Add load testing setup to docs

README.md

@@ -127,12 +127,11 @@ spec:
       interval: 30s
     # external checks (optional)
     webhooks:
-      - name: integration-tests
-        url: http://podinfo.test:9898/echo
-        timeout: 1m
+      - name: load-test
+        url: http://flagger-loadtester.test/
+        timeout: 5s
         metadata:
-          test: "all"
-          token: "16688eb5e9f289f1991c"
+          cmd: "hey -z 1m -q 10 -c 2 http://podinfo.test:9898/"
 ```
 
 The canary analysis is using the following promql queries:
@@ -211,6 +210,13 @@ kubectl apply -f ${REPO}/artifacts/canaries/deployment.yaml
 kubectl apply -f ${REPO}/artifacts/canaries/hpa.yaml
 ```
 
+Deploy the load testing service to generate traffic during the canary analysis:
+
+```bash
+kubectl -n test apply -f ${REPO}/artifacts/loadtester/deployment.yaml
+kubectl -n test apply -f ${REPO}/artifacts/loadtester/service.yaml
+```
+
 Create a canary promotion custom resource (replace the Istio gateway and the internet domain with your own):
 
 ```bash
@@ -239,7 +245,7 @@ Trigger a canary deployment by updating the container image:
 
 ```bash
 kubectl -n test set image deployment/podinfo \
-podinfod=quay.io/stefanprodan/podinfo:1.2.1
+podinfod=quay.io/stefanprodan/podinfo:1.4.0
 ```
 
 Flagger detects that the deployment revision changed and starts a new canary analysis:

artifacts/canaries/canary.yaml

@@ -51,9 +51,8 @@ spec:
       interval: 30s
     # external checks (optional)
     webhooks:
-      - name: integration-tests
-        url: https://httpbin.org/post
-        timeout: 1m
+      - name: load-test
+        url: http://flagger-loadtester.test/
+        timeout: 5s
         metadata:
-          test: "all"
-          token: "16688eb5e9f289f1991c"
+          cmd: "hey -z 1m -q 10 -c 2 http://podinfo.test:9898/"

docs/gitbook/how-it-works.md

@@ -281,4 +281,45 @@ Response status codes:
 
 On a non-2xx response Flagger will include the response body (if any) in the failed checks log and Kubernetes events.
 
+### Load Testing
+
+For workloads that are not receiving constant traffic Flagger can be configured with a webhook, 
+that when called, will start a load test for the target workload.
+If the target workload doesn't receive any traffic during the canary analysis, 
+Flagger metric checks will fail with "no values found for metric istio_requests_total".
+
+Flagger comes with a load testing service based on [rakyll/hey](https://github.com/rakyll/hey) 
+that generates traffic during analysis when configured as a webhook.
+
+First you need to deploy the load test runner in a namespace with Istio sidecar injection enabled:
+
+```bash
+export REPO=https://raw.githubusercontent.com/stefanprodan/flagger/master
+
+kubectl -n test apply -f ${REPO}/artifacts/loadtester/deployment.yaml
+kubectl -n test apply -f ${REPO}/artifacts/loadtester/service.yaml
+```
+
+When deployed the load tester API will be available at `http://flagger-loadtester.test/`. 
+
+Now you can add webhooks to the canary analysis spec:
+
+```yaml
+webhooks:
+  - name: load-test-get
+    url: http://flagger-loadtester.test/
+    timeout: 5s
+    metadata:
+      cmd: "hey -z 1m -q 10 -c 2 http://podinfo.test:9898/"
+  - name: load-test-post
+    url: http://flagger-loadtester.test/
+    timeout: 5s
+    metadata:
+      cmd: "hey -z 1m -q 10 -c 2 -m POST -d '{test: 2}' http://podinfo.test:9898/echo"
+```
+
+When the canary analysis starts, Flagger will call the webhooks and the load tester will run the `hey` commands 
+in the background, if they are not already running. This will ensure that during the 
+analysis, the `podinfo.test` virtual service will receive a steady steam of GET and POST requests.
+
 

docs/gitbook/usage/progressive-delivery.md

@@ -17,6 +17,13 @@ kubectl apply -f ${REPO}/artifacts/canaries/deployment.yaml
 kubectl apply -f ${REPO}/artifacts/canaries/hpa.yaml
 ```
 
+Deploy the load testing service to generate traffic during the canary analysis:
+
+```bash
+kubectl -n test apply -f ${REPO}/artifacts/loadtester/deployment.yaml
+kubectl -n test apply -f ${REPO}/artifacts/loadtester/service.yaml
+```
+
 Create a canary custom resource \(replace example.com with your own domain\):
 
 ```yaml
@@ -70,6 +77,13 @@ spec:
       # milliseconds
       threshold: 500
       interval: 30s
+    # generate traffic during analysis
+    webhooks:
+      - name: load-test
+        url: http://flagger-loadtester.test/
+        timeout: 5s
+        metadata:
+          cmd: "hey -z 1m -q 10 -c 2 http://podinfo.test:9898/"
 ```
 
 Save the above resource as podinfo-canary.yaml and then apply it:
@@ -99,7 +113,7 @@ Trigger a canary deployment by updating the container image:
 
 ```bash
 kubectl -n test set image deployment/podinfo \
-podinfod=quay.io/stefanprodan/podinfo:1.2.1
+podinfod=quay.io/stefanprodan/podinfo:1.4.0
 ```
 
 Flagger detects that the deployment revision changed and starts a new rollout: