7c2ba62b56
- user-guide review. - add DataDog and StatD configuration. - sync sample.toml and doc. - split entry points doc. - Deprecated.
563 lines
24 KiB
Markdown
563 lines
24 KiB
Markdown
# Basics
|
||
|
||
## Concepts
|
||
|
||
Let's take our example from the [overview](https://docs.traefik.io/#overview) again:
|
||
|
||
|
||
> Imagine that you have deployed a bunch of microservices on your infrastructure. You probably used a service registry (like etcd or consul) and/or an orchestrator (swarm, Mesos/Marathon) to manage all these services.
|
||
> If you want your users to access some of your microservices from the Internet, you will have to use a reverse proxy and configure it using virtual hosts or prefix paths:
|
||
|
||
> - domain `api.domain.com` will point the microservice `api` in your private network
|
||
> - path `domain.com/web` will point the microservice `web` in your private network
|
||
> - domain `backoffice.domain.com` will point the microservices `backoffice` in your private network, load-balancing between your multiple instances
|
||
|
||
> 
|
||
|
||
Let's zoom on Træfik and have an overview of its internal architecture:
|
||
|
||
|
||
|
||
|
||
- Incoming requests end on [entrypoints](#entrypoints), as the name suggests, they are the network entry points into Træfik (listening port, SSL, traffic redirection...).
|
||
- Traffic is then forwarded to a matching [frontend](#frontends). A frontend defines routes from [entrypoints](#entrypoints) to [backends](#backends).
|
||
Routes are created using requests fields (`Host`, `Path`, `Headers`...) and can match or not a request.
|
||
- The [frontend](#frontends) will then send the request to a [backend](#backends). A backend can be composed by one or more [servers](#servers), and by a load-balancing strategy.
|
||
- Finally, the [server](#servers) will forward the request to the corresponding microservice in the private network.
|
||
|
||
### Entrypoints
|
||
|
||
Entrypoints are the network entry points into Træfik.
|
||
They can be defined using:
|
||
|
||
- a port (80, 443...)
|
||
- SSL (Certificates, Keys, authentication with a client certificate signed by a trusted CA...)
|
||
- redirection to another entrypoint (redirect `HTTP` to `HTTPS`)
|
||
|
||
Here is an example of entrypoints definition:
|
||
|
||
```toml
|
||
[entryPoints]
|
||
[entryPoints.http]
|
||
address = ":80"
|
||
[entryPoints.http.redirect]
|
||
entryPoint = "https"
|
||
[entryPoints.https]
|
||
address = ":443"
|
||
[entryPoints.https.tls]
|
||
[[entryPoints.https.tls.certificates]]
|
||
certFile = "tests/traefik.crt"
|
||
keyFile = "tests/traefik.key"
|
||
```
|
||
|
||
- Two entrypoints are defined `http` and `https`.
|
||
- `http` listens on port `80` and `https` on port `443`.
|
||
- We enable SSL on `https` by giving a certificate and a key.
|
||
- We also redirect all the traffic from entrypoint `http` to `https`.
|
||
|
||
And here is another example with client certificate authentication:
|
||
|
||
```toml
|
||
[entryPoints]
|
||
[entryPoints.https]
|
||
address = ":443"
|
||
[entryPoints.https.tls]
|
||
clientCAFiles = ["tests/clientca1.crt", "tests/clientca2.crt"]
|
||
[[entryPoints.https.tls.certificates]]
|
||
certFile = "tests/traefik.crt"
|
||
keyFile = "tests/traefik.key"
|
||
```
|
||
|
||
- We enable SSL on `https` by giving a certificate and a key.
|
||
- One or several files containing Certificate Authorities in PEM format are added.
|
||
- It is possible to have multiple CA:s in the same file or keep them in separate files.
|
||
|
||
### Frontends
|
||
|
||
A frontend consists of a set of rules that determine how incoming requests are forwarded from an entrypoint to a backend.
|
||
|
||
Rules may be classified in one of two groups: Modifiers and matchers.
|
||
|
||
#### Modifiers
|
||
|
||
Modifier rules only modify the request. They do not have any impact on routing decisions being made.
|
||
|
||
Following is the list of existing modifier rules:
|
||
|
||
- `AddPrefix: /products`: Add path prefix to the existing request path prior to forwarding the request to the backend.
|
||
- `ReplacePath: /serverless-path`: Replaces the path and adds the old path to the `X-Replaced-Path` header. Useful for mapping to AWS Lambda or Google Cloud Functions.
|
||
|
||
#### Matchers
|
||
|
||
Matcher rules determine if a particular request should be forwarded to a backend.
|
||
|
||
Separate multiple rule values by `,` (comma) in order to enable ANY semantics (i.e., forward a request if any rule matches). Does not work for `Headers` and `HeadersRegexp`.
|
||
|
||
Separate multiple rule values by `;` (semicolon) in order to enable ALL semantics (i.e., forward a request if all rules match).
|
||
|
||
You can optionally enable `passHostHeader` to forward client `Host` header to the backend. You can also optionally enable `passTLSCert` to forward TLS Client certificates to the backend.
|
||
|
||
Following is the list of existing matcher rules along with examples:
|
||
|
||
- `Headers: Content-Type, application/json`: Match HTTP header. It accepts a comma-separated key/value pair where both key and value must be literals.
|
||
- `HeadersRegexp: Content-Type, application/(text|json)`: Match HTTP header. It accepts a comma-separated key/value pair where the key must be a literal and the value may be a literal or a regular expression.
|
||
- `Host: traefik.io, www.traefik.io`: Match request host. It accepts a sequence of literal hosts.
|
||
- `HostRegexp: traefik.io, {subdomain:[a-z]+}.traefik.io`: Match request host. It accepts a sequence of literal and regular expression hosts.
|
||
- `Method: GET, POST, PUT`: Match request HTTP method. It accepts a sequence of HTTP methods.
|
||
- `Path: /products/, /articles/{category}/{id:[0-9]+}`: Match exact request path. It accepts a sequence of literal and regular expression paths.
|
||
- `PathStrip: /products/`: Match exact path and strip off the path prior to forwarding the request to the backend. It accepts a sequence of literal paths.
|
||
- `PathStripRegex: /articles/{category}/{id:[0-9]+}`: Match exact path and strip off the path prior to forwarding the request to the backend. It accepts a sequence of literal and regular expression paths.
|
||
- `PathPrefix: /products/, /articles/{category}/{id:[0-9]+}`: Match request prefix path. It accepts a sequence of literal and regular expression prefix paths.
|
||
- `PathPrefixStrip: /products/`: Match request prefix path and strip off the path prefix prior to forwarding the request to the backend. It accepts a sequence of literal prefix paths. Starting with Traefik 1.3, the stripped prefix path will be available in the `X-Forwarded-Prefix` header.
|
||
- `PathPrefixStripRegex: /articles/{category}/{id:[0-9]+}`: Match request prefix path and strip off the path prefix prior to forwarding the request to the backend. It accepts a sequence of literal and regular expression prefix paths. Starting with Traefik 1.3, the stripped prefix path will be available in the `X-Forwarded-Prefix` header.
|
||
- `Query: foo=bar, bar=baz`: Match Query String parameters. It accepts a sequence of key=value pairs.
|
||
|
||
In order to use regular expressions with Host and Path matchers, you must declare an arbitrarily named variable followed by the colon-separated regular expression, all enclosed in curly braces. Any pattern supported by [Go's regexp package](https://golang.org/pkg/regexp/) may be used. Example: `/posts/{id:[0-9]+}`.
|
||
|
||
(Note that the variable has no special meaning; however, it is required by the gorilla/mux dependency which embeds the regular expression and defines the syntax.)
|
||
|
||
##### Path Matcher Usage Guidelines
|
||
|
||
This section explains when to use the various path matchers.
|
||
|
||
Use `Path` if your backend listens on the exact path only. For instance, `Path: /products` would match `/products` but not `/products/shoes`.
|
||
|
||
Use a `*Prefix*` matcher if your backend listens on a particular base path but also serves requests on sub-paths. For instance, `PathPrefix: /products` would match `/products` but also `/products/shoes` and `/products/shirts`. Since the path is forwarded as-is, your backend is expected to listen on `/products`.
|
||
|
||
Use a `*Strip` matcher if your backend listens on the root path (`/`) but should be routeable on a specific prefix. For instance, `PathPrefixStrip: /products` would match `/products` but also `/products/shoes` and `/products/shirts`. Since the path is stripped prior to forwarding, your backend is expected to listen on `/`.
|
||
If your backend is serving assets (e.g., images or Javascript files), chances are it must return properly constructed relative URLs. Continuing on the example, the backend should return `/products/shoes/image.png` (and not `/images.png` which Traefik would likely not be able to associate with the same backend). The `X-Forwarded-Prefix` header (available since Traefik 1.3) can be queried to build such URLs dynamically.
|
||
|
||
Instead of distinguishing your backends by path only, you can add a Host matcher to the mix. That way, namespacing of your backends happens on the basis of hosts in addition to paths.
|
||
|
||
#### Examples
|
||
|
||
Here is an example of frontends definition:
|
||
|
||
```toml
|
||
[frontends]
|
||
[frontends.frontend1]
|
||
backend = "backend2"
|
||
[frontends.frontend1.routes.test_1]
|
||
rule = "Host:test.localhost,test2.localhost"
|
||
[frontends.frontend2]
|
||
backend = "backend1"
|
||
passHostHeader = true
|
||
passTLSCert = true
|
||
priority = 10
|
||
entrypoints = ["https"] # overrides defaultEntryPoints
|
||
[frontends.frontend2.routes.test_1]
|
||
rule = "HostRegexp:localhost,{subdomain:[a-z]+}.localhost"
|
||
[frontends.frontend3]
|
||
backend = "backend2"
|
||
[frontends.frontend3.routes.test_1]
|
||
rule = "Host:test3.localhost;Path:/test"
|
||
```
|
||
|
||
- Three frontends are defined: `frontend1`, `frontend2` and `frontend3`
|
||
- `frontend1` will forward the traffic to the `backend2` if the rule `Host:test.localhost,test2.localhost` is matched
|
||
- `frontend2` will forward the traffic to the `backend1` if the rule `Host:localhost,{subdomain:[a-z]+}.localhost` is matched (forwarding client `Host` header to the backend)
|
||
- `frontend3` will forward the traffic to the `backend2` if the rules `Host:test3.localhost` **AND** `Path:/test` are matched
|
||
|
||
#### Combining multiple rules
|
||
|
||
As seen in the previous example, you can combine multiple rules.
|
||
In TOML file, you can use multiple routes:
|
||
|
||
```toml
|
||
[frontends.frontend3]
|
||
backend = "backend2"
|
||
[frontends.frontend3.routes.test_1]
|
||
rule = "Host:test3.localhost"
|
||
[frontends.frontend3.routes.test_2]
|
||
rule = "Path:/test"
|
||
```
|
||
|
||
Here `frontend3` will forward the traffic to the `backend2` if the rules `Host:test3.localhost` **AND** `Path:/test` are matched.
|
||
You can also use the notation using a `;` separator, same result:
|
||
|
||
```toml
|
||
[frontends.frontend3]
|
||
backend = "backend2"
|
||
[frontends.frontend3.routes.test_1]
|
||
rule = "Host:test3.localhost;Path:/test"
|
||
```
|
||
|
||
Finally, you can create a rule to bind multiple domains or Path to a frontend, using the `,` separator:
|
||
|
||
```toml
|
||
[frontends.frontend2]
|
||
[frontends.frontend2.routes.test_1]
|
||
rule = "Host:test1.localhost,test2.localhost"
|
||
[frontends.frontend3]
|
||
backend = "backend2"
|
||
[frontends.frontend3.routes.test_1]
|
||
rule = "Path:/test1,/test2"
|
||
```
|
||
|
||
#### Rules Order
|
||
|
||
When combining `Modifier` rules with `Matcher` rules, it is important to remember that `Modifier` rules **ALWAYS** apply after the `Matcher` rules.
|
||
The following rules are both `Matchers` and `Modifiers`, so the `Matcher` portion of the rule will apply first, and the `Modifier` will apply later.
|
||
|
||
- `PathStrip`
|
||
- `PathStripRegex`
|
||
- `PathPrefixStrip`
|
||
- `PathPrefixStripRegex`
|
||
|
||
`Modifiers` will be applied in a pre-determined order regardless of their order in the `rule` configuration section.
|
||
|
||
1. `PathStrip`
|
||
2. `PathPrefixStrip`
|
||
3. `PathStripRegex`
|
||
4. `PathPrefixStripRegex`
|
||
5. `AddPrefix`
|
||
6. `ReplacePath`
|
||
|
||
#### Priorities
|
||
|
||
By default, routes will be sorted (in descending order) using rules length (to avoid path overlap):
|
||
`PathPrefix:/12345` will be matched before `PathPrefix:/1234` that will be matched before `PathPrefix:/1`.
|
||
|
||
You can customize priority by frontend:
|
||
|
||
```toml
|
||
[frontends]
|
||
[frontends.frontend1]
|
||
backend = "backend1"
|
||
priority = 10
|
||
passHostHeader = true
|
||
[frontends.frontend1.routes.test_1]
|
||
rule = "PathPrefix:/to"
|
||
[frontends.frontend2]
|
||
priority = 5
|
||
backend = "backend2"
|
||
passHostHeader = true
|
||
[frontends.frontend2.routes.test_1]
|
||
rule = "PathPrefix:/toto"
|
||
```
|
||
|
||
Here, `frontend1` will be matched before `frontend2` (`10 > 5`).
|
||
|
||
#### Custom headers
|
||
|
||
Custom headers can be configured through the frontends, to add headers to either requests or responses that match the frontend's rules. This allows for setting headers such as `X-Script-Name` to be added to the request, or custom headers to be added to the response:
|
||
|
||
```toml
|
||
[frontends]
|
||
[frontends.frontend1]
|
||
backend = "backend1"
|
||
[frontends.frontend1.headers.customresponseheaders]
|
||
X-Custom-Response-Header = "True"
|
||
[frontends.frontend1.headers.customrequestheaders]
|
||
X-Script-Name = "test"
|
||
[frontends.frontend1.routes.test_1]
|
||
rule = "PathPrefixStrip:/cheese"
|
||
```
|
||
|
||
In this example, all matches to the path `/cheese` will have the `X-Script-Name` header added to the proxied request, and the `X-Custom-Response-Header` added to the response.
|
||
|
||
#### Security headers
|
||
|
||
Security related headers (HSTS headers, SSL redirection, Browser XSS filter, etc) can be added and configured per frontend in a similar manner to the custom headers above. This functionality allows for some easy security features to quickly be set. An example of some of the security headers:
|
||
|
||
```toml
|
||
[frontends]
|
||
[frontends.frontend1]
|
||
backend = "backend1"
|
||
[frontends.frontend1.headers]
|
||
FrameDeny = true
|
||
[frontends.frontend1.routes.test_1]
|
||
rule = "PathPrefixStrip:/cheddar"
|
||
[frontends.frontend2]
|
||
backend = "backend2"
|
||
[frontends.frontend2.headers]
|
||
SSLRedirect = true
|
||
[frontends.frontend2.routes.test_1]
|
||
rule = "PathPrefixStrip:/stilton"
|
||
```
|
||
|
||
In this example, traffic routed through the first frontend will have the `X-Frame-Options` header set to `DENY`, and the second will only allow HTTPS request through, otherwise will return a 301 HTTPS redirect.
|
||
|
||
### Backends
|
||
|
||
A backend is responsible to load-balance the traffic coming from one or more frontends to a set of http servers.
|
||
Various methods of load-balancing are supported:
|
||
|
||
- `wrr`: Weighted Round Robin
|
||
- `drr`: Dynamic Round Robin: increases weights on servers that perform better than others. It also rolls back to original weights if the servers have changed.
|
||
|
||
A circuit breaker can also be applied to a backend, preventing high loads on failing servers.
|
||
Initial state is Standby. CB observes the statistics and does not modify the request.
|
||
In case the condition matches, CB enters Tripped state, where it responds with predefined code or redirects to another frontend.
|
||
Once Tripped timer expires, CB enters Recovering state and resets all stats.
|
||
In case the condition does not match and recovery timer expires, CB enters Standby state.
|
||
|
||
It can be configured using:
|
||
|
||
- Methods: `LatencyAtQuantileMS`, `NetworkErrorRatio`, `ResponseCodeRatio`
|
||
- Operators: `AND`, `OR`, `EQ`, `NEQ`, `LT`, `LE`, `GT`, `GE`
|
||
|
||
For example:
|
||
|
||
- `NetworkErrorRatio() > 0.5`: watch error ratio over 10 second sliding window for a frontend
|
||
- `LatencyAtQuantileMS(50.0) > 50`: watch latency at quantile in milliseconds.
|
||
- `ResponseCodeRatio(500, 600, 0, 600) > 0.5`: ratio of response codes in range [500-600) to [0-600)
|
||
|
||
To proactively prevent backends from being overwhelmed with high load, a maximum connection limit can
|
||
also be applied to each backend.
|
||
|
||
Maximum connections can be configured by specifying an integer value for `maxconn.amount` and
|
||
`maxconn.extractorfunc` which is a strategy used to determine how to categorize requests in order to
|
||
evaluate the maximum connections.
|
||
|
||
For example:
|
||
```toml
|
||
[backends]
|
||
[backends.backend1]
|
||
[backends.backend1.maxconn]
|
||
amount = 10
|
||
extractorfunc = "request.host"
|
||
```
|
||
|
||
- `backend1` will return `HTTP code 429 Too Many Requests` if there are already 10 requests in progress for the same Host header.
|
||
- Another possible value for `extractorfunc` is `client.ip` which will categorize requests based on client source ip.
|
||
- Lastly `extractorfunc` can take the value of `request.header.ANY_HEADER` which will categorize requests based on `ANY_HEADER` that you provide.
|
||
|
||
Sticky sessions are supported with both load balancers. When sticky sessions are enabled, a cookie called `_TRAEFIK_BACKEND` is set on the initial
|
||
request. On subsequent requests, the client will be directed to the backend stored in the cookie if it is still healthy. If not, a new backend
|
||
will be assigned.
|
||
|
||
For example:
|
||
```toml
|
||
[backends]
|
||
[backends.backend1]
|
||
[backends.backend1.loadbalancer]
|
||
sticky = true
|
||
```
|
||
|
||
A health check can be configured in order to remove a backend from LB rotation
|
||
as long as it keeps returning HTTP status codes other than 200 OK to HTTP GET
|
||
requests periodically carried out by Traefik. The check is defined by a path
|
||
appended to the backend URL and an interval (given in a format understood by [time.ParseDuration](https://golang.org/pkg/time/#ParseDuration)) specifying how
|
||
often the health check should be executed (the default being 30 seconds).
|
||
Each backend must respond to the health check within 5 seconds.
|
||
By default, the port of the backend server is used, however, this may be overridden.
|
||
|
||
A recovering backend returning 200 OK responses again is being returned to the
|
||
LB rotation pool.
|
||
|
||
For example:
|
||
```toml
|
||
[backends]
|
||
[backends.backend1]
|
||
[backends.backend1.healthcheck]
|
||
path = "/health"
|
||
interval = "10s"
|
||
```
|
||
|
||
To use a different port for the healthcheck:
|
||
```toml
|
||
[backends]
|
||
[backends.backend1]
|
||
[backends.backend1.healthcheck]
|
||
path = "/health"
|
||
interval = "10s"
|
||
port = 8080
|
||
```
|
||
|
||
### Servers
|
||
|
||
Servers are simply defined using a `URL`. You can also apply a custom `weight` to each server (this will be used by load-balancing).
|
||
|
||
Here is an example of backends and servers definition:
|
||
|
||
```toml
|
||
[backends]
|
||
[backends.backend1]
|
||
[backends.backend1.circuitbreaker]
|
||
expression = "NetworkErrorRatio() > 0.5"
|
||
[backends.backend1.servers.server1]
|
||
url = "http://172.17.0.2:80"
|
||
weight = 10
|
||
[backends.backend1.servers.server2]
|
||
url = "http://172.17.0.3:80"
|
||
weight = 1
|
||
[backends.backend2]
|
||
[backends.backend2.LoadBalancer]
|
||
method = "drr"
|
||
[backends.backend2.servers.server1]
|
||
url = "http://172.17.0.4:80"
|
||
weight = 1
|
||
[backends.backend2.servers.server2]
|
||
url = "http://172.17.0.5:80"
|
||
weight = 2
|
||
```
|
||
|
||
- Two backends are defined: `backend1` and `backend2`
|
||
- `backend1` will forward the traffic to two servers: `http://172.17.0.2:80"` with weight `10` and `http://172.17.0.3:80` with weight `1` using default `wrr` load-balancing strategy.
|
||
- `backend2` will forward the traffic to two servers: `http://172.17.0.4:80"` with weight `1` and `http://172.17.0.5:80` with weight `2` using `drr` load-balancing strategy.
|
||
- a circuit breaker is added on `backend1` using the expression `NetworkErrorRatio() > 0.5`: watch error ratio over 10 second sliding window
|
||
|
||
### Custom Error pages
|
||
|
||
Custom error pages can be returned, in lieu of the default, according to frontend-configured ranges of HTTP Status codes.
|
||
In the example below, if a 503 status is returned from the frontend "website", the custom error page at http://2.3.4.5/503.html is returned with the actual status code set in the HTTP header.
|
||
Note, the 503.html page itself is not hosted on traefik, but some other infrastructure.
|
||
|
||
```toml
|
||
[frontends]
|
||
[frontends.website]
|
||
backend = "website"
|
||
[errors]
|
||
[error.network]
|
||
status = ["500-599"]
|
||
backend = "error"
|
||
query = "/{status}.html"
|
||
[frontends.website.routes.website]
|
||
rule = "Host: website.mydomain.com"
|
||
|
||
[backends]
|
||
[backends.website]
|
||
[backends.website.servers.website]
|
||
url = "https://1.2.3.4"
|
||
[backends.error]
|
||
[backends.error.servers.error]
|
||
url = "http://2.3.4.5"
|
||
```
|
||
|
||
In the above example, the error page rendered was based on the status code.
|
||
Instead, the query parameter can also be set to some generic error page like so: `query = "/500s.html"`
|
||
|
||
Now the 500s.html error page is returned for the configured code range.
|
||
The configured status code ranges are inclusive; that is, in the above example, the 500s.html page will be returned for status codes 500 through, and including, 599.
|
||
|
||
## Configuration
|
||
|
||
Træfik's configuration has two parts:
|
||
|
||
- The [static Træfik configuration](/basics#static-trfk-configuration) which is loaded only at the beginning.
|
||
- The [dynamic Træfik configuration](/basics#dynamic-trfk-configuration) which can be hot-reloaded (no need to restart the process).
|
||
|
||
|
||
### Static Træfik configuration
|
||
|
||
The static configuration is the global configuration which is setting up connections to configuration backends and entrypoints.
|
||
|
||
Træfik can be configured using many configuration sources with the following precedence order.
|
||
Each item takes precedence over the item below it:
|
||
|
||
- [Key-value store](/basics/#key-value-stores)
|
||
- [Arguments](/basics/#arguments)
|
||
- [Configuration file](/basics/#configuration-file)
|
||
- Default
|
||
|
||
It means that arguments override configuration file, and key-value store overrides arguments.
|
||
|
||
Note that the provider-enabling argument parameters (e.g., `--docker`) set all default values for the specific provider. It must not be used if a configuration source with less precedence wants to set a non-default provider value.
|
||
|
||
#### Configuration file
|
||
|
||
By default, Træfik will try to find a `traefik.toml` in the following places:
|
||
|
||
- `/etc/traefik/`
|
||
- `$HOME/.traefik/`
|
||
- `.` *the working directory*
|
||
|
||
You can override this by setting a `configFile` argument:
|
||
|
||
```bash
|
||
$ traefik --configFile=foo/bar/myconfigfile.toml
|
||
```
|
||
|
||
Please refer to the [global configuration](/toml/#global-configuration) section to get documentation on it.
|
||
|
||
#### Arguments
|
||
|
||
Each argument (and command) is described in the help section:
|
||
|
||
```bash
|
||
$ traefik --help
|
||
```
|
||
|
||
Note that all default values will be displayed as well.
|
||
|
||
#### Key-value stores
|
||
|
||
Træfik supports several Key-value stores:
|
||
|
||
- [Consul](https://consul.io)
|
||
- [etcd](https://coreos.com/etcd/)
|
||
- [ZooKeeper](https://zookeeper.apache.org/)
|
||
- [boltdb](https://github.com/boltdb/bolt)
|
||
|
||
Please refer to the [User Guide Key-value store configuration](/user-guide/kv-config/) section to get documentation on it.
|
||
|
||
### Dynamic Træfik configuration
|
||
|
||
The dynamic configuration concerns :
|
||
|
||
- [Frontends](/basics/#frontends)
|
||
- [Backends](/basics/#backends)
|
||
- [Servers](/basics/#servers)
|
||
|
||
Træfik can hot-reload those rules which could be provided by [multiple configuration backends](/toml/#configuration-backends).
|
||
|
||
We only need to enable `watch` option to make Træfik watch configuration backend changes and generate its configuration automatically.
|
||
Routes to services will be created and updated instantly at any changes.
|
||
|
||
Please refer to the [configuration backends](/toml/#configuration-backends) section to get documentation on it.
|
||
|
||
## Commands
|
||
|
||
Usage: `traefik [command] [--flag=flag_argument]`
|
||
|
||
List of Træfik available commands with description :
|
||
|
||
- `version` : Print version
|
||
- `storeconfig` : Store the static traefik configuration into a Key-value stores. Please refer to the [Store Træfik configuration](/user-guide/kv-config/#store-trfk-configuration) section to get documentation on it.
|
||
- `bug`: The easiest way to submit a pre-filled issue.
|
||
- `healthcheck`: Calls traefik `/ping` to check health.
|
||
|
||
Each command may have related flags.
|
||
All those related flags will be displayed with :
|
||
|
||
```bash
|
||
$ traefik [command] --help
|
||
```
|
||
|
||
Note that each command is described at the beginning of the help section:
|
||
|
||
```bash
|
||
$ traefik --help
|
||
```
|
||
|
||
### Command: bug
|
||
|
||
Here is the easiest way to submit a pre-filled issue on [Træfik GitHub](https://github.com/containous/traefik).
|
||
|
||
```bash
|
||
$ traefik bug
|
||
```
|
||
|
||
See https://www.youtube.com/watch?v=Lyz62L8m93I.
|
||
|
||
### Command: healthcheck
|
||
|
||
This command allows to check the health of Traefik. Its exit status is `0` if Traefik is healthy and `1` if it is unhealthy.
|
||
This can be used with Docker [HEALTHCHECK](https://docs.docker.com/engine/reference/builder/#healthcheck) instruction or any other health check orchestration mechanism.
|
||
|
||
Note: the `web` provider must be enabled to allow `/ping` calls by the `healthcheck` command.
|
||
|
||
```bash
|
||
$ traefik healthcheck
|
||
OK: http://:8082/ping
|
||
```
|
||
|
||
## Log Rotation
|
||
|
||
Traefik will close and reopen its log files, assuming they're configured, on receipt of a USR1 signal. This allows the logs
|
||
to be rotated and processed by an external program, such as `logrotate`.
|
||
|
||
Note that this does not work on Windows due to the lack of USR signals.
|
||
|