Add a section to the config file called "health". Within this section,
"filecheckers" and "httpcheckers" list checks to run. Each check
specifies a file or URI, a time interval for the check, and a threshold
specifying how many times the check must fail to reach an unhealthy
state.
Document the new options in docs/configuration.md.
Add unit testing for both types of checkers. Add an UnregisterAll
function in the health package to support the unit tests, and an
Unregister function for consistency with Register.
Fix a string conversion problem in the health package's HTTP checker.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
Because health check errors may expose sensitive data, we shouldn't expose the
details of the failure to clients. Instead, an error is returned to the client
with a hint about where they could find further information on why the service
is down.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
To ensure the ensure the web application is properly operating, we've added a
periodic health check for the storage driver. If the health check fails three
times in a row, the registry will serve 503 response status for any request
until the condition is resolved. The condition is reported in the response body
and via the /debug/health endpoint.
To ensure that all drivers will properly operate with this health check, a
function has been added to the driver testsuite.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
