PowerCLI – Page 50

Remotely query an ESXi host without adding it to vCenter Server

07.19.2016 by William Lam // Leave a Comment

I was browsing through the vSphere API Reference the other day and I came across an interesting vSphere API called QueryConnectionInfoViaSpec() which was introduced in vSphere 6.0. This new API is similiar to the existing QueryConnectionInfo() method which also allows you to remotely query an ESXi host without requiring you to add it to your vCenter Server Inventory, which I did not know about before. Some of the information that you can retrieve is whether it is currently being managed by an existing vCenter Server and if so, what is its IP Address, any registered Virtual Machines, networks and datastores that may be configured along with underlying host capabilities.

The main difference between this new API is that instead of accepting a list of arguments to the method, it accepts a HostConnectSpec. It is a minor difference, but what this allows you to do is to be able to re-use that exact same spec in the AddHost_Task() API if you determine that you would like to add the ESXi host to your vCenter Server Inventory after inspecting the remote ESXi host. I think this is a useful API if you want to validate that you are not stealing an ESXi host from another managed vCenter Server and if you are, at least you know which vCenter Server it was being managed by. To demonstrate this vSphere API, I have created a simple PowerCLI script called Get-RemoteESXi.ps1 which requires a vCenter Server login as well as the Hostname/IP Address and credentials of the remote ESXi host you wish to query.

Here is an example output of running the script which stores the returned output to the $results variable.

If you want to check whether the ESXi host is being managed by an existing vCenter Server, you can check the following property which will hold the IP Address of the vCenter Server if it is currently being managed:

$result.Host.ManagementServerIp

If you want to check if there are running VMs already on the ESXi host, you can check the following property:

$result.vm

As mentioned earlier, there is a ton of other information returned from the remote ESXi host and I will leave it as an exercise for the reader to explore further.

How to automate vSphere MOB operations using PowerShell?

07.13.2016 by William Lam // 5 Comments

A couple of weeks back I was investigating something that involved the use of the vSphere Managed Object Browser (MOB) and I needed to automate a particular operation. For those of you not familiar with the vSphere MOB, it is a UI debugging tool that allows you to visualize and invoke vSphere APIs using just a web browser. The vSphere MOB is available on both vCenter Server and ESXi and uses the underlying vSphere API. Outside of learning about the vSphere APIs and potentially for troubleshooting purposes, there really is no good reason to be directly interacting with the vSphere MOB on a regular basis. Customers can use any one of the many vSphere SDK/CLIs to easily automate and interact with the vSphere API.

Having said that, there may be cases where you might want to invoke a specific operation using the vSphere MOB, such as private API for example. Obviously, using any private/internal APIs is not officially supported by VMware and their use will be at your own risk. Nonetheless, I had a specific operation that I needed to call from the vSphere MOB and wanted to do so using PowerShell. Several years back I had demonstrated how you could invoke the vSphere MOB using Python but I could not find any PowerShell examples that actually worked. I figured this would be a good learning opportunity for myself and probably something I or others could benefit in the future.

To provide a concrete example, I will be invoking a supported vSphere API called the QueryOptions which is used for accessing either a vCenter Server or ESXi Advanced Settings. For our example, I will be connecting to the vCenter Server's MOB and will be querying for a specific vCenter Server Advanced Setting. If we were to do this manually in the vSphere MOB, we would first open a web browser and login to the following URL: https://[VC-SERVER]/mob/?moid=VpxSettings&method=queryView

If you wanted to see all advanced settings, you would leave the "name" parameter blank. For our example, we will query for the VirtualCenter.InstanceName property as shown in the screenshot above and then click on the "Invoke Method" to execute the vSphere API operation. If successful, it should display the results which in our case is the IP Address of my vCenter Server. Pretty straight forward vSphere MOB example. OK, onto automating this from PowerShell. I have created a sample PowerShell script called automate-vsphere-mob.ps1 which you will need to edit and provide your vCenter Server Hostname/IP Address and the vCenter Server credentials (can be read-only) since we are not performing any write operations.

Here are some more specific details on what is happening in the script for those interested:

Authenticate to the vSphere MOB URL that you wish to invoke using an HTTP GET operation and storing the session into a variable named vmware (Line 28-29)
Extract the hidden vmware-session-nonce property used to prevent Cross-Site Request Forgery (CSRF) (Line 31-40)
Create the body request which must include the vmware-session-nounce property along with the vSphere API payload (Line 42-45)
Invoke the actual vSphere API call using an HTTP POST along with the existing session from Step 1 and body payload
Process the results (this will be specific to API call) and profit! (Line 50-59)

If you now run the script, you will see that the result is exactly what we saw from interactively using the vSphere MOB. Hopefully this will be useful for anyone who may have a need to automate against the vSphere MOB. For those curious on what I was investigating with the vSphere MOB, stay tuned for more details 🙂

How to audit vSphere Standalone VMRC or HTML5 VMRC connections?

07.11.2016 by William Lam // Leave a Comment

An interesting question that came in last week from one of our TAMs was how to identify and audit Virtual Machine Remote Console (VMRC) logins from vSphere? The TAM was specifically interested in being able to correlate that a particular user had logged into the VMRC of a VM during a specific period of time. Luckily, this is easily retrievable through vCenter Servers's Event sub-system that stores information about everything that happens in your vSphere environment. The Events can be accessed using either the vSphere Web Client shown below or programmatically using the vSphere API which the UI is built on top of.

You can obviously filter your search in the UI and focus on a particular VM, but often times there can be dozens if not hundreds of "Events" generated for a given VM. I personally prefer to leverage Automation when needing to look for a specific type of Event and more importantly, you can further process the results to either send out reports or hook into other third party systems. Now that we know, "where" to find our data, the next thing is identifying the type of Event that is generated for a VMRC connection.

As of vSphere 5.5 Update 2b, the VMRC in the vSphere Web Client can be accessed in one of two ways: The new HTML5 VMRC by clicking onto the VM screenshot thumbnail or the Standalone VMRC by clicking on the link directly beneath the VM screenshot.

Each VMRC connection method will generate a unique vCenter Server Event. For HTML5 VMRC connections, the Event is called VmAcquiredMksTicketEvent and for Standalone VMRC connections, the Event is called VmAcquiredTicketEvent. As I mentioned earlier, the vCenter Server Event sub-system can be accessed using the vSphere API and you can find the complete list of Events documented here. To demonstrate the use of this particular vSphere API, below is a PowerCLI example using the Get-VIEvent cmdlet. My fellow colleague Alan Renouf has actually blogged about working with Events using PowerCLI which I will be adapting one of his examples for our use case.

We first retrieve the VM that we are interested in by running the following command (specify the name of your VM):

$vm = Get-VM -Name "VCSA-60u2"

To retrieve HTML5 VMRC connections, run the following PowerCLI command:

Get-VIEvent -Entity $vm | Where { $_.Gettype().Name -eq "VmAcquiredMksTicketEvent"} | Select CreatedTime, UserName, FullFormattedMessage | ft -wrap -AutoSize

Here is an example of what the output would look like

To retrieve Standalone VMRC connections, run the following PowerCLI command:

Get-VIEvent -Entity $vm | Where { $_.Gettype().Name -eq "VmAcquiredTicketEvent"} | Select CreatedTime, UserName, UserAgent, FullFormattedMessage | ft -wrap -AutoSize

Here is an example of what the output would look like: