CRI: Stable sort for RuntimeHandlers

EricMountain · k8s-infra-cherrypick-robot · commit d822c90480c0 · 2025-07-02T00:52:55.000Z
The runtimeHandlers list in the response to `crictl info` has unstable ordering since commit 97eb1cd (underlying switch from list to map) that was shipped in v2.1.0. On Kubernetes nodes this causes the kubelet to update node status subresources every time the order of runtime handlers changes in the status response from containerd. The lieklihood increases with the number of runtime handlers present on nodes. In some clusters this leads to every single node sending a status update every few seconds leading to excessive Kube API server load. This change enforces stable ordering on runtime handler names. Signed-off-by: Eric Mountain <eric.mountain@datadoghq.com>
diff --git a/internal/cri/server/status.go b/internal/cri/server/status.go
@@ -23,6 +23,7 @@ import (
 	"maps"
 	goruntime "runtime"
 	"slices"
+	"sort"
 
 	"github.com/containerd/containerd/api/services/introspection/v1"
 	"github.com/containerd/log"
@@ -59,9 +60,15 @@ func (c *criService) Status(ctx context.Context, r *runtime.StatusRequest) (*run
 			runtimeCondition,
 			networkCondition,
 		}},
-		RuntimeHandlers: slices.Collect(maps.Values(c.runtimeHandlers)),
-		Features:        c.runtimeFeatures,
+		Features: c.runtimeFeatures,
 	}
+
+	// Ensure stable ordering of runtime handlers in response
+	resp.RuntimeHandlers = slices.Collect(maps.Values(c.runtimeHandlers))
+	sort.SliceStable(resp.RuntimeHandlers, func(i, j int) bool {
+		return resp.RuntimeHandlers[i].Name < resp.RuntimeHandlers[j].Name
+	})
+
 	if r.Verbose {
 		configByt, err := json.Marshal(c.config)
 		if err != nil {
