# Configure Fault Injection

Chaos engineering is essential for building reliable systems. The [`fault-injection`](https://docs.api7.ai/hub/fault-injection.md) plugin allows you to test your application's resilience by simulating failures and latency at the Gateway level before requests reach your upstream services.

## Prerequisites[​](#prerequisites "Direct link to Prerequisites")

* An API7 Enterprise instance is running.
* A Gateway Group is created and a Gateway instance is running.
* A [token from the Dashboard](https://docs.api7.ai/api7-gateway/reference/obtain-dashboard-token.md).

## Configure HTTP Aborts[​](#configure-http-aborts "Direct link to Configure HTTP Aborts")

You can return specific HTTP status codes to a percentage of requests to simulate service failures.

* Admin API
* ADC

```
curl -k "https://localhost:7443/apisix/admin/services/fault-injection-service?gateway_group_id={gateway_group_id}" -X PUT \

  -H "X-API-KEY: ${API_KEY}" \

  -H "Content-Type: application/json" \

  -d '{

    "name": "fault-injection-service",

    "upstream": {

      "type": "roundrobin",

      "scheme": "http",

      "nodes": [

        {

          "host": "httpbin.org",

          "port": 80,

          "weight": 100

        }

      ]

    }

  }'



curl -k "https://localhost:7443/apisix/admin/routes/fault-injection-route?gateway_group_id={gateway_group_id}" -X PUT \

  -H "X-API-KEY: ${API_KEY}" \

  -H "Content-Type: application/json" \

  -d '{

    "name": "fault-injection-route",

    "paths": ["/get"],

    "service_id": "fault-injection-service",

    "plugins": {

      "fault-injection": {

        "abort": {

          "http_status": 503,

          "body": "Service Temporarily Unavailable",

          "percentage": 10

        }

      }

    }

  }'
```

adc.yaml

```
services:

  - name: fault-injection-service

    upstream:

      nodes:

        - host: httpbin.org

          port: 80

          weight: 1

    routes:

      - name: fault-injection-route

        uris:

          - /get

        plugins:

          fault-injection:

            abort:

              http_status: 503

              body: "Service Temporarily Unavailable"

              percentage: 10

    labels:

      docs-example: fault-injection-service
```

Preview the changes owned by this example and confirm that the diff contains no unintended updates or deletions:

```
adc diff -f adc.yaml \

  --include-resource-type service \

  --label-selector docs-example=fault-injection-service
```

Synchronize the reviewed configuration:

```
adc sync -f adc.yaml \

  --include-resource-type service \

  --label-selector docs-example=fault-injection-service
```

## Configure Response Delays[​](#configure-response-delays "Direct link to Configure Response Delays")

You can also simulate slow network conditions or backend latency by delaying responses.

* Admin API
* ADC

```
curl -k "https://localhost:7443/apisix/admin/services/delay-fault-injection-service?gateway_group_id={gateway_group_id}" -X PUT \

  -H "X-API-KEY: ${API_KEY}" \

  -H "Content-Type: application/json" \

  -d '{

    "name": "delay-fault-injection-service",

    "upstream": {

      "type": "roundrobin",

      "scheme": "http",

      "nodes": [

        {

          "host": "httpbin.org",

          "port": 80,

          "weight": 100

        }

      ]

    }

  }'



curl -k "https://localhost:7443/apisix/admin/routes/delay-fault-injection-route?gateway_group_id={gateway_group_id}" -X PUT \

  -H "X-API-KEY: ${API_KEY}" \

  -H "Content-Type: application/json" \

  -d '{

    "name": "delay-fault-injection-route",

    "paths": ["/delay/5"],

    "service_id": "delay-fault-injection-service",

    "plugins": {

      "fault-injection": {

        "delay": {

          "duration": 5,

          "percentage": 20

        }

      }

    }

  }'
```

adc.yaml

```
services:

  - name: delay-fault-injection-service

    upstream:

      nodes:

        - host: httpbin.org

          port: 80

          weight: 1

    routes:

      - name: delay-fault-injection-route

        uris:

          - /delay/5

        plugins:

          fault-injection:

            delay:

              duration: 5

              percentage: 20

    labels:

      docs-example: delay-fault-injection-service
```

Preview the changes owned by this example and confirm that the diff contains no unintended updates or deletions:

```
adc diff -f adc.yaml \

  --include-resource-type service \

  --label-selector docs-example=delay-fault-injection-service
```

Synchronize the reviewed configuration:

```
adc sync -f adc.yaml \

  --include-resource-type service \

  --label-selector docs-example=delay-fault-injection-service
```

## Validate the Configuration[​](#validate-the-configuration "Direct link to Validate the Configuration")

To validate an abort configuration with a 10% percentage, send multiple requests:

```
for i in {1..20}; do curl -i "http://127.0.0.1:9080/get"; done
```

You should see some requests receiving the injected `503 Service Temporarily Unavailable` response. For delays, the `curl` command should hang for the configured `duration` when the fault is injected.

To verify the delay example, measure a few requests against the delay route:

```
time curl -i "http://127.0.0.1:9080/delay/5"
```

If the route returns `404` immediately after you apply the configuration, wait a few seconds for the latest configuration to reach the gateway and retry.

## Next Steps[​](#next-steps "Direct link to Next Steps")

* [Configure Proxy Mirror](https://docs.api7.ai/api7-gateway/how-to-guides/traffic-management/proxy-mirror.md) — test your application with real production traffic.
* [Configure Response Rewrite](https://docs.api7.ai/api7-gateway/how-to-guides/traffic-management/response-rewrite.md) — modify response data before returning to the client.
* [Configure Rate Limiting](https://docs.api7.ai/api7-gateway/how-to-guides/traffic-management/rate-limiting.md) — protect your system from traffic spikes.