159 lines
6.4 KiB
Markdown
159 lines
6.4 KiB
Markdown
---
|
|
title: "Traefik Getting Started FAQ"
|
|
description: "Check out our FAQ page for answers to commonly asked questions on getting started with Traefik Proxy. Read the technical documentation."
|
|
---
|
|
|
|
# FAQ
|
|
|
|
## Why is Traefik Answering `XXX` HTTP Response Status Code?
|
|
|
|
Traefik is a dynamic reverse proxy,
|
|
and while the documentation often demonstrates configuration options through file examples,
|
|
the core feature of Traefik is its dynamic configurability,
|
|
directly reacting to changes from providers over time.
|
|
|
|
Notably, a part of the configuration is [static](../configuration-overview/#the-static-configuration),
|
|
and can be provided by a file on startup, whereas various providers,
|
|
such as the file provider,
|
|
contribute dynamically all along the traefik instance lifetime to its [dynamic configuration](../configuration-overview/#the-dynamic-configuration) changes.
|
|
|
|
In addition, the configuration englobes concepts such as the EntryPoint which can be seen as a listener on the Transport Layer (TCP),
|
|
as apposed to the Router which is more about the Presentation (TLS) and Application layers (HTTP).
|
|
And there can be as many routers as one wishes for a given EntryPoint.
|
|
|
|
In other words, for a given Entrypoint,
|
|
at any given time the traffic seen is not bound to be just about one protocol.
|
|
It could be HTTP, or otherwise. Over TLS, or not.
|
|
Not to mention that dynamic configuration changes potentially make that kind of traffic vary over time.
|
|
|
|
Therefore, in this dynamic context,
|
|
the static configuration of an `entryPoint` does not give any hint whatsoever about how the traffic going through that `entryPoint` is going to be routed.
|
|
Or whether it's even going to be routed at all,
|
|
i.e. whether there is a Router matching the kind of traffic going through it.
|
|
|
|
### `404 Not found`
|
|
|
|
Traefik returns a `404` response code in the following situations:
|
|
|
|
- A request reaching an EntryPoint that has no Routers
|
|
- An HTTP request reaching an EntryPoint that has no HTTP Router
|
|
- An HTTPS request reaching an EntryPoint that has no HTTPS Router
|
|
- A request reaching an EntryPoint that has HTTP/HTTPS Routers that cannot be matched
|
|
|
|
From Traefik's point of view,
|
|
every time a request cannot be matched with a router the correct response code is a `404 Not found`.
|
|
|
|
In this situation, the response code is not a `503 Service Unavailable`
|
|
because Traefik is not able to confirm that the lack of a matching router for a request is only temporary.
|
|
Traefik's routing configuration is dynamic and aggregated from different providers,
|
|
hence it's not possible to assume at any moment that a specific route should be handled or not.
|
|
|
|
??? info "This behavior is consistent with rfc7231"
|
|
|
|
```txt
|
|
The server is currently unable to handle the request due to a
|
|
temporary overloading or maintenance of the server. The implication
|
|
is that this is a temporary condition which will be alleviated after
|
|
some delay. If known, the length of the delay MAY be indicated in a
|
|
Retry-After header. If no Retry-After is given, the client SHOULD
|
|
handle the response as it would for a 500 response.
|
|
|
|
Note: The existence of the 503 status code does not imply that a
|
|
server must use it when becoming overloaded. Some servers may wish
|
|
to simply refuse the connection.
|
|
```
|
|
|
|
Extract from [rfc7231#section-6.6.4](https://datatracker.ietf.org/doc/html/rfc7231#section-6.6.4).
|
|
|
|
### `502 Bad Gateway`
|
|
|
|
Traefik returns a `502` response code when an error happens while contacting the upstream service.
|
|
|
|
### `503 Service Unavailable`
|
|
|
|
Traefik returns a `503` response code when a Router has been matched
|
|
but there are no servers ready to handle the request.
|
|
|
|
This situation is encountered when a service has been explicitly configured without servers,
|
|
or when a service has healthcheck enabled and all servers are unhealthy.
|
|
|
|
### `XXX` Instead of `404`
|
|
|
|
Sometimes, the `404` response code doesn't play well with other parties or services (such as CDNs).
|
|
|
|
In these situations, you may want Traefik to always reply with a `503` response code,
|
|
instead of a `404` response code.
|
|
|
|
To achieve this behavior, a simple catchall router,
|
|
with the lowest possible priority and routing to a service without servers,
|
|
can handle all the requests when no other router has been matched.
|
|
|
|
The example below is a file provider only version (`yaml`) of what this configuration could look like:
|
|
|
|
```yaml tab="Static configuration"
|
|
# traefik.yml
|
|
|
|
entrypoints:
|
|
web:
|
|
address: :80
|
|
|
|
providers:
|
|
file:
|
|
filename: dynamic.yaml
|
|
```
|
|
|
|
```yaml tab="Dynamic configuration"
|
|
# dynamic.yaml
|
|
|
|
http:
|
|
routers:
|
|
catchall:
|
|
# attached only to web entryPoint
|
|
entryPoints:
|
|
- "web"
|
|
# catchall rule
|
|
rule: "PathPrefix(`/`)"
|
|
service: unavailable
|
|
# lowest possible priority
|
|
# evaluated when no other router is matched
|
|
priority: 1
|
|
|
|
services:
|
|
# Service that will always answer a 503 Service Unavailable response
|
|
unavailable:
|
|
loadBalancer:
|
|
servers: {}
|
|
```
|
|
|
|
!!! info "Dedicated service"
|
|
If there is a need for a response code other than a `503` and/or a custom message,
|
|
the principle of the above example above (a catchall router) still stands,
|
|
but the `unavailable` service should be adapted to fit such a need.
|
|
|
|
## Why Is My TLS Certificate Not Reloaded When Its Contents Change?
|
|
|
|
With the file provider,
|
|
a configuration update is only triggered when one of the [watched](../providers/file.md#provider-configuration) configuration files is modified.
|
|
|
|
Which is why, when a certificate is defined by path,
|
|
and the actual contents of this certificate change,
|
|
a configuration update is _not_ triggered.
|
|
|
|
To take into account the new certificate contents, the update of the dynamic configuration must be forced.
|
|
One way to achieve that, is to trigger a file notification,
|
|
for example, by using the `touch` command on the configuration file.
|
|
|
|
## What Are the Forwarded Headers When Proxying HTTP Requests?
|
|
|
|
By default, the following headers are automatically added when proxying requests:
|
|
|
|
| Property | HTTP Header |
|
|
|---------------------------|----------------------------|
|
|
| Client's IP | X-Forwarded-For, X-Real-Ip |
|
|
| Host | X-Forwarded-Host |
|
|
| Port | X-Forwarded-Port |
|
|
| Protocol | X-Forwarded-Proto |
|
|
| Proxy Server's Hostname | X-Forwarded-Server |
|
|
|
|
For more details,
|
|
please check out the [forwarded header](../routing/entrypoints.md#forwarded-headers) documentation.
|