vSphere 6.0 REST API: A History Lesson

I’m glad to see how VMware products are becoming more and more automation-focused these days. NSX has always had rich REST API capabilities, which I can’t complain about. And vSphere is now starting to catch up. vSphere 6.5 was the first release where REST API started getting much more attention. See these official blog posts for example:

• What’s New with Developer and Automation Interfaces for vSphere 6.5?
• Getting Started with the vSphere Automation SDK for REST
• Introducing Developer and Automation Interfaces for vSphere 6.7

But not many people know that vSphere 6.5 wasn’t the first release where REST API became available. Check this forum thread on VMTN “Does vCenter 6.0 support RESTFUL api?”:

I think its only supported for 6.5 as below blogs has a customer asked the same question and reply is no..

It’s not entirely true, even though I know why the OP got a “No” answer. Let me explain.

vSphere 6.0 REST API

VMware started to make first steps towards REST API starting from 6.0 release. If you have a legacy vSphere 6.0 environment you can play with, you can easily test that by opening the following URL:

https://vcenter/rest/com/vmware/vapi/metadata/cli/command

You will get a long list of commands available in 6.0 release:

It may look impressive, but if you look closely you will quickly notice that they are all Content Library or Tagging related. Quote from the referenced blog post:

VMware vCenter has received some new extensions to its REST based API. In vSphere 6.0, this API set provides the ability to manage the Content Library and Tagging but now also includes the ability to manage and configure the vCenter Server Appliance (VCSA) based functionality and basic VM management.

That is right, in vSphere 6.0 REST API is very limited, you won’t get inventory data, backup or update API. All you can do is manage Content Library and Tagging, which, frankly, is not very practical.

Making REST API Calls

If Content Library and Tagging use cases are applicable to you or you are just feeling adventurous this is an example of how you can make a call to vSphere 6.0 REST API via Postman.

All calls are POST-based and action (get, list, create, etc.) is specified as a parameter, so pay close attention to request format.

First you will need to generate authentication token by making a POST call to https://vcenter/rest/com/vmware/cis/session, using “Basic Auth” for Authorization and you will get a token in response:

Then change Authorization to “No auth” and specify the token in “vmware-api-session-id” header in your next call. In this example I’m getting a list of all content libraries (you will obviously get an empty response if you haven’t actually created one):

Some commands require a body, to determine the body format use the following POST call to https://vcenter/rest/com/vmware/vapi/metadata/cli/command?~action=get, with the following body in JSON format:

{
	"identity": {
        "name": "get",
        "path": "com.vmware.content.library"
	}
}

Where “path” is the operation and “name” is the action from the https://vcenter/rest/com/vmware/vapi/metadata/cli/command call above.

If you’re looking for more detailed information, I found this blog post by Mitch Tulloch very useful:

• Understanding the VMware REST API Interface

Conclusion

There you have it. vSphere 6.0 does support REST API, it’s just not very useful, that’s why no one talks about it.

This blog post won’t help you if you are stuck in a stone age and need to manage vSphere 6.0 via REST API, but it at least gives you a definitive answer of whether REST API is supported in vSphere 6.0 and what you can do with it.

If you do find yourself in such situation, I recommend to fall back on PowerCLI, if possible.

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Quick Start With Lifecycle Manager REST APIs

Just a few years ago coming across an infrastructure product (software or hardware) that supports REST APIs was a rare thing. Today it’s the opposite. Buying, say, a storage array from a major vendor, that doesn’t support some sort of an API can be seen as a potential drawback. It’s now gotten to a point where certain operations can only be done via API and are not available in the GUI. So basic programming skills become more and more important.

I have come across such situation with vRealize Suite Lifecycle Manager (vRSLCM or just LCM) product from VMware. If you have a request that got stuck, the only way to cancel it (at least at the time of writing) is to use LCM’s REST APIs. It can’t be done from the GUI.

While I was tackling this issue, I noticed that there aren’t many articles on how to make REST calls to LCM on the Internet, so I though I’d use this opportunity to show how to do it.

Authentication

First challenge you have to deal with is authentication. LCM doesn’t support basic authentication, like other products, for instance NSX. You need a token.

This is how you can get a token in Postman:

• Submit a POST call
• Use the following URL – https://lcm-hostname/lcm/api/v1/login
• Enter the following body:

{
	"username":"admin@localhost",
	"password":"vmware"
}

This is what it will look like in Postman:

When you click send you should get a token in response:

Making REST Calls

Now you need to specify the token as one of the headers, with “x-xenon-auth-token” as key and the token itself as value:

From here, you are ready to make actual REST API calls. Coming back to our example, we can go to LCM GUI and copy the ID of the stuck request from the browser window:

And then make a DELETE call with empty body to cancel the request:

As a result, traces of the request will be completely deleted from LCM.

Note: The only catch here, that you have to remove “v1” version of the API from the URL. Or it will not work.

Swagger UI

LCM supports Swagger, which lets you run REST API calls straight from the browser. So if you want to feel yourself a hacker, open the https://lcm-hostname/api URL and you can get the token and make requests by simply using the “Try It Out” button, specifying required parameters and hitting “Execute”.