Make CheckUpdateInterval configurable or document it

[danielehc]

Current Issue

When adding new external services to Consul it takes 5+ minutes for them to change status from Failing to Healthy even if

• the node_probe_interval in Consul ESM configuration is set to 10s
• the Service.Check.Interval in the service configuration is set to 10s

This is confusing and leads to the idea that something is not working in the background.

From my understanding of the code the behavior is due to the CheckUpdateInterval configuration value that:

• Is not configurable from the configuration file
• Is not documented on the Github repository

Proposed solution

To avoid this confusion is either possible:

1. Allow for the configuration of the CheckUpdateInterval in Consul ESM configuration file
2. Document the expected behavior in the README mentioning that after adding new nodes to Consul, Consul ESM will take up to 5 minutes to identify them and to start performing checks.

[Esity]

We have seen this exact thing, 100% agree with this request, CC @blake

[Esity]

@danielehc , does #256 fix this issue?