feat: Use command probe for increased accuracy (#344) #359
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The liveness & readiness probes previously checked that the web server was up, but did not check that FTL was running. There are conditions under which the web server starts, but FTL fails to start. Using HTTP probes does not catch those conditions, but the web server offers an endpoint that returns the DNS status. If the web server is not up, this probe will continue to fail since it can't `curl` the endpoint. In addition, it will now also fail if the DNS server is down. Signed-off-by: javex <code@inexplicity.de>
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Description of the change
The liveness & readiness probes previously checked that the web server was up, but did not check that FTL was running. There are conditions under which the web server starts, but FTL fails to start. Using HTTP probes does not catch those conditions, but the web server offers an endpoint that returns the DNS status. If the web server is not up, this probe will continue to fail since it can't
curlthe endpoint. In addition, it will now also fail if the DNS server is down.Benefits
Increased accuracy in both readiness & liveness check
Possible drawbacks
curlthis is a breaking change. I think it's highly unlikely, ascurlis in just about every image./loginendpoint is used when visiting the login screen, so it doesn't require auth but gets information about the DNS server. However, I don't know if this might not change at some point in the future. I think it's worth the risk, it's an easy fix if Pi-Hole changes this endpoint.Applicable issues
Additional information
Checklist