chore: upgrade Go toolchain references to 1.26.6

.github/.copilot/breadcrumbs/2026-08-19-2233-upgrade-go-toolchain-1.26.6.md

@@ -0,0 +1,38 @@
+# Go 1.26.6 Toolchain Upgrade
+
+## Requirements
+- Upgrade the same files changed by PR #403 from Go 1.25.13 to Go 1.26.6.
+
+## Additional comments from user
+- Upgrade same files from PR #403 to 1.26.6.
+
+## Plan
+1. Update the Go directive, Docker builder images, and CI Go version variables.
+2. Verify all targeted references are updated and no stale references remain.
+3. Run applicable validation, secret scanning, and CodeQL checks.
+
+## Decisions
+- Keep the scope identical to PR #403: the four Dockerfiles, six workflows, and `go.mod`.
+
+## Implementation Details
+- Updated the Go directive and Docker builder image tags to `1.26.6`.
+- Updated the six workflow `GO_VERSION` values to `1.26.6`.
+
+## Changes Made
+- `go.mod`
+- `docker/hub-net-controller-manager.Dockerfile`
+- `docker/mcs-controller-manager.Dockerfile`
+- `docker/member-net-controller-manager.Dockerfile`
+- `docker/net-crd-installer.Dockerfile`
+- `.github/workflows/go.yml`
+- `.github/workflows/build-publish-mcr.yml`
+- `.github/workflows/unit-integration-tests.yml`
+- `.github/workflows/trivy.yml`
+- `.github/workflows/e2e-tests.yml`
+- `.github/workflows/publish-image.yml`
+
+## Before/After Comparison
+- Go 1.25.13 references in the PR #403 files are now Go 1.26.6.
+
+## References
+- PR #403: Go toolchain bump from 1.25.12 to 1.25.13.

.github/workflows/build-publish-mcr.yml

@@ -17,7 +17,7 @@ env:
   # `public` indicates images to MCR wil be publicly available, and will be removed in the final MCR images
   REGISTRY_REPO: public/aks/fleet
 
-  GO_VERSION: '1.25.13'
+  GO_VERSION: '1.26.6'
 
 jobs:
   prepare-variables:

.github/workflows/e2e-tests.yml

@@ -13,7 +13,7 @@ permissions:
   contents: read
 
 env:
-  GO_VERSION: '1.25.13'
+  GO_VERSION: '1.26.6'
 
 jobs:
   detect-noop:

.github/workflows/go.yml

@@ -14,7 +14,7 @@ on:
 
 env:
   # Common versions
-  GO_VERSION: '1.25.13'
+  GO_VERSION: '1.26.6'
 
 jobs:
 

.github/workflows/publish-image.yml

@@ -19,7 +19,7 @@ env:
   REGISTRY: ghcr.io
   IMAGE_VERSION: latest
 
-  GO_VERSION: '1.25.13'
+  GO_VERSION: '1.26.6'
 
 jobs:
   export-registry:

.github/workflows/trivy.yml

@@ -21,7 +21,7 @@ env:
   MEMBER_NET_CONTROLLER_MANAGER_IMAGE_NAME: member-net-controller-manager
   MCS_CONTROLLER_MANAGER_IMAGE_NAME: mcs-controller-manager
 
-  GO_VERSION: '1.25.13'
+  GO_VERSION: '1.26.6'
 
 jobs:
   export-registry:

.github/workflows/unit-integration-tests.yml

@@ -16,7 +16,7 @@ permissions:
   contents: read
 
 env:
-  GO_VERSION: '1.25.13'
+  GO_VERSION: '1.26.6'
 
 jobs:
   detect-noop:

docker/hub-net-controller-manager.Dockerfile

@@ -1,5 +1,5 @@
 # Build the hub-net-controller-manager binary
-FROM mcr.microsoft.com/oss/go/microsoft/golang:1.25.13 AS builder
+FROM mcr.microsoft.com/oss/go/microsoft/golang:1.26.6 AS builder
 
 ARG GOOS=linux
 ARG GOARCH=amd64

docker/mcs-controller-manager.Dockerfile

@@ -1,5 +1,5 @@
 # Build the mcs-controller-manager binary
-FROM mcr.microsoft.com/oss/go/microsoft/golang:1.25.13 AS builder
+FROM mcr.microsoft.com/oss/go/microsoft/golang:1.26.6 AS builder
 
 ARG GOOS=linux
 ARG GOARCH=amd64

docker/member-net-controller-manager.Dockerfile

@@ -1,5 +1,5 @@
 # Build the member-net-controller-manager binary
-FROM mcr.microsoft.com/oss/go/microsoft/golang:1.25.13 AS builder
+FROM mcr.microsoft.com/oss/go/microsoft/golang:1.26.6 AS builder
 
 ARG GOOS=linux
 ARG GOARCH=amd64

docker/net-crd-installer.Dockerfile

@@ -1,5 +1,5 @@
 # Build the net-crd-installer binary
-FROM mcr.microsoft.com/oss/go/microsoft/golang:1.25.13 AS builder
+FROM mcr.microsoft.com/oss/go/microsoft/golang:1.26.6 AS builder
 
 ARG GOOS=linux
 ARG GOARCH=amd64

go.mod

@@ -1,6 +1,6 @@
 module go.goms.io/fleet-networking
 
-go 1.25.13
+go 1.26.6
 
 require go.goms.io/fleet v0.14.0