Upgrade GKE cluster gke-fleet-dev to Kubernetes 1.34

[plural-copilot]

Summary

This PR upgrades the GKE cluster gke-fleet-dev from Kubernetes 1.33 to 1.34 by updating the nextKubernetesVersion configuration in the ServiceDeployment.

Changes

• Updated nextKubernetesVersion from "1.33" to "1.34" in bootstrap/fleets/gke-fleet/clusters/dev.yaml

Impact

This change will trigger:

1. GKE control plane upgrade to Kubernetes 1.34
2. Blue/green node pool rotation to deploy nodes running 1.34
3. Zero-downtime upgrade via the terraform blue/green strategy

Stack Reference

Plural Stack: gke-fleet-cluster-dev

[plural-copilot]

This PR was generated by the claude Plural Agent Runtime. Here's some useful information you might want to know to evaluate the ai's perfomance:

Name	Details
💬 Prompt	## Task: Upgrade GKE cluster gke-fleet-dev from Kubernetes 1.33 to 1.34...
🔗 Run history	View run history

[plural-copilot]

Plural has generated a plan for this PR, full details here

Plan Details

Note: Objects have changed outside of Terraform

Terraform detected the following changes made outside of Terraform since the
last "terraform apply" which may have affected this plan:

  # module.gke.google_container_cluster.primary has changed
  ~ resource "google_container_cluster" "primary" {
        id                                       = "projects/pluralsh-test-384515/locations/us-central1/clusters/gke-fleet-dev"
      ~ master_version                           = "1.33.5-gke.2392000" -> "1.33.10-gke.1067000"
        name                                     = "gke-fleet-dev"
      ~ node_version                             = "1.33.5-gke.2392000" -> "1.33.9-gke.1060000"
        # (37 unchanged attributes hidden)

      ~ node_pool {
            name                        = "default-pool"
          ~ version                     = "1.33.5-gke.2392000" -> "1.33.10-gke.1067000"
            # (7 unchanged attributes hidden)

            # (4 unchanged blocks hidden)
        }
      ~ node_pool {
            name                        = "blue"
          ~ version                     = "1.33.8-gke.1026000" -> "1.33.9-gke.1060000"
            # (7 unchanged attributes hidden)

            # (5 unchanged blocks hidden)
        }
      ~ node_pool {
            name                        = "green"
          ~ version                     = "1.33.8-gke.1026000" -> "1.33.9-gke.1060000"
            # (7 unchanged attributes hidden)

            # (5 unchanged blocks hidden)
        }

        # (28 unchanged blocks hidden)
    }


Unless you have made equivalent changes to your configuration, or ignored the
relevant attributes using ignore_changes, the following plan may include
actions to undo or respond to these changes.

─────────────────────────────────────────────────────────────────────────────

Terraform used the selected providers to generate the following execution
plan. Resource actions are indicated with the following symbols:
  ~ update in-place

Terraform will perform the following actions:

  # plural_cluster.this will be updated in-place
  ~ resource "plural_cluster" "this" {
      ~ agent_deployed = true -> (known after apply)
        id             = "5e1553c4-aa35-49c6-aae6-7a12551a0341"
      ~ kubeconfig     = {
          ~ token                  = (sensitive value)
            # (2 unchanged attributes hidden)
        }
        name           = "gke-fleet-dev"
        tags           = {
            "fleet" = "gke-fleet"
            "tier"  = "dev"
        }
        # (7 unchanged attributes hidden)
    }

  # module.gke.google_container_node_pool.pools["blue"] will be updated in-place
  ~ resource "google_container_node_pool" "pools" {
        id                          = "projects/pluralsh-test-384515/locations/us-central1/clusters/gke-fleet-dev/nodePools/blue"
        name                        = "blue"
      ~ version                     = "1.33.9-gke.1060000" -> "1.33"
        # (10 unchanged attributes hidden)

        # (6 unchanged blocks hidden)
    }

  # module.gke.google_container_node_pool.pools["green"] will be updated in-place
  ~ resource "google_container_node_pool" "pools" {
        id                          = "projects/pluralsh-test-384515/locations/us-central1/clusters/gke-fleet-dev/nodePools/green"
        name                        = "green"
      ~ version                     = "1.33.9-gke.1060000" -> "1.33"
        # (10 unchanged attributes hidden)

        # (6 unchanged blocks hidden)
    }

Plan: 0 to add, 3 to change, 0 to destroy.

[plural-copilot]

Plural AI has generated a summary of what this plan entails here

Plan Summary

Summary

GKE cluster gke-fleet-dev is performing a blue/green node pool rotation for Kubernetes version management. This is a low-risk, configuration-only change with no immediate infrastructure impact.

Root Cause

The Terraform plan reflects drift reconciliation from out-of-band Kubernetes version upgrades that already occurred in GKE. The node pools have been upgraded outside of Terraform (master: 1.33.10, nodes: 1.33.9), and Terraform is now adjusting the version configuration to align with the cluster's blue/green deployment strategy by setting node pool versions to 1.33 (which pins to the master's minor version).

Key Evidence

• No resources are being created or destroyed - Plan shows 0 to add, 0 to destroy, 3 to change
• Changes are configuration-only - The plan only updates the version attribute on two node pools (blue and green) from 1.33.9-gke.1060000 → 1.33 and refreshes the plural_cluster resource
• Drift detected externally - Terraform detected that GKE auto-upgraded the master from 1.33.5 → 1.33.10 and nodes from 1.33.5/1.33.8 → 1.33.9/1.33.10 outside of Terraform's control
• Blue/green strategy in action - The code uses local.active_node_group and local.drain_node_group logic to determine which node pool should be active based on whether the version number is even/odd, implementing a zero-downtime upgrade pattern
• Version simplification - Changing from specific patch versions (e.g., 1.33.9-gke.1060000) to minor version (1.33) allows GKE to manage patch updates within the same minor version automatically

Contextual Observations

• This is a dev environment - Cluster tags indicate tier = dev, so the blast radius is limited to non-production workloads
• Blue/green node pools are designed for safe upgrades - The cluster uses two node pools (blue and green) that alternate as active/drain during upgrades. Based on version 1.33 (odd minor version), green should be the active pool and blue should be draining
• No immediate node replacements - Since the actual GKE node versions are already at 1.33.9, this configuration change won't trigger node pool recreation or rolling updates
• Plural cluster resource refresh - The plural_cluster resource will be updated with the current cluster state (kubeconfig token refresh), which is a normal state refresh operation
• Auto-upgrade is disabled - The code explicitly sets auto_upgrade = false for node pools, giving you control over upgrade timing
• Workload identity configured - The cluster has proper IAM bindings for Plural stacks and external-dns, indicating this is an actively managed fleet cluster