A single unified web frontend for all the Skia properties.
+--------------------------+ | GKE Ingress | +----+------------------+--+ | | | | v v +-------------+ +-------------+ | (envoy) | ... | (envoy) | +------+------+ +------+------+ | | +---+-------------+----------+-----+ v v v +---------+ +---------+ +-----------+ |skia perf| ... |skia gold| |skia alerts| +---------+ +---------+ +-----------+
A single static IP is handled by GKE Ingress which handles SSL and then distributes requests to multiple envoy pods: They, in turn, distribute the calls to the backend as kubernetes sevices. The certs for all Skia properties are handled at the GKE Ingress level, see http://go/skia-ssl-cert for more details.
The configuration for the envoy server comes from envoy-starter.json and metadata annotations on services running in the skia-public k8s cluster.
The generation of the configuration involves three files, two of which are auto-generated:
envoy-starter.json simple.json computed.json
The simple.json and computed.json are generated files.
The envoy-starter.json file contains our liveness handling, all redirects, and complicated routes for services like Gold. It is a hand-written file.
The contents of simple.json are generated directly from metadata in kubernetes Services.
We need three pieces of information, the domain name, the target service name, and the port that the service is running on. Consider the following configuration for https://perf.skia.org.
apiVersion: v1
kind: Service
metadata:
labels:
app: skiaperf
name: skiaperf
annotations:
beta.cloud.google.com/backend-config: '{"ports": {"8000":"skia-default-backendconfig"}}'
skia.org.domain: perf.skia.org
spec:
ports:
- name: metrics
port: 20000
- name: http
port: 8000
selector:
app: skiaperf
type: NodePort
The parts of the Service spec that are important are the skia.org.domain annotation which specifies the public domain name where this service should be available. It must be a sub-domain of .skia.org. There also must be a .spec.ports with a name of “http” that specifies the port at which the service is available. Along with the name of the service those values are combined to produce the simple.json config file. We then run merge_envoy to merge simple.json and envoy-starter.json into computed.json which is then used in the envoy image. Making this a two step process makes it easier to debug the output of each step, as Envoy configs are very wordy.
Finally update_probers can be run to add all the redirects from envoy-starter.json to probersk.json5.
Run
make
To build the computed.json config file which is then reviewed and submitted.
After that file has landed then run:
make push
to push the computed.json file to production.
You can reach the Envoy admin interface by
kubectl port-forward <envoy-skia-org pod name> 9000:9000
And then visit
http://localhost:9000
The admin interface also provides the metrics endpoint to prometheus.
Our DNS Zone file is checked in here as skia.org.zone. See that file for instructions on how to update our DNS records.
Q: Why not just use GKE Ingress?
A: GKE Ingress is limited to 50 total rules, which we currently exceed.
Q: Why not use TCP Load Balancing and a custom ingress on GKE?
A: GKE Ingress is the only public facing option available to us.