ChromeOS on-device Health Service (healthd)

Health Service (a.k.a healthd) aims to provide one-stop APIs, including diagnostic and telemetry, for Chromium and non-Chromium clients. It is strongly suggested that anyone with requests in telemetry or diagnostic to contact us for a quick check on the latest status just in case the documentation is behind the reality.

By using healthd's APIs, the following benefits could be brought instantly with only one-time integration effort:

  • Unified data source: Necessary assembling is required to get a generic data, since it is common that a data from the certain source is only valid under some constraint. We provide a trusted and unified data source, and hide the complicate logics from our clients. Moreover, with the visions that more and more clients utilize our service, unified data source will help the data to be processed on the server side. Especially when it needs to perform join-like operations.
  • Single endpoint: Different components data are usually scattered across varies services and processes. Our clients could save the work of communicating over IPC (e.g. DBus and Mojo), dealing with varies API flow designs. We wrap all the things under a simple API endpoint.
  • Easier lifetime management: Our clients only need to handle/test the standard behavior on the Mojo channels. The common practices are well explored. Maintaining the lifetime to different services is a common difficulty.
  • Sandboxed: healthd enforces least privilege needed for each information listed. The ChromeOS security policy requires applying sandbox when accessing privileged APIs (e.g. ioctl syscall) or files. This is a common challenge when accessing platform related information if building from scratch.
  • Focused test coverage: We have team members rotating to monitor the alarm from labs. This will ease our clients to focus test effort on their own application. Our clients are also free from the effort of triage the lab hardware failure. It is another common pain point if building from scratch.

Here are more benefits for the whole ChromeOS ecosystem:

  • One-time work benefits everyone: All clients get benefited once one of their new request is implemented by us.
  • Lower system's loading: healthd plans to cache information in a feasible time frame. Multiple requests from different clients will be benefited by those caching.


  • The docs/ subdirectory contains all other documentations.
  • internal team doc could give more information for internal contributors.

Code structure

The repository hosts the core ChromeOS Health Service components, including: