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HTML5 VM Console does not work after rebooting the VCSA or Windows vCenter Server 5.5

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There was an issue that was identified by some folks internally as well as myself around the new HTML5 VM Console for the VCSA 5.5 (vCenter Server Appliance). The issue is that after a reboot of the VCSA, the new HTML5 VM Console no longer functions. When you launch the console from the vSphere Web Client, you will get the following error "could not connect to x.x.x.x:7331"

After troubleshooting the issue with some of the engineers, it turns out there is an environmental variable that is not being properly set. There is a simple workaround to restore HTML5 VM Console functionality, take a look at the steps below:

Step 1 - Open up /usr/lib/vmware-vsphere-client/server/wrapper/conf/wrapper.conf (for Windows it is under C:\Program Files\VMware\Infrastructure\vSphereWebClient\server\bin\service\conf\wrapper.conf) and add set.default.VMWARE_JAVA_HOME=/usr/java/jre-vmware under the environmental section and save the file.

Step 2 - Restart the vSphere Web Client by running the following command:

/etc/init.d/vsphere-client restart

Once the vSphere Web Client is available, you will now be able to access the HTML5 VM Console when launching from a Mac OS X system or an automatic generated URL. This issue has already been reported internally and we will also get a VMware KB article published with the workaround.

Here is the official VMware KB 2060604

How to generate a pre-authenticated HTML5 VM console link in vSphere 5.5 that works on all OSes!

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One of the coolest feature that I have been personally looking forward to is the ability to access a virtual machine's remote console on a Mac OS X system which is now available as part of the vSphere 5.5 release. When you launch the VM's remote console using the vSphere Web Client on a Mac OS X system, instead of using the regular VMRC, it launches an HTML5 based console for your VM.

One thing that you might have noticed when performing this same action on a Windows desktop using the vSphere Web Client is that VMRC is used instead of the HTML5 console (notice the generated URLs are different). My understanding is that the VMRC is currently more performant than the HTML5 console and hence it is preferred when possible. I have been using the HTML5 based console for quite sometime now and I have not had any issues with it. I really hope to see us use the HTML5 console as the default console in the future!

Having said all this, there is a way for all users can benefit from this new HTML5 based VM console which is to automatically generate the URL which can then be loaded into any HTML5 supported web browser on either a Mac OS X, Windows or even Linux system. I used a similar method in generating the VM Remote Console for the vSphere Web Client which is VMRC specific.

UPDATE (07/26/17): I have just published a PowerCLI script called GenerateVMConsoleURL.ps1 which runs against a vSphere 6.5 environment and supports generating the HTML5 VM Console, Standalone VMRC and WebMKS URLs. As noted by several folks in the comments below, the pre-auth mechanism no longer works post-6.0, so you will need to have logged already for the console to automatically load OR you will be prompted to login before being re-directed. For those that wish to generate VM Console URLs for older vSphere versions, you can modify the script to handle those other scenarios.

The really cool part about this solution is that you can provide a one time pre-authenticated HTML5 based VM console URL that can then be given to your end users to access their VM. This of course can be automatically generated through a custom portal without needing to provide direct access to the vSphere Web Client.

Here is an example of what the HTML5 VM console URL looks like in vSphere 5.5:

http://reflex.primp-industries.com:7331/console/?vmId=vm-23&vmName=VCSA&host=reflex.primp-industries.com&sessionTicket=cst-VCT-5254c455-4340-2185-e149-01ce44b146e1--tp-4A-88-17-7C-F5-D0-79-E6-9D-A1-E3-83-97-52-97-EA-E5-D3-D8-07&thumbprint=4A:88:17:7C:F5:D0:79:E6:9D:A1:E3:83:97:52:97:EA:E5:D3:D8:07

In vSphere 5.5 Update 2, the HTML5 VM Console now defaults to a secure connection and the two components of the URL that needs to be modified is from HTTP to HTTPS and from port 7331 to port 7343. The script has been updated to support a new command-line option called isvSphere55u2 which by default is set to false but can be set to true to generate an updated URL if you are running vSphere 5.5 Update 2

There are basically seven important components to the URL:

  • Hostname of the vCenter Server - reflex.primp-industries.com
  • The HTML5 console port, default is 7331 but can automatically change depending on available ports on the system (for vSphere 5.5 Update 2 the port has changed to 7343 for a secure connection)
  • The MoRef ID of the virtual machine - vm-23
  • The virtual machine name - VCSA
  • The vCenter Server advanced setting "VirtualCenter.FQDN" - reflex.primp-industries.com
  • The session ticket generated from vCenter Server - cst-VCT-5254c455-4340-2185-e149-01ce44b146e1--tp-4A-88-17-7C-F5-D0-79-E6-9D-A1-E3-83-97-52-97-EA-E5-D3-D8-07
  • The vCenter Server SHA1 SSL Thumbprint - 4A:88:17:7C:F5:D0:79:E6:9D:A1:E3:83:97:52:97:EA:E5:D3:D8:07

Disclaimer: The HTML5 VM console URL format/behavior is not guaranteed and may change in the future. The only officially supported method of accessing the console is by launching it through the vSphere Web Client.

Here is a vSphere SDK for Perl script called generateHTML5VMConsole.pl that given a VM name as input, will automatically generate a one-time pre-authetnicated HTML5 VM console URL that can be loaded into any supported web browser.

Note: To ensure the URL is valid, you will need to make sure your application is setup to run like a daemon or agent. To simulate this in my sample script, I just sleep for 60 seconds before disconnecting the session. I also used the openssl utility to extract the SHA1 thumbprint, so you will need a system that has that installed along with the vSphere SDK for Perl if you wish to use the script. The quickest way is to leverage vMA.

To load the HTML5 VM console, take the URL that is generated and point it to a browser:

Since this is an HTML5 based VM console, I can even load this into my iPad!

Hopefully this article will give you new ideas on how you can leverage and integrate the new HTML5 VM Console within your environment and hopefully this will be the defacto console in the future!

Here is an example of what the URL looks like for vSphere 5.1 & 5.5:

https://reflex.primp-industries.com:9443/vsphere-clien/vmrc/vmrc.jsp?vm=urn:vmomi:VirtualMachine:vm-1506:EE26E7F6-591B-4256-BD7A-402E5AC9E0A8

There are basicallythree important components to the URL:

  • Hostname of the vCenter Server - reflex.primp-industries.com
  • The vCenter instanceUUID which used to uniquely identify a vCenter Server - EE26E7F6-591B-4256-BD7A-402E5AC9E0A8
  • The MoRef ID of the virtual machine - vm-1506

How to clear the ARP cache on ESXi using new ESXCLI 5.5

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The ability to clear the ARP cache/table for an ESXi host is feature that has been requested from customers from time to time and usually for diagnosing network related issues. In previous releases, this was not something you could easily do and it was nice to see this feature get implemented in a new ESXCLI command that will be available as part of the vSphere 5.5 release.

The ESXCLI "network ip neighbor" namespace has been enhanced to include a new option:

You can list ARP table entries using the "list" operation and you can now clear a specific ARP entry using the "remove" operation.

To clear an ARP entry, you will need to specify the IP Address you wish to clear, the IP protocol whether it is IPv4 or IPv6 and you also have the option to specify the particular VMkernel interface. If you do not specify the particular VMKernel interface, then the entry will be removed for all interfaces.

Here is a screenshot of listing of the current ARP entries and then removing an entry for VMkernel interface 1:

This will definitely be a useful ESXCLI command to be aware of the next time you need to troubleshoot a network issue!

Note: I mentioned earlier that clearing the ARP cache was not something that you could do prior to vSphere 5.5. However, while working on this article, I actually learned it was possible to clear the ARP cache, but it was not very user friendly like the new ESXCLI 5.5 command. In a separate article, I will show you how can clear the ARP cache on earlier versions of ESXi.

If you wish to clear the ARP cache on an ESXi host prior to ESXi 5.5, please take a look at this article for more details.