112 lines
4.3 KiB
Markdown
112 lines
4.3 KiB
Markdown
# Sentinel Envoy RLS - Kubernetes sample
|
||
|
||
This sample will illustrate how to use Sentinel RLS token server with Envoy in Kubernetes clusters.
|
||
|
||
## Build the Docker image
|
||
|
||
We could use the pre-built Docker image: `registry.cn-hangzhou.aliyuncs.com/sentinel-docker-repo/sentinel-envoy-rls-server:latest`
|
||
|
||
We can also manually build the Docker image in the `sentinel-cluster-server-envoy-rls` directory:
|
||
|
||
```bash
|
||
docker build -t "sentinel/sentinel-envoy-rls-server:latest" -f ./Dockerfile .
|
||
```
|
||
|
||
## Deploy Sentinel RLS token server
|
||
|
||
Next we could deploy the Sentinel RLS token server in the K8S cluster.
|
||
We've provided a deployment template for Sentinel RLS token server in `sentinel-rls.yml`.
|
||
It includes:
|
||
|
||
- A `ConfigMap` that contains the cluster flow control rule for Envoy global rate limiting.
|
||
This will be mounted as a file in the target `Deployment`, so that the Sentinel RLS token server
|
||
could load the rules dynamically as soon as the rule in the `ConfigMap` has been updated.
|
||
- A `Deployment` for Sentinel RLS token server. It will mount the `ConfigMap` as a volume
|
||
for dynamic rule configuration.
|
||
- A `Service` that exports the Sentinel command port (8719) and the RLS gRPC port (by default 10245)
|
||
on a cluster-internal IP so that the Envoy pods could communicate with the RLS server.
|
||
|
||
The sample rate limiting rule in the `sentinel-rule-cm`:
|
||
|
||
```yaml
|
||
domain: foo
|
||
descriptors:
|
||
# For requests to the "service_httpbin" cluster, limit the max QPS to 1
|
||
- resources:
|
||
- key: "destination_cluster"
|
||
value: "service_httpbin"
|
||
count: 1
|
||
```
|
||
|
||
You may enable the access log in the Sentinel RLS token server (output to console)
|
||
via the `SENTINEL_RLS_ACCESS_LOG` env:
|
||
|
||
```yaml
|
||
env:
|
||
- name: SENTINEL_RLS_ACCESS_LOG
|
||
value: "on"
|
||
```
|
||
|
||
You may also append JVM opts via the `JAVA_OPTS` env.
|
||
|
||
After preparing the yaml template, you may deploy the Sentinel RLS token server:
|
||
|
||
```bash
|
||
kubectl apply -f sample/k8s/sentinel-rls.yml
|
||
```
|
||
|
||
## Deploy Envoy
|
||
|
||
Next we could deploy the Envoy instances in the K8S cluster. If you've already had Envoy instances running,
|
||
you could configure the address (`sentinel-rls-service`) and the port (`10245`)
|
||
of the rate limit cluster in your Envoy configuration.
|
||
|
||
We've provided a deployment template for Envoy in `envoy.yml`.
|
||
It includes:
|
||
|
||
- A `ConfigMap` that contains the configuration for Envoy.
|
||
This will be mounted as a file in the target `Deployment`, which will be loaded as the configuration
|
||
file by Envoy.
|
||
- A `Deployment` for Envoy. It will mount the `ConfigMap` as a volume
|
||
for configuration.
|
||
- A `Service` that exports the Envoy endpoint port (by default 10000) on a cluster-internal IP
|
||
so that it could be accessible from other pods. If you need external access, you could choose the
|
||
`LoadBalancer` type or add a frontend ingress.
|
||
|
||
In the sample, we have two [Envoy clusters](https://www.envoyproxy.io/docs/envoy/latest/api-v2/clusters/clusters):
|
||
|
||
- `service_httpbin`: HTTP proxy to `httpbin.org`
|
||
- `rate_limit_cluster`: the cluster of the Sentinel RLS token server
|
||
|
||
This route configuration tells Envoy to route incoming requests to `httpbin.org`. In the `http_filters` conf item,
|
||
we added the `envoy.rate_limit` filter to the filter chain so that the global rate limiting is enabled.
|
||
We set the rate limit domain as `foo`, which matches the item in the Envoy RLS rule.
|
||
In the `route_config`, we provide the rate limit action: `{destination_cluster: {}}`, which will
|
||
generate the rate limit descriptor containing the actual target cluster name (e.g. `service_httpbin`).
|
||
Then we could set rate limit rules for each target clusters.
|
||
|
||
After preparing the yaml template, you may deploy the Envoy instance:
|
||
|
||
```bash
|
||
kubectl apply -f sample/k8s/envoy.yml
|
||
```
|
||
|
||
for v3 api：
|
||
|
||
```bash
|
||
kubectl apply -f sample/k8s/envoy-v3-api.yml
|
||
```
|
||
|
||
## Test the rate limiting
|
||
|
||
Now it's show time! We could visit the URL `envoy-service:10000/json` in K8S pods.
|
||
Since we set the max QPS to 1, we could emit concurrent requests to the URL, and we
|
||
could see the first request passes, while the latter requests are blocked (status 429):
|
||
|
||
|
||
|
||
## Update the rules dynamically
|
||
|
||
You could update the rules in the `sentinel-rule-cm` ConfigMap. Once the content is updated,
|
||
Sentinel will perceive the changes and load the new rules to `EnvoyRlsRuleManager`.
|