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docs: clarify multi-levels stickiness

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150
docs/content/routing/providers/kubernetes-crd.md
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@ -646,7 +646,6 @@ referencing services in the [`IngressRoute`](#kind-ingressroute) objects, or rec
* services [Weighted Round Robin](#weighted-round-robin) load balancing. * services [Weighted Round Robin](#weighted-round-robin) load balancing.
* services [mirroring](#mirroring). * services [mirroring](#mirroring).
#### Server Load Balancing #### Server Load Balancing
More information in the dedicated server [load balancing](../services/index.md#load-balancing) section. More information in the dedicated server [load balancing](../services/index.md#load-balancing) section.
@ -916,6 +915,154 @@ More information in the dedicated [mirroring](../services/index.md#mirroring-ser
Specifying a namespace attribute in this case would not make any sense, and will be ignored (except if the provider is `kubernetescrd`). Specifying a namespace attribute in this case would not make any sense, and will be ignored (except if the provider is `kubernetescrd`).
#### Stickiness and load-balancing
As explained in the section about [Sticky sessions](../../services/#sticky-sessions), for stickiness to work all the way,
it must be specified at each load-balancing level.
For instance, in the example below, there is a first level of load-balancing because there is a (Weighted Round Robin) load-balancing of the two `whoami` services,
and there is a second level because each whoami service is a `replicaset` and is thus handled as a load-balancer of servers.
??? "Stickiness on two load-balancing levels"
```yaml tab="IngressRoute"
apiVersion: traefik.containo.us/v1alpha1
kind: IngressRoute
metadata:
name: ingressroutebar
namespace: default
spec:
entryPoints:
- web
routes:
- match: Host(`example.com`) && PathPrefix(`/foo`)
kind: Rule
services:
- name: wrr1
namespace: default
kind: TraefikService
```
```yaml tab="Weighted Round Robin"
apiVersion: traefik.containo.us/v1alpha1
kind: TraefikService
metadata:
name: wrr1
namespace: default
spec:
weighted:
services:
- name: whoami1
kind: Service
port: 80
weight: 1
sticky:
cookie:
name: lvl2
- name: whoami2
kind: Service
weight: 1
port: 80
sticky:
cookie:
name: lvl2
sticky:
cookie:
name: lvl1
```
```yaml tab="K8s Service"
apiVersion: v1
kind: Service
metadata:
name: whoami1
spec:
ports:
- protocol: TCP
name: web
port: 80
selector:
app: whoami1
---
apiVersion: v1
kind: Service
metadata:
name: whoami2
spec:
ports:
- protocol: TCP
name: web
port: 80
selector:
app: whoami2
```
```yaml tab="Deployment (to illustrate replicas)"
kind: Deployment
apiVersion: apps/v1
metadata:
namespace: default
name: whoami1
labels:
app: whoami1
spec:
replicas: 2
selector:
matchLabels:
app: whoami1
template:
metadata:
labels:
app: whoami1
spec:
containers:
- name: whoami1
image: containous/whoami
ports:
- name: web
containerPort: 80
---
kind: Deployment
apiVersion: apps/v1
metadata:
namespace: default
name: whoami2
labels:
app: whoami2
spec:
replicas: 2
selector:
matchLabels:
app: whoami2
template:
metadata:
labels:
app: whoami2
spec:
containers:
- name: whoami2
image: containous/whoami
ports:
- name: web
containerPort: 80
```
To keep a session open with the same server, the client would then need to specify the two levels within the cookie for each request, e.g. with curl:
```bash
curl -H Host:example.com -b "lvl1=default-whoami1-80; lvl2=http://10.42.0.6:80" http://localhost:8000/foo
```
assuming `10.42.0.6` is the IP address of one of the replicas (a pod then) of the `whoami1` service.
### Kind `IngressRouteTCP` ### Kind `IngressRouteTCP`
`IngressRouteTCP` is the CRD implementation of a [Traefik TCP router](../routers/index.md#configuring-tcp-routers). `IngressRouteTCP` is the CRD implementation of a [Traefik TCP router](../routers/index.md#configuring-tcp-routers).
@ -1386,6 +1533,7 @@ or referencing TLS stores in the [`IngressRoute`](#kind-ingressroute) / [`Ingres
tls.crt: LS0tLS1CRUdJTiBDRVJUSUZJQ0FURS0tLS0tCi0tLS0tRU5EIENFUlRJRklDQVRFLS0tLS0= tls.crt: LS0tLS1CRUdJTiBDRVJUSUZJQ0FURS0tLS0tCi0tLS0tRU5EIENFUlRJRklDQVRFLS0tLS0=
tls.key: LS0tLS1CRUdJTiBQUklWQVRFIEtFWS0tLS0tCi0tLS0tRU5EIFBSSVZBVEUgS0VZLS0tLS0= tls.key: LS0tLS1CRUdJTiBQUklWQVRFIEtFWS0tLS0tCi0tLS0tRU5EIFBSSVZBVEUgS0VZLS0tLS0=
``` ```
## Further ## Further
Also see the [full example](../../user-guides/crd-acme/index.md) with Let's Encrypt. Also see the [full example](../../user-guides/crd-acme/index.md) with Let's Encrypt.

82
docs/content/routing/services/index.md
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@ -167,8 +167,12 @@ For now, only round robin load balancing is supported:
#### Sticky sessions #### Sticky sessions
When sticky sessions are enabled, a cookie is set on the initial request to track which server handles the first response. When sticky sessions are enabled, a cookie is set on the initial request and response to let the client know which server handles the first response.
On subsequent requests, the client is forwarded to the same server. On subsequent requests, to keep the session alive with the same server, the client should resend the same cookie.
!!! info "Stickiness on multiple levels"
When chaining or mixing load-balancers (e.g. a load-balancer of servers is one of the "children" of a load-balancer of services), for stickiness to work all the way, the option needs to be specified at all required levels. Which means the client needs to send a cookie with as many key/value pairs as there are sticky levels.
!!! info "Stickiness & Unhealthy Servers" !!! info "Stickiness & Unhealthy Servers"
@ -226,6 +230,80 @@ On subsequent requests, the client is forwarded to the same server.
httpOnly: true httpOnly: true
``` ```
??? example "Setting Stickiness on all the required levels -- Using the [File Provider](../../providers/file.md)"
```toml tab="TOML"
## Dynamic configuration
[http.services]
[http.services.wrr1]
[http.services.wrr1.weighted.sticky.cookie]
name = "lvl1"
[[http.services.wrr1.weighted.services]]
name = "whoami1"
weight = 1
[[http.services.wrr1.weighted.services]]
name = "whoami2"
weight = 1
[http.services.whoami1]
[http.services.whoami1.loadBalancer]
[http.services.whoami1.loadBalancer.sticky.cookie]
name = "lvl2"
[[http.services.whoami1.loadBalancer.servers]]
url = "http://127.0.0.1:8081"
[[http.services.whoami1.loadBalancer.servers]]
url = "http://127.0.0.1:8082"
[http.services.whoami2]
[http.services.whoami2.loadBalancer]
[http.services.whoami2.loadBalancer.sticky.cookie]
name = "lvl2"
[[http.services.whoami2.loadBalancer.servers]]
url = "http://127.0.0.1:8083"
[[http.services.whoami2.loadBalancer.servers]]
url = "http://127.0.0.1:8084"
```
```yaml tab="YAML"
## Dynamic configuration
http:
services:
wrr1:
weighted:
sticky:
cookie:
name: lvl1
services:
- name: whoami1
weight: 1
- name: whoami2
weight: 1
whoami1:
loadBalancer:
sticky:
cookie:
name: lvl2
servers:
- url: http://127.0.0.1:8081
- url: http://127.0.0.1:8082
whoami2:
loadBalancer:
sticky:
cookie:
name: lvl2
servers:
- url: http://127.0.0.1:8083
- url: http://127.0.0.1:8084
```
To keep a session open with the same server, the client would then need to specify the two levels within the cookie for each request, e.g. with curl:
```
curl -b "lvl1=whoami1; lvl2=http://127.0.0.1:8081" http://localhost:8000
```
#### Health Check #### Health Check
Configure health check to remove unhealthy servers from the load balancing rotation. Configure health check to remove unhealthy servers from the load balancing rotation.

2
docs/content/user-guides/crd-acme/index.md
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@ -101,7 +101,7 @@ curl [-k] https://your.example.com/tls
``` ```
```bash ```bash
curl [-k] http://your.example.com:8000/notls curl http://your.example.com:8000/notls
``` ```
Note that you'll have to use `-k` as long as you're using the staging server of Let's Encrypt, since it is not an authorized certificate authority on systems where it hasn't been manually added. Note that you'll have to use `-k` as long as you're using the staging server of Let's Encrypt, since it is not an authorized certificate authority on systems where it hasn't been manually added.

27
pkg/provider/kubernetes/crd/traefik/v1alpha1/ingressroute.go
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@ -1,9 +1,6 @@
package v1alpha1 package v1alpha1
import ( import (
"errors"
"fmt"
"github.com/containous/traefik/v2/pkg/config/dynamic" "github.com/containous/traefik/v2/pkg/config/dynamic"
"github.com/containous/traefik/v2/pkg/types" "github.com/containous/traefik/v2/pkg/types"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1" metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@ -82,30 +79,6 @@ type LoadBalancerSpec struct {
Weight *int `json:"weight,omitempty"` Weight *int `json:"weight,omitempty"`
} }
// IsServersLB reports whether lb is a load-balancer of servers
// (as opposed to a traefik load-balancer of services).
func (lb LoadBalancerSpec) IsServersLB() (bool, error) {
if lb.Name == "" {
return false, errors.New("missing Name field in service")
}
if lb.Kind == "" || lb.Kind == "Service" {
return true, nil
}
if lb.Kind != "TraefikService" {
return false, fmt.Errorf("invalid kind value: %v", lb.Kind)
}
if lb.Port != 0 ||
lb.Scheme != "" ||
lb.HealthCheck != nil ||
lb.Strategy != "" ||
lb.PassHostHeader != nil ||
lb.ResponseForwarding != nil ||
lb.Sticky != nil {
return false, fmt.Errorf("service of kind %v is incompatible with Kubernetes Service related fields", lb.Kind)
}
return false, nil
}
// Service defines an upstream to proxy traffic. // Service defines an upstream to proxy traffic.
type Service struct { type Service struct {
LoadBalancerSpec LoadBalancerSpec