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Fault injection

Test the resilience of your apps by injecting delays and connection failures.

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:

For more information, see the following resources.

If you import or export resources across workspaces, your policies might not apply. For more information, see Import and export policies.

Before you begin

This guide assumes that you use the same names for components like clusters, workspaces, and namespaces as in the getting started, and that your Kubernetes context is set to the cluster you store your Gloo config in (typically the management cluster). If you have different names, make sure to update the sample configuration files in this guide.

Follow the getting started instructions to:

  1. Set up Gloo Gateway in a single cluster.
  2. Deploy sample apps.
  3. Configure an HTTP listener on your gateway and set up basic routing for the sample apps.

Configure fault injection policies

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

Review the following sample configuration files.

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.

Setting Description
spec.applyToRoutes Use 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.abort Because no percentage field is set, the policy defaults to aborting 100% of requests. The httpStatus field configures the HTTP response code that you want to send back. In this example, the 418 HTTP response code is set. The value must be an integer in the range [200, 600]. For HTTP response status codes, see the mdn web docs.

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.

Setting Description
spec.applyToRoutes Use 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.delay Because 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.

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
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.

Setting Description
spec.applyToRoutes Use 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.abort The httpStatus field configures the HTTP response code that you want to send back. In this example, the 418 HTTP response code is set. 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.delay The 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. Apply the example fault injection policy in the cluster with the Bookinfo workspace in your example setup. 
    kubectl apply -f fault-injection.yml
  2. Send a request to the ratings app through the ingress gateway. 
    curl -vik --resolve www.example.com:80:${INGRESS_GW_IP} http://www.example.com:80/ratings/1

    curl -vik --resolve www.example.com:443:${INGRESS_GW_IP} https://www.example.com:443/ratings/1
  3. 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.
  4. Optional: Clean up the resources that you created. 
    kubectl -n bookinfo delete faultinjectionpolicy faultinjection-basic