traefik/docs/configuration/backends/docker.md

Docker Backend

Træfik can be configured to use Docker as a backend configuration.

Docker

################################################################
# Docker configuration backend
################################################################

# Enable Docker configuration backend.
[docker]

# Docker server endpoint. Can be a tcp or a unix socket endpoint.
#
# Required
#
endpoint = "unix:///var/run/docker.sock"

# Default domain used.
# Can be overridden by setting the "traefik.domain" label on a container.
#
# Required
#
domain = "docker.localhost"

# Enable watch docker changes.
#
# Optional
#
watch = true

# Override default configuration template.
# For advanced users :)
#
# Optional
#
# filename = "docker.tmpl"

# Override template version
# For advanced users :)
#
# Optional
# - "1": previous template version (must be used only with older custom templates, see "filename")
# - "2": current template version (must be used to force template version when "filename" is used)
#
# templateVersion = "2"

# Expose containers by default in Traefik.
# If set to false, containers that don't have `traefik.enable=true` will be ignored.
#
# Optional
# Default: true
#
exposedByDefault = true

# Use the IP address from the binded port instead of the inner network one.
# For specific use-case :)
#
# Optional
# Default: false
#
usebindportip = true

# Use Swarm Mode services as data provider.
#
# Optional
# Default: false
#
swarmMode = false

# Enable docker TLS connection.
#
# Optional
#
#  [docker.tls]
#  ca = "/etc/ssl/ca.crt"
#  cert = "/etc/ssl/docker.crt"
#  key = "/etc/ssl/docker.key"
#  insecureSkipVerify = true

To enable constraints see backend-specific constraints section.

Docker Swarm Mode

################################################################
# Docker Swarm Mode configuration backend
################################################################

# Enable Docker configuration backend.
[docker]

# Docker server endpoint.
# Can be a tcp or a unix socket endpoint.
#
# Required
# Default: "unix:///var/run/docker.sock"
#
endpoint = "tcp://127.0.0.1:2375"

# Default domain used.
# Can be overridden by setting the "traefik.domain" label on a services.
#
# Optional
# Default: ""
#
domain = "docker.localhost"

# Enable watch docker changes.
#
# Optional
# Default: true
#
watch = true

# Use Docker Swarm Mode as data provider.
#
# Optional
# Default: false
#
swarmMode = true

# Override default configuration template.
# For advanced users :)
#
# Optional
#
# filename = "docker.tmpl"

# Override template version
# For advanced users :)
#
# Optional
# - "1": previous template version (must be used only with older custom templates, see "filename")
# - "2": current template version (must be used to force template version when "filename" is used)
#
# templateVersion = "2"

# Expose services by default in Traefik.
#
# Optional
# Default: true
#
exposedByDefault = false

# Enable docker TLS connection.
#
# Optional
#
#  [docker.tls]
#  ca = "/etc/ssl/ca.crt"
#  cert = "/etc/ssl/docker.crt"
#  key = "/etc/ssl/docker.key"
#  insecureSkipVerify = true

To enable constraints see backend-specific constraints section.

Labels: overriding default behavior

Using Docker with Swarm Mode

If you use a compose file with the Swarm mode, labels should be defined in the deploy part of your service. This behavior is only enabled for docker-compose version 3+ (Compose file reference).

version: "3"
services:
  whoami:
    deploy:
      labels:
        traefik.docker.network: traefik

Using Docker Compose

If you are intending to use only Docker Compose commands (e.g. docker-compose up --scale whoami=2 -d), labels should be under your service, otherwise they will be ignored.

version: "3"
services:
  whoami:
    labels:
      traefik.docker.network: traefik

On Containers

Labels can be used on containers to override default behavior.

Label	Description
traefik.docker.network	Set the docker network to use for connections to this container. [1]
traefik.enable=false	Disable this container in Træfik
traefik.port=80	Register this port. Useful when the container exposes multiples ports.
traefik.protocol=https	Override the default http protocol
traefik.weight=10	Assign this weight to the container
traefik.backend=foo	Give the name foo to the generated backend for this container.
traefik.backend.buffering.maxRequestBodyBytes=0	See buffering section.
traefik.backend.buffering.maxResponseBodyBytes=0	See buffering section.
traefik.backend.buffering.memRequestBodyBytes=0	See buffering section.
traefik.backend.buffering.memResponseBodyBytes=0	See buffering section.
traefik.backend.buffering.retryExpression=EXPR	See buffering section.
traefik.backend.circuitbreaker.expression=EXPR	Create a circuit breaker to be used against the backend
traefik.backend.healthcheck.path=/health	Enable health check for the backend, hitting the container at path.
traefik.backend.healthcheck.port=8080	Allow to use a different port for the health check.
traefik.backend.healthcheck.interval=1s	Define the health check interval.
traefik.backend.healthcheck.hostname=foobar.com	Define the health check hostname.
traefik.backend.healthcheck.headers=EXPR	Define the health check request headers Format: HEADER:value||HEADER2:value2
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)
traefik.backend.loadbalancer.swarm=true	Use Swarm's inbuilt load balancer (only relevant under Swarm Mode).
traefik.backend.maxconn.amount=10	Set a maximum number of connections to the backend. Must be used in conjunction with the below label to take effect.
traefik.backend.maxconn.extractorfunc=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.frontend.auth.basic=EXPR	Sets basic authentication for that frontend in CSV format: User:Hash,User:Hash
traefik.frontend.entryPoints=http,https	Assign this frontend to entry points http and https. Overrides defaultEntryPoints
traefik.frontend.errors.<name>.backend=NAME	See custom error pages section.
traefik.frontend.errors.<name>.query=PATH	See custom error pages section.
traefik.frontend.errors.<name>.status=RANGE	See custom error pages section.
traefik.frontend.passHostHeader=true	Forward client Host header to the backend.
traefik.frontend.passTLSCert=true	Forward TLS Client certificates to the backend.
traefik.frontend.priority=10	Override default frontend priority
traefik.frontend.rateLimit.extractorFunc=EXP	See rate limiting section.
traefik.frontend.rateLimit.rateSet.<name>.period=6	See rate limiting section.
traefik.frontend.rateLimit.rateSet.<name>.average=6	See rate limiting section.
traefik.frontend.rateLimit.rateSet.<name>.burst=6	See rate limiting section.
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.redirect.permanent=true	Return 301 instead of 302.
traefik.frontend.rule=EXPR	Override the default frontend rule. Default: Host:{containerName}.{domain} or Host:{service}.{project_name}.{domain} if you are using docker-compose.
traefik.frontend.whiteList.sourceRange=RANGE	List of IP-Ranges which are allowed to access. 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.
traefik.frontend.whiteList.useXForwardedFor=true	Use X-Forwarded-For header as valid source of IP for the white list.

[1] traefik.docker.network: If a container is linked to several networks, be sure to set the proper network name (you can check with docker inspect <container_id>) otherwise it will randomly pick one (depending on how docker is returning them). For instance when deploying docker stack from compose files, the compose defined networks will be prefixed with the stack name. Or if your service references external network use it's name instead.

Custom Headers

Label	Description
traefik.frontend.headers.customRequestHeaders=EXPR	Provides the container with custom request headers that will be appended to each request forwarded to the container. Format: HEADER:value||HEADER2:value2
traefik.frontend.headers.customResponseHeaders=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

Label	Description
traefik.frontend.headers.allowedHosts=EXPR	Provides a list of allowed hosts that requests will be processed. Format: Host1,Host2
traefik.frontend.headers.hostsProxyHeaders=EXPR	Provides a list of headers that the proxied hostname may be stored. Format: HEADER1,HEADER2
traefik.frontend.headers.SSLRedirect=true	Forces the frontend to redirect to SSL if a non-SSL request is sent.
traefik.frontend.headers.SSLTemporaryRedirect=true	Forces the frontend to redirect to SSL if a non-SSL request is sent, but by sending a 302 instead of a 301.
traefik.frontend.headers.SSLHost=HOST	This setting configures the hostname that redirects will be based on. Default is "", which is the same host as the request.
traefik.frontend.headers.SSLProxyHeaders=EXPR	Header combinations that would signify a proper SSL Request (Such as X-Forwarded-For:https). Format: HEADER:value||HEADER2:value2
traefik.frontend.headers.STSSeconds=315360000	Sets the max-age of the STS header.
traefik.frontend.headers.STSIncludeSubdomains=true	Adds the IncludeSubdomains section of the STS header.
traefik.frontend.headers.STSPreload=true	Adds the preload flag to the STS header.
traefik.frontend.headers.forceSTSHeader=false	Adds the STS header to non-SSL requests.
traefik.frontend.headers.frameDeny=false	Adds the X-Frame-Options header with the value of DENY.
traefik.frontend.headers.customFrameOptionsValue=VALUE	Overrides the X-Frame-Options header with the custom value.
traefik.frontend.headers.contentTypeNosniff=true	Adds the X-Content-Type-Options header with the value nosniff.
traefik.frontend.headers.browserXSSFilter=true	Adds the X-XSS-Protection header with the value 1; mode=block.
traefik.frontend.headers.customBrowserXSSValue=VALUE	Set custom value for X-XSS-Protection header. This overrides the BrowserXssFilter option.
traefik.frontend.headers.contentSecurityPolicy=VALUE	Adds CSP Header with the custom value.
traefik.frontend.headers.publicKey=VALUE	Adds pinned HTST public key header.
traefik.frontend.headers.referrerPolicy=VALUE	Adds referrer policy header.
traefik.frontend.headers.isDevelopment=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.

On containers with Multiple Ports (segment labels)

Segment labels are used to define routes to a container exposing multiple ports. A segment is a group of labels that apply to a port exposed by a container. You can define as many segments as ports exposed in a container.

Segment labels override the default behavior.

Label	Description
traefik.<segment_name>.port=PORT	Overrides traefik.port. If several ports need to be exposed, the segment labels could be used.
traefik.<segment_name>.protocol	Overrides traefik.protocol.
traefik.<segment_name>.weight	Assign this segment weight. Overrides traefik.weight.
traefik.<segment_name>.frontend.auth.basic	Sets a Basic Auth for that frontend
traefik.<segment_name>.frontend.backend=BACKEND	Assign this segment frontend to BACKEND. Default is to assign to the segment backend.
traefik.<segment_name>.frontend.entryPoints	Overrides traefik.frontend.entrypoints
traefik.<segment_name>.frontend.errors.<name>.backend=NAME	See custom error pages section.
traefik.<segment_name>.frontend.errors.<name>.query=PATH	See custom error pages section.
traefik.<segment_name>.frontend.errors.<name>.status=RANGE	See custom error pages section.
traefik.<segment_name>.frontend.passHostHeader	Overrides traefik.frontend.passHostHeader.
traefik.<segment_name>.frontend.passTLSCert	Overrides traefik.frontend.passTLSCert.
traefik.<segment_name>.frontend.priority	Overrides traefik.frontend.priority.
traefik.<segment_name>.frontend.rateLimit.extractorFunc=EXP	See rate limiting section.
traefik.<segment_name>.frontend.rateLimit.rateSet.<name>.period=6	See rate limiting section.
traefik.<segment_name>.frontend.rateLimit.rateSet.<name>.average=6	See rate limiting section.
traefik.<segment_name>.frontend.rateLimit.rateSet.<name>.burst=6	See rate limiting section.
traefik.<segment_name>.frontend.redirect.entryPoint=https	Overrides traefik.frontend.redirect.entryPoint.
traefik.<segment_name>.frontend.redirect.regex=^http://localhost/(.*)	Overrides traefik.frontend.redirect.regex.
traefik.<segment_name>.frontend.redirect.replacement=http://mydomain/$1	Overrides traefik.frontend.redirect.replacement.
traefik.<segment_name>.frontend.redirect.permanent=true	Return 301 instead of 302.
traefik.<segment_name>.frontend.rule	Overrides traefik.frontend.rule.
traefik.<segment_name>.frontend.whiteList.sourceRange=RANGE	Overrides traefik.frontend.whiteList.sourceRange.
traefik.<segment_name>.frontend.whiteList.useXForwardedFor=true	Overrides traefik.frontend.whiteList.useXForwardedFor.

Custom Headers

Label	Description
traefik.<segment_name>.frontend.headers.customRequestHeaders=EXPR	Provides the container with custom request headers that will be appended to each request forwarded to the container. Format: HEADER:value||HEADER2:value2
traefik.<segment_name>.frontend.headers.customResponseHeaders=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

Label	Description
traefik.<segment_name>.frontend.headers.allowedHosts=EXPR	Provides a list of allowed hosts that requests will be processed. Format: Host1,Host2
traefik.<segment_name>.frontend.headers.hostsProxyHeaders=EXPR	Provides a list of headers that the proxied hostname may be stored. Format: HEADER1,HEADER2
traefik.<segment_name>.frontend.headers.SSLRedirect=true	Forces the frontend to redirect to SSL if a non-SSL request is sent.
traefik.<segment_name>.frontend.headers.SSLTemporaryRedirect=true	Forces the frontend to redirect to SSL if a non-SSL request is sent, but by sending a 302 instead of a 301.
traefik.<segment_name>.frontend.headers.SSLHost=HOST	This setting configures the hostname that redirects will be based on. Default is "", which is the same host as the request.
traefik.<segment_name>.frontend.headers.SSLProxyHeaders=EXPR	Header combinations that would signify a proper SSL Request (Such as X-Forwarded-For:https). Format: HEADER:value||HEADER2:value2
traefik.<segment_name>.frontend.headers.STSSeconds=315360000	Sets the max-age of the STS header.
traefik.<segment_name>.frontend.headers.STSIncludeSubdomains=true	Adds the IncludeSubdomains section of the STS header.
traefik.<segment_name>.frontend.headers.STSPreload=true	Adds the preload flag to the STS header.
traefik.<segment_name>.frontend.headers.forceSTSHeader=false	Adds the STS header to non-SSL requests.
traefik.<segment_name>.frontend.headers.frameDeny=false	Adds the X-Frame-Options header with the value of DENY.
traefik.<segment_name>.frontend.headers.customFrameOptionsValue=VALUE	Overrides the X-Frame-Options header with the custom value.
traefik.<segment_name>.frontend.headers.contentTypeNosniff=true	Adds the X-Content-Type-Options header with the value nosniff.
traefik.<segment_name>.frontend.headers.browserXSSFilter=true	Adds the X-XSS-Protection header with the value 1; mode=block.
traefik.<segment_name>.frontend.headers.customBrowserXSSValue=VALUE	Set custom value for X-XSS-Protection header. This overrides the BrowserXssFilter option.
traefik.<segment_name>.frontend.headers.contentSecurityPolicy=VALUE	Adds CSP Header with the custom value.
traefik.<segment_name>.frontend.headers.publicKey=VALUE	Adds pinned HTST public key header.
traefik.<segment_name>.frontend.headers.referrerPolicy=VALUE	Adds referrer policy header.
traefik.<segment_name>.frontend.headers.isDevelopment=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.

!!! note If a label is defined both as a container label and a segment label (for example traefik.<segment_name>.port=PORT and traefik.port=PORT ), the segment label is used to defined the <segment_name> property (port in the example).

It's possible to mix `container labels` and `segment labels`, in this case `container labels` are used as default value for missing `segment labels` but no frontends are going to be created with the `container labels`.

More details in this [example](/user-guide/docker-and-lets-encrypt/#labels).

!!! warning When running inside a container, Træfik will need network access through:

`docker network connect <network> <traefik-container>`