Traffic Mirroring
Traffic mirroring, also known as shadowing, is a technique used to test new versions of an application in a safe and efficient manner. It involves creating a mirrored service that receives a copy of live traffic for testing and troubleshooting purposes. This approach is especially useful for acceptance testing, as it can help identify issues in advance, before they impact end-users.
One of the key benefits of traffic mirroring is that it occurs outside the primary request path for the main service. This means that end-users are not affected by any changes or issues that may occur during the testing process. As such, traffic mirroring is a powerful and low-risk approach for validating new versions of an application.
By using traffic mirroring, you can get valuable insights into how your application will perform in a live environment, without putting your users at risk. This approach can help you identify and address issues quickly and efficiently, which can ultimately improve the overall performance and reliability of your application.
Prerequisites
- Kubernetes cluster running Kubernetes v1.19.0 or greater.
- Have fsm installed.
- Have
kubectlavailable to interact with the API server. - Have
fsmCLI available for managing the service mesh.
Deploy demo services
kubectl create namespace curl
fsm namespace add curl
kubectl apply -n curl -f https://raw.githubusercontent.com/flomesh-io/fsm-docs/main/manifests/samples/plugins/curl.yaml
kubectl create namespace pipy
fsm namespace add pipy
kubectl apply -n pipy -f https://raw.githubusercontent.com/flomesh-io/fsm-docs/main/manifests/samples/plugins/pipy-ok.pipy.yaml
# Wait for pods to be up and ready
sleep 2
kubectl wait --for=condition=ready pod -n curl -l app=curl --timeout=180s
kubectl wait --for=condition=ready pod -n pipy -l app=pipy-ok -l version=v1 --timeout=180s
kubectl wait --for=condition=ready pod -n pipy -l app=pipy-ok -l version=v2 --timeout=180s
Enable plugin policy mode
kubectl patch meshconfig fsm-mesh-config -n "$fsm_namespace" -p '{"spec":{"featureFlags":{"enablePluginPolicy":true}}}' --type=merge
Declaring a plugin
kubectl apply -f https://raw.githubusercontent.com/flomesh-io/fsm-docs/main/manifests/samples/plugins/traffic-mirror.yaml
Setting up plugin-chain
kubectl apply -f - <<EOF
kind: PluginChain
apiVersion: plugin.flomesh.io/v1alpha1
metadata:
name: traffic-mirror-chain
namespace: pipy
spec:
chains:
- name: outbound-http
plugins:
- traffic-mirror
selectors:
podSelector:
matchLabels:
app: curl
matchExpressions:
- key: app
operator: In
values: ["curl"]
namespaceSelector:
matchExpressions:
- key: flomesh.io/monitored-by
operator: In
values: ["fsm"]
EOF
Setting up plugin configuration
kubectl apply -f - <<EOF
kind: PluginConfig
apiVersion: plugin.flomesh.io/v1alpha1
metadata:
name: traffic-mirror-config
namespace: curl
spec:
config:
namespace: pipy
service: pipy-ok-v2
port: 8080
percentage:
value: 1.0
plugin: traffic-mirror
destinationRefs:
- kind: Service
name: pipy-ok-v1
namespace: pipy
EOF
Test
Use the below command to perform a test
curl_client="$(kubectl get pod -n curl -l app=curl -o jsonpath='{.items[0].metadata.name}')"
kubectl exec ${curl_client} -n curl -c curl -- curl -ksi http://pipy-ok-v1.pipy:8080
Accessing service pipy-ok-v1 should be mirrored to pipy-ok-v2, so we should be seeing access logs in both services.
Testing pipy-ok-v1 logs
pipy_ok_v1="$(kubectl get pod -n pipy -l app=pipy-ok,version=v1 -o jsonpath='{.items[0].metadata.name}')"
kubectl logs pod/${pipy_ok_v1} -n pipy -c pipy
You will see something similar
[2023-03-29 08:41:04 +0000] [1] [INFO] Starting gunicorn 19.9.0
[2023-03-29 08:41:04 +0000] [1] [INFO] Listening at: http://0.0.0.0:8080 (1)
[2023-03-29 08:41:04 +0000] [1] [INFO] Using worker: sync
[2023-03-29 08:41:04 +0000] [14] [INFO] Booting worker with pid: 14
127.0.0.6 - - [29/Mar/2023:08:45:35 +0000] "GET / HTTP/1.1" 200 9593 "-" "curl/7.85.0-DEV"
Testing pipy-ok-v2 logs
pipy_ok_v2="$(kubectl get pod -n pipy -l app=pipy-ok,version=v2 -o jsonpath='{.items[0].metadata.name}')"
kubectl logs pod/${pipy_ok_v2} -n pipy -c pipy
You will see something similar
[2023-03-29 08:41:09 +0000] [1] [INFO] Starting gunicorn 19.9.0
[2023-03-29 08:41:09 +0000] [1] [INFO] Listening at: http://0.0.0.0:8080 (1)
[2023-03-29 08:41:09 +0000] [1] [INFO] Using worker: sync
[2023-03-29 08:41:09 +0000] [15] [INFO] Booting worker with pid: 15
127.0.0.6 - - [29/Mar/2023:08:45:35 +0000] "GET / HTTP/1.1" 200 9593 "-" "curl/7.85.0-DEV"
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