WilliamLam.com

Workaround to deploy vSphere Integrated Containers 1.1 OVA using PowerCLI (SHA256 not supported)

by // 2 Comments

Last week I had noticed several folks were having issues deploying the latest vSphere Integrated Containers (vIC) 1.1 OVA using PowerCLI. The following error message was observed when using the Get-OvfConfiguration cmdlet which is needed before importing an OVF/OVA:

PowerCLI doesn't support SHA256 hash codes in OVF manifest

As you probably have guessed, the issue is that PowerCLI currently does not support the SHA256 hashing algorithm, which the latest vIC OVA was generated with. I suspect this is probably related to the change with OVFTool 4.2 which now defaults to SHA256 which also has some implications on which vSphere UI you can use to import OVF/OVAs which I had written about here. As of today, PowerCLI currently only supports SHA1 and anything greater will not work. I have already reported this to Jake Robinson who is the PM for PowerCLI and hopefully this will get addressed in a future update.

In the meantime, you can deploy vIC using either the vSphere Web Client and/or ESXi Embedded Host Client, both support SHA256. If you wish to Automate the deployment of vIC, the only option right now is to convert the OVA from SHA256 to SHA1. You can easily do this by using OVFTool which is available on all OS platforms. If you already have downloaded the vCenter Server Appliance (VCSA) ISO, you can even make use of its bundled OVFTool in case you did not want to install OVFTool (You can find it under vcsa/ovftool in extracted ISO).

To convert the hashing algorithm, we just need to pass in our desire hash to the --shaAlgorithm parameter.

ovftool.exe --shaAlgorithm=SHA1 C:\Users\primp\Desktop\vic-v1.1.1_56a309fb.ova C:\Users\primp\Desktop\vic-v1.1.1_56a309fb-SHA1.ova

Once the conversion is done, you can delete the original vIC OVA and then use PowerCLI to import the new OVA just like you would with any other OVF/OVA!

Default hashing algorithm changed in OVFTool 4.2 preventing OVF/OVA import using vSphere C# Client

by // 11 Comments

After upgrading my home lab recently to vSphere 6.5, I also updated some of the related utilities such as the various SDKs and CLIs. One of the CLIs that I had updated was the latest version of OVFTool which is now at 4.2. I use OVFTool extensively to automate various Virtual Machine deployments (import/export). While testing out a new OVA that I had been working on, I needed to verify that it also worked with previous release of vSphere like vSphere 6.0 Update 2. I happen to have the vSphere C# Client open and connected to a vCenter Server and when I tried to import the newly created OVA, but it failed with the following error message:

The following manifest file entry(line1) is invalid: SHA256

screen-shot-2016-11-17-at-7-37-47-am
I was pretty surprised by this since I went through this exact same workflow a couple of days ago without any problems. The only change that had happened was OVFTool and error seems to indicate an issue with the hashing algorithm. I ran OVFTool again using just the --help option to check what the default SHA hashing algorithm was, it was SHA256. I then compared that to an older version of OVFTool and it looks like the default had changed from SHA1 to SHA256.

From a security standpoint, this is a positive change as SHA1 is no longer considered a secure hashing algorithm and a stronger version should be used. It also turns out that the vSphere C# Client can only support SHA1 which is why I received the error after upgrading to the new version of OVFTool. Luckily, this is NOT a problem when using the vSphere Web Client or the vSphere HTML5 Client and only affects the vSphere C# Client. If you do need to use the vSphere C# Client for importing OVF/OVAs exported from the latest version of OVFTool, the workaround is quite simple, just override the default hashing algorithim when exporting by adding the additional CLI option:

--shaAlgorithm=sha1

Extracting SSL Thumbprint from ESXi

by // 13 Comments

While browsing the VMTN forums earlier this week, I noticed an interesting request from a user who was trying to compile an inventory of the SHA1 Thumbprints for all his ESXi hosts. The challenge the user had, was that he was capturing this information manually by "looking" at the DCUI screen which is where the SHA1 Thumbprint for an ESXi host is displayed by default.

As you might have guessed, this can be very tedious and error prone by copying down this very long string by just looking at the screen. Even if you do not make a mistake copying this long string, I bet your eyes will eventually give out. Luckily, there are a few ways to retrieve this information and I will show you some methods to help automate this across all of your ESXi hosts.

UPDATE (05/22/16) - Here's how you can extract SSL Thumbprint using PowerShell

Option 1 - Retrieve SSL Thumbprint using the DCUI as shown above, this is going to be the most manual method.

Option 2 - If you have remote SSH or direct console access to ESXi Shell, you can login to your ESXi host and using openssl utility, you can retrieve the SSL Thumbprint which you can then use or copy off to a remote host.

openssl x509 -in /etc/vmware/ssl/rui.crt -fingerprint -sha1 -noout

Option 3 - You can remotely retrieve the SSL Thumbprint by leveraging just the openssl utility and you do not even need to login to the ESXi host. This not only allows you to retrieve the SSL Thumbprint from a centralized location, but you can easily automate this across all your hosts.

echo -n | openssl s_client -connect 172.30.0.252:443 2>/dev/null | openssl x509 -noout -fingerprint -sha1

Using Option 3, you can easily wrap this in a simple "for" loop to iterate through all your ESXi hosts as long as you have either the hostname/IP Address. Here is a simple shell script that you can use to iterate through all your ESXi hosts to extract the SSL Thumbprint.

In the script above, I have a list of three ESXi hosts and it is simply going through each host and executing the two commands to extract the SSL Thumbprint and displaying it on the screen.

Option 4 - You can also retrieve the SSL Thumbprint using the vSphere API, but the property is only displayed when it is connected to a vCenter Server. There is a property on the ESXi host called sslThumbprint that is populated when querying against the vCenter Server that is managing the ESXi host. You can use the vSphere Health Check script which captures this and other useful information about your vSphere infrastructure.

As you can see, there are several options on obtaining the SSL Thumbprint for an ESXi host, you definitely do not have to manually read it off the DCUI screen. Automation FTW again! 🙂