No built-in remote state backend storage (s3, gcs, etc) locking except their proprietary hosting. Obviously they need to make money, but this makes driving migration from terraform to pulumi a lot more difficult.
I've got a PR opened to implement this but due to S3 CAP limitations, it hasn't been merged. The current state is that it could be merged for non-S3 backends and a DynamoDB type lock could be added for S3 backends. I don't have much interest to keep pushing it forward (its been nearly a year of "ill get back to you next week") although their new VP has been more responsive.
Alternately I was considering just implementing the server API to do state storage & locking, but we have implemented some workarounds that are good enough for now.
I just want to say thanks for your initiative on opening https://github.com/pulumi/pulumi/pull/2697. (I've seen you active on a few other issues and in the Slack channel too)
I think it's really unfortunate (whatever the reason) that the team was this slow to provide meaningful feedback on the PR.
Alternately I was considering just implementing the server API to do state storage & locking, but we have implemented some workarounds that are good enough for now.