traefik/docs/configuration/backends/kubernetes.md

Kubernetes Ingress Backend

Træfik can be configured to use Kubernetes Ingress as a backend configuration.

See also Kubernetes user guide.

Configuration

################################################################
# Kubernetes Ingress configuration backend
################################################################

# Enable Kubernetes Ingress configuration backend.
[kubernetes]

# Kubernetes server endpoint.
#
# Optional for in-cluster configuration, required otherwise.
# Default: empty
#
# endpoint = "http://localhost:8080"

# Bearer token used for the Kubernetes client configuration.
#
# Optional
# Default: empty
#
# token = "my token"

# Path to the certificate authority file.
# Used for the Kubernetes client configuration.
#
# Optional
# Default: empty
#
# certAuthFilePath = "/my/ca.crt"

# Array of namespaces to watch.
#
# Optional
# Default: all namespaces (empty array).
#
# namespaces = ["default", "production"]

# Ingress label selector to identify Ingress objects that should be processed.
#
# Optional
# Default: empty (process all Ingresses)
#
# labelselector = "A and not B"

# Disable PassHost Headers.
#
# Optional
# Default: false
#
# disablePassHostHeaders = true

# Enable PassTLSCert Headers.
#
# Optional
# Default: false
#
# enablePassTLSCert = true

# Override default configuration template.
#
# Optional
# Default: <built-in template>
#
# filename = "kubernetes.tmpl"

endpoint

The Kubernetes server endpoint.

When deployed as a replication controller in Kubernetes, Traefik will use the environment variables KUBERNETES_SERVICE_HOST and KUBERNETES_SERVICE_PORT to construct the endpoint.

Secure token will be found in /var/run/secrets/kubernetes.io/serviceaccount/token and SSL CA cert in /var/run/secrets/kubernetes.io/serviceaccount/ca.crt

The endpoint may be given to override the environment variable values.

When the environment variables are not found, Traefik will try to connect to the Kubernetes API server with an external-cluster client. In this case, the endpoint is required. Specifically, it may be set to the URL used by kubectl proxy to connect to a Kubernetes cluster from localhost.

labelselector

Ingress label selector to identify Ingress objects that should be processed.

See label-selectors for details.

Annotations

Annotations can be used on containers to override default behaviour for the whole Ingress resource:

• traefik.frontend.rule.type: PathPrefixStrip
  Override the default frontend rule type. Default: PathPrefix.
• traefik.frontend.priority: "3" Override the default frontend rule priority.
• traefik.frontend.redirect.entryPoint: https: Enables Redirect to another entryPoint for that frontend (e.g. HTTPS).
• traefik.frontend.redirect.regex: ^http://localhost/(.*): Redirect to another URL for that frontend. Must be set with traefik.frontend.redirect.replacement.
• traefik.frontend.redirect.replacement: http://mydomain/$1: Redirect to another URL for that frontend. Must be set with traefik.frontend.redirect.regex.
• traefik.frontend.entryPoints: http,https
  Override the default frontend endpoints.
• traefik.frontend.passTLSCert: true
  Override the default frontend PassTLSCert value. Default: false.
• ingress.kubernetes.io/rewrite-target: /users Replaces each matched Ingress path with the specified one, and adds the old path to the X-Replaced-Path header.

!!! note Please note that traefik.frontend.redirect.regex and traefik.frontend.redirect.replacement do not have to be set if traefik.frontend.redirect.entryPoint is defined for the redirection (they will not be used in this case).

Annotations can be used on the Kubernetes service to override default behaviour:

• traefik.backend.loadbalancer.method=drr
  Override the default wrr load balancer algorithm
• traefik.backend.loadbalancer.stickiness=true
  Enable backend sticky sessions
• traefik.backend.loadbalancer.stickiness.cookieName=NAME
  Manually set the cookie name for sticky sessions
• traefik.backend.loadbalancer.sticky=true
  Enable backend sticky sessions (DEPRECATED)

Additionally, an annotation can be used on Kubernetes services to set the circuit breaker expression for a backend.

• traefik.backend.circuitbreaker: <expression>
  Set the circuit breaker expression for the backend. Default: nil.

As known from nginx when used as Kubernetes Ingress Controller, a list of IP-Ranges which are allowed to access can be configured by using an ingress annotation:

• ingress.kubernetes.io/whitelist-source-range: "1.2.3.0/24, fe80::/16"

An unset or empty list allows all Source-IPs to access. If one of the Net-Specifications are invalid, the whole list is invalid and allows all Source-IPs to access.

Security annotations

The following security annotations can be applied to the ingress object to add security features:

Annotation	Description
ingress.kubernetes.io/allowed-hosts:EXPR	Provides a list of allowed hosts that requests will be processed. Format: Host1,Host2
ingress.kubernetes.io/custom-request-headers:EXPR	Provides the container with custom request headers that will be appended to each request forwarded to the container. Format: HEADER:value||HEADER2:value2
ingress.kubernetes.io/custom-response-headers:EXPR	Appends the headers to each response returned by the container, before forwarding the response to the client. Format: HEADER:value||HEADER2:value2
ingress.kubernetes.io/proxy-headers:EXPR	Provides a list of headers that the proxied hostname may be stored. Format: HEADER1,HEADER2
ingress.kubernetes.io/ssl-redirect:true	Forces the frontend to redirect to SSL if a non-SSL request is sent.
ingress.kubernetes.io/ssl-temporary-redirect:true	Forces the frontend to redirect to SSL if a non-SSL request is sent, but by sending a 302 instead of a 301.
ingress.kubernetes.io/ssl-host:HOST	This setting configures the hostname that redirects will be based on. Default is "", which is the same host as the request.
ingress.kubernetes.io/ssl-proxy-headers:EXPR	Header combinations that would signify a proper SSL Request (Such as X-Forwarded-For:https). Format: HEADER:value||HEADER2:value2
ingress.kubernetes.io/hsts-max-age:315360000	Sets the max-age of the HSTS header.
ngress.kubernetes.io/hsts-include-subdomains:true	Adds the IncludeSubdomains section of the STS header.
ingress.kubernetes.io/hsts-preload:true	Adds the preload flag to the HSTS header.
ingress.kubernetes.io/force-hsts:false	Adds the STS header to non-SSL requests.
ingress.kubernetes.io/frame-deny:false	Adds the X-Frame-Options header with the value of DENY.
ingress.kubernetes.io/custom-frame-options-value:VALUE	Overrides the X-Frame-Options header with the custom value.
ingress.kubernetes.io/content-type-nosniff:true	Adds the X-Content-Type-Options header with the value nosniff.
ingress.kubernetes.io/browser-xss-filter:true	Adds the X-XSS-Protection header with the value 1; mode=block.
ingress.kubernetes.io/content-security-policy:VALUE	Adds CSP Header with the custom value.
ingress.kubernetes.io/public-key:VALUE	Adds pinned HTST public key header.
ingress.kubernetes.io/referrer-policy:VALUE	Adds referrer policy header.
ingress.kubernetes.io/is-development:false	This will cause the AllowedHosts, SSLRedirect, and STSSeconds/STSIncludeSubdomains options to be ignored during development. When deploying to production, be sure to set this to false.

Authentication

Is possible to add additional authentication annotations in the Ingress rule. The source of the authentication is a secret that contains usernames and passwords inside the key auth.

• ingress.kubernetes.io/auth-type: basic
• ingress.kubernetes.io/auth-secret: mysecret
  Contains the usernames and passwords with access to the paths defined in the Ingress Rule.

The secret must be created in the same namespace as the Ingress rule.

Limitations:

• Basic authentication only.
• Realm not configurable; only traefik default.
• Secret must contain only single file.