|
| 1 | +# Routing across multiple Knative services with Kong |
| 2 | + |
| 3 | +This example shows how to map multiple Knative services to different paths under |
| 4 | +a single domain name using [Kong Gateway](https://docs.konghq.com/gateway-oss/). |
| 5 | +Kong Gateway is a general-purpose reverse proxy and API gateway built on |
| 6 | +[Nginx](https://www.nginx.com/), therefore these directions can also be used to |
| 7 | +configure routing based on other request data such as headers, or even to map |
| 8 | +Knative and external resources under the same domain name. |
| 9 | + |
| 10 | +In this sample, we set up two web services: _Search_ service and _Login_ |
| 11 | +service, which simply read in an env variable `SERVICE_NAME` and print |
| 12 | +`"${SERVICE_NAME} is called"`. We'll then define routing rules via [Kong's |
| 13 | +Kubernetes Ingress |
| 14 | +Controller](https://docs.konghq.com/kubernetes-ingress-controller/) and [Kong's |
| 15 | +request transformer |
| 16 | +plugin](https://docs.konghq.com/hub/kong-inc/request-transformer/), so that |
| 17 | +`example.com/search` maps to the _Search_ service, and `example.com/login` maps |
| 18 | +to the _Login_ service. |
| 19 | + |
| 20 | +## Prerequisites |
| 21 | + |
| 22 | +1. A Kubernetes cluster with [Knative Serving](../../../install/) and |
| 23 | + [Kong](https://docs.konghq.com/kubernetes-ingress-controller/1.3.x/guides/using-kong-with-knative/) |
| 24 | + installed. |
| 25 | +1. Install |
| 26 | + [Docker](https://docs.docker.com/get-started/#prepare-your-docker-environment). |
| 27 | +1. Acquire a domain name. |
| 28 | + - In this example, we use `example.com`. If you don't have a domain name, |
| 29 | + you can modify your hosts file (on macOS or Linux) to map `example.com` to |
| 30 | + your cluster's ingress IP. |
| 31 | + - If you have configured a custom domain for your Knative installation, we |
| 32 | + will refer to it as `<YOUR_DOMAIN_NAME>` in the rest of this document |
| 33 | +1. Check out the code: |
| 34 | + |
| 35 | + ```bash |
| 36 | + go get -d github.com/knative/docs/docs/serving/samples/kong-routing-go |
| 37 | + ``` |
| 38 | + |
| 39 | +## Setup |
| 40 | + |
| 41 | +To check the domain name, run the following command: |
| 42 | + |
| 43 | +```bash |
| 44 | +kubectl get cm -n knative-serving config-domain -o yaml |
| 45 | +``` |
| 46 | + |
| 47 | +Then, check the value for `data`. The domain name should be in the format of |
| 48 | +`<YOUR_DOMAIN_NAME>: ""`, if it is available. |
| 49 | + |
| 50 | +Build the application container and publish it to a container registry: |
| 51 | + |
| 52 | +1. Move into the sample directory: |
| 53 | + |
| 54 | + ```bash |
| 55 | + cd $GOPATH/src/github.com/knative/docs |
| 56 | + ``` |
| 57 | + |
| 58 | +1. Set your preferred container registry: |
| 59 | + |
| 60 | + If you use Google Container Registry (GCR), you will need to enable the [GCR |
| 61 | + API](https://console.cloud.google.com/apis/library/containerregistry.googleapis.com) |
| 62 | + in your GCP project. |
| 63 | + |
| 64 | + ```bash |
| 65 | + export REPO="gcr.io/<YOUR_PROJECT_ID>" |
| 66 | + ``` |
| 67 | + |
| 68 | + If you use Docker Hub as your Docker image registry, replace `<username>` |
| 69 | + with your Docker Hub username and run the following command: |
| 70 | + |
| 71 | + ```bash |
| 72 | + export REPO="docker.io/<username>" |
| 73 | + ``` |
| 74 | + |
| 75 | +1. Use Docker to build your application container: |
| 76 | + |
| 77 | + ```bash |
| 78 | + docker build \ |
| 79 | + --tag "${REPO}/kong-routing-go" \ |
| 80 | + --file=docs/serving/samples/kong-routing-go/Dockerfile . |
| 81 | + ``` |
| 82 | + |
| 83 | +1. Push your container to a container registry: |
| 84 | + |
| 85 | + ```bash |
| 86 | + docker push "${REPO}/kong-routing-go" |
| 87 | + ``` |
| 88 | + |
| 89 | +1. Replace the image reference path with our published image path in the |
| 90 | + configuration file `docs/serving/samples/kong-routing-go/sample.yaml` in one |
| 91 | + of the following ways: |
| 92 | + |
| 93 | + - Manually replace `image: |
| 94 | + github.com/knative/docs/docs/serving/samples/kong-routing-go` with `image: |
| 95 | + ${REPO}/kong-routing-go`. If you manually changed the `.yaml` file, you |
| 96 | + must replace `${REPO}` with the correct path on your local machine. |
| 97 | + - Run this command: |
| 98 | + ```bash |
| 99 | + perl -pi -e "[email protected]/knative/docs/docs/serving/samples@${REPO}@g" docs/serving/samples/kong-routing-go/sample.yaml |
| 100 | + ``` |
| 101 | + |
| 102 | +## Deploy the Service |
| 103 | + |
| 104 | +Deploy the Knative Serving sample: |
| 105 | + |
| 106 | +```bash |
| 107 | +kubectl apply -f docs/serving/samples/kong-routing-go/sample.yaml |
| 108 | +``` |
| 109 | + |
| 110 | +Inspect the deployed Knative services with: |
| 111 | + |
| 112 | +```bash |
| 113 | +kubectl get ksvc |
| 114 | +``` |
| 115 | + |
| 116 | +You should see 2 Knative services: `search-service` and `login-service`. |
| 117 | + |
| 118 | +## Exploring the Routes |
| 119 | + |
| 120 | +Kong Gateway serves all incoming traffic to services managed by Knative. You can |
| 121 | +inspect the corresponding Kubernetes service for the gateway: |
| 122 | + |
| 123 | +```bash |
| 124 | +INGRESSGATEWAY=kong-proxy |
| 125 | +
|
| 126 | +kubectl get svc $INGRESSGATEWAY -n kong --output yaml |
| 127 | +``` |
| 128 | + |
| 129 | +### Access the Services |
| 130 | + |
| 131 | +1. Find the gateway IP and export it as an environment variable: |
| 132 | + |
| 133 | + ```bash |
| 134 | + export GATEWAY_IP=`kubectl get svc $INGRESSGATEWAY -n kong \ |
| 135 | + --output jsonpath="{.status.loadBalancer.ingress[*]['ip']}"` |
| 136 | + ``` |
| 137 | + |
| 138 | +1. Find the _Search_ service URL: |
| 139 | + |
| 140 | + ```bash |
| 141 | + kubectl get route search-service --output=custom-columns=NAME:.metadata.name,URL:.status.url |
| 142 | + ``` |
| 143 | + |
| 144 | + The output should looks like this: |
| 145 | + |
| 146 | + ``` |
| 147 | + NAME URL |
| 148 | + search-service http://search-service.default.example.com |
| 149 | + ``` |
| 150 | + |
| 151 | +1. Make a cURL request to the service: |
| 152 | + |
| 153 | + ```bash |
| 154 | + curl http://${GATEWAY_IP} --header "Host:search-service.default.example.com" |
| 155 | + ``` |
| 156 | + |
| 157 | + The output should look like this: |
| 158 | + |
| 159 | + ``` |
| 160 | + Search Service is called! |
| 161 | + ``` |
| 162 | + |
| 163 | +1. Similarly, you can also directly access _Login_ service: |
| 164 | + |
| 165 | + ```bash |
| 166 | + curl http://${GATEWAY_IP} --header "Host:login-service.default.example.com" |
| 167 | + ``` |
| 168 | + |
| 169 | + The output should look like this: |
| 170 | + |
| 171 | + ``` |
| 172 | + Login Service is called! |
| 173 | + ``` |
| 174 | + |
| 175 | +## Apply Custom Routing Rule |
| 176 | + |
| 177 | +1. Apply the custom routing rules defined in the `routing.yaml` file: |
| 178 | + |
| 179 | + ```bash |
| 180 | + kubectl apply -f docs/serving/samples/kong-routing-go/routing.yaml |
| 181 | + ``` |
| 182 | + |
| 183 | + If you have configured a custom domain name for your service, please replace |
| 184 | + all mentions of `example.com` in `routing.yaml` with `<YOUR_DOMAIN_NAME>`. |
| 185 | + |
| 186 | + In addition, you need to verify how your domain template is defined. By |
| 187 | + default, we use the format of {% raw %}`{{.Name}}.{{.Namespace}}`{% endraw |
| 188 | + %}, like `search-service.default` and `login-service.default`. However, some |
| 189 | + Knative environments may use other formats like {% raw |
| 190 | + %}`{{.Name}}-{{.Namespace}}`{% endraw %}. You can find out the format by |
| 191 | + running the command: |
| 192 | + |
| 193 | + ```bash |
| 194 | + kubectl get cm config-network -n knative-serving -o yaml |
| 195 | + ``` |
| 196 | + |
| 197 | + Then, look for the value for `domainTemplate`. If it is {% raw |
| 198 | + %}`{{.Name}}-{{.Namespace}}.{{.Domain}}`{% endraw %}, you need to change |
| 199 | + `search-service.default` into `search-service-default` and |
| 200 | + `login-service.default` into `login-service-default` as well in |
| 201 | + `routing.yaml`. |
| 202 | + |
| 203 | +1. The `routing.yaml` file will create an ingress that forwards incoming |
| 204 | + requests at `example.com/search` to `search-service.default.example.com` by |
| 205 | + updating the "Host" header to `search-service.default.example.com` and |
| 206 | + stripping the request path. This modified request is then forwarded to the |
| 207 | + Knative ingress (Kong) and routed to the service as usual. Another ingress |
| 208 | + like this is also created for the _Login_ service. |
| 209 | + |
| 210 | + ```bash |
| 211 | + kubectl get ingress {search,login}-service-ingress -n kong --output yaml |
| 212 | + ``` |
| 213 | + |
| 214 | +1. Send a request to the _Search_ service and the _Login_ service by using |
| 215 | + their corresponding URLs. You should get the same results as directly |
| 216 | + accessing these services. |
| 217 | + |
| 218 | + - Send a request to the _Search_ service: |
| 219 | + ```bash |
| 220 | + curl http://${GATEWAY_IP}/search --header "Host: example.com" |
| 221 | + ``` |
| 222 | + or |
| 223 | + ```bash |
| 224 | + curl http://${GATEWAY_IP}/search --header "Host: <YOUR_DOMAIN_NAME>" |
| 225 | + ``` |
| 226 | + for the case using your own domain. |
| 227 | + |
| 228 | + - Send a request to the _Login_ service: |
| 229 | + ```bash |
| 230 | + curl http://${GATEWAY_IP}/login --header "Host: example.com" |
| 231 | + ``` |
| 232 | + or |
| 233 | + ```bash |
| 234 | + curl http://${GATEWAY_IP}/login --header "Host: <YOUR_DOMAIN_NAME>" |
| 235 | + ``` |
| 236 | + for the case using your own domain. |
| 237 | + |
| 238 | +## How It Works |
| 239 | + |
| 240 | +When a request with host `example.com` or your own domain name reaches Kong |
| 241 | +Gateway, Kong will check if the URL path prefix is `/search` or `/login`. If the |
| 242 | +URL matches on of the two rules, then the "Host" header of the request will be |
| 243 | +rewritten into the host of the _Search_ service or _Login_ service, |
| 244 | +respectively, and the path will be stripped. The modified request will be |
| 245 | +forwarded to Kong again. Kong will check the "Host" header and forward the |
| 246 | +request to the _Search_ or _Login_ service according to the header value. |
| 247 | + |
| 248 | + |
| 249 | + |
| 250 | +## Clean Up |
| 251 | + |
| 252 | +To clean up the sample resources: |
| 253 | + |
| 254 | +```bash |
| 255 | +kubectl delete --filename docs/serving/samples/kong-routing-go/sample.yaml |
| 256 | +kubectl delete --filename docs/serving/samples/kong-routing-go/routing.yaml |
| 257 | +``` |
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