Running a Bash command after scaling an Azure VM Scale Set

Question

Hello,

I am working with an Azure VM Scale Set running Ubuntu OS and have written Java code to scale it up or down. However, I am struggling with post-deployment scripts. I need each new VM created in the set to run a Bash script when it starts, and the script should be unique for each VM, with only one variable changing.

What is the solution for running these scripts after a new VM is created and running? I have explored the possibility of using Custom Script, but I have not been able to find any API in the Java SDK to accomplish this.

Thank you,

Barak.

Answer 1

Hello, @Barak Pahima !

How do I run a script after a VM deployment using the Java SDK?

It looks like you're specifically looking for something that you can use with a Java SDK deployment workflow. You can use custom data and there's a detailed post that goes through what this looks like.

Looking at the Azure Java SDK examples, this is what caught my attention:

// Use a VM extension to install Apache Web servers
                        .defineNewExtension("CustomScriptForLinux")
                            .withPublisher("Microsoft.OSTCExtensions")
                            .withType("CustomScriptForLinux")
                            .withVersion("1.4")
                            .withMinorVersionAutoUpgrade()
                            .withPublicSetting("fileUris", fileUris)
                            .withPublicSetting("commandToExecute", installCommand)
                            .attach()

Let me know in the comments if this is useful or if you need additional guidance.

Answer 2

You can use Azure Custom Script Extension for post-deployment configuration on Linux Machines.

You can check the following link.

https://learn.microsoft.com/en-us/azure/virtual-machines/extensions/custom-script-linux

Azure Instance Metadata Service can be another option to configure virtual machines

https://learn.microsoft.com/en-us/azure/virtual-machines/instance-metadata-service?tabs=windows