mirror of
https://github.com/kubernetes-sigs/external-dns.git
synced 2025-08-07 01:56:57 +02:00
83 lines
3.1 KiB
Markdown
83 lines
3.1 KiB
Markdown
# Gateway sources
|
|
|
|
The gateway-grcproute, gateway-httproute, gateway-tcproute, gateway-tlsroute, and gateway-udproute
|
|
sources create DNS entries based on their respective `gateway.networking.k8s.io` resources.
|
|
|
|
## Filtering the Routes considered
|
|
|
|
These sources support the `--label-filter` flag, which filters *Route resources
|
|
by a set of labels.
|
|
|
|
## Domain names
|
|
|
|
To calculate the Domain names created from a *Route, this source first collects a set
|
|
of [domain names from the *Route](#domain-names-from-route).
|
|
|
|
It then iterates over each of the `status.parents` with
|
|
a [matching Gateway](#matching-gateways) and at least one [matching listener](#matching-listeners).
|
|
For each matching listener, if the
|
|
listener has a `hostname`, it narrows the set of domain names from the *Route to the portion
|
|
that overlaps the `hostname`. If a matching listener does not have a `hostname`, it uses
|
|
the un-narrowed set of domain names.
|
|
|
|
### Domain names from Route
|
|
|
|
The set of domain names from a *Route is sourced from the following places:
|
|
|
|
* If the *Route is a GRPCRoute, HTTPRoute, or TLSRoute, adds each of the`spec.hostnames`.
|
|
|
|
* Adds the hostnames from any `external-dns.alpha.kubernetes.io/hostname` annotation on the *Route.
|
|
This behavior is suppressed if the `--ignore-hostname-annotation` flag was specified.
|
|
|
|
* If no endpoints were produced by the previous steps
|
|
or the `--combine-fqdn-annotation` flag was specified, then adds hostnames
|
|
generated from any`--fqdn-template` flag.
|
|
|
|
* If no endpoints were produced by the previous steps, each
|
|
attached Gateway listener will use its `hostname`, if present.
|
|
|
|
### Matching Gateways
|
|
|
|
Matching Gateways are discovered by iterating over the *Route's `status.parents`:
|
|
|
|
* Ignores parents with a `parentRef.group` other than
|
|
`gateway.networking.k8s.io` or a `parentRef.kind` other than `Gateway`.
|
|
|
|
* If the `--gateway-namespace` flag was specified, ignores parents with a `parentRef.namespace` other
|
|
than the specified value.
|
|
|
|
* If the `--gateway-label-filter` flag was specified, ignores parents whose Gateway does not match the
|
|
specified label filter.
|
|
|
|
* Ignores parents whose Gateway either does not exist or has not accepted the route.
|
|
|
|
### Matching listeners
|
|
|
|
Iterates over all listeners for the parent's `parentRef.sectionName`:
|
|
|
|
* Ignores listeners whose `protocol` field does not match the kind of the *Route per the following table:
|
|
|
|
| kind | protocols |
|
|
|------------|-------------|
|
|
| GRPCRoute | HTTP, HTTPS |
|
|
| HTTPRoute | HTTP, HTTPS |
|
|
| TCPRoute | TCP |
|
|
| TLSRoute | TLS |
|
|
| UDPRoute | UDP |
|
|
|
|
* If the parent's `parentRef.port` port is specified, ignores listeners without a matching `port`.
|
|
|
|
* Ignores listeners which specify an `allowedRoutes` which does not allow the route.
|
|
|
|
## Targets
|
|
|
|
The targets of the DNS entries created from a *Route are sourced from the following places:
|
|
|
|
1. If a matching parent Gateway has an `external-dns.alpha.kubernetes.io/target` annotation, uses
|
|
the values from that.
|
|
|
|
2. Otherwise, iterates over that parent Gateway's `status.addresses`,
|
|
adding each address's `value`.
|
|
|
|
The targets from each parent Gateway matching the *Route are then combined and de-duplicated.
|