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New way of enabling and disabling services using vSphere 4.1

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While checking out the PlanetV12n feed, I noticed a new video from David Davis about the new vSphere 4.1 Tech Support Mode. In the short video, David goes over the new method of enabling "hidden" unsupported Busybox Console, also known as Tech Support Mode. In the past, you had to be on the console of your ESXi host, type ALT+F1, and then "unsupported" to gain access. Once in, to enable remote SSH access or Remote Tech Support Mode, you had to edit /etc/inetd.conf and restart inetd service. This was pretty tedious if you needed access for a short period of time. In the video, David goes over the new method showing how it can be done using the DCUI and the old method is no longer required.

What surprised me after watching the video was that he did not mention the other method of enabling and disabling Tech Support Mode both local and remote. One issue I had with past releases of ESXi is that you could restart some services such as ntp or vmware-vpxa via the vSphere API, but others were just not available. In vSphere 4.1, VMware introduces a few new services around their Likewise Active Directory integration but also includes controlling both local and remote Tech Support Mode as well as DCUI itself.

These services can be enabled and disabled using the vSphere Client, here is a screenshot:

To enable or disable TSM, just click on the service and then click on options:

You will then have the option to configure the startup policy including enabling or disabling the service:

If you needed to perform this operation against one or two host, it is not that big of a deal. Though if you needed to enable remote Tech Support Mode (SSH access) across few dozen hosts, then can still be tedious. Luckily I wrote a script (hostServiceMangement.pl) last year that allowed you to enable and disable supported services using the vSphere API. Without any modifications, it supports vSphere 4.1 and can take advantage of the new services that are available for control.

Here is an example of listing the services on an ESXi 4.1 host:

Here is an example enabling remote Tech Support Mode:

Here is an example of disabling remote TSM:

The script can be executed on a host that has vCLI 4.1 installed or on vMA 4.1 and can bulk update a list of ESX/ESXi host or individual host. For more details, please check out the documentation for hostServiceManagement.pl.

What's new in the vSphere 4.1 MOB

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The vSphere MOB (Managed Object Browser) is not a well known tool and unless you are a developer, you probably do not know of its existence. The simplest way to describe the vSphere MOB is that it is a debugging tool to graphical visualize all entities within the vSphere API through a web browser. It is often used to better understand the vSphere API/inventory and aide in developing your own vSphere application or script. For a detailed deep dive of the vSphere inventory, check out Steve Jin's post here.

The vSphere MOB can be reached by pointing your web browser to either an ESX(i) or vCenter host followed by the path "/mob". You will be prompted for credentials as you normally would prior to gaining access to the MOB.

The vSphere MOB may not always be the easiest to navigate. Understanding the vSphere inventory structure is definitely helpful, otherwise it can be very confusing to users. With the release of vSphere 4.1, there are two major changes in the MOB that can help make the navigation easier for developers.

Previous to vSphere 4.1, the MOB would display managed entities using their Managed Object IDs (MoRef ID) as a way to uniquely identify these objects. This made it very difficult for developers to identify the specific object you are viewing without having to dig further.

In vSphere 4.1, the MOB provides both the MoRef ID and the translated the names of the managed entities.

The vSphere MOB not only displays information about the managed entities but also provides a way to interact with the system. It does this by listing the available API methods for each managed entity at the bottom of the page and can be executed by providing the correct input parameters. The issue arises when trying to execute methods which requires complex input that require more than a simple string or integer value. The format of the input is XML-based and it can be challenging to generate the correct format, especially without any examples.

In the new version of the MOB, you are now presented with an XML template of the required parameters which can then be filled out to execute the method.

The following example will demonstrate the change of an ESXi advanced configuration value for configuring a syslog server:

Once you have filled in the required parameters, you will need to click on the "Invoke Method" to execute the specific method.

Here we verify the advanced configuration key "Syslog.Remote.Hostname" has been changed and is set to our new syslog server.

I think these two changes will make it easier for developers to navigate the vSphere MOB and assist with understanding the vSphere API and it's managed entities.