)]}'
{
  "commit": "33c3e765a63f94c9e848aab452d6dcd00edbeefd",
  "tree": "d206c5d5e19147f0296eb0923789382a9d4d542f",
  "parents": [
    "c44ccf37f19d7032d10321da06f2729dd2ba3a5c"
  ],
  "author": {
    "name": "Yun Peng",
    "email": "pcloudy@google.com",
    "time": "Mon Sep 21 13:06:38 2026 +0200"
  },
  "committer": {
    "name": "GitHub",
    "email": "noreply@github.com",
    "time": "Mon Sep 21 13:06:38 2026 +0200"
  },
  "message": "Migrate GCE runner pools to Regional MIGs (RMIG) across us-central1 (#2870)\n\nMigrate Linux (x86) and Windows runner instance groups from zonal MIGs\n(in us-central1-c) to regional MIGs in us-central1 with ANY distribution\nshape to prevent capacity stockouts.\n\n### Problem\nUpgrading `default_vm` in single-zone `us-central1-c` caused severe\ncapacity exhaustion across Linux Docker and Windows runners, draining\nthe active runner fleet as runners terminated after each job.\n\n### Solution\n- Migrate runner pools to Regional Managed Instance Groups (RMIGs)\nacross `us-central1` using `--target-distribution-shape\u003dANY`. GCE will\ndynamically distribute VMs across `us-central1-a`, `b`, `c`, and `f`\nbased on real-time hardware capacity.\n- Inherit `region: us-central1` from `default_vm` for `bk-docker`,\n`bk-windows`, and their testing/trusted variants.\n- Retain explicit `zone: us-central1-c` on ARM64 pools\n(`c4a-standard-8`).\n- In `buildkite/create_instances.py`, set\n`target_distribution_shape\u003d\"ANY\"` for regional MIG creation and\nautomatically check for and delete legacy zonal MIGs with the same name\nto prevent naming and resource conflicts during migration.\n\n---------\n\nCo-authored-by: Salma Samy \u003c16399431+SalmaSamy@users.noreply.github.com\u003e",
  "tree_diff": [
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