Bug Report: /debug/health in vtorc returns false healthy state

[timvaillancourt]

Overview of the Issue

vtorc will return a healthy state at /debug/health when it starts with an incorrect topo config

Returning true for health in this scenario can lead to the appearance of vtorc successfully deploying (if a deployment relies on /debug/health, examples kube/docker) when it is actually unable to reach the topology, making it (in my opinion) unhealthy

In this scenario I'd prefer for VTOrc to return "Healthy": false. In a rolling deployment that checks /debug/health this will mean a VTOrc deploy will fail on the 1st node instead of rolling out a bad config to all instances. I feel VTOrc must be able to do a trivial read from the topo, even if the topo is empty (no keyspaces/shards/tablets)

Reproduction Steps

1. Start vtorc with a known-broken topology config:

tvaillancourt@tvailla-ltmxctu vitess % ./bin/vtorc --topo_global_server_address http://nowhere --topo_global_root /vitess --topo_implementation consul --port 15000
W1030 23:27:19.107977   71758 log.go:39] Failed to read in config : Config File "vtconfig" Not Found in "[/Users/tvaillancourt/github/timvaillancourt/vitess]". This is optional, and can be ignored if you are not using config files. For a detailed explanation, see https://github.com/vitessio/vitess/blob/main/doc/viper/viper.md#config-files.
E1030 23:27:19.207979   71758 tablet_discovery.go:98] Get "http://nowhere/v1/kv/vitess/cells/?keys=": dial tcp: lookup nowhere: no such host
E1030 23:27:19.208033   71758 keyspace_shard_discovery.go:41] Get "http://nowhere/v1/kv/vitess/keyspaces/?keys=": dial tcp: lookup nowhere: no such host
E1030 23:27:34.213108   71758 keyspace_shard_discovery.go:41] Get "http://nowhere/v1/kv/vitess/keyspaces/?keys=": dial tcp: lookup nowhere: no such host
E1030 23:27:34.213123   71758 tablet_discovery.go:98] Get "http://nowhere/v1/kv/vitess/cells/?keys=": dial tcp: lookup nowhere: no such host
...

2. In a 2nd shell, test if vtorc is healthy:

tvaillancourt@tvailla-ltmxctu vitess % curl localhost:15000/debug/health
{
 "Healthy": true,
 "LastReported": "2024-10-30T23:27:55.231167+01:00"
}%

(notice it returns "Healthy": true)

Binary Version

v19-based fork/branch

Operating System and Environment details

N/A

Log Fragments

N/A