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

# Value of `kubernetes.io/ingress.class` annotation that identifies Ingress objects to be processed.
# If the parameter is non-empty, only Ingresses containing an annotation with the same value are processed.
# Otherwise, Ingresses missing the annotation, having an empty value, or the value `traefik` are processed.
#
# Note : `ingressClass` option must begin with the "traefik" prefix.
#
# Optional
# Default: empty
#
# ingressClass = "traefik-internal"

# 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 as URL.

When deployed into Kubernetes, Traefik will read the environment variables KUBERNETES_SERVICE_HOST and KUBERNETES_SERVICE_PORT to construct the endpoint.

The access token will be looked up in /var/run/secrets/kubernetes.io/serviceaccount/token and the SSL CA certificate in /var/run/secrets/kubernetes.io/serviceaccount/ca.crt. Both are provided mounted automatically when deployed inside Kubernetes.

The endpoint may be specified to override the environment variable values inside a cluster.

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 using the granted autentication and authorization of the associated kubeconfig.

labelselector

By default, Traefik processes all Ingress objects in the configured namespaces. A label selector can be defined to filter on specific Ingress objects only.

See label-selectors for details.

TLS communication between Traefik and backend pods

Traefik automatically requests endpoint information based on the service provided in the ingress spec. Although traefik will connect directly to the endpoints (pods), it still checks the service port to see if TLS communication is required. If the service port defined in the ingress spec is 443, then the backend communication protocol is assumed to be TLS, and will connect via TLS automatically.

!!! note Please note that by enabling TLS communication between traefik and your pods, you will have to have trusted certificates that have the proper trust chain and IP subject name. If this is not an option, you may need to skip TLS certificate verification. See the insecureSkipVerify setting for more details.

Annotations

General annotations

The following general annotations are applicable on the Ingress object:

Annotation	Description
traefik.ingress.kubernetes.io/buffering: <YML>	(3) See buffering section.
traefik.ingress.kubernetes.io/error-pages: <YML>	(1) See custom error pages section.
traefik.ingress.kubernetes.io/frontend-entry-points: http,https	Override the default frontend endpoints.
traefik.ingress.kubernetes.io/pass-tls-cert: "true"	Override the default frontend PassTLSCert value. Default: false.
traefik.ingress.kubernetes.io/preserve-host: "true"	Forward client Host header to the backend.
traefik.ingress.kubernetes.io/priority: "3"	Override the default frontend rule priority.
traefik.ingress.kubernetes.io/rate-limit: <YML>	(2) See rate limiting section.
traefik.ingress.kubernetes.io/redirect-entry-point: https	Enables Redirect to another entryPoint for that frontend (e.g. HTTPS).
traefik.ingress.kubernetes.io/redirect-permanent: "true"	Return 301 instead of 302.
traefik.ingress.kubernetes.io/redirect-regex: ^http://localhost/(.*)	Redirect to another URL for that frontend. Must be set with traefik.ingress.kubernetes.io/redirect-replacement.
traefik.ingress.kubernetes.io/redirect-replacement: http://mydomain/$1	Redirect to another URL for that frontend. Must be set with traefik.ingress.kubernetes.io/redirect-regex.
traefik.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.
traefik.ingress.kubernetes.io/rule-type: PathPrefixStrip	Override the default frontend rule type. Default: PathPrefix.
traefik.ingress.kubernetes.io/whitelist-source-range: "1.2.3.0/24, fe80::/16"	A comma-separated list of IP ranges permitted for access. all source IPs are permitted if the list is empty or a single range is ill-formatted.
traefik.ingress.kubernetes.io/app-root: "/index.html"	Redirects all requests for / to the defined path. (4)

<1> traefik.ingress.kubernetes.io/error-pages example:

foo:
  status:
  - "404"
  backend: bar
  query: /bar
fii:
  status:
  - "503"
  - "500"
  backend: bar
  query: /bir

<2> traefik.ingress.kubernetes.io/rate-limit example:

extractorfunc: client.ip
rateset:
  bar:
    period: 3s
    average: 6
    burst: 9
  foo:
    period: 6s
    average: 12
    burst: 18

<3> traefik.ingress.kubernetes.io/buffering example:

maxrequestbodybytes: 10485760
memrequestbodybytes: 2097153
maxresponsebodybytes: 10485761
memresponsebodybytes: 2097152
retryexpression: IsNetworkError() && Attempts() <= 2

<4> traefik.ingress.kubernetes.io/app-root: Non-root paths will not be affected by this annotation and handled normally. This annotation may not be combined with the ReplacePath rule type or any other annotation leveraging that rule type. Trying to do so leads to an error and the corresponding Ingress object being ignored.

!!! note Please note that traefik.ingress.kubernetes.io/redirect-regex and traefik.ingress.kubernetes.io/redirect-replacement do not have to be set if traefik.ingress.kubernetes.io/redirect-entry-point is defined for the redirection (they will not be used in this case).

The following annotations are applicable on the Service object associated with a particular Ingress object:

Annotation	Description
traefik.backend.loadbalancer.sticky: "true"	Enable backend sticky sessions (DEPRECATED).
traefik.ingress.kubernetes.io/affinity: "true"	Enable backend sticky sessions.
traefik.ingress.kubernetes.io/circuit-breaker-expression: <expression>	Set the circuit breaker expression for the backend.
traefik.ingress.kubernetes.io/load-balancer-method: drr	Override the default wrr load balancer algorithm.
traefik.ingress.kubernetes.io/max-conn-amount: 10	Set a maximum number of connections to the backend. Must be used in conjunction with the below label to take effect.
traefik.ingress.kubernetes.io/max-conn-extractor-func: client.ip	Set the function to be used against the request to determine what to limit maximum connections to the backend by. Must be used in conjunction with the above label to take effect.
traefik.ingress.kubernetes.io/session-cookie-name: <NAME>	Manually set the cookie name for sticky sessions.

!!! note traefik.ingress.kubernetes.io/ and ingress.kubernetes.io/ are supported prefixes.

Custom Headers Annotations

Annotation	Description
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

Security Headers Annotations

The following security annotations are applicable on the Ingress object:

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/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/content-type-nosniff: "true"	Adds the X-Content-Type-Options header with the value nosniff.
ingress.kubernetes.io/custom-browser-xss-value: VALUE	Set custom value for X-XSS-Protection header. This overrides the BrowserXssFilter option.
ingress.kubernetes.io/custom-frame-options-value: VALUE	Overrides the X-Frame-Options header with the custom value.
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/hsts-max-age: "315360000"	Sets the max-age of the HSTS header.
ingress.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/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.
ingress.kubernetes.io/proxy-headers: EXPR	Provides a list of headers that the proxied hostname may be stored. Format: HEADER1,HEADER2
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/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

Authentication

Additional authentication annotations can be added to the Ingress object. The source of the authentication is a Secret object that contains the credentials.

Annotation	Description
ingress.kubernetes.io/auth-type: basic	Contains the authentication type. The only permitted type is basic.
ingress.kubernetes.io/auth-secret: mysecret	Name of Secret containing the username and password with access to the paths defined in the Ingress object.

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

The following limitations hold:

• The realm is not configurable; the only supported (and default) value is traefik.
• The Secret must contain a single file only.

TLS certificates management

TLS certificates can be managed in Secrets objects. More information are available in the User Guide.

!!! note Only TLS certificates provided by users can be stored in Kubernetes Secrets. Let's Encrypt certificates cannot be managed in Kubernets Secrets yet.