Design a Multi-Tenant Cloud IDE: Isolation, Workspaces, Run/Build, Failure Modes

Design a cloud IDE: a browser-based development environment in which each user gets a workspace containing their project files, a terminal, and the ability to run and build their code, with an editor that feels responsive. Focus on four areas: **multi-tenancy** (many untrusted users sharing infrastructure), **workspace management** (creating, starting, stopping and resuming workspaces), **running and building code**, and **failure modes**. ```hint Untrusted code by design Every user runs arbitrary code, including code that is malicious or simply buggy; decide what boundary contains a workspace, and what it must be unable to reach. ``` ```hint Most workspaces are idle Think about what state a workspace must keep while nobody is using it, and how fast it must come back when its owner returns. ``` ### Clarifying Questions - How many users and concurrently active workspaces, and what resources does a typical workspace need? - Which languages and toolchains must be supported? Do users bring their own container images? - Must running applications be reachable over the network, for example to preview a web server? - How quickly must a stopped workspace resume, and must files survive indefinitely? - Is real-time collaboration (several users in one workspace) in scope? ### What a Strong Answer Covers - An isolation model for untrusted code, covering compute, network, storage and noisy neighbors - The workspace lifecycle, persistence of files and environment, and fast start and resume - The architecture of the run and build path: resource limits, build caching, and how output and preview ports reach the browser - Connectivity for the editor, terminal and language services, and routing of traffic to the right workspace - An analysis of concrete failure modes, with detection and recovery for each - Capacity estimates, cost controls for idle workspaces, and abuse prevention ### Follow-up Questions - A host running 50 workspaces dies. What does each user experience, and what is lost? - How would you stop users from mining cryptocurrency or launching attacks from their workspaces? - How would you make a workspace for a large repository start in seconds? - How would you add real-time collaborative editing to a workspace?