REST APIs - Part I

REST APIs - Part I

In this post I wanted to introduce APIs a bit. I've used Powershell and PowerCLI with VMware mostly for many years but with DevOps, Ansible, Github, Openstack, Chef, Puppet etc REST is now becoming a skill I need to understand, or at least know about.

I loaded up HP OneView 2.0 and Veeam Backup & Recovery 9.0 to get a feel for using an API to drive things. Both were a little different but interesting to explore in this way. Of course you can still use Powershell but this exploration was intended to expand my knowledge beyond the traditional tools I was familiar with.

Firstly you need a REST Client. I used a Chrome Application/Extension. You'll see the Apps icon on the Taskbar on the left as shown below:

Next, Click on the Web Store

Now do a search for REST. Here's a few - I've heard a lot about POSTMAN which is what I'll be using here

I've already installed Postman, you just need to click "+ Add to Chrome" and click on the Chrome Apps Taskbar button and this time you'll see the new App

Next Click on the new Application and a new Browser Window opens up for you to play with!

Give yourself time to get used to the interface. What we'll do next is some basic requests with OneView and get used to using this tool to query and operate this API.

Once you have configured the OneView administrator password and set IP Address etc we're all ready to go. You should be able to browse to the admin interface with a browser. Now we'll access it with POSTMAN and see what that looks like.

Do a "GET" and put in the URL to the OneView appliance, in my case "https://192.168.10.51" and Click Send. You should get a 200 OK Status Response. The fun starts here!!!

Now, we need to get authentication worked out by generating a sessionID. We do this by adding some headers. There are two needed, by the way I'm following the guide here:
http://h17007.www1.hp.com/docs/enterprise/servers/oneview1.2/cic-rest/en/content/s_start-working-with-restapis-sdk-fusion.html

Content-type: application/json
Accept: application/json

The headers should match mine shown below

Now make sure you change the type to POST and edit the URL to add "/rest/login-sessions" and then click the Body section and choose RAW and enter in the following into the text box below

{"userName":"administrator","password":"mypassword"}

change the password for your environment and Click SEND. You should get a sessionID in the box lower down with a Status 200 OK. The sessionID can now be copied and added as a third header row so you can send authenticated commands to OneView as shown here

Then Run a GET and set the request to be https://192.168.10.51/rest/version and see if you get this result

You are now set to have some fun!! 

HP Lists the API commands on the following page:

http://h17007.www1.hp.com/docs/enterprise/servers/oneviewhelp/oneviewRESTAPI/content/images/api/

The commands each have an examples and vary from basic to complex. Let's try a few.

List the Users on OneView

Click the Security/Users link on the API webpage above. It shows a GET option with url /rest/users. You can click on the triangle to the left to expand this command for an example. The top grey box appears to be the command used and the expected result is shown in the second box. 

So, by just changing one word from the last test from "version" to "users" and adding an extra header for X-Api-Version: 100" I can SEND this and get the result below

Add a User to OneView

Now let's try adding a User. Copy the command given against "POST /rest/users" including the {} and POST it as follows:

Now you should see the user in the OneView web console. You just make your first step into DevOps Territory!! Well Done!!

I'll cover Veeam and more options in OneView in the next Post, Enjoy!