traefik/docs/content/routing/services/index.md
2019-08-26 10:00:04 -07:00

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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 tab="TOML"
[http.services]
[http.services.my-service.loadBalancer]
[[http.services.my-service.loadBalancer.servers]]
url = "http://private-ip-server-1/"
[[http.services.my-service.loadBalancer.servers]]
url = "http://private-ip-server-2/"
```
```yaml tab="YAML"
http:
services:
my-service:
loadBalancer:
servers:
- url: "http://private-ip-server-1/"
- url: "http://private-ip-server-2/"
```
??? example "Declaring a TCP Service with Two Servers -- Using the [File Provider](../../providers/file.md)"
```toml tab="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"
```
```yaml tab="YAML"
tcp:
services:
my-service:
loadBalancer:
servers:
- address: "xx.xx.xx.xx:xx"
- address: "xx.xx.xx.xx:xx"
```
## Configuring HTTP Services
### Servers 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 tab="TOML"
[http.services]
[http.services.my-service.loadBalancer]
[[http.services.my-service.loadBalancer.servers]]
url = "http://private-ip-server-1/"
[[http.services.my-service.loadBalancer.servers]]
url = "http://private-ip-server-2/"
```
```yaml tab="YAML"
http:
services:
my-service:
loadBalancer:
servers:
- url: "http://private-ip-server-1/"
- url: "http://private-ip-server-2/"
```
#### Servers
Servers declare a single instance of your program.
The `url` option point to a specific instance.
!!! 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 tab="TOML"
[http.services]
[http.services.my-service.loadBalancer]
[[http.services.my-service.loadBalancer.servers]]
url = "http://private-ip-server-1/"
```
```yaml tab="YAML"
http:
services:
my-service:
loadBalancer:
servers:
url: "http://private-ip-server-1/"
```
#### Load-balancing
For now, only round robin load balancing is supported:
??? example "Load Balancing -- Using the [File Provider](../../providers/file.md)"
```toml tab="TOML"
[http.services]
[http.services.my-service.loadBalancer]
[[http.services.my-service.loadBalancer.servers]]
url = "http://private-ip-server-1/"
[[http.services.my-service.loadBalancer.servers]]
url = "http://private-ip-server-2/"
```
```yaml tab="YAML"
http:
services:
my-service:
loadBalancer:
servers:
- url: "http://private-ip-server-1/"
- url: "http://private-ip-server-2/"
```
#### 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`).
!!! note "Secure & HTTPOnly flags"
By default, the affinity cookie is created without those flags. One however can change that through configuration.
??? example "Adding Stickiness"
```toml tab="TOML"
[http.services]
[http.services.my-service]
[http.services.my-service.loadBalancer.sticky.cookie]
```
```yaml tab="YAML"
http:
services:
my-service:
loadBalancer:
sticky:
cookie: {}
```
??? example "Adding Stickiness with custom Options"
```toml tab="TOML"
[http.services]
[http.services.my-service]
[http.services.my-service.loadBalancer.sticky.cookie]
name = "my_sticky_cookie_name"
secure = true
httpOnly = true
```
```yaml tab="YAML"
http:
services:
my-service:
loadBalancer:
sticky:
cookie:
name: my_sticky_cookie_name
secure: true
httpOnly: true
```
#### Health Check
Configure health check 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 health check endpoint.
- `scheme`, if defined, will replace the server URL `scheme` for the health check endpoint
- `hostname`, if defined, will replace the server URL `hostname` for the health check endpoint.
- `port`, if defined, will replace the server URL `port` for the health check endpoint.
- `interval` defines the frequency of the health check calls.
- `timeout` defines the maximum duration Traefik will wait for a health check request before considering the server failed (unhealthy).
- `headers` defines custom headers to be sent to the health check 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](../../providers/file.md)"
```toml tab="TOML"
[http.services]
[http.servicess.Service-1]
[http.services.Service-1.loadBalancer.healthCheck]
path = "/health"
interval = "10s"
timeout = "3s"
```
```yaml tab="YAML"
http:
servicess:
Service-1:
loadBalancer:
healthCheck:
path: /health
interval: "10s"
timeout: "3s"
```
??? example "Custom Port -- Using the [File Provider](../../providers/file.md)"
```toml tab="TOML"
[http.services]
[http.services.Service-1]
[http.services.Service-1.loadBalancer.healthCheck]
path = "/health"
port = 8080
```
```yaml tab="YAML"
http:
services:
Service-1:
loadBalancer:
healthCheck:
path: /health
port: 8080
```
??? example "Custom Scheme -- Using the [File Provider](../../providers/file.md)"
```toml tab="TOML"
[http.services]
[http.services.Service-1]
[http.services.Service-1.loadBalancer.healthCheck]
path = "/health"
scheme = "http"
```
```yaml tab="YAML"
http:
services:
Service-1:
loadBalancer:
healthCheck:
path: /health
scheme: http
```
??? example "Additional HTTP Headers -- Using the [File Provider](../../providers/file.md)"
```toml tab="TOML"
[http.services]
[http.services.Service-1]
[http.services.Service-1.loadBalancer.healthCheck]
path = "/health"
[http.services.Service-1.loadBalancer.healthCheck.headers]
My-Custom-Header = "foo"
My-Header = "bar"
```
```yaml tab="YAML"
http:
services:
Service-1:
loadBalancer:
healthCheck:
path: /health
headers:
My-Custom-Header: foo
My-Header: bar
```
### Weighted Round Robin (service)
The WRR is able to load balance the requests between multiple services based on weights.
This strategy is only available to load balance between [services](./index.md) and not between [servers](./index.md#servers).
This strategy can be defined only with [File](../../providers/file.md).
```toml tab="TOML"
[http.services]
[http.services.canary]
[[http.services.canary.weighted.services]]
name = "appv1"
weight = 3
[[http.services.canary.weighted.services]]
name = "appv2"
weight = 1
[http.services.appv1]
[http.services.appv1.loadBalancer]
[[http.services.appv1.loadBalancer.servers]]
url = "http://private-ip-server-1/"
[http.services.appv2]
[http.services.appv2.loadBalancer]
[[http.services.appv2.loadBalancer.servers]]
url = "http://private-ip-server-2/"
```
```yaml tab="YAML"
http:
services:
canary:
weighted:
services:
- name: appv1
weight: 3
- name: appv2
weight: 1
appv1:
loadBalancer:
servers:
- url: "http://private-ip-server-1/"
appv2:
loadBalancer:
servers:
- url: "http://private-ip-server-2/"
```
### Mirroring (service)
The mirroring is able to mirror requests sent to a service to other services.
This strategy can be defined only with [File](../../providers/file.md).
```toml tab="TOML"
[http.services]
[http.services.mirroring]
[http.services.mirroring.mirroring]
service = "app"
[[http.services.mirroring.mirroring.mirrors]]
name = "mirror"
percent = 10
[http.services.app]
[http.services.app.loadBalancer]
[[http.services.appv1.loadBalancer.servers]]
url = "http://private-ip-server-1/"
[http.services.mirror]
[http.services.mirror.loadBalancer]
[[http.services.mirror.loadBalancer.servers]]
url = "http://private-ip-server-2/"
```
```yaml tab="YAML"
http:
services:
mirroring:
mirroring:
service: app
mirrors:
- name: mirror
percent: 10
app:
loadBalancer:
servers:
- url: "http://private-ip-server-1/"
mirror:
loadBalancer:
servers:
- url: "http://private-ip-server-2/"
```
## 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 tab="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"
```
```yaml tab="YAML"
tcp:
services:
my-service:
loadBalancer:
servers:
- address: "xx.xx.xx.xx:xx"
- 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 tab="TOML"
[tcp.services]
[tcp.services.my-service.loadBalancer]
[[tcp.services.my-service.loadBalancer.servers]]
address = "xx.xx.xx.xx:xx"
```
```yaml tab="YAML"
tcp:
services:
my-service:
loadBalancer:
servers:
address: "xx.xx.xx.xx:xx"
```