Registry production cluster: reduce platform node group 4 -> 2 - #1072
Merged
Conversation
added 2 commits
September 3, 2026 08:10
The private node group hosts only shared platform services (ingress-nginx, coredns, cert-manager, external-secrets, EBS CSI controllers, metrics-server, New Relic + CloudWatch agents) — ~1.9Gi of requests total. It sat idle at 4x t3.large because cluster-autoscaler never scales down nodes running kube-system pods (skip-nodes-with-system-pods). Raise priv_ng_min_size 0 -> 2 (explicit HA floor, 1 per AZ). Actual reduction to 2 is triggered by setting desiredSize=2 via the EKS API, since TF ignores desired_size (CA-managed). PDBs on ingress/coredns/ebs-csi-controller keep the drain safe (one disruption at a time).
arielr-lt
changed the title
rohit-joy
reviewed
Sep 3, 2026
Addresses PR review (Rohit): the private node group runs only platform/system services, so downsize from t3.large to t3.medium (~half the cost) and cap max at 3 (was 10 — surge headroom for node upgrades, not the excessive 10). t3.medium is capped at 17 pods by the VPC CNI ENI limit and the platform layer runs ~19/node, so this requires prefix delegation: - ENABLE_PREFIX_DELEGATION=true on the aws-node DaemonSet (set on the cluster) - a launch template on the private node group with a nodeadm maxPods=110 override Attaching the LT + changing instance type forces a node-group replacement, so name_prefix + create_before_destroy roll the new t3.medium group in before the old t3.large group is destroyed. Registry app nodes (prod-v2) are untouched; only platform pods reschedule (PDB-protected).
rohit-joy
approved these changes
Sep 4, 2026
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Summary
Reduces the platform node group
eks-ng-privateon the productionce-registry-ekscluster from 4× t3.large → 2× t3.large.