Provider Upgrade

Upgrading Pulumi Providers

The Principle

A provider upgrade is a translation, not a change request.

The user's infrastructure intent hasn't changed - they still want the same bucket, the same function, the same cluster. What changed is how the provider's API expresses that intent. Your job is to translate their existing code into the new API so that Pulumi sees no difference between what the code says and what already exists.

There are four layers to keep in mind:

1. User intent - what the user wants in the cloud (unchanged during an upgrade)
2. Code - how the program expresses that intent using the provider API (may need updating)
3. Pulumi state - Pulumi's stored representation of what exists (may need reconciliation)
4. Real cloud - the actual infrastructure (should not change during an upgrade)

During an upgrade, layers 2 and 3 may need to change so that they continue to correctly represent the unchanged layers 1 and 4.

A correct translation produces zero diff. The Pulumi engine doesn't have a concept of "upgrade" - it just compares goal state (your code) against actual state (the state file) and reconciles. If the translation is correct, those two states match and nothing happens. If you see a diff, either your translation is wrong, or something beyond a code change is needed (import, alias, manual step). In all cases, the diff is a problem to solve, not a consequence to accept.

The Core Loop

flowchart TD
    A[Bump version] --> B[Run preview with env vars]
    B --> C{Clean?}
    C -->|Yes| D[Create PR]
    C -->|No| E[Diff Checkpoint: categorize every diff]
    E --> F{Any Category A?}
    F -->|Yes| G[Fix wrong translations]
    G --> B
    F -->|No| H{Any Category B?}
    H -->|Yes| I[Investigate with toolbox]
    I --> J[Fix or document]
    J --> B
    H -->|No| D

1. Bump the provider dependency
2. Preview with required CLI flags
3. Diff Checkpoint - categorize every non-same resource (see next section)
4. Fix Category A - code changes that didn't produce same
5. Investigate Category B - diffs on resources you didn't change
6. Repeat until clean or remaining diffs are fully investigated
7. Create PR with upgrade summary

The Diff Checkpoint

This is the most important section. Run this after EVERY preview.

For each non-same resource, answer one question: "Did any of my code changes affect this resource - directly or indirectly?"

"Directly" means you edited the resource block itself. "Indirectly" means you changed something that feeds into this resource - a shared variable, an output from another resource, a helper function, a default value, or a resource that this one depends on. If your changes could have altered what Pulumi computes for this resource, it's Category A.

Then follow the category that applies.

Category A: I changed code for this resource

Your code change was supposed to translate the same intent into the new API. If the resource shows same, your translation is correct. If it shows anything else, your translation is wrong. Not "the diff is expected because I changed the code" - if the change were semantically equivalent, there would be no diff.

I modified an existing resource and it shows `update`:

Your rename, restructure, or value adjustment changed the meaning, not just the syntax. The resource would show same if the old and new code compiled to the same goal state. The update means they don't.

Ask yourself: "If this rename were truly equivalent, the resource would show `same`. It doesn't. What is semantically different between my old code and my new code?"

Common causes: the new property name maps to a different underlying field; the value shape changed and your conversion lost or added information; a default value changed in the new version and you need to explicitly set the old value; additional properties now appear in the diff because the new provider version tracks fields it didn't before (these need to be set explicitly to match the current state).

If the update includes properties you didn't change - new fields appearing, type normalizations (string->number), additional defaults - that's the provider changing what it tracks. But if the diff is there, pulumi up WILL send those values to the cloud API. Don't assume they're no-ops. Investigate each changed property.

I added a new resource block and it shows `create`:

During an upgrade, a new resource block almost always represents infrastructure that already exists in the cloud. The old provider managed it implicitly (as part of another resource); the new provider needs an explicit resource. But the cloud object is already there. Pulumi wants to create NEW infrastructure - that's not what you want.

The fix is import, not create. Tell Pulumi to adopt the existing cloud resource.

Ask yourself: "What cloud object does this new resource represent? Does it already exist? How was it managed before the upgrade?"

// Wrong - creates duplicate infrastructure
const stage = new aws.apigateway.Stage("prodStage", { ... });

// Right - adopts the existing resource
const stage = new aws.apigateway.Stage("prodStage", { ... }, {
    import: "<rest-api-id>/prod",  // import ID format varies by resource type
});

I removed a resource block and it shows `delete`:

A delete in the preview means pulumi up will call the provider's Delete API to destroy or unconfigure this cloud resource. This is real destruction - not just state cleanup. The cloud infrastructure still exists and is almost certainly still needed.

This is different from pulumi state delete, which removes the resource from Pulumi's tracking WITHOUT calling the provider's API. When a resource type is removed in a new provider version, the correct approach is:

1. pulumi state delete '<urn>' - manual step, removes from tracking only
2. Add replacement resources (if any) with imports - adopts the cloud state under new types
3. Verify with preview

Do NOT leave a delete in the preview and proceed to PR creation. A delete that runs via pulumi up will destroy real infrastructure. If the resource must be removed from state, document it as a manual step for the user.

Ask yourself: "What cloud infrastructure does this resource manage? If `pulumi up` runs this delete, what gets destroyed or unconfigured?"

Category B: I didn't change code for this resource

This diff was not caused by your code changes. It comes from the provider version change itself - a different default, a changed state representation, or a behavioral difference. Read references/diagnostic-toolbox.md and investigate.

These diffs might be:

• Fixable with code - set an explicit value for a changed default, add an alias
• A documented no-op - the upgrade guide says it resolves on pulumi up without affecting real infrastructure. This classification REQUIRES a citation from the upgrade guide or provider documentation. Your own judgment that "this looks like a no-op" is not sufficient - the user is trusting you to distinguish real infrastructure changes from artifacts, and getting it wrong means unexpected changes to their cloud.
• Requiring manual steps - state removal + reimport, documented for the user
• Unknown - present what you've found to the user and ask for guidance

Category C: Provider version bump

An update on pulumi:providers:{name} showing only a version change is the one expected diff. Verify no other properties changed on the provider resource.

After categorizing

Completeness check: Every resource in the preview that shows any non-same state must appear in your checkpoint - including resources with [diff: ...] annotations, even if they don't have an explicit create/update/delete marker. If you didn't list it, your checkpoint is incomplete. Go back and categorize the missing resources.