Retry

Retrying until it Succeeds

The Retry middleware reissues requests a given number of times when it cannot contact the backend service. This applies at the transport level (TCP). If the service does not respond to the initial connection attempt, the middleware retries. However, once the service responds, regardless of the HTTP status code, the middleware considers it operational and stops retrying. This means that the retry mechanism does not handle HTTP errors; it only retries when there is no response at the TCP level. The Retry middleware has an optional configuration to enable an exponential backoff.

Configuration Examples

Docker

# Retry 4 times with exponential backoff
labels:
  - "traefik.http.middlewares.test-retry.retry.attempts=4"
  - "traefik.http.middlewares.test-retry.retry.initialinterval=100ms"

Kubernetes

# Retry 4 times with exponential backoff
apiVersion: traefik.io/v1alpha1
kind: Middleware
metadata:
  name: test-retry
spec:
  retry:
    attempts: 4
    initialInterval: 100ms

Consul Catalog

# Retry 4 times with exponential backoff
- "traefik.http.middlewares.test-retry.retry.attempts=4"
- "traefik.http.middlewares.test-retry.retry.initialinterval=100ms"

Marathon

"labels": {
  "traefik.http.middlewares.test-retry.retry.attempts": "4",
  "traefik.http.middlewares.test-retry.retry.initialinterval": "100ms",
}

Rancher

# Retry 4 times with exponential backoff
labels:
  - "traefik.http.middlewares.test-retry.retry.attempts=4"
  - "traefik.http.middlewares.test-retry.retry.initialinterval=100ms"

File (YAML)

# Retry 4 times with exponential backoff
http:
  middlewares:
    test-retry:
      retry:
        attempts: 4
        initialInterval: 100ms

File (TOML)

# Retry 4 times with exponential backoff
[http.middlewares]
  [http.middlewares.test-retry.retry]
    attempts = 4
    initialInterval = "100ms"

Configuration Options

attempts

mandatory

The attempts option defines how many times the request should be retried.

initialInterval

The initialInterval option defines the first wait time in the exponential backoff series. The maximum interval is calculated as twice the initialInterval. If unspecified, requests will be retried immediately.

The value of initialInterval should be provided in seconds or as a valid duration format, see time.ParseDuration.