ReferenceGlossary
Health check
A periodic probe, such as an HTTP request to a status endpoint, that decides whether a server should receive traffic. A shallow check tests only the server; a deep check also tests what it depends on, such as its database.
Reliability
In Quorum#
A Load Balancer probes its App Servers every 10 s and stops sending traffic to a dead one at the next check. The Health checks research adds 2 s and 30 s intervals and a deep check that also removes App Servers whose Database is down or overloaded. It also lets DNS drop a dead host once its TTL runs out; without it, DNS keeps sending that host its share.
Read next#
Load balancer, DNS round robin, MTTR, Vertical and horizontal scaling