Adding support for OS disk size specification on TRE config file.

[cptanalatriste]

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🚦 Depends on

N/A

⤴️ Summary

As part of this PR:

• Users are able to define the size of the OS Disk in the SRE config file. For example, defining a 64GB size OS disk is done with the following:

        storage_quota_gb:
            home: 100
            shared: 100
            data_disk: 0
            os_disk: 64

• The default OS disk size for workspaces in now 64GB, since the default 30GB have proven to be insufficient.
• We're disabling updating the size of the data disk, since at the moment it triggers the creation of a new VM/Disk, erasing the previously present data.

IMPORTANT!: It is not possible to update the OS Disk size using the DSH CLI, due to Pulumi limitations. Attempts of doing it will fail with the following error:

Pulumi error:  ~  azure-native:compute:VirtualMachine sre_workspaces_vm_workspace_01 **updating failed** [diff: ~storageProfile];    
error: Status=400 Code="Conflict" Message="Disk resizing is allowed only when creating a VM or when the VM is deallocated."                             

We expect users to manually update OS Disk size (using the Portal or Azure CLI), and normalise Pulumi state later.

🌂 Related issues

Closes: #2545

🔬 Tests

The workspaces are created with the right disk size:

[github-actions]

Coverage report

Click to see where and how coverage changed

File	Statements	Missing	Coverage	Coverage (new stmts)	Lines missing
data_safe_haven/config
config_sections.py
data_safe_haven/infrastructure/components/composite
virtual_machine.py					39-40, 49-55, 187
data_safe_haven/infrastructure/programs/sre
workspaces.py					43, 97
Project Total

This report was generated by python-coverage-comment-action

[martintoreilly]

Code changes LGTM. Note that I was at the desk with Carlos while these changes were made so we applied the second pair of eyes at code change time.

@cptanalatriste Please could you re-run the end to end VM deployment using an OS disk size that is different to the 64GB default specified in the code, to validate that this does override the defaults and propagate the user-specified OS disk size to the deployed VM.

I added a couple of inline notes where the defaults are set asking if we can easily add unit tests that validate the defaults are overridden when a different value is provided as input.

If the end to end test shows the user-specified OS disk value propagating to the deployed VM, I'm happy to merge this PR. If its easy to incorporate unit tests baking this validation into the test suite, it would be great to see these added but I would not consider the lack of these a blocker to merging.

[cptanalatriste]

Code changes LGTM. Note that I was at the desk with Carlos while these changes were made so we applied the second pair of eyes at code change time.

@cptanalatriste Please could you re-run the end to end VM deployment using an OS disk size that is different to the 64GB default specified in the code, to validate that this does override the defaults and propagate the user-specified OS disk size to the deployed VM.

I added a couple of inline notes where the defaults are set asking if we can easily add unit tests that validate the defaults are overridden when a different value is provided as input.

If the end to end test shows the user-specified OS disk value propagating to the deployed VM, I'm happy to merge this PR. If its easy to incorporate unit tests baking this validation into the test suite, it would be great to see these added but I would not consider the lack of these a blocker to merging.

Hi @martintoreilly , I did the requested end-to-end test. Given the new TRE configuration (see the first screenshot), we can see that the deployed OS disk has the size specified (see second screenshot).

[martintoreilly]

Approved.