fix(ci): auto-resolve the ECS base image for the runner rebuild

The automated rebuild failed with 'Missing required configuration:
--base-image-id' because the ALIYUN_ECS_BASE_IMAGE_ID repo variable
does not exist yet (it was flagged as a one-time setup item).

Remove the setup dependency instead: build-ecs-image.py now defaults
--base-image-id to the latest public Ubuntu 24.04 x86_64 system image
in the region (DescribeImages with image_owner_alias=system), so no
manual variable is required. The runner Dockerfile pins every tool
version itself, so base-image drift is low-risk; --base-image-id or
the ALIYUN_ECS_BASE_IMAGE_ID variable still pin a specific base image
deterministically, and the workflow only passes the flag when the
variable is set.

Part of #9289.

Signed-off-by: Ning Sun <sunning@greptime.com>

.github/runner-scale-sets/query-regression/README.md

@@ -101,9 +101,15 @@ The manual fallback (also what the workflow runs):
 ALIBABA_CLOUD_ACCESS_KEY_ID=... ALIBABA_CLOUD_ACCESS_KEY_SECRET=... \
 uv run .github/runner-scale-sets/query-regression/ecs-image/build-ecs-image.py \
   --region-id <region> --vswitch-id <vsw-...> --security-group-id <sg-...> \
-  --base-image-id <ubuntu-24.04-image-id>
+  [--base-image-id <ubuntu-24.04-image-id>]
 ```
 
+`--base-image-id` is optional: the script defaults to the latest public
+Ubuntu 24.04 image in the region (the Dockerfile pins every tool version
+itself, so base drift is low-risk); pass it — or set the
+`ALIYUN_ECS_BASE_IMAGE_ID` repo variable consumed by the automated job —
+to pin a specific base image.
+
 The script boots a temporary builder instance, `docker build`s the runner
 image, materializes `/opt/rustup`, `/opt/cargo`, `/usr/local/bin` tools, and
 `/home/runner` (actions-runner) onto the host, installs the ephemeral-runner

.github/runner-scale-sets/query-regression/ecs-image/build-ecs-image.py

@@ -235,6 +235,48 @@ def call_api_with_retry(fn, description: str, attempts: int = 5):
     raise RuntimeError("unreachable: retry loop exited without returning")
 
 
+def resolve_base_image_id(client, region_id: str) -> str:
+    """Resolve the latest public Ubuntu 24.04 x86_64 system image.
+
+    Used as the default for --base-image-id: the runner Dockerfile pins
+    every tool version itself, so a current stock Ubuntu 24.04 base is all
+    the builder needs. Pass --base-image-id (or ALIYUN_ECS_BASE_IMAGE_ID)
+    to pin a specific base image deterministically.
+    """
+    from alibabacloud_ecs20140526 import models as ecs_models
+
+    response = call_api_with_retry(
+        lambda: client.describe_images(
+            ecs_models.DescribeImagesRequest(
+                region_id=region_id,
+                image_owner_alias="system",
+                os_type="linux",
+            )
+        ),
+        "DescribeImages(system base)",
+    )
+    candidates = [
+        image
+        for image in (response.body.images.image or [])
+        if (image.architecture or "") == "x86_64"
+        and "Ubuntu" in (image.os_name or "")
+        and "24.04" in (image.os_name or "")
+    ]
+    if not candidates:
+        raise SystemExit(
+            "No public Ubuntu 24.04 x86_64 system image found in region "
+            f"{region_id}; pass --base-image-id explicitly"
+        )
+    candidates.sort(key=lambda image: image.creation_time or "", reverse=True)
+    picked = candidates[0]
+    print(
+        f"Resolved base image: {picked.image_id} ({picked.os_name}, "
+        f"created {picked.creation_time}) from {len(candidates)} candidates",
+        flush=True,
+    )
+    return picked.image_id
+
+
 def read_console_output(client, region_id: str, instance_id: str) -> str:
     """Fetch the instance's serial console output; no in-guest agent needed."""
     from alibabacloud_ecs20140526 import models as ecs_models
@@ -259,13 +301,19 @@ def main() -> int:
     parser.add_argument("--image-name", default=None, help="Defaults to a timestamped name.")
     args = parser.parse_args()
 
-    for name in ("region_id", "vswitch_id", "security_group_id", "base_image_id"):
+    for name in ("region_id", "vswitch_id", "security_group_id"):
         if not getattr(args, name):
             raise SystemExit(f"Missing required configuration: --{name.replace('_', '-')}")
 
     from alibabacloud_ecs20140526 import models as ecs_models
 
     client = make_ecs_client(args.region_id)
+    # --base-image-id is optional: default to the latest public Ubuntu 24.04
+    # image in the region (the Dockerfile pins every tool version itself, so
+    # base drift is low-risk; pass --base-image-id or set
+    # ALIYUN_ECS_BASE_IMAGE_ID to pin deterministically).
+    if not args.base_image_id:
+        args.base_image_id = resolve_base_image_id(client, args.region_id)
     image_name = args.image_name or time.strftime(
         "greptimedb-query-regression-runner-%Y%m%d%H%M%S", time.gmtime()
     )

.github/workflows/release-dev-builder-images.yaml

@@ -344,11 +344,11 @@ jobs:
     #
     # Required repository configuration (same names the provisioning job
     # uses): vars ALIYUN_ECS_REGION_ID, ALIYUN_ECS_VSWITCH_ID,
-    # ALIYUN_ECS_SECURITY_GROUP_ID, ALIYUN_ECS_BASE_IMAGE_ID (Ubuntu 24.04
-    # public image id in the region; specific to this rebuild), optionally
-    # ALIYUN_ECS_RESOURCE_GROUP_ID; secrets ALICLOUD_ECS_ACCESS_KEY_ID,
-    # ALICLOUD_ECS_ACCESS_KEY_SECRET, GH_PERSONAL_ACCESS_TOKEN (repo push +
-    # actions-variable write).
+    # ALIYUN_ECS_SECURITY_GROUP_ID, optionally ALIYUN_ECS_RESOURCE_GROUP_ID
+    # and ALIYUN_ECS_BASE_IMAGE_ID (deterministic base-image pin; otherwise
+    # the rebuild auto-resolves the latest public Ubuntu 24.04 image).
+    # Secrets: ALICLOUD_ECS_ACCESS_KEY_ID, ALICLOUD_ECS_ACCESS_KEY_SECRET,
+    # GH_PERSONAL_ACCESS_TOKEN (repo push + actions-variable write).
     name: Rebuild query-regression runner image
     needs: [changes]
     if: ${{ github.repository == 'GreptimeTeam/greptimedb' && ((github.event_name == 'push' && needs.changes.outputs.query-regression-runner == 'true') || inputs.release_query_regression_runner_image) }}