Add tag-based image resolution to the controller (milestone 5a)

api/v1alpha1/bootcnodepool_types.go

@@ -45,6 +45,10 @@ const (
 	// digest ref, or a malformed nodeSelector).
 	PoolInvalidSpec string = "InvalidSpec"
 
+	// PoolRegistryError means the controller failed to contact the
+	// container registry to resolve a tag to a digest.
+	PoolRegistryError string = "RegistryError"
+
 	// PoolHealthy means no issues.
 	PoolHealthy string = "Healthy"
 )
@@ -159,6 +163,11 @@ type BootcNodePoolStatus struct {
 	// +optional
 	TargetDigest string `json:"targetDigest,omitempty"`
 
+	// nextTagResolutionTime is when the controller will next resolve a
+	// tag ref to a digest. Only set for tag-based image refs.
+	// +optional
+	NextTagResolutionTime *metav1.Time `json:"nextTagResolutionTime,omitempty"`
+
 	// deployedDigest is the last digest fully rolled out to all nodes in
 	// the pool.
 	// +optional

cmd/controller/main.go

@@ -5,6 +5,7 @@ package main
 import (
 	"flag"
 	"os"
+	"time"
 
 	"k8s.io/apimachinery/pkg/runtime"
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
@@ -16,6 +17,7 @@ import (
 
 	bootcv1alpha1 "github.com/jlebon/bootc-operator/api/v1alpha1"
 	"github.com/jlebon/bootc-operator/internal/controller"
+	"github.com/jlebon/bootc-operator/internal/registry"
 )
 
 var (
@@ -31,7 +33,12 @@ func init() {
 func main() {
 	var enableLeaderElection bool
 	var probeAddr string
+	var tagResolutionInterval time.Duration
+	var allowInsecureRegistry bool
 	flag.StringVar(&probeAddr, "health-probe-bind-address", ":8081", "The address the probe endpoint binds to.")
+	flag.DurationVar(&tagResolutionInterval, "tag-resolution-interval", 5*time.Minute, "How often to re-resolve tag-based image refs.")
+	flag.BoolVar(&allowInsecureRegistry, "allow-insecure-registry", false,
+		"Allow falling back to HTTP when resolving tag-based image refs against registries that do not serve TLS.")
 	flag.BoolVar(&enableLeaderElection, "leader-elect", false,
 		"Enable leader election for controller manager. "+
 			"Enabling this will ensure there is only one active controller manager.")
@@ -61,9 +68,11 @@ func main() {
 	}
 
 	if err := (&controller.BootcNodePoolReconciler{
-		Client:     mgr.GetClient(),
-		Scheme:     mgr.GetScheme(),
-		KubeClient: kubeClient,
+		Client:                mgr.GetClient(),
+		Scheme:                mgr.GetScheme(),
+		KubeClient:            kubeClient,
+		TagResolver:           &registry.GGCRResolver{AllowInsecure: allowInsecureRegistry},
+		TagResolutionInterval: tagResolutionInterval,
 	}).SetupWithManager(mgr); err != nil {
 		setupLog.Error(err, "Failed to create controller", "controller", "bootcnodepool")
 		os.Exit(1)

config/crd/bases/node.bootc.dev_bootcnodepools.yaml

@@ -243,6 +243,12 @@ spec:
                   deployedDigest is the last digest fully rolled out to all nodes in
                   the pool.
                 type: string
+              nextTagResolutionTime:
+                description: |-
+                  nextTagResolutionTime is when the controller will next resolve a
+                  tag ref to a digest. Only set for tag-based image refs.
+                format: date-time
+                type: string
               nodeCount:
                 description: nodeCount is the total number of nodes in this pool.
                 format: int32

go.mod

@@ -5,6 +5,7 @@ go 1.26.0
 require (
 	github.com/distribution/reference v0.6.0
 	github.com/go-logr/logr v1.4.3
+	github.com/google/go-containerregistry v0.21.7
 	github.com/onsi/gomega v1.42.0
 	k8s.io/api v0.36.2
 	k8s.io/apimachinery v0.36.2
@@ -21,6 +22,8 @@ require (
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
 	github.com/chai2010/gettext-go v1.0.2 // indirect
 	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
+	github.com/docker/cli v29.5.3+incompatible // indirect
+	github.com/docker/docker-credential-helpers v0.9.3 // indirect
 	github.com/emicklei/go-restful/v3 v3.13.0 // indirect
 	github.com/evanphx/json-patch/v5 v5.9.11 // indirect
 	github.com/exponent-io/jsonpath v0.0.0-20210407135951-1de76d718b3f // indirect
@@ -38,6 +41,7 @@ require (
 	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 v1.18.6 // indirect
 	github.com/liggitt/tabwriter v0.0.0-20181228230101-89fcab3d43de // indirect
 	github.com/mailru/easyjson v0.7.7 // indirect
 	github.com/mitchellh/go-wordwrap v1.0.1 // indirect
@@ -47,25 +51,27 @@ require (
 	github.com/monochromegane/go-gitignore v0.0.0-20200626010858-205db1a8cc00 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
 	github.com/opencontainers/go-digest v1.0.0 // indirect
+	github.com/opencontainers/image-spec v1.1.1 // indirect
 	github.com/peterbourgon/diskv v2.0.1+incompatible // indirect
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
 	github.com/prometheus/client_golang v1.23.2 // indirect
 	github.com/prometheus/client_model v0.6.2 // indirect
 	github.com/prometheus/common v0.67.5 // indirect
 	github.com/prometheus/procfs v0.19.2 // indirect
 	github.com/russross/blackfriday/v2 v2.1.0 // indirect
+	github.com/sirupsen/logrus v1.9.4 // indirect
 	github.com/spf13/cobra v1.10.2 // indirect
-	github.com/spf13/pflag v1.0.9 // indirect
+	github.com/spf13/pflag v1.0.10 // indirect
 	github.com/x448/float16 v0.8.4 // indirect
 	github.com/xlab/treeprint v1.2.0 // indirect
 	go.uber.org/multierr v1.11.0 // indirect
 	go.uber.org/zap v1.27.1 // indirect
 	go.yaml.in/yaml/v2 v2.4.3 // indirect
 	go.yaml.in/yaml/v3 v3.0.4 // indirect
 	golang.org/x/net v0.49.0 // indirect
-	golang.org/x/oauth2 v0.34.0 // indirect
-	golang.org/x/sync v0.19.0 // indirect
-	golang.org/x/sys v0.40.0 // indirect
+	golang.org/x/oauth2 v0.36.0 // indirect
+	golang.org/x/sync v0.21.0 // indirect
+	golang.org/x/sys v0.46.0 // indirect
 	golang.org/x/term v0.39.0 // indirect
 	golang.org/x/text v0.33.0 // indirect
 	golang.org/x/time v0.14.0 // indirect
@@ -74,6 +80,7 @@ require (
 	gopkg.in/evanphx/json-patch.v4 v4.13.0 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
+	gotest.tools/v3 v3.5.2 // indirect
 	k8s.io/apiextensions-apiserver v0.36.0 // indirect
 	k8s.io/cli-runtime v0.36.2 // indirect
 	k8s.io/component-base v0.36.2 // indirect

go.sum

@@ -22,6 +22,10 @@ github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1
 github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/distribution/reference v0.6.0 h1:0IXCQ5g4/QMHHkarYzh5l+u8T3t73zM5QvfrDyIgxBk=
 github.com/distribution/reference v0.6.0/go.mod h1:BbU0aIcezP1/5jX/8MP0YiH4SdvB5Y4f/wlDRiLyi3E=
+github.com/docker/cli v29.5.3+incompatible h1:nbEFfz774vBwQ5KRYv7c/AghjReqnGISvrRhzjV0evs=
+github.com/docker/cli v29.5.3+incompatible/go.mod h1:JLrzqnKDaYBop7H2jaqPtU4hHvMKP+vjCwu2uszcLI8=
+github.com/docker/docker-credential-helpers v0.9.3 h1:gAm/VtF9wgqJMoxzT3Gj5p4AqIjCBS4wrsOh9yRqcz8=
+github.com/docker/docker-credential-helpers v0.9.3/go.mod h1:x+4Gbw9aGmChi3qTLZj8Dfn0TD20M/fuWy0E5+WDeCo=
 github.com/emicklei/go-restful/v3 v3.13.0 h1:C4Bl2xDndpU6nJ4bc1jXd+uTmYPVUwkD6bFY/oTyCes=
 github.com/emicklei/go-restful/v3 v3.13.0/go.mod h1:6n3XBCmQQb25CM2LCACGz8ukIrRry+4bhvbpWn3mrbc=
 github.com/evanphx/json-patch v0.5.2 h1:xVCHIVMUu1wtM/VkR9jVZ45N3FhZfYMMYGorLCR8P3k=
@@ -56,6 +60,8 @@ github.com/google/gnostic-models v0.7.0 h1:qwTtogB15McXDaNqTZdzPJRHvaVJlAl+HVQnL
 github.com/google/gnostic-models v0.7.0/go.mod h1:whL5G0m6dmc5cPxKc5bdKdEN3UjI7OUGxBlw57miDrQ=
 github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
 github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
+github.com/google/go-containerregistry v0.21.7 h1:/vPFuVXDjtFREsVArW+0h1CIl5urnOhzei4X2DMW9IU=
+github.com/google/go-containerregistry v0.21.7/go.mod h1:kjSbt7/zMsKLWfnHrIvKvhXHUw91jbe9DNjPPJ32gXE=
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/google/gofuzz v1.2.0 h1:xRy4A+RhZaiKjJ1bPfwQ8sedCA+YS2YcCHW6ec7JMi0=
 github.com/google/gofuzz v1.2.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
@@ -69,8 +75,8 @@ github.com/josharian/intern v1.0.0 h1:vlS4z54oSdjm0bgjRigI+G1HpF+tI+9rE5LLzOg8Hm
 github.com/josharian/intern v1.0.0/go.mod h1:5DoeVV0s6jJacbCEi61lwdGj/aVlrQvzHFFd8Hwg//Y=
 github.com/json-iterator/go v1.1.12 h1:PV8peI4a0ysnczrg+LtxykD8LfKY9ML6u2jnxaEnrnM=
 github.com/json-iterator/go v1.1.12/go.mod h1:e30LSqwooZae/UwlEbR2852Gd8hjQvJoHmT4TnhNGBo=
-github.com/klauspost/compress v1.18.0 h1:c/Cqfb0r+Yi+JtIEq73FWXVkRonBlf0CRNYc8Zttxdo=
-github.com/klauspost/compress v1.18.0/go.mod h1:2Pp+KzxcywXVXMr50+X0Q/Lsb43OQHYWRCY2AiWywWQ=
+github.com/klauspost/compress v1.18.6 h1:2jupLlAwFm95+YDR+NwD2MEfFO9d4z4Prjl1XXDjuao=
+github.com/klauspost/compress v1.18.6/go.mod h1:cwPg85FWrGar70rWktvGQj8/hthj3wpl0PGDogxkrSQ=
 github.com/kr/pretty v0.2.1/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI=
 github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
 github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
@@ -104,6 +110,8 @@ github.com/onsi/gomega v1.42.0 h1:CJby8u36xb7v34W78F8WKvqTQP7PCMIPB78IVDB73l4=
 github.com/onsi/gomega v1.42.0/go.mod h1:M/Uqpu/8qTjtzCLUA2zJHX9Iilrau25x1PdoSRbWh5A=
 github.com/opencontainers/go-digest v1.0.0 h1:apOUWs51W5PlhuyGyz9FCeeBIOUDA/6nW8Oi/yOhh5U=
 github.com/opencontainers/go-digest v1.0.0/go.mod h1:0JzlMkj0TRzQZfJkVvzbP0HBR3IKzErnv2BNG4W4MAM=
+github.com/opencontainers/image-spec v1.1.1 h1:y0fUlFfIZhPF1W537XOLg0/fcx6zcHCJwooC2xJA040=
+github.com/opencontainers/image-spec v1.1.1/go.mod h1:qpqAh3Dmcf36wStyyWU+kCeDgrGnAve2nCC8+7h8Q0M=
 github.com/peterbourgon/diskv v2.0.1+incompatible h1:UBdAOUP5p4RWqPBg048CAvpKN+vxiaj6gdUUzhl4XmI=
 github.com/peterbourgon/diskv v2.0.1+incompatible/go.mod h1:uqqh8zWWbv1HBMNONnaR/tNboyR3/BZd58JJSHlUSCU=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
@@ -125,10 +133,13 @@ github.com/russross/blackfriday/v2 v2.1.0 h1:JIOH55/0cWyOuilr9/qlrm0BSXldqnqwMsf
 github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
 github.com/sergi/go-diff v1.4.0 h1:n/SP9D5ad1fORl+llWyN+D6qoUETXNZARKjyY2/KVCw=
 github.com/sergi/go-diff v1.4.0/go.mod h1:A0bzQcvG0E7Rwjx0REVgAGH58e96+X0MeOfepqsbeW4=
+github.com/sirupsen/logrus v1.9.4 h1:TsZE7l11zFCLZnZ+teH4Umoq5BhEIfIzfRDZ1Uzql2w=
+github.com/sirupsen/logrus v1.9.4/go.mod h1:ftWc9WdOfJ0a92nsE2jF5u5ZwH8Bv2zdeOC42RjbV2g=
 github.com/spf13/cobra v1.10.2 h1:DMTTonx5m65Ic0GOoRY2c16WCbHxOOw6xxezuLaBpcU=
 github.com/spf13/cobra v1.10.2/go.mod h1:7C1pvHqHw5A4vrJfjNwvOdzYu0Gml16OCs2GRiTUUS4=
-github.com/spf13/pflag v1.0.9 h1:9exaQaMOCwffKiiiYk6/BndUBv+iRViNW+4lEMi0PvY=
 github.com/spf13/pflag v1.0.9/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
+github.com/spf13/pflag v1.0.10 h1:4EBh2KAYBwaONj6b2Ye1GiHfwjqyROoF4RwYO+vPwFk=
+github.com/spf13/pflag v1.0.10/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
 github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
@@ -156,25 +167,25 @@ go.yaml.in/yaml/v2 v2.4.3 h1:6gvOSjQoTB3vt1l+CU+tSyi/HOjfOjRLJ4YwYZGwRO0=
 go.yaml.in/yaml/v2 v2.4.3/go.mod h1:zSxWcmIDjOzPXpjlTTbAsKokqkDNAVtZO0WOMiT90s8=
 go.yaml.in/yaml/v3 v3.0.4 h1:tfq32ie2Jv2UxXFdLJdh3jXuOzWiL1fo0bu/FbuKpbc=
 go.yaml.in/yaml/v3 v3.0.4/go.mod h1:DhzuOOF2ATzADvBadXxruRBLzYTpT36CKvDb3+aBEFg=
-golang.org/x/mod v0.32.0 h1:9F4d3PHLljb6x//jOyokMv3eX+YDeepZSEo3mFJy93c=
-golang.org/x/mod v0.32.0/go.mod h1:SgipZ/3h2Ci89DlEtEXWUk/HteuRin+HHhN+WbNhguU=
+golang.org/x/mod v0.37.0 h1:vF1DjpVEshcIqoEaauuHebaLk1O1forxjxBaVn884JQ=
+golang.org/x/mod v0.37.0/go.mod h1:m8S8VeM9r4dzDwjrKO0a1sZP3YjeMamRRlD+fmR2Q/0=
 golang.org/x/net v0.49.0 h1:eeHFmOGUTtaaPSGNmjBKpbng9MulQsJURQUAfUwY++o=
 golang.org/x/net v0.49.0/go.mod h1:/ysNB2EvaqvesRkuLAyjI1ycPZlQHM3q01F02UY/MV8=
-golang.org/x/oauth2 v0.34.0 h1:hqK/t4AKgbqWkdkcAeI8XLmbK+4m4G5YeQRrmiotGlw=
-golang.org/x/oauth2 v0.34.0/go.mod h1:lzm5WQJQwKZ3nwavOZ3IS5Aulzxi68dUSgRHujetwEA=
-golang.org/x/sync v0.19.0 h1:vV+1eWNmZ5geRlYjzm2adRgW2/mcpevXNg50YZtPCE4=
-golang.org/x/sync v0.19.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
+golang.org/x/oauth2 v0.36.0 h1:peZ/1z27fi9hUOFCAZaHyrpWG5lwe0RJEEEeH0ThlIs=
+golang.org/x/oauth2 v0.36.0/go.mod h1:YDBUJMTkDnJS+A4BP4eZBjCqtokkg1hODuPjwiGPO7Q=
+golang.org/x/sync v0.21.0 h1:HLII4xRRTtCRkxYp4HNFF0Js/Og6q2i++KXbg0gHCwM=
+golang.org/x/sync v0.21.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
 golang.org/x/sys v0.0.0-20210616094352-59db8d763f22/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.40.0 h1:DBZZqJ2Rkml6QMQsZywtnjnnGvHza6BTfYFWY9kjEWQ=
-golang.org/x/sys v0.40.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
+golang.org/x/sys v0.46.0 h1:noSf2Fq6F8DBgS+LysIkx7rIExoNHJsxOAtPp4rthXw=
+golang.org/x/sys v0.46.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
 golang.org/x/term v0.39.0 h1:RclSuaJf32jOqZz74CkPA9qFuVTX7vhLlpfj/IGWlqY=
 golang.org/x/term v0.39.0/go.mod h1:yxzUCTP/U+FzoxfdKmLaA0RV1WgE0VY7hXBwKtY/4ww=
 golang.org/x/text v0.33.0 h1:B3njUFyqtHDUI5jMn1YIr5B0IE2U0qck04r6d4KPAxE=
 golang.org/x/text v0.33.0/go.mod h1:LuMebE6+rBincTi9+xWTY8TztLzKHc/9C1uBCG27+q8=
 golang.org/x/time v0.14.0 h1:MRx4UaLrDotUKUdCIqzPC48t1Y9hANFKIRpNx+Te8PI=
 golang.org/x/time v0.14.0/go.mod h1:eL/Oa2bBBK0TkX57Fyni+NgnyQQN4LitPmob2Hjnqw4=
-golang.org/x/tools v0.41.0 h1:a9b8iMweWG+S0OBnlU36rzLp20z1Rp10w+IY2czHTQc=
-golang.org/x/tools v0.41.0/go.mod h1:XSY6eDqxVNiYgezAVqqCeihT4j1U2CCsqvH3WhQpnlg=
+golang.org/x/tools v0.46.0 h1:7jTurBkPZu4moS/Uy4OQT1M+QBlsj3wejyZwsT8Z7rk=
+golang.org/x/tools v0.46.0/go.mod h1:FrD85F8l+NWL+9XWBSyVSHO6Ne4jutsfIFba7AWQ5Ys=
 gomodules.xyz/jsonpatch/v2 v2.4.0 h1:Ci3iUJyx9UeRx7CeFN8ARgGbkESwJK+KB9lLcWxY/Zw=
 gomodules.xyz/jsonpatch/v2 v2.4.0/go.mod h1:AH3dM2RI6uoBZxn3LVrfvJ3E0/9dG4cSrbuBJT4moAY=
 google.golang.org/protobuf v1.36.12-0.20260120151049-f2248ac996af h1:+5/Sw3GsDNlEmu7TfklWKPdQ0Ykja5VEmq2i817+jbI=
@@ -189,6 +200,8 @@ gopkg.in/inf.v0 v0.9.1/go.mod h1:cWUDdTG/fYaXco+Dcufb5Vnc6Gp2YChqWtbxRZE0mXw=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gotest.tools/v3 v3.5.2 h1:7koQfIKdy+I8UTetycgUqXWSDwpgv193Ka+qRsmBY8Q=
+gotest.tools/v3 v3.5.2/go.mod h1:LtdLGcnqToBH83WByAAi/wiwSFCArdFIUV/xxN4pcjA=
 k8s.io/api v0.36.2 h1:TF6YDLIzKfccK7cq9YpTcGX8TJmEkHVRv78DM51fRYY=
 k8s.io/api v0.36.2/go.mod h1:F4LbMO4brjZYh7yFkXWhynSvtB7YauxV4c+HHkNRGNg=
 k8s.io/apiextensions-apiserver v0.36.0 h1:Wt7E8J+VBCbj4FjiBfDTK/neXDDjyJVJc7xfuOHImZ0=

internal/controller/bootcnodepool_controller.go

@@ -35,6 +35,7 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/source"
 
 	bootcv1alpha1 "github.com/jlebon/bootc-operator/api/v1alpha1"
+	"github.com/jlebon/bootc-operator/internal/registry"
 )
 
 // drainStatus tracks an in-progress drain goroutine for a single node.
@@ -52,6 +53,9 @@ type BootcNodePoolReconciler struct {
 	KubeClient kubernetes.Interface
 	Recorder   events.EventRecorder
 
+	TagResolver           registry.TagResolver
+	TagResolutionInterval time.Duration
+
 	// drainCh receives events from drain goroutines to re-enqueue the
 	// owning pool after a drain completes.
 	drainCh chan event.GenericEvent
@@ -239,12 +243,22 @@ func (r *BootcNodePoolReconciler) Reconcile(ctx context.Context, req ctrl.Reques
 	// the end.
 
 	// Resolve the target digest from the image ref.
-	if err := r.resolveTargetDigest(&pool); err != nil {
+	resolveResult, err := r.resolveTargetDigest(ctx, &pool)
+	if err != nil {
 		if isInvalidSpecError(err) {
 			return r.setInvalidSpecCondition(ctx, &pool, err)
 		}
 		return ctrl.Result{}, fmt.Errorf("resolving target digest: %w", err)
 	}
+	if pool.Status.TargetDigest == "" {
+		// First tag resolution failed — nothing to roll out yet.
+		if !reflect.DeepEqual(pool.Status, *statusOrig) {
+			if err := r.Status().Update(ctx, &pool); err != nil {
+				return ctrl.Result{}, fmt.Errorf("updating pool status: %w", err)
+			}
+		}
+		return resolveResult, nil
+	}
 
 	// Sync pool membership and retrieve BootcNodes we own.
 	ownedBootcNodes, err := r.syncMembership(ctx, &pool)
@@ -274,24 +288,56 @@ func (r *BootcNodePoolReconciler) Reconcile(ctx context.Context, req ctrl.Reques
 		}
 	}
 
-	return ctrl.Result{}, nil
+	return resolveResult, nil
 }
 
-// resolveTargetDigest parses the digest from the pool's image ref and
-// sets pool.Status.TargetDigest. For digest refs (the only kind
-// supported now), the digest is extracted directly. Tag resolution is
-// deferred to Milestone 5.
-func (r *BootcNodePoolReconciler) resolveTargetDigest(pool *bootcv1alpha1.BootcNodePool) error {
+// resolveTargetDigest resolves the target digest from the pool's image
+// ref. Digest refs are extracted directly. Tag refs are resolved via
+// the registry, respecting the re-resolution interval.
+func (r *BootcNodePoolReconciler) resolveTargetDigest(ctx context.Context, pool *bootcv1alpha1.BootcNodePool) (ctrl.Result, error) {
+	log := logf.FromContext(ctx)
+
 	ref, err := parseImageRef(pool.Spec.Image.Ref)
 	if err != nil {
-		return newInvalidSpecError(fmt.Sprintf("invalid image ref %q: %v", pool.Spec.Image.Ref, err))
+		return ctrl.Result{}, newInvalidSpecError(fmt.Sprintf("invalid image ref %q: %v", pool.Spec.Image.Ref, err))
 	}
+
 	digested, ok := ref.(reference.Digested)
-	if !ok {
-		return newInvalidSpecError(fmt.Sprintf("image ref %q has no digest (tag resolution not yet supported)", pool.Spec.Image.Ref))
+	if ok {
+		pool.Status.TargetDigest = digested.Digest().String()
+		return ctrl.Result{}, nil
 	}
-	pool.Status.TargetDigest = digested.Digest().String()
-	return nil
+
+	// Tag ref — check if resolution is due.
+	now := time.Now()
+	if pool.Status.NextTagResolutionTime != nil && now.Before(pool.Status.NextTagResolutionTime.Time) {
+		remaining := pool.Status.NextTagResolutionTime.Time.Sub(now)
+		log.V(1).Info("Tag resolution not yet due", "remaining", remaining)
+		return ctrl.Result{RequeueAfter: remaining}, nil
+	}
+
+	digest, err := r.TagResolver.Resolve(ctx, pool.Spec.Image.Ref)
+	if err != nil {
+		log.Error(err, "Failed to resolve tag", "ref", pool.Spec.Image.Ref)
+		apimeta.SetStatusCondition(&pool.Status.Conditions, metav1.Condition{
+			Type:    bootcv1alpha1.PoolDegraded,
+			Status:  metav1.ConditionTrue,
+			Reason:  bootcv1alpha1.PoolRegistryError,
+			Message: err.Error(),
+		})
+		next := metav1.NewTime(now.Add(r.TagResolutionInterval))
+		pool.Status.NextTagResolutionTime = &next
+		return ctrl.Result{RequeueAfter: r.TagResolutionInterval}, nil
+	}
+
+	if pool.Status.TargetDigest != digest {
+		log.Info("Resolved tag to new digest", "ref", pool.Spec.Image.Ref, "digest", digest)
+	}
+	pool.Status.TargetDigest = digest
+	next := metav1.NewTime(now.Add(r.TagResolutionInterval))
+	pool.Status.NextTagResolutionTime = &next
+	// Requeue the tag resolution for the next interval
+	return ctrl.Result{RequeueAfter: r.TagResolutionInterval}, nil
 }
 
 // parseImageRef parses an image reference string into a named