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"

# 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 Swarmmode 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"

# 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 behaviour

On Containers

Labels can be used on containers to override default behaviour.

Label	Description
traefik.backend=foo	Give the name foo to the generated backend for this container.
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.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.circuitbreaker.expression=EXPR	Create a circuit breaker to be used against the backend
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.enable=false	Disable this container in Træfik
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.passHostHeader=true	Forward client Host header to the backend.
traefik.frontend.priority=10	Override default frontend priority
traefik.frontend.entryPoints=http,https	Assign this frontend to entry points http and https. Overrides defaultEntryPoints
traefik.frontend.auth.basic=EXPR	Sets basic authentication for that frontend in CSV format: User:Hash,User:Hash
traefik.frontend.whitelistSourceRange: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.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
traefik.docker.network	Set the docker network to use for connections to this container. 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.

On Service

Services labels can be used for overriding default behaviour

Label	Description
traefik.<service-name>.port=PORT	Overrides traefik.port. If several ports need to be exposed, the service labels could be used.
traefik.<service-name>.protocol	Overrides traefik.protocol.
traefik.<service-name>.weight	Assign this service weight. Overrides traefik.weight.
traefik.<service-name>.frontend.backend=BACKEND	Assign this service frontend to BACKEND. Default is to assign to the service backend.
traefik.<service-name>.frontend.entryPoints	Overrides traefik.frontend.entrypoints
traefik.<service-name>.frontend.auth.basic	Sets a Basic Auth for that frontend
traefik.<service-name>.frontend.passHostHeader	Overrides traefik.frontend.passHostHeader.
traefik.<service-name>.frontend.priority	Overrides traefik.frontend.priority.
traefik.<service-name>.frontend.rule	Overrides traefik.frontend.rule.

!!! note if a label is defined both as a container label and a service label (for example traefik.<service-name>.port=PORT and traefik.port=PORT ), the service label is used to defined the <service-name> property (port in the example). It's possible to mix container labels and service labels, in this case container labels are used as default value for missing service labels but no frontends are going to be created with the container labels. More details in this example.

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

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