Expand description
DNS seed discovery for tellus cluster bootstrap: DnsSeeds implements SeedDiscovery, resolving seed addresses from SRV records, which carry address and port (e.g. a Kubernetes headless service), or from A/AAAA records paired with a configured port. Pass it to bootstrap, which resolves until the view settles and joins the cluster through it, retrying resolve failures, e.g. records still appearing while an orchestrator starts the other nodes. SRV targets resolve concurrently; a failing target is skipped while any other resolves, and a set resolving no address at all remains an error so bootstrap does not settle on it. Nothing here distinguishes a stale target from a transient failure, because the resolver does not either, so both are skipped alike. A partial view does settle, so a target failing throughout the settle window shrinks the universe a FormationProvider counts its majority against.
Whatever is queried must resolve to one address per node, since bootstrap counts addresses and a peer is only admitted at the address it advertises; on Kubernetes that makes the headless service single stack, see this crate’s README.
The default resolver keeps no response cache. Bootstrap polls DNS to see nodes come and go, and a cached answer would hide a node registered after it for the record’s TTL, e.g. a sibling restarting a moment later than this one. A resolver given via DnsSeeds::with_resolver is used as configured.
Structs§
- DnsSeeds
- Seed discovery via DNS, the SeedDiscovery for clusters whose nodes are named by DNS records instead of configured addresses.
- DnsSeeds
Error - A DNS resolution failure; bootstrap logs and retries it.