EVERYTHING About the Scale Set Agents for Azure Pipelines (VMSS) 

Thanks! In my video I usually try to get beyond the docs that are readily available adding information that I have gained through experience or experimentation. I want to give the highest value I can to my viewers. And I’m very happy to know this came through in this video ☺️

Thanks!

You are very welcome ☺️

Welcome ☺️

Sorry but I can’t do that shortly , I’ve never used them in AWS so it’d take me a while to understand how they work.

hey. So the price of VMSS is the same as for normal Azure VMs... so when you create a VMSS you can select the size and therefore you know they price for a single agent. Things get a little more complex if you wanna know the overall cost per month... that would depend on the number of max agents you can scale to, and how much utilization you would have on the platform

No, I didn't have to install anything manually. AzDO does that for you. Just create the VMSS in Azure, and then create a new Agent Pool in AzDO selecting the VMSS as target

Hi, you can create a custom Scale Set Template, that uses a custom image. And in the custom image you can install anything you want/need. You can read more about it here: docs.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-mvss-custom-image

I am looking for the same. Are you able to achieve this?

Hey, do you mean you need to create the ScaleSet with a script? Never done that, but you could use ARM or Terraform for that instead

@@CoderDave Hi! Exact! But Terraform has no module for that. We already tried with REST API and although the scale set is generated and scaling is achieved, but on the AzDevops side no agent appears within the Agent Pool.

What do you mean by "switch"? you have to create a new VMSS with the agent installed and add it to AzDO

hey there. In case of key vault secrets, or other job-level environment variables, those are kept even between different machines. It's part of the featureset of Pipelines. If instead you need to use the output of one job into another one, then you have to use the upload artifact in job A, and use download artifact in job B

@@CoderDaveHi, thank you for your reply. Can I run all the jobs/stages of a pipeline on a single machine of the VMSS?

AFAIK there is no way to control that, it’s up to the azure pipelines engine

Also how can you do the auto scaling in AWS instead of a VMSS?

Hey, thanks for reaching out. Not really sure why your agents are that slow... that's quite strange. One thing I can think of is disks... perhaps the hosted agents use SSDs (don't quote me on this :) ) or it could just be the Azure region... sometimes you land on a older cluster, but that shouldn't make the agents 2-3x slower anyway For me when I went with VMSS I;ve actually noticed the opposite, my agents were slightly faster due to no noisy neighbors...

If you want to do it in AWS (or anything else that is not Azure) then you'd need to do it "manually". You could for example use the containerized agents in K8S. But the scaling mechanisms may be on the actual utilization rather than on the build/release queue... so not that efficient. Or you can use something like KEDA which takes in consideration the queue: keda.sh/blog/2021-05-27-azure-pipelines-scaler/ Maybe I can make a video on this :)

@@CoderDave My agents aren't in the same region as our org, do you think that would factor in at all?

That could have an impact on the operations that require connection to the instance; like for checkout, upload/download artifacts, etc… but I don’t expect it to be huge since the traffic between azure regions still travels on the Azure Backbone