Fault Injection

Adding Fault Injection functionality to fsm sidecar via Plugins

Fault injection testing is a software testing technique that intentionally introduces errors into a system to verify its ability to handle and bounce back from error conditions. This testing method is usually performed before deployment to identify any possible faults that may have arisen during production. This demo demonstrates on how to implement Fault Injection functionality via a plugin.

Prerequisites

  • Kubernetes cluster running Kubernetes v1.19.0 or greater.
  • Have fsm installed.
  • Have kubectl available to interact with the API server.
  • Have fsm CLI 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/fault-injection.yaml

Setting up plugin-chain

kubectl apply -f - <<EOF
kind: PluginChain
apiVersion: plugin.flomesh.io/v1alpha1
metadata:
  name: http-fault-injection-chain
  namespace: pipy
spec:
  chains:
    - name: inbound-http
      plugins:
        - http-fault-injection
  selectors:
    podSelector:
      matchLabels:
        app: pipy-ok
      matchExpressions:
        - key: app
          operator: In
          values: ["pipy-ok"]
    namespaceSelector:
      matchExpressions:
        - key: flomesh.io/monitored-by
          operator: In
          values: ["fsm"]
EOF

Setting up plugin configuration

In below configuration, we need to have either of delay or abort

kubectl apply -f - <<EOF
kind: PluginConfig
apiVersion: plugin.flomesh.io/v1alpha1
metadata:
  name: http-fault-injection-config
  namespace: pipy
spec:
  config:
    delay:
      percentage:
        value: 0.5
      fixedDelay: 5s
    abort:
      percentage:
        value: 0.5
      httpStatus: 400
  plugin: http-fault-injection
  destinationRefs:
    - kind: Service
      name: pipy-ok
      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}')"

date;  kubectl exec ${curl_client} -n curl -c curl -- curl -ksi http://pipy-ok.pipy:8080 ;  echo "";  date

Run the above command a few times, and you will see that after a few more visits, and there is approximately a 50% chance of receiving the following result (HTTP status code 400, with a delay of 5 seconds).

Thu Mar 30 06:47:58 UTC 2023
HTTP/1.1 400 Bad Request
content-length: 0
connection: keep-alive


Thu Mar 30 06:48:04 UTC 2023

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Last modified April 11, 2024: update versions of fsm and pipy (cea5b3e)