IstIO egress gateway gives HTTP 503 error - kubernetes

Question

I have the following manifest for deploying a IstIO egress gateway routing:
---
apiVersion: networking.istio.io/v1alpha3
kind: ServiceEntry
metadata:
name: REDACTED-egress-se
spec:
hosts:
- sahfpxa.REDACTED
ports:
- number: 8080
name: http-port
protocol: HTTP
resolution: DNS
---
apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
name: sahfpxa-REDACTED-egress-gw
spec:
selector:
istio: egressgateway
servers:
- port:
number: 8080
name: http
protocol: HTTP
hosts:
- sahfpxa.REDACTED
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
name: egressgateway-for-sahfpxa-REDACTED
spec:
host: istio-egressgateway.istio-system.svc.cluster.local
subsets:
- name: sahfpxa
---
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
name: direct-sahfpxa-REDACTED-through-egress-gateway
spec:
hosts:
- sahfpxa.REDACTED
gateways:
- REDACTED/REDACTED-egress-gw
- mesh
http:
- match:
- gateways:
- mesh
port: 8080
route:
- destination:
host: istio-egressgateway.istio-system.svc.cluster.local
subset: sahfpxa
port:
number: 80
weight: 100
- match:
- gateways:
- REDACTED/sahfpxa-REDACTED-egress-gw
port: 8080
route:
- destination:
host: sahfpxa.REDACTED
port:
number: 8080
weight: 100
But I get a connection refused from the sidecar istio-proxy container Pod of the affected namespace and a HTTP 503 error from the workload container in that namespace.
Any ideas what could be wrong with the configuration or how I can debug it?
Thanks in advance.
Best regards,
rforberger

Answer 1

There were few errors in Your deployment manifest like DestinationRule was not pointing at Your ServiceEntry.
You can try to match Yours with these manifest files:
apiVersion: networking.istio.io/v1alpha3
kind: ServiceEntry
metadata:
name: etth
spec:
hosts:
- etth.pl
ports:
- number: 8080
name: http-port
protocol: HTTP
resolution: DNS
apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
name: istio-egressgateway
spec:
selector:
istio: egressgateway
servers:
- port:
number: 80
name: http
protocol: HTTP
hosts:
- etth.pl
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
name: egressgateway-for-cnn
spec:
host: istio-egressgateway.istio-system.svc.cluster.local
subsets:
- name: etth
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
name: direct-cnn-through-egress-gateway
spec:
hosts:
- etth.pl
gateways:
- istio-egressgateway
- mesh
http:
- match:
- gateways:
- mesh
port: 80
route:
- destination:
host: istio-egressgateway.istio-system.svc.cluster.local
subset: etth
port:
number: 80
weight: 100
- match:
- gateways:
- istio-egressgateway
port: 80
route:
- destination:
host: etth.pl
port:
number: 8080
weight: 100
You can check if routes are present in:
istioctl pc routes $(kubectl get pods -l istio=egressgateway -o jsonpath='{.items[0].metadata.name}' -n istio-system).istio-system -o json
$ istioctl pc routes $(kubectl get pods -l istio=egressgateway -o jsonpath='{.items[0].metadata.name}' -n istio-system).istio-system -o json
[
{
"name": "http.80",
"virtualHosts": [
{
"name": "etth.pl:80",
"domains": [
"etth.pl",
"etth.pl:80"
],
"routes": [
{
"match": {
"prefix": "/",
"caseSensitive": true
},
"route": {
"cluster": "outbound|8080||etth.pl",
"timeout": "0s",
"retryPolicy": {
"retryOn": "connect-failure,refused-stream,unavailable,cancelled,resource-exhausted,retriable-status-codes",
"numRetries": 2,
"retryHostPredicate": [
{
"name": "envoy.retry_host_predicates.previous_hosts"
}
],
"hostSelectionRetryMaxAttempts": "5",
"retriableStatusCodes": [
503
]
},
"maxGrpcTimeout": "0s"
},
"metadata": {
"filterMetadata": {
"istio": {
"config": "/apis/networking/v1alpha3/namespaces/default/virtual-service/direct-cnn-through-egress-gateway"
}
}
},
"decorator": {
"operation": "etth.pl:8080/*"
},
"typedPerFilterConfig": {
"mixer": {
"#type": "type.googleapis.com/istio.mixer.v1.config.client.ServiceConfig",
"disableCheckCalls": true,
"mixerAttributes": {
"attributes": {
"destination.service.host": {
"stringValue": "etth.pl"
},
"destination.service.name": {
"stringValue": "etth.pl"
},
"destination.service.namespace": {
"stringValue": "default"
}
}
},
"forwardAttributes": {
"attributes": {
"destination.service.host": {
"stringValue": "etth.pl"
},
"destination.service.name": {
"stringValue": "etth.pl"
},
"destination.service.namespace": {
"stringValue": "default"
}
}
}
}
}
}
]
}
],
"validateClusters": false
},
{
"virtualHosts": [
{
"name": "backend",
"domains": [
"*"
],
"routes": [
{
"match": {
"prefix": "/stats/prometheus"
},
"route": {
"cluster": "prometheus_stats"
}
}
]
}
]
}
]