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Add Swarm section to the Docker Provider Documentation

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Damien Duportal 2019-11-27 17:12:04 +01:00 committed by Traefiker Bot
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183
docs/content/providers/docker.md
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@ -7,6 +7,9 @@ A Story of Labels & Containers
Attach labels to your containers and let Traefik do the rest!
Traefik works with both [Docker (standalone) Engine](https://docs.docker.com/engine/)
and [Docker Swarm Mode](https://docs.docker.com/engine/swarm/).
!!! tip "The Quick Start Uses Docker"
If you haven't already, maybe you'd like to go through the [quick start](../getting-started/quick-start.md) that uses the docker provider!
@ -80,15 +83,136 @@ Attach labels to your containers and let Traefik do the rest!
- traefik.http.services.my-container-service.loadbalancer.server.port=8080
```
!!! important "Labels in Docker Swarm Mode"
While in Swarm Mode, Traefik uses labels found on services, not on individual containers.
Therefore, if you use a compose file with 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](https://docs.docker.com/compose/compose-file/#labels-1)).
## Routing Configuration
See the dedicated section in [routing](../routing/providers/docker.md).
When using Docker as a [provider](https://docs.traefik.io/providers/overview/),
Trafik uses [container labels](https://docs.docker.com/engine/reference/commandline/run/#set-metadata-on-container--l---label---label-file) to retrieve its routing configuration.
See the list of labels in the dedicated [routing](../routing/providers/docker.md) section.
### Routing Configuration with Labels
By default, Traefik watches for [container level labels](https://docs.docker.com/config/labels-custom-metadata/) on a standalone Docker Engine.
When using Docker Compose, labels are specified by the directive
[`labels`](https://docs.docker.com/compose/compose-file/#labels) from the
["services" objects](https://docs.docker.com/compose/compose-file/#service-configuration-reference).
!!! tip "Not Only Docker"
Please note that any tool like Nomad, Terraform, Ansible, etc.
that is able to define a Docker container with labels can work
with Traefik & the Docker provider.
### Port Detection
Traefik retrieves the private IP and port of containers from the Docker API.
Ports detection works as follows:
- If a container [exposes](https://docs.docker.com/engine/reference/builder/#expose) only one port,
then Traefik uses this port for private communication.
- If a container [exposes](https://docs.docker.com/engine/reference/builder/#expose) multiple ports,
or does not expose any port, then you must manually specify which port Traefik should use for communication
by using the label `traefik.http.services.<service_name>.loadbalancer.server.port`
(Read more on this label in the dedicated section in [routing](../routing/providers/docker.md#port)).
### Docker API Access
Traefik requires access to the docker socket to get its dynamic configuration.
You can specify which Docker API Endpoint to use with the directive [`endpoint`](#endpoint).
!!! warning "Security Note"
Accessing the Docker API without any restriction is a security concern:
If Traefik is attacked, then the attacker might get access to the underlying host.
{: #security-note }
As explained in the Docker documentation: ([Docker Daemon Attack Surface page](https://docs.docker.com/engine/security/security/#docker-daemon-attack-surface)):
!!! quote
[...] only **trusted** users should be allowed to control your Docker daemon [...]
??? success "Solutions"
Expose the Docker socket over TCP, instead of the default Unix socket file.
It allows different implementation levels of the [AAA (Authentication, Authorization, Accounting) concepts](https://en.wikipedia.org/wiki/AAA_(computer_security)), depending on your security assessment:
- Authentication with Client Certificates as described in ["Protect the Docker daemon socket."](https://docs.docker.com/engine/security/https/)
- Authorize and filter requests to restrict possible actions with [the TecnativaDocker Socket Proxy](https://github.com/Tecnativa/docker-socket-proxy).
- Authorization with the [Docker Authorization Plugin Mechanism](https://docs.docker.com/engine/extend/plugins_authorization/)
- Accounting at networking level, by exposing the socket only inside a Docker private network, only available for Traefik.
- Accounting at container level, by exposing the socket on a another container than Traefik's.
With Swarm mode, it allows scheduling of Traefik on worker nodes, with only the "socket exposer" container on the manager nodes.
- Accounting at kernel level, by enforcing kernel calls with mechanisms like [SELinux](https://en.wikipedia.org/wiki/Security-Enhanced_Linux), to only allows an identified set of actions for Traefik's process (or the "socket exposer" process).
??? info "More Resources and Examples"
- ["Paranoid about mounting /var/run/docker.sock?"](https://medium.com/@containeroo/traefik-2-0-paranoid-about-mounting-var-run-docker-sock-22da9cb3e78c)
- [Traefik and Docker: A Discussion with Docker Captain, Bret Fisher](https://blog.containo.us/traefik-and-docker-a-discussion-with-docker-captain-bret-fisher-7f0b9a54ff88)
- [KubeCon EU 2018 Keynote, Running with Scissors, from Liz Rice](https://www.youtube.com/watch?v=ltrV-Qmh3oY)
- [Don't expose the Docker socket (not even to a container)](https://www.lvh.io/posts/dont-expose-the-docker-socket-not-even-to-a-container/)
- [A thread on Stack Overflow about sharing the `/var/run/docker.sock` file](https://news.ycombinator.com/item?id=17983623)
- [To DinD or not to DinD](https://blog.loof.fr/2018/01/to-dind-or-not-do-dind.html)
- [Traefik issue GH-4174 about security with Docker socket](https://github.com/containous/traefik/issues/4174)
- [Inspecting Docker Activity with Socat](https://developers.redhat.com/blog/2015/02/25/inspecting-docker-activity-with-socat/)
- [Letting Traefik run on Worker Nodes](https://blog.mikesir87.io/2018/07/letting-traefik-run-on-worker-nodes/)
- [Docker Socket Proxy from Tecnativa](https://github.com/Tecnativa/docker-socket-proxy)
## Docker Swarm Mode
To enable Docker Swarm (instead of standalone Docker) as a configuration provider,
set the [`swarmMode`](#swarmmode) directive to `true`.
### Routing Configuration with Labels
While in Swarm Mode, Traefik uses labels found on services, not on individual containers.
Therefore, if you use a compose file with Swarm Mode, labels should be defined in the
[`deploy`](https://docs.docker.com/compose/compose-file/#labels-1) part of your service.
This behavior is only enabled for docker-compose version 3+ ([Compose file reference](https://docs.docker.com/compose/compose-file)).
### Port Detection
Docker Swarm does not provide any [port detection](#port-detection) information to Traefik.
Therefore you **must** specify the port to use for communication by using the label `traefik.http.services.<service_name>.loadbalancer.server.port`
(Check the reference for this label in the [routing section for Docker](../routing/providers/docker.md#port)).
### Docker API Access
Docker Swarm Mode follows the same rules as Docker [API Access](#docker-api-access).
As the Swarm API is only exposed on the [manager nodes](https://docs.docker.com/engine/swarm/how-swarm-mode-works/nodes/#manager-nodes), you should schedule Traefik on the Swarm manager nodes by default,
by deploying Traefik with a [constraint](https://success.docker.com/article/using-contraints-and-labels-to-control-the-placement-of-containers) on the node's "role":
```shell tab="With Docker CLI"
docker service create \
--constraint=node.role==manager \
#... \
```
```yml tab="With Docker Compose"
version: '3'
services:
traefik:
# ...
deploy:
placement:
constraints:
- node.role == manager
```
!!! tip "Scheduling Traefik on Worker Nodes"
Following the guidelines given in the previous section ["Docker API Access"](#docker-api-access),
if you expose the Docker API through TCP, then Traefik can be scheduled on any node if the TCP
socket is reachable.
Please consider the security implications by reading the [Security Note](#security-note).
A good example can be found on [Bret Fisher's repository](https://github.com/BretFisher/dogvscat/blob/master/stack-proxy-global.yml#L124).
## Provider Configuration
@ -111,48 +235,7 @@ providers:
--providers.docker.endpoint=unix:///var/run/docker.sock
```
Traefik requires access to the docker socket to get its dynamic configuration.
??? warning "Security Notes"
Depending on your context, accessing the Docker API without any restriction can be a security concern: If Traefik is attacked, then the attacker might get access to the Docker (or Swarm Mode) backend.
As explained in the Docker documentation: ([Docker Daemon Attack Surface page](https://docs.docker.com/engine/security/security/#docker-daemon-attack-surface)):
`[...] only **trusted** users should be allowed to control your Docker daemon [...]`
!!! tip "Improved Security"
[TraefikEE](https://containo.us/traefikee) solves this problem by separating the control plane (connected to Docker) and the data plane (handling the requests).
??? info "Resources about Docker's Security"
- [KubeCon EU 2018 Keynote, Running with Scissors, from Liz Rice](https://www.youtube.com/watch?v=ltrV-Qmh3oY)
- [Don't expose the Docker socket (not even to a container)](https://www.lvh.io/posts/dont-expose-the-docker-socket-not-even-to-a-container/)
- [A thread on Stack Overflow about sharing the `/var/run/docker.sock` file](https://news.ycombinator.com/item?id=17983623)
- [To DinD or not to DinD](https://blog.loof.fr/2018/01/to-dind-or-not-do-dind.html)
??? tip "Security Compensation"
Expose the Docker socket over TCP, instead of the default Unix socket file.
It allows different implementation levels of the [AAA (Authentication, Authorization, Accounting) concepts](https://en.wikipedia.org/wiki/AAA_(computer_security)), depending on your security assessment:
- Authentication with Client Certificates as described in ["Protect the Docker daemon socket."](https://docs.docker.com/engine/security/https/)
- Authorization with the [Docker Authorization Plugin Mechanism](https://docs.docker.com/engine/extend/plugins_authorization/)
- Accounting at networking level, by exposing the socket only inside a Docker private network, only available for Traefik.
- Accounting at container level, by exposing the socket on a another container than Traefik's.
With Swarm mode, it allows scheduling of Traefik on worker nodes, with only the "socket exposer" container on the manager nodes.
- Accounting at kernel level, by enforcing kernel calls with mechanisms like [SELinux](https://en.wikipedia.org/wiki/Security-Enhanced_Linux), to only allows an identified set of actions for Traefik's process (or the "socket exposer" process).
??? info "Additional Resources"
- [Traefik issue GH-4174 about security with Docker socket](https://github.com/containous/traefik/issues/4174)
- [Inspecting Docker Activity with Socat](https://developers.redhat.com/blog/2015/02/25/inspecting-docker-activity-with-socat/)
- [Letting Traefik run on Worker Nodes](https://blog.mikesir87.io/2018/07/letting-traefik-run-on-worker-nodes/)
- [Docker Socket Proxy from Tecnativa](https://github.com/Tecnativa/docker-socket-proxy)
!!! info "Traefik & Swarm Mode"
To let Traefik access the Docker Socket of the Swarm manager, it is mandatory to schedule Traefik on the Swarm manager nodes.
See the sections [Docker API Access](#docker-api-access) and [Docker Swarm API Access](#docker-api-access_1) for more information.
??? example "Using the docker.sock"
@ -343,7 +426,7 @@ providers:
# ...
```
Activates the Swarm Mode.
Activates the Swarm Mode (instead of standalone Docker).
### `swarmModeRefreshSeconds`

5
docs/content/routing/providers/docker.md
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@ -243,11 +243,12 @@ you'd add the label `traefik.http.services.<name-of-your-choice>.loadbalancer.pa
!!! warning "The character `@` is not authorized in the service name `<service_name>`."
??? info "`traefik.http.services.<service_name>.loadbalancer.server.port`"
Registers a port.
Useful when the container exposes multiples ports.
Mandatory for Docker Swarm.
Mandatory for Docker Swarm (see the section ["Port Detection with Docker Swarm"](../../providers/docker.md#port-detection_1)).
{: #port }
```yaml
- "traefik.http.services.myservice.loadbalancer.server.port=8080"