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Allow setting service topology aware routing mode #41

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Jan 19, 2024
Merged

Allow setting service topology aware routing mode #41

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31 changes: 19 additions & 12 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -202,15 +202,22 @@ spec:
egress.monzo.com/gateway: egress-gateway-name
```

| Variable name | Default | Description |
|------------------------------------|-------------------------------------------|----------------------------------------------------|
| ENVOY_IMAGE | `envoyproxy/envoy-alpine:v1.16.5` | Name of the Envoy Proxy image to use |
| TAINT_TOLERATION_KEY | Empty, no tolerations applied | Toleration key to apply to gateway pods |
| TAINT_TOLERATION_VALUE | Empty, no tolerations applied | Toleration value to apply to gateway pods |
| NODE_SELECTOR_KEY | Empty, no node selector added | Node selector label key to apply to gateway pods |
| NODE_SELECTOR_VALUE | Empty, no node selector added | Node selector label value to apply to gateway pods |
| POD_TOPOLOGY_ZONE_MAX_SKEW_KEY | `topology.kubernetes.io/zone` | Topology key for the zone constraint |
| POD_TOPOLOGY_ZONE_MAX_SKEW | Empty, won't inject a zone constraint | Value of maxSkew for the zone constraint |
| POD_TOPOLOGY_HOSTNAME_MAX_SKEW_KEY | `kubernetes.io/hostname` | Topology key for the hostname constraint |
| POD_TOPOLOGY_HOSTNAME_MAX_SKEW | Empty, won't inject a hostname constraint | Value of maxSkew for the hostname constraint |

You can also setup services to have their endpoints aware of network topologies with [topology aware routing](https://kubernetes.io/docs/concepts/services-networking/topology-aware-routing/).

If you set the environment variable `ENABLE_SERVICE_TOPOLOGY_MODE="true"` this will enable setting the annotations `service.kubernetes.io/topology-mode="auto"`.

If you turn this on you can also set `spec.serviceTopologyMode` to any value if you want to disable this for particular egress'. For example
if you set `spec.serviceTopologyMode: "None"` this will disable topology aware routing for your ExternalService.

| Variable name | Default | Description |
|------------------------------------|-------------------------------------------|-----------------------------------------------------------|
| ENVOY_IMAGE | `envoyproxy/envoy-alpine:v1.16.5` | Name of the Envoy Proxy image to use |
| TAINT_TOLERATION_KEY | Empty, no tolerations applied | Toleration key to apply to gateway pods |
| TAINT_TOLERATION_VALUE | Empty, no tolerations applied | Toleration value to apply to gateway pods |
| NODE_SELECTOR_KEY | Empty, no node selector added | Node selector label key to apply to gateway pods |
| NODE_SELECTOR_VALUE | Empty, no node selector added | Node selector label value to apply to gateway pods |
| POD_TOPOLOGY_ZONE_MAX_SKEW_KEY | `topology.kubernetes.io/zone` | Topology key for the zone constraint |
| POD_TOPOLOGY_ZONE_MAX_SKEW | Empty, won't inject a zone constraint | Value of maxSkew for the zone constraint |
| POD_TOPOLOGY_HOSTNAME_MAX_SKEW_KEY | `kubernetes.io/hostname` | Topology key for the hostname constraint |
| POD_TOPOLOGY_HOSTNAME_MAX_SKEW | Empty, won't inject a hostname constraint | Value of maxSkew for the hostname constraint |
| ENABLE_SERVICE_TOPOLOGY_MODE | Empty, won't add the annotation | Set to 'true' to add the topology mode service annotation |
4 changes: 4 additions & 0 deletions api/v1/externalservice_types.go
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Expand Up @@ -62,6 +62,10 @@ type ExternalServiceSpec struct {
// If this circuit breaker overflows the upstream_cx_overflow counter for the cluster will increment.
// +optional
EnvoyClusterMaxConnections *uint32 `json:"envoyClusterMaxConnections,omitempty"`

// Provides a way to override the global default
// +optional
ServiceTopologyMode string `json:"serviceTopologyMode,omitempty"`
}

type ExternalServicePort struct {
Expand Down
16 changes: 14 additions & 2 deletions controllers/externalservice_controller.go
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Expand Up @@ -18,9 +18,9 @@ package controllers
import (
"bytes"
"context"
"os"

"github.com/go-logr/logr"
egressv1 "github.com/monzo/egress-operator/api/v1"
appsv1 "k8s.io/api/apps/v1"
autoscalingv1 "k8s.io/api/autoscaling/v1"
corev1 "k8s.io/api/core/v1"
Expand All @@ -29,6 +29,8 @@ import (
"k8s.io/apimachinery/pkg/runtime"
ctrl "sigs.k8s.io/controller-runtime"
"sigs.k8s.io/controller-runtime/pkg/client"

egressv1 "github.com/monzo/egress-operator/api/v1"
)

const namespace = "egress-operator-system"
Expand Down Expand Up @@ -106,9 +108,19 @@ func labels(es *egressv1.ExternalService) map[string]string {
}

func annotations(es *egressv1.ExternalService) map[string]string {
return map[string]string{
annotations := map[string]string{
"egress.monzo.com/dns-name": es.Spec.DnsName,
}
// Allow setting the topology aware routing annotation
value, ok := os.LookupEnv("ENABLE_SERVICE_TOPOLOGY_MODE")
if ok && value == "true" {
if es.Spec.ServiceTopologyMode != "" {
annotations["service.kubernetes.io/topology-mode"] = es.Spec.ServiceTopologyMode
} else {
annotations["service.kubernetes.io/topology-mode"] = "Auto"
}
}
return annotations
}

func labelsToSelect(es *egressv1.ExternalService) map[string]string {
Expand Down
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