PATH Not Persisting in Azure DevOps Agent (VMSS) Despite Image Configuration Body:

[sharmila1310]

Hi team,

I'm trying to persist a custom tool path (/usr/local/MATLAB/R2025a/polyspace/bin) across Azure DevOps pipeline runs using a VMSS-based agent. The goal is for this path to be available to the pipeline agent without redefining it inside the pipeline YAML every time.

What I’ve Tried:
I've baked the required path into the image using the following approaches:

1. /etc/environment:
   Updated during image build to include the custom path. But the path does not appear in the agent's environment during pipeline runs.
2. /etc/profile.d/polyspace_path.sh:
   Works if manually sourced in the YAML pipeline, but doesn’t persist automatically.
3. .bashrc and .profile:
   Not applicable — DevOps agent doesn’t run as a login shell.
4. Systemd global override (/etc/systemd/system.conf.d/path.conf):
   Added:
   [Manager]
   DefaultEnvironment="PATH=/usr/local/MATLAB/R2025a/polyspace/bin:..."
   But it’s not picked up by the agent process — possibly because the agent is installed after image capture via VMSS extension.
5. First-boot script via systemd service:
   Created a script that waits for the vsts.agent.*.service to appear, then writes a drop-in override. This failed (agent not ready yet).
6. Cron-based fallback (@reboot):
   Delays script for 5–30 minutes post-boot. Still unreliable — PATH not updated in pipeline runs.

Temporary Workaround
I’ve used the following in the pipeline YAML, which does work, but isn’t a persistent solution:

• script: |
  echo "##vso[task.setvariable variable=PS_BIN;isOutput=true]/usr/local/MATLAB/R2025a/polyspace/bin"

What I Need Help With:

What’s the correct/preferred method to:
Persist a custom PATH in the VM image
Ensure its applied to the Azure DevOps agent (running via VMSS)
Without having to redefine or source paths inside every pipeline

If there’s a way to hook into the VMSS agent install process or inject environment during provisioning, I’d love to explore it.