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How to Access USB Storage in ESXi Shell

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While performing some experiments in my home lab, I needed to access a USB storage key directly on my ESXi host (not pass-through to VMs) and found it required a small trick after some tinkering. I thought I share the process in case this comes in handy for others.

Disclaimer: This is mainly for educational and testing purposes as this is not officially supported by VMware. Please use at your own risk.

Before I begin, you should know that only USB storage devices formatted with FAT16 can be accessed in the ESXi shell and is applicable to both ESXi 4.1 and 5.0.

Step 1 - Login to ESXi Shell via SSH and disable the USB Arbitrator service (this is automatically enabled by default to allow pass-through of USB devices to your VMs) using the following command: /etc/init.d/usbarbitrator stop

Step 2 - Plug-in your USB device to your ESXi host and you can verify by using the two ESXCLI commands: verifying the storage device using the command: esxcli storage core device list | grep -i usb or viewing the mounted filesystems using the command: esxcli storage filesystem list

Step 3 - Lastly, after you verify the USB device can be seen by the ESXi host, you can of course browse and access your USB device by looking under /vmfs/volumes/

Te re-enable pass-through of USB devices to your VMs, you just need to start the usbarbitrator service.

Datastore File Management using vCLI vifs

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There are many useful scripts that are bundled with the VMware vCLI, one such script, that is not very well known is the vifs utility which provides datastore file management. When you right click on a datastore and browse using the vSphere Client, you can create a new folder, download/upload, delete and move files.

Using the vCLI's vifs utility, you can perform the same set of operations via the command-line and behind the scenes it uses the vSphere API fileManager to perform these operations. You can also browse datastore by just having access to a web browser, just point it to the following address: https://[ESXI_HOSTNAME]/folder and you can access the datastores by clicking through the links.

To browse the datastore using vifs, you will need vCLI installed on either a Windows/Linux system or you may use VMware vMA.

To browse a specific datastore for an ESXi host, you will need to first list the available datastores by using the following command: vifs --server [SERVER] --username [USERNAME] --listds

Once you have identified the datastore you are interested in, you will then use the --dir flag to list the contents of the directory and their sub-directories by using the following command: vifs --server [SERVER] --username [USERNAME] --dir '[DATASTORENAME]'

Note: The format of the datastore name must be in brackets '[datastorename]' which is how a datastore path is identified in the vSphere API. To list sub-directories, you will need a space between the datastore name and the directory name and do not forget to quote the parameter

Let's say you would like to download the .vmx configuration file for in the directory, you can use --get flag to by using the following command:

vifs --server [SERVER] --username [USERNAME] --get '[DATASTORENAME] somedir/somefile.vmx'

Note: In the example above, we are downloading the file in the current working directory denoted by the "." (period). If you wish to download it somewhere else or even renaming the file, you will need to specify the full path to the destination


If you wanted to automate the downloading of say all .vmx configuration files, it might be pretty tedious to run through the directory discovery, so here is a quick shell script called getVMVMX.sh that is more user friendly that allows you to easily download all .vmx configurations for a given datastore.

To use the script, you will need vCLI installed on either a Linux system or use VMware vMA and be sure to set the executable permission on the shell script. You will need to specify the credentials to the ESX(i) host and the specific datastore you wish to either "list" or "download" all .vmx configuration files.

Using the --listds flag, you will need to identify the datastore you wish to use. Next you will use the following command to "list" all .vmx configuration file: ./getVMVMX.sh [ESXI_SERVER] [USERNAME] "[PASSWORD]" [DATASTORE] list

To download all .vmx configuration file you will use the following command:

./getVMVMX.sh [ESXI_SERVER] [USERNAME] "[PASSWORD]" [DATASTORE] download [FOLDER]

where FOLDER is a directory that will automatically be created for you to store all .vmx configuration files

Note: You can easily modify the script to add an additional "for loop" at the beginning to automatically download .vmx configurations for all datastores. I will leave that as an exercise for the reader.

So if you ever need to grab a vmware.log file for a specific VM or upload an ISO to datastore, you can do so from the command-line using the vifs utility that is bundled with the vCLI.

Ghetto webAccess for ESXi

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I got the idea for this post a few months back after noticing several questions on the VMTN forums on how to enable webAccess for ESXi. With ESXi, the webAccess interface is no longer available as it was with classic ESX. After seeing the question and randomly browsing through the various flings on VMware Labs, I noticed an interesting fling called Ops Panel for ESX. Ops Panel provides a simple javascript that leverages the vSphere MOB to perform basic power operations for virtual machines and it is loaded onto the homepage of a classic ESX host remotely using Greasemonkey.

I immediately wondered if I could run the javascript directly on an ESX or ESXi host without the use of Greasemonkey. With a quick tweak of the default index.html homepage, I was able to get a simple "ghetto" webAccess running on both an ESX and ESXi host. I also ran into several bugs, one that dealt with how the power state of a virtual machines was being captured by the differences in the ESX(i) 4.0, 4.1 and 5.0 APIs and a recent fix to a CSRF (Cross-Site Request Forgery) vulnerability in ESX(i) 4.1 Update 1 that made it difficult to get Ops Panel running on more than just ESX(i) 4.0.

I reached out to the fling creator Ivan Donchev and he was kind enough to help assist me in the issues I ran into and also provided an updated version of his script to properly handle both the power state and the CSRF workaround. He recently published an update to his script a few weeks back supporting both ESX 4 and ESXi 5 but missed ESX(i) 4.1 support due to limited amount of testing. This was an easy fix and I modified the script to include support for ESX(i) 4.1 and also changed the default power off operation to a guestOS shutdown. The modified version of the script can be downloaded here.

When you browse to the homepage of your ESX(i) host using the browser, you will be prompted to login which require the same credentials as if you were to login to the host directly using the vSphere Client or vSphere MOB.

Once you have logged in, it will search for all virtual machines running on the host and generate the list of virtual machines and their respective power states.

You can then perform the appropriate power operation such as a power on, shutdown or suspend using the icons on the right. This can be really useful if you don't have access to vCenter Server, vSphere Client or SSH access to the host but just have a web browser.

To load the Ops Panel script on an ESX(i) host, you will need to do the following:

Note: These instructions are applicable for both ESX and ESXi, but with ESXi, it is important that the commands to copy both the modified index.html and Ops Panel script to docroot are executed as changes are not persisted after a reboot for ESXi hosts.

You can also add this to your kickstart file by appending the lines above in your %firstboot stanza so you automatically get Ops Panel after install. Though this will not give you a full webAccess that classic ESX did but it definitely is a useful way to quickly get to your virtual machines and perform simple power operations using a web browser.