traefik/docs/content/routing/services/index.md
Julien Salleyron 4a68d29ce2 Add a new protocol
Co-authored-by: Gérald Croës <gerald@containo.us>
2019-03-14 09:30:04 +01:00

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# Services
Configuring How to Reach the Services
{: .subtitle }
![services](../../assets/img/services.png)
The `Services` are responsible for configuring how to reach the actual services that will eventually handle the incoming requests.
## Configuration Example
??? example "Declaring an HTTP Service with Two Servers -- Using the [File Provider](../../providers/file.md)"
```toml
[http.services]
[http.services.my-service.LoadBalancer]
method = "wrr" # Load Balancing based on weights
[[http.services.my-service.LoadBalancer.servers]]
url = "http://private-ip-server-1/"
weight = 30 # 30% of the requests will go to that instance
[[http.services.my-service.LoadBalancer.servers]]
url = "http://private-ip-server-2/"
weight = 70 # 70% of the requests will go to that instance
```
??? example "Declaring a TCP Service with Two Servers -- Using the [File Provider](../../providers/file.md)"
```toml
[tcp.services]
[tcp.services.my-service.LoadBalancer]
[[tcp.services.my-service.LoadBalancer.servers]]
address = "xx.xx.xx.xx:xx"
[[tcp.services.my-service.LoadBalancer.servers]]
address = "xx.xx.xx.xx:xx"
```
## Configuring HTTP Services
### General
Currently, `LoadBalancer` is the only supported kind of HTTP `Service` (see below).
However, since Traefik is an ever evolving project, other kind of HTTP Services will be available in the future,
reason why you have to specify it.
### Load Balancer
The load balancers are able to load balance the requests between multiple instances of your programs.
??? example "Declaring a Service with Two Servers (with Load Balancing) -- Using the [File Provider](../../providers/file.md)"
```toml
[http.services]
[http.services.my-service.LoadBalancer]
method = "wrr" # Load Balancing based on weights
[[http.services.my-service.LoadBalancer.servers]]
url = "http://private-ip-server-1/"
weight = 50 # 50% of the requests will go to that instance
[[http.services.my-service.LoadBalancer.servers]]
url = "http://private-ip-server-2/"
weight = 50 # 50% of the requests will go to that instance
```
#### Servers
Servers declare a single instance of your program.
The `url` option point to a specific instance.
The `weight` option defines the weight of the server for the load balancing algorithm.
!!! note
Paths in the servers' `url` have no effet.
If you want the requests to be sent to a specific path on your servers,
configure your [`routers`](../routers/index.md) to use a corresponding [middleware](../../middlewares/overview.md) (e.g. the [AddPrefix](../../middlewares/addprefix.md) or [ReplacePath](../../middlewares/replacepath.md)) middlewares.
??? example "A Service with One Server -- Using the [File Provider](../../providers/file.md)"
```toml
[http.services]
[http.services.my-service.LoadBalancer]
[[http.services.my-service.LoadBalancer.servers]]
url = "http://private-ip-server-1/"
```
#### Load-balancing
Various methods of load balancing are supported:
- `wrr`: Weighted Round Robin.
- `drr`: Dynamic Round Robin: increases weights on servers that perform better than others (rolls back to original weights when the server list is updated)
??? example "Load Balancing Using DRR -- Using the [File Provider](../../providers/file.md)"
```toml
[http.services]
[http.services.my-service.LoadBalancer]
method = "drr"
[[http.services.my-service.LoadBalancer.servers]]
url = "http://private-ip-server-1/"
[[http.services.my-service.LoadBalancer.servers]]
url = "http://private-ip-server-1/"
```
#### Sticky sessions
When sticky sessions are enabled, a cookie is set on the initial request to track which server handles the first response.
On subsequent requests, the client is forwarded to the same server.
!!! note "Stickiness & Unhealthy Servers"
If the server specified in the cookie becomes unhealthy, the request will be forwarded to a new server (and the cookie will keep track of the new server).
!!! note "Cookie Name"
The default cookie name is an abbreviation of a sha1 (ex: `_1d52e`).
??? example "Adding Stickiness"
```toml
[http.services]
[http.services.my-service]
[http.services.my-service.LoadBalancer.stickiness]
```
??? example "Adding Stickiness with a Custom Cookie Name"
```toml
[http.services]
[http.services.my-service]
[http.services.my-service.LoadBalancer.stickiness]
cookieName = "my_stickiness_cookie_name"
```
#### Health Check
Configure healthcheck to remove unhealthy servers from the load balancing rotation.
Traefik will consider your servers healthy as long as they return status codes between `2XX` and `3XX` to the health check requests (carried out every `interval`).
Below are the available options for the health check mechanism:
- `path` is appended to the server URL to set the healcheck endpoint.
- `scheme`, if defined, will replace the server URL `scheme` for the healthcheck endpoint
- `hostname`, if defined, will replace the server URL `hostname` for the healthcheck endpoint.
- `port`, if defined, will replace the server URL `port` for the healthcheck endpoint.
- `interval` defines the frequency of the healthcheck calls.
- `timeout` defines the maximum duration Traefik will wait for a healthcheck request before considering the server failed (unhealthy).
- `headers` defines custom headers to be sent to the healthcheck endpoint.
!!! note "Interval & Timeout Format"
Interval and timeout are to be given in a format understood by [time.ParseDuration](https://golang.org/pkg/time/#ParseDuration).
The interval must be greater than the timeout. If configuration doesn't reflect this, the interval will be set to timeout + 1 second.
!!! note "Recovering Servers"
Traefik keeps monitoring the health of unhealthy servers.
If a server has recovered (returning `2xx` -> `3xx` responses again), it will be added back to the load balacer rotation pool.
??? example "Custom Interval & Timeout -- Using the File Provider"
```toml
[http.services]
[http.servicess.Service-1]
[http.services.Service-1.healthcheck]
path = "/health"
interval = "10s"
timeout = "3s"
```
??? example "Custom Port -- Using the File Provider"
```toml
[http.services]
[http.services.Service-1]
[http.services.Service-1.healthcheck]
path = "/health"
port = 8080
```
??? example "Custom Scheme -- Using the File Provider"
```toml
[http.services]
[http.services.Service-1]
[http.services.Service-1.healthcheck]
path = "/health"
scheme = "http"
```
??? example "Additional HTTP Headers -- Using the File Provider"
```toml
[http.services]
[http.services.Service-1]
[http.servicess.Service-1.healthcheck]
path = "/health"
[Service.Service-1.healthcheck.headers]
My-Custom-Header = "foo"
My-Header = "bar"
```
## Configuring TCP Services
### General
Currently, `LoadBalancer` is the only supported kind of TCP `Service`.
However, since Traefik is an ever evolving project, other kind of TCP Services will be available in the future,
reason why you have to specify it.
### Load Balancer
The load balancers are able to load balance the requests between multiple instances of your programs.
??? example "Declaring a Service with Two Servers -- Using the [File Provider](../../providers/file.md)"
```toml
[tcp.services]
[tcp.services.my-service.LoadBalancer]
[[tcp.services.my-service.LoadBalancer.servers]]
address = "xx.xx.xx.xx:xx"
[[tcp.services.my-service.LoadBalancer.servers]]
address = "xx.xx.xx.xx:xx"
```
#### Servers
Servers declare a single instance of your program.
The `address` option (IP:Port) point to a specific instance.
??? example "A Service with One Server -- Using the [File Provider](../../providers/file.md)"
```toml
[tcp.services]
[tcp.services.my-service.LoadBalancer]
[[tcp.services.my-service.LoadBalancer.servers]]
address = "xx.xx.xx.xx:xx"
```
!!! note "Weight"
The TCP LoadBalancer is currently a round robin only implementation and doesn't yet support weights.