Inject faults in a percentage of your requests to test how your app handles the errors. By using the policy, you can avoid deleting pods, delaying packets, or corrupting packets.

You can set two types of faults injection:

  • Delays: Delays are timing failures, such as network latency or overloaded upstreams.
  • Aborts: Aborts are crash failures, such as HTTP error codes or TCP connection failures.

For more information, see the following resources.

Before you begin

  1. Complete the multicluster getting started guide to set up the following testing environment.

    • Three clusters along with environment variables for the clusters and their Kubernetes contexts.
    • The Gloo meshctl CLI, along with other CLI tools such as kubectl and istioctl.
    • The Gloo management server in the management cluster, and the Gloo agents in the workload clusters.
    • Istio installed in the workload clusters.
    • A simple Gloo workspace setup.
  2. Install Bookinfo and other sample apps.

Configure fault injection policies

You can apply a fault injection policy at the route level. For more information, see Applying policies.

Abort example

The following example is for a simple fault injection abort policy that returns a 418 HTTP response. No delay is configured.

  apiVersion: resilience.policy.gloo.solo.io/v2
kind: FaultInjectionPolicy
metadata:
  annotations:
    cluster.solo.io/cluster: ""
  name: faultinjection-basic
  namespace: bookinfo
spec:
  applyToRoutes:
  - route:
      labels:
        route: ratings
  config:
    abort:
      httpStatus: 418

Review the following table to understand this configuration. For more information, see the API docs.

SettingDescription
spec.applyToRoutesUse labels to configure which routes to apply the policy to. This example label matches the app and route from the example route table that you apply separately. If omitted and you do not have another selector such as applyToDestinations, the policy applies to all routes in the workspace.
spec.config.abortBecause no percentage field is set, the policy defaults to aborting 100% of requests. The httpStatus field sets the HTTP response code to return that you want to send back. This example sets the 418 HTTP response code. The value must be an integer in the range [200, 600]. For HTTP response status codes, see the mdn web docs.

Delay example

The following example is for a simple fault injection delay policy with a default value for the percentage. No abort is configured.

  apiVersion: resilience.policy.gloo.solo.io/v2
kind: FaultInjectionPolicy
metadata:
  name: faultinjection-basic-delay
  namespace: bookinfo
spec:
  applyToRoutes:
    - route:
        labels:
          route: ratings
  config:
    delay:
      fixedDelay: 5s

Review the following table to understand this configuration. For more information, see the API docs.

SettingDescription
spec.applyToRoutesUse labels to configure which routes to apply the policy to. This example label matches the app and route from the example route table that you apply separately. If omitted and you do not have another selector such as applyToDestinations, the policy applies to all routes in the workspace.
spec.config.delayBecause no percentage field is set, the policy defaults to delaying 100% of requests. The fixedDelay field is required, and sets the duration in seconds to delay the request.

Abort and delay example

The following example is for a fault injection policy that both delays and aborts requests. Delays and aborts are independent of one another. When both values are set, your requests are either delayed only, delayed and aborted, or aborted only.

  apiVersion: resilience.policy.gloo.solo.io/v2
kind: FaultInjectionPolicy
metadata:
  name: faultinjection-basic-abort-and-delay
  namespace: bookinfo
  annotations:
    cluster.solo.io/cluster: $REMOTE_CLUSTER1
spec:
  applyToRoutes:
    - route:
        labels:
          route: ratings
  config:
    abort:
      httpStatus: 418
      percentage: 10
    delay:
      percentage: 40
      fixedDelay: 5s

Review the following table to understand this configuration. For more information, see the API docs.

SettingDescription
spec.applyToRoutesUse labels to configure which routes to apply the policy to. This example label matches the app and route from the example route table that you apply separately. If omitted and you do not have another selector such as applyToDestinations, the policy applies to all routes in the workspace.
spec.config.abortThe httpStatus field sets the HTTP response code to return that you want to send back. This example sets the 418 HTTP response code. The value must be an integer in the range [200, 600]. For HTTP response status codes, see the mdn web docs. The percentage field is set to 10, so 10% of the requests are aborted. If the request is also chosen for a delay, the delay happens before the request is aborted.
spec.config.delayThe fixedDelay field is required, and sets the duration in seconds to delay the request. The percentage field is set to 40, so 40% of the requests are delayed. If the request is also chosen to be aborted, the delay happens before the request is aborted.

Verify fault injection policies

  1. Create the example fault injection policy for the ratings app.
      kubectl apply --context ${REMOTE_CONTEXT1} -f - << EOF
apiVersion: resilience.policy.gloo.solo.io/v2
kind: FaultInjectionPolicy
metadata:
  annotations:
    cluster.solo.io/cluster: ""
  name: faultinjection-basic
  namespace: bookinfo
spec:
  applyToRoutes:
  - route:
      labels:
        route: ratings
  config:
    abort:
      httpStatus: 418
EOF

  2. Create a route table for the ratings app. Because the policy applies at the route level, Gloo checks for the route in a route table resource.

      kubectl apply --context ${REMOTE_CONTEXT1} -f - << EOF
apiVersion: networking.gloo.solo.io/v2
kind: RouteTable
metadata:
  name: ratings-rt
  namespace: bookinfo
spec:
  hosts:
  - ratings
  http:
  - forwardTo:
      destinations:
      - ref:
          name: ratings
          namespace: bookinfo
    labels:
      route: ratings
  workloadSelectors:
  - {}
EOF

    Review the following table to understand this configuration. For more information, see the API docs.

    SettingDescription
    hostsThe host that the route table routes traffic for. In this example, the ratings host matches the ratings service within the mesh.
    http.forwardTo.destinationsThe destination to forward requests that come in along the host route. In this example, the ratings service is selected.
    http.labelsThe label for the route. This label must match the label that the policy selects.
    workloadSelectorsThe source workloads within the mesh that this route table routes traffic for. In the example, all workloads are selected. This way, the curl container that you create in subsequent steps can send a request along the ratings route.
  3. Send a request to the app. Create a temporary curl pod in the bookinfo namespace, so that you can test the app setup. You can also use this method in Kubernetes 1.23 or later, but an ephemeral container might be simpler.
    1. Create the curl pod.
        kubectl run -it -n bookinfo --context $REMOTE_CONTEXT1 curl \
  --image=curlimages/curl:7.73.0 --rm  -- sh
    2. Send a request to the ratings app.
        curl http://ratings:9080/ratings/1 -v
    3. Exit the temporary pod. The pod deletes itself.
        exit
  4. Verify that you notice the fault from the previous examples.
    • Abort: All inbound requests to the ratings service result in a 418 Unknown HTTP status code.
    • Delay: All inbound requests to the ratings service have a five second delay.
    • Both abort and delay: 10% of the calls return 418 Unknown HTTP status code responses, and 40% have a five second delay before they send a response.

Cleanup

You can optionally remove the resources that you set up as part of this guide.
  kubectl --context $REMOTE_CONTEXT1 -n bookinfo delete RouteTable ratings-rt
kubectl --context $REMOTE_CONTEXT1 -n bookinfo delete FaultInjectionPolicy faultinjection-basic