When Ignition is fetching a resource over http(s), if the resource is unavailable Ignition will continually retry to fetch the resource with an exponential backoff between requests.
For a given retry attempt, Ignition will wait 10 seconds for the server to send the response headers for the request. If response headers are not received in this time, or an HTTP 5XX error code is received, the request is cancelled, Ignition waits for the backoff, and a new request is made.
Any HTTP response code less than 500 results in the request being completed, and either the resource will be fetched or Ignition will fail.
Ignition will initially wait 100 milliseconds between failed attempts, and the amount of time to wait doubles for each failed attempt until it reaches 5 seconds.