HTTPRoute weighted backends with filters attached sends traffic to the wrong backend #5230
Description
Description:
When I add an weighted backend to an HTTPRoute I expect traffic to go to that backend with the correct filters applied
Instead I'm seeing traffic being sent to the wrong backend.
Repro steps:
- I have a simple go server that prints request headers.
Go HTTP Sever
package main
import (
"fmt"
"log"
"net/http"
"os"
)
func main() {
target := os.Getenv("TARGET")
if target == "" {
target = "World"
}
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
// Log all request headers
fmt.Println("Request Headers:")
for name, values := range r.Header {
for _, value := range values {
fmt.Printf("%s: %s\n", name, value)
}
}
// Send response
fmt.Fprintf(w, "Hello %s!\n", target)
})
port := os.Getenv("PORT")
if port == "" {
port = "8080"
}
log.Printf("Starting server on port %s...\n", port)
if err := http.ListenAndServe(":"+port, nil); err != nil {
log.Fatal(err)
}
}Next deploy two workloads using this go application
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: second
namespace: default
spec:
replicas: 1
selector:
matchLabels:
app: second
template:
metadata:
labels:
app: second
spec:
containers:
- name: helloworld
image: test-image
env:
- name: TARGET
value: "second"
ports:
- containerPort: 8080
---
apiVersion: v1
kind: Service
metadata:
name: second
namespace: default
spec:
type: ClusterIP
ports:
- port: 80
targetPort: 8080
protocol: TCP
selector:
app: second
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: first
namespace: default
spec:
replicas: 1
selector:
matchLabels:
app: first
template:
metadata:
labels:
app: first
spec:
containers:
- name: helloworld
image: test-image
env:
- name: TARGET
value: "first"
ports:
- containerPort: 8080
---
apiVersion: v1
kind: Service
metadata:
name: first
namespace: default
spec:
type: ClusterIP
ports:
- port: 80
targetPort: 8080
protocol: TCP
selector:
app: firstNext we configure two routes with equal weights. For each backend we add request headers to correctly identify the split that should occur.
---
apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
name: sample
namespace: default
labels:
app: sample
spec:
parentRefs:
- name: external-gateway
namespace: default
hostnames:
- "sample.com"
rules:
- backendRefs:
- name: first
port: 80
weight: 10
filters:
- type: RequestHeaderModifier
requestHeaderModifier:
set:
- name: first
value: first
- name: second
port: 80
weight: 10
filters:
- type: RequestHeaderModifier
requestHeaderModifier:
set:
- name: second
value: secondAfter making requests to sample.com - you'll see the wrong headers end up in the wrong backend
See: First: first in the below logs
second-764d49d88f-bgmtc helloworld Request Headers:
second-764d49d88f-bgmtc helloworld User-Agent: curl/8.7.1
second-764d49d88f-bgmtc helloworld Accept: */*
second-764d49d88f-bgmtc helloworld X-Forwarded-For: 172.18.0.3
second-764d49d88f-bgmtc helloworld X-Forwarded-Proto: http
second-764d49d88f-bgmtc helloworld X-Envoy-External-Address: 172.18.0.3
second-764d49d88f-bgmtc helloworld X-Request-Id: 19f2119b-d88f-4be2-9806-b043528d3f84
second-764d49d88f-bgmtc helloworld First: first
Environment:
Using Envoy Gateway v1.3.0 testing on kind using cloud-provider-kind
Logs: