Automation – Page 178

New method of enabling Multiwriter VMDK flag in vSphere 6.0 Update 1 (UI + API)

10.19.2015 by William Lam // 22 Comments

Prior to vSphere 6.0, in order for multiple Virtual Machines to share a VMFS-backed VMDK, the Multiwriter VMDK flag must be enabled, which is accomplished by adding a specific VM Advanced Setting as shown in this VMware KB 1034165. For customers who were accustomed to this old method, you may have found that this option no longer works. This was true regardless if you had used the vSphere Web/C# Client or the vSphere API to apply the configuration.

To provide for a better user experience, this behavior was changed in vSphere 6.0 and a new API was introduced for enabling and disabling the Multiwriter VMDK flag. In vSphere 6.0, there is now a new sharing attribute on the Virtual Disk backing property which accepts one of two values: sharingMultiWriter or sharingNone for specifying the Multiwriter flag. In my opinion, this is a positive change as we too often rely on the VM Advanced Setting as a generic "catch all" for enabling or configuring various settings versus adding proper APIs to a VM.

Although there is now a proper API which will can help enable new Automation use cases, one thing that was still lacking was an easy way to enable the Multiwriter VMDK flag using the UI. In vSphere 6.0 Update 1, we have now introduced a new UI dropdown option called "sharing" in the vSphere Web Client for configuring the Multiwriter VMDK flag which can be found in the Virtual Disk section when editing a VM as shown in the screenshot below.

Note: The new Sharing property is only available in the vSphere Web Client UI and is not available in the vSphere C# Client. If you need to configure the Multiwriter VMDK flag and do not have access to the vSphere Web Client, you can use the vSphere API to help automate this configuration change.

UPDATE (06/27/16) - Created two scripts which now cover scenarios where VM is online and/or offline.

For those interested in Automating the Multiwriter VMDK flag, I have created two PowerCLI scripts called: configureMultiwriterVMDK.ps1 (offline VM configuration) and addMultiwriterVMDK.ps1 (online VM configuration) which demonstrates this new vSphere API.

The first script configureMultiwriterVMDK.ps1 allows you enable the Multiwriter Flag for an existing VMDK that has already been added to a VM. This operation must be done while the VM is powered off and to use the script you will need to specify the name of the VM as well as the label of the VMDK in which you wish to enable the Multiwriter VMDK flag (e.g. Hard disk 2). Below is an example of running the script.

The second script addMultiwriterVMDK.ps1 allows you to hot-add a new VMDK and enables the Multiwriter Flag to a VM. This operation is done while the VM is powered on which is a common workflow for customers needing to hot-add storage to an existing Cluster solution such as Oracle RAC for example all while the system is running. To use the script, there are a few variables you will need to edit:

vmName - The name of the VM you wish to perform th operation on
vmdkFileNamePath - This is the full datastore path to the name of the underlying VMDK. See the script for more information but the syntax will look like "[datastore-name] vm-home-dir/vmdk-name.vmdk"
diskSizeGB - The capacity of the VMDK to add (GB)
diskControllerNumber - The SCSI controller number (0-3)
diskUnitNumber - The Unit number (0-16)

UEFI PXE boot is possible in ESXi 6.0

10.09.2015 by William Lam // 21 Comments

A couple of days ago I received an interesting question from fellow colleague Paudie O'Riordan, who works over in our Storage and Availability Business Unit at VMware. He was helping a customer who was interested in PXE booting/installing ESXi using UEFI which is short for Unified Extensible Firmware Interface. Historically, we only had support for PXE booting/installing ESXi using the BIOS firmware. You also could boot an ESXi ISO using UEFI, but we did not have support for UEFI when it came to booting/installing ESXi over the network using PXE and other variants such as iPXE/gPXE.

For those of you who may not know, UEFI is meant to eventually replace the legacy BIOS firmware. There are many benefits with using UEFI over BIOS, a recent article that does a good job of explaining the differences can be found here. In doing some research and pinging a few of our ESXi experts internally, I found that UEFI PXE boot support is actually possible with ESXi 6.0. Not only is it possible to PXE boot/install ESXi 6.x using UEFI, but the changes in the EFI boot image are also backwards compatible, which means you could potentially PXE boot/install an older release of ESXi.

Note: Auto Deploy still requires legacy BIOS firmware, UEFI is not currently supported today. This is something we will be addressing in the future, so stay tuned.

Not having worked with ESXi and UEFI before, I thought this would be a great opportunity for me to give this a try in my homelab which would also allow me to document the process in case others were interested. For my PXE server, I am using CentOS 6.7 Minimal (64-Bit) which runs both the DHCP and TFTP services but you can use any distro that you are comfortable with.

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How to configure shared folders in VMware AppCatalyst?

10.02.2015 by William Lam // Leave a Comment

A widely used feature in VMware's hosted products (Fusion & Workstation) is the shared folders capabilities which allows you to easily share files between the host system and your Virtual Machines. With the latest release of VMware's AppCatalyst TP2, shared folders is now officially supported and can be configured using the AppCatalyst's REST API. Below are the instructions on setting up shared folders for your VMs running in AppCatalyst. Thanks to Fabio for sharing the details.

I will assume that you already have a VM that is running under AppCatalyst. If you do not, you can run the following commands to quickly deploy a new VM called "photon" from the default VMware Photon OS template and retrieve the IP Address assigned to the VM (which we will make use later).

/opt/vmware/appcatalyst/bin/appcatalyst vm create photon
/opt/vmware/appcatalyst/bin/appcatalyst vmpower on photon
/opt/vmware/appcatalyst/bin/appcatalyst guest getip photon

If you have not used AppCatalyst before, be sure to check out this getting started guide here.

Step 1 - Open a terminal and start the AppCatalyst Daemon by running the following command:

/opt/vmware/appcatalyst/bin/appcatalyst-daemon

Step 2 - Open a browser to connect to the following URL https://localhost:8080 to access the REST API explorer provided by Swagger.

Step 3 - Expand the POST /vms/{id}/folders which is the API to configure shared folders for a particular VM. You will need to fill in the id property which specifies the name of the VM and the state property defines the shared folder configuration.

Here is an example for creating a shared folder in the guest called "shared-folder" and mapping that to the host folder under /Users/lamw/Development. The flags property specifies how the folder will be accessed by the VM. Currently, there is only one flag implemented which is "4" and means read/write access. In the future there maybe more flags implemented for different types of access.

{
"guestPath":"shared-folder",
"hostPath":"/Users/lamw/Development",
"flags":4
}

Once you have entered the information into the UI, to execute the API request you just need to click on the "Try it out" button at the bottom. If the operation was successful, you should get back a 200 response from the UI.

Note: The guestPath property is not actually a path in the VM but rather the name of the directory which will map to the host shared folder.

Step 4 - We can now login to our VM to confirm that the shared folder has been configured. If you are using the default Photon template, you can login by specifying the default SSH keys included with AppCatalyst and the IP Address of the Photon VM we deployed earlier.

Here is the command to login (be sure to replace with the IP Address from your enviornment):

ssh -i /opt/vmware/appcatalyst/etc/appcatalyst_insecure_ssh_key [email protected]

Step 5 - Once logged in, if we now look under /mnt/hgfs directory, we should now see the shared directory automatically created and mapped to the host shared folder we created earlier.

If you wish to remove shared folders from a VM, you can do so by executing the DELETE /vms/{id}/folders/{folderId} API and specifying the id for both the VM and folder. Hopefully in the future, shared folders can also be easily consumed through the simple AppCatalyst CLI, but for now you can do so using the REST API.