[node-local-dns] Add spec.trafficDistribution #738
Description
Hi!
Can you please implement/add trafficDistribution key to Upstream Service manifest?
🎯 Use Case: Multi-AZ Kubernetes Clusters
Problem:
In multi-AZ clusters, DNS queries from nodes in one availability zone (AZ) may be routed to DNS servers in different AZs, causing unnecessary cross-AZ network traffic, increased latency, and higher costs.
Solution: upstreamServiceTrafficDistribution: PreferClose
upstreamServiceTrafficDistribution: PreferCloseHow It Works:
- Node in AZ-A → Prefers DNS upstream endpoints in AZ-A
- Node in AZ-B → Prefers DNS upstream endpoints in AZ-B
- Node in AZ-C → Prefers DNS upstream endpoints in AZ-C
Benefits:
- ⚡ Reduced Latency: DNS queries stay within local AZ
- 💰 Lower Costs: Eliminates cross-AZ data transfer charges
- 🛡️ Better Reliability: AZ failures don't affect DNS resolution in other AZs
- 🎯 Optimized Performance: Local network routing for DNS traffic
Real-World Impact:
In a 3-AZ cluster with 10 nodes per AZ, this can reduce cross-AZ DNS traffic by ~67%, significantly lowering cloud networking costs while improving DNS query performance.
Commit Message:
feat: add upstreamServiceTrafficDistribution parameter
Add optional trafficDistribution field to upstream service with support for:
- PreferClose: Route traffic to endpoints in the same zone
- PreferSameZone: Alias for PreferClose (clearer naming)
- PreferSameNode: Route traffic to endpoints on the same node
Parameter is optional and only applied when configured. Includes:
- Updated values.yaml with documentation and examples
- Modified service-upstream.yaml template with conditional field rendering
- Updated README.md with parameter documentation and link to Kubernetes docs
Files Changed:
stable/node-local-dns/README.md(1 addition)stable/node-local-dns/templates/service-upstream.yaml(3 additions)stable/node-local-dns/values.yaml(4 additions)
Git Diff:
diff --git a/stable/node-local-dns/README.md b/stable/node-local-dns/README.md
index e2816b0..3bee758 100644
--- a/stable/node-local-dns/README.md
+++ b/stable/node-local-dns/README.md
@@ -86,6 +86,7 @@ helm install my-release oci://ghcr.io/deliveryhero/helm-charts/node-local-dns -f
| resources.requests.memory | string | `"128Mi"` | |
| securityContext.capabilities.add[0] | string | `"NET_ADMIN"` | |
| service.annotations | object | `{}` | Annotations to add to the service. |
+| upstreamServiceTrafficDistribution | string | `nil` | Traffic distribution policy for the upstream service. Options: PreferClose, PreferSameZone, PreferSameNode. @see https://kubernetes.io/docs/concepts/services-networking/service/#traffic-distribution |
| serviceAccount.annotations | object | `{}` | Annotations to add to the service account. |
| serviceAccount.create | bool | `true` | Specifies whether a service account should be created. |
| serviceAccount.name | string | `""` | If not set and create is true, a name is generated using the fullname template. |
diff --git a/stable/node-local-dns/templates/service-upstream.yaml b/stable/node-local-dns/templates/service-upstream.yaml
index d11ecc0..92055be 100644
--- a/stable/node-local-dns/templates/service-upstream.yaml
+++ b/stable/node-local-dns/templates/service-upstream.yaml
@@ -7,6 +7,9 @@ metadata:
labels:
{{- include "node-local-dns.labels" . | nindent 4 }}
spec:
+ {{- with .Values.upstreamServiceTrafficDistribution }}
+ trafficDistribution: {{ . }}
+ {{- end }}
ports:
- name: dns
port: 53
diff --git a/stable/node-local-dns/values.yaml b/stable/node-local-dns/values.yaml
index 2bce944..1754d0d 100644
--- a/stable/node-local-dns/values.yaml
+++ b/stable/node-local-dns/values.yaml
@@ -56,6 +56,10 @@ config:
nameOverride: ""
fullnameOverride: ""
+# -- Traffic distribution policy for the upstream service. Options: PreferClose, PreferSameZone, PreferSameNode
+# @see https://kubernetes.io/docs/concepts/services-networking/service/#traffic-distribution
+# upstreamServiceTrafficDistribution: PreferClose
+
serviceAccount:
# -- Specifies whether a service account should be created.
create: true