QUICK UPDATE: NSX ALB documentation

To be honest, I have been complaining some over the last year, or so, about the NSX Advanced Load Balancer documentation. Mostly that it was not easy to be found, and one was having to fall back on the avinetworks.com site, which was not great either.

On docs.vmware.com the navigation links were not existing. However, if and when you knew the page titles, you could search for them through search engines. That showed that a lot of those documentation pages were there, in fact, but only not visible with non-existing links.

However, since a couple weeks, there is a banner on the avinetworks.com site that 22.1.4 is the latest release that was documented on avinetworks.com.

NSX ALB documentation deprecation on avinetworks.com
NSX ALB documentation deprecation on avinetworks.com

This means that the single source of truth will be on the NSX Advanced Load Balancer page on docs.vmware.com (the link does redirect you to that location 😀).

Quick tip: if you want to search within a site through a browser, e.g. chrome, use the following as an example:

Enable Workload Management does not finish

Some time ago we were having issues in the Tanzu PoC class for partners we were teaching. One of the students had an environment where the Enable Workload Management process was unable to finish the creation of the Supervisor Cluster.

It was an interesting issue because when we verified all the settings we saw everything configured correctly on a UI level. Nevertheless when went to the virtualservice we saw that it was down because of the servers in the pool were not up.

When the Enable Workload Management is unable to finish, there are some usual suspects. Most of the time the details within the Enable Workload Management wizard are just not correct. Validation on the values supplied could be better I believe. You only know when it takes to long, that you need to start verifying the components. The following milestones can be checked.

  • Are the Supervisor Control Plane VMs created?
  • Do the Supervisor Control Plane VMs have the correct amount of IPs
  • Are the NSX ALB Service Engine VMs created?

During the troubleshooting, we verified these usual suspects. We also verified all values supplied in the different consoles, being the Workload Management configuration page in the vSphere client but also on the NSX ALB. It seemed that this student had done everything correct. We started to exclude issues with pinging, executing curl to the relevant ip’s and checking the logs.

At a moment we arrived at the Service Engines and went from there. At lunch time I stumbled onto this blog post from Nick Schmidt (a fellow vExpert), which made a jump in to the troubleshooting phase:


This showed how to connect to the networking namespace on the Service Engine and this helped a lot.

If you do not connect to the networking namespace, you will see the configuration on an OS level. Within the networking namespace you troubleshoot within the correct context.

Although the web UI shows the correct values for the configured routes, they were not applied correct on the NSX ALB SE.

Here are the steps that I executed when connected to one of the NSX ALB Service Engines:

Now we saw that there was a route missing within this namespace. We went back to the web UI deleted the route and re-created, et voila the servers in the pool came up and therefor the virtualservice was alive.

How to request Let’s Encrypt certificates on the NSX Advanced Load Balancer


Lately, I have been doing quite some work on VMware vSphere with Tanzu. A prerequisite to configure vSphere with Tanzu is a load balancer of some sort. Currently the following are supported, HAProxy, the NSX-T integrated load balancer or the NSX Advanced Load Balancer (ALB). (Support for the NSX ALB was added with the release of vSphere 7 U1.)

The endgoal of the setup is to host several websites in combination with a Horizon environment on a single IP. Because not all systems can handle Let’s Encrypt requests, eg UAG, I want one system that handles the certificate request and does the SSL offloading for the endpoints. So I was looking for a load balancer solution with Let’s Encrypt ability, The NSX Advanced Load Balancer (ALB) adds the ability to request Let’s Encrypt certificates through ControlScripts.

I already learned a lot on the NSX ALB and having some experience with other brands of load balancers certainly helped me to get up to speed quickly.

The goal of this post is to set up a standard Virtual Service (VS) and request a Let’s Encrypt certificate for that VS. You will see that it is quite easy.


I will not configure some necessary configuration settings. They are, however, required to successfully execute the steps below. I will assume the following prerequisites are in place.

The following post shows how to deploy the NSX Advanced Load Balancer and how to configure a ‘VMware vCenter/vSphere ESX’ cloud.


  1. The NSX ALB registered with a cloud. I use a ‘VMware vCenter/vSphere ESX’ cloud
  2. A public DNS entry for the Virtual Service. (Let’s Encrypt needs to be able to check your Virtual Service)
  3. Some way to get to the virtual service from the internet. I have setup a NAT rule on my firewall for this.
  4. Server Pool. (Needed to create the Virtual Service. It is obvious that the Virtual Service needs some endpoint to send the requests to.)
  5. Network config for VIP and SE. (Once you configure a ‘VMware vCenter/vSphere ESX’ cloud, you’ll have access to the networks known to vCenter. You will need to configure ‘Subnets’ and ‘IP Address Pools’ for the NSX ALB to use for the VSs.)
  6. IPAM/DNS Profile. (You need to add the Domain Names for the Virtual Services here.)

I will cover these in a later post but for now I added them as a prerequisite.

What does the ControlScript do?

The ControlScript generates a challenge token for the Let’s Encrypt servers to check the service. Secondly, it searches for a Virtual Service with an fqdn with the Common Name supplied on the certificate request. Once it finds that Virtual Service, it checks if it is listening on port 80. If not, it configures the Virtual Service to handle the request on port 80. Then it adds the challenge token to the Virtual Service. Finally, after a succesful certificate request the changes are cleared.

Download the ControlScript

Download the controlscript here (either copy the contents or download the file): https://github.com/avinetworks/devops/blob/master/cert_mgmt/letsencrypt_mgmt_profile.py

Add the Let’s Encrypt ControlScript to the NSX Advanced Load Balancer

Navigate to Templates > Scripts > ControlScripts and click CREATE

Create a ControlScript for Let's Encrypt on the NSX Advanced Load Balancer

Supply the script name, eg ControlScript_LetsEncrypt_VS, and choose either ‘Enter Text’ or ‘Upload File’. Now we will choose the ‘Enter Text’ option and paste the contents of the python script on github.

Upload a text based ControlScript to NSX Advanced Load Balancer

Create a Certificate Management profile

Navigate to Templates > Security > Certificate Mangement and click CREATE

Create a Certificate Management profile

Enter the Name ‘CertMgmt_LetsEncrypt_VS’ and select the Control Script ‘ControlScript_LetsEncrypt_VS’

Configure the Certificate Management profile to use the Let's Encrypt ControlScript

Click ‘Enable Custom Parameters’ and add the following:

password<enter your NSX ALB controller password for the admin user>(toggle Sensitive)
tenantadminthis is important, otherwise the script won’t have clue on which tenant it should be applied

Add the Custom Parameter ‘tenant’ even if you only have one tenant, the default tenant (admin). I have struggled a lot with the script failing without having a clue why that was. Ultimately, after a long search and monitoring the log through tail, there was something in the logs that pointed me in this direction.

Create the Custom Parameters for the ControlScript on the Certificate Management profile

There is a possibility to add a fourth parameter ‘dryrun’, with value true or false. This will toggle the script to use the Let’s Encrypt staging server.

Create the Virtual Service

Navigate to Applications > Virtual Services > CREATE VIRTUAL SERVICE and click ‘Advanced Setup’

Create a Virtual Service through advanced setup on NSX Advanced Load Balancer

Create the VS with the SNI, in this example I will create ‘vpn.vconsultants.be’. Configure the settings page and leave the other tabs with the default settings.

  1. Supply the VS name (I use the fqdn/SNI just for manageability)
  2. Leave the checkbox ‘Virtual Hosting VS’ unchecked (default). (We will setup a standard VS.)
  3. Leave the checkbox ‘Auto Allocate’ checked (default). (It takes an IP from the Network pool.)
  4. Change the ‘Application Profile’ to ‘System-Secure-HTTP’.
  5. Supply a ‘Floating IPv4’. (I use a static one so that I’m able to setup NAT to this IP on my firewall.)
  6. Select a ‘Network for VIP Address Allocation’. (The SE will create the VIP in this network.)
  7. Select a ‘IPv4 Subnet’. (Only the ones created in the Network config for VIP and SE will be available.)
  8. Change the ‘Application Domain Name’ so that it matches the fqdn of the SNI. (This will fill automatically based on the VS Name.)
  9. Check SSL and verify that the port changes to 443
  10. Select the correct Pool
  11. Change the ‘SSL Profile’ to ‘System-Standard’
Configure the NSX Advanced Load Balancer Virtual Service

Note: Item 7 is a bit awkward. Hovering over the question mark for help, it states that it is only applicable if the VirtualService belongs to an OpenStack or AWS cloud. When you don’t set this option, you cannot go forward. This confuses me somewhat, as I only use a vSphere cloud.

Request a Let’s Encrypt certificate for the NSX ALB Virtual Service

Navigate to Templates > Security > SSL/TLS Certificates > CREATE and click Application Certificate

Initiate a Let's Encrypt certificate request from the NSX Advanced Load Balancer.

Fill in the details for the Certificate Request (CSR) with the SNI for the certificate you want to request. The script will run when the SAVE button is clicked.

  1. Supply the Certificate name (I use the fqdn/SNI just for manageability)
  2. Select ‘Type’ ‘CSR’.
  3. Supply the certificate ‘Common Name’. This is where you supply the actual name of the certificate you want to request, in this case vpn.vconsultants.be.
  4. Supply the certificate ‘Common Name’ as ‘Subject Alternative Name’.
  5. I started to use ‘EC’ as the certificate ‘Algorithm’ over ‘RSA’
  6. Select a ‘Key Size’. Be aware that when choosing ‘EC’ as ‘Algorithm’, ‘SECP384R1’ is the latest that Let’s Encrypt supports for now.
  7. Select ‘Certificate Management Profile’ ‘CertMgmt_LetsEncrypt_VS’.
  8. Check ‘Enable OCSP Stapling’, this will speed up the certificate validation process.
Configure the Let's Encrypt certificate request.

Now watch the magic.

The Let's Encrypt certificate request from the NSX Advanced Load Balancer succeeded.

Note: I added the Root and Intermediates certificates to the NSX ALB controller to validate the certificate. That is why the color of the circle is green.

Add the Let’s Encrypt certificate to the NSX ALB Virtual Service

A final step to do in this setup is to apply the certificate on the VS.

Apply the Let's Encrypt certificate on the Virtual Service

In the end, you will have an NSX Advanced Load Balancer (ALB) Virtual Service configured with a Let’s Encrypt certificate.


In the next post I’ll show the customized script that enables Let’s Encrypt Certificate Management for Enhanced Virtual Hosting (EVH) where the certificate will be requested for a EVH child Virtual Service.