fix: pin images after CRI pull to prevent kubelet GC

After each successful CRI PullImage, use the containerd native client
API to set io.cri-containerd.pinned=pinned on the image. This tells
kubelet's image GC to skip the image.

The CRI API doesn't support setting image labels, so we connect to
containerd directly (same socket) using the containerd client library
in the k8s.io namespace. The pinning happens immediately after each
successful pull, before GC has a chance to evict the image.

This is a proof-of-concept to test if pinning at pull time (via the
containerd API) works better than post-hoc pinning via ctr CLI, which
has known bugs (containerd#9328, #10270).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: porridge

go.mod

@@ -4,6 +4,7 @@ go 1.25.0
 
 require (
 	github.com/cenkalti/backoff/v4 v4.3.0
+	github.com/containerd/containerd/v2 v2.2.1
 	github.com/google/uuid v1.6.0
 	github.com/neilotoole/slogt v1.1.0
 	github.com/spf13/cobra v1.10.2
@@ -19,31 +20,72 @@ require (
 )
 
 require (
-	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
-	github.com/emicklei/go-restful/v3 v3.12.2 // indirect
+	github.com/Microsoft/go-winio v0.6.2 // indirect
+	github.com/Microsoft/hcsshim v0.14.0-rc.1 // indirect
+	github.com/cespare/xxhash/v2 v2.3.0 // indirect
+	github.com/containerd/cgroups/v3 v3.1.2 // indirect
+	github.com/containerd/containerd/api v1.10.0 // indirect
+	github.com/containerd/continuity v0.4.5 // indirect
+	github.com/containerd/errdefs v1.0.0 // indirect
+	github.com/containerd/errdefs/pkg v0.3.0 // indirect
+	github.com/containerd/fifo v1.1.0 // indirect
+	github.com/containerd/log v0.1.0 // indirect
+	github.com/containerd/platforms v1.0.0-rc.2 // indirect
+	github.com/containerd/plugin v1.0.0 // indirect
+	github.com/containerd/ttrpc v1.2.7 // indirect
+	github.com/containerd/typeurl/v2 v2.2.3 // indirect
+	github.com/cyphar/filepath-securejoin v0.5.1 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/distribution/reference v0.6.0 // indirect
+	github.com/emicklei/go-restful/v3 v3.13.0 // indirect
+	github.com/felixge/httpsnoop v1.0.4 // indirect
 	github.com/fxamacker/cbor/v2 v2.9.0 // indirect
 	github.com/go-logr/logr v1.4.3 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/go-openapi/jsonpointer v0.21.0 // indirect
 	github.com/go-openapi/jsonreference v0.20.2 // indirect
 	github.com/go-openapi/swag v0.23.0 // indirect
+	github.com/gogo/protobuf v1.3.2 // indirect
+	github.com/golang/groupcache v0.0.0-20241129210726-2c02b8208cf8 // indirect
 	github.com/google/gnostic-models v0.7.0 // indirect
+	github.com/google/go-cmp v0.7.0 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/josharian/intern v1.0.0 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
+	github.com/klauspost/compress v1.18.1 // indirect
 	github.com/mailru/easyjson v0.7.7 // indirect
+	github.com/moby/locker v1.0.1 // indirect
+	github.com/moby/sys/mountinfo v0.7.2 // indirect
+	github.com/moby/sys/sequential v0.6.0 // indirect
+	github.com/moby/sys/signal v0.7.1 // indirect
+	github.com/moby/sys/user v0.4.0 // indirect
+	github.com/moby/sys/userns v0.1.0 // indirect
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.3-0.20250322232337-35a7c28c31ee // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
-	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
+	github.com/opencontainers/go-digest v1.0.0 // indirect
+	github.com/opencontainers/image-spec v1.1.1 // indirect
+	github.com/opencontainers/runtime-spec v1.3.0 // indirect
+	github.com/opencontainers/selinux v1.13.1 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/sirupsen/logrus v1.9.3 // indirect
 	github.com/x448/float16 v0.8.4 // indirect
+	go.opencensus.io v0.24.0 // indirect
+	go.opentelemetry.io/auto/sdk v1.2.1 // indirect
+	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.60.0 // indirect
+	go.opentelemetry.io/otel v1.39.0 // indirect
+	go.opentelemetry.io/otel/metric v1.39.0 // indirect
+	go.opentelemetry.io/otel/trace v1.39.0 // indirect
 	go.yaml.in/yaml/v2 v2.4.3 // indirect
 	go.yaml.in/yaml/v3 v3.0.4 // indirect
 	golang.org/x/net v0.48.0 // indirect
 	golang.org/x/oauth2 v0.34.0 // indirect
+	golang.org/x/sync v0.19.0 // indirect
 	golang.org/x/sys v0.39.0 // indirect
 	golang.org/x/term v0.38.0 // indirect
 	golang.org/x/text v0.32.0 // indirect
-	golang.org/x/time v0.9.0 // indirect
+	golang.org/x/time v0.14.0 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217 // indirect
 	gopkg.in/evanphx/json-patch.v4 v4.13.0 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect