have the local egress feature enabled within a universal logical router. The local egress feature allows routes to be customized at host, cluster, or router level.


From the NSX Edges page double click the new universal DLR, select Manage, Settings, Interfaces and click the add button. In order for traffic to route from the universal DLR to the ESG(s) we must add an uplink interface connecting them to the universal transit network. Change the logical router interface to Uplink, in the Connected To field select the transit network universal logical switch we created earlier. Configure the IP and MTU settings of the interface per your own environment.


You can also add Internal interfaces here corresponding with universal logical switches for virtual machine subnets. Before these subnets can route out follow the same process to add an Internal interface to the ESG(s) connecting them to the same transit network.

A virtual machine connected to the test universal logical switch can now vMotion between sites keeping the same IP addressing, providing L2 over L3 capability. As well as remaining on the same logical network a virtual machine can also be migrated across sites without any additional firewall rules, this is achieved with the use of universal firewall rules. Universal firewall rules require a dedicated section creating under the Firewall section of Networking & Security, you must select Mark this section for Universal Synchronization. For assistance with creating universal firewall rules see here.


Additional Resources

To plan a cross-vCenter NSX installation review the VMware Cross-vCenter NSX Design Guide, Cross-vCenter NSX Topologies Guide, and the VMware Cross-vCenter Installation Guide. For more information on cross-vCenter NSX design see the following blog posts: