diff --git a/cmd/okra/create_or_update_cell.go b/cmd/okra/create_or_update_cell.go
new file mode 100644
index 0000000..699013d
--- /dev/null
+++ b/cmd/okra/create_or_update_cell.go
@@ -0,0 +1,145 @@
+package okra
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+	"time"
+
+	rolloutsv1alpha1 "github.com/mumoshu/okra/api/rollouts/v1alpha1"
+	okrav1alpha1 "github.com/mumoshu/okra/api/v1alpha1"
+	"github.com/mumoshu/okra/pkg/cell"
+	"github.com/spf13/cobra"
+	"github.com/spf13/pflag"
+	"k8s.io/apimachinery/pkg/util/intstr"
+)
+
+func createOrUpdateCellCommand() *cobra.Command {
+	var input func() *cell.ApplyInput
+	cmd := &cobra.Command{
+		Use: "create-or-update-cell",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			err := cell.CreateOrUpdate(*input())
+			return err
+		},
+	}
+	input = initApplyCellFlags(cmd.Flags(), &cell.ApplyInput{})
+	return cmd
+}
+
+func initApplyCellFlags(flag *pflag.FlagSet, c *cell.ApplyInput) func() *cell.ApplyInput {
+	var (
+		replicas            int
+		listenerARN         string
+		targetGroupSelector okrav1alpha1.TargetGroupSelector
+		canarySteps         []string
+		matchLabels         []string
+	)
+
+	flag.StringVar(&c.Cell.Namespace, "namespace", "", "Namespace of the target cell")
+	flag.StringVar(&c.Cell.Name, "name", "", "Name of the target cell")
+	flag.StringVar(&listenerARN, "listener-arn", "", "ARN of the target AWS Application Load Balancer Listener that is used to receive all the traffic across cluster versions")
+	flag.StringSliceVar(&matchLabels, "match-label", []string{}, "KVs of labels that is used as target group selector")
+	flag.StringSliceVar(&targetGroupSelector.VersionLabels, "version-label", []string{okrav1alpha1.DefaultVersionLabelKey}, "Key of the label that is used to indicate the version number of the target group")
+	flag.IntVar(&replicas, "", 0, "")
+	flag.StringSliceVar(&canarySteps, "canary-steps", []string{}, "List of canary step definitions. Each step is delimited by a comma(,) and can be one of \"weight=INT\", \"pause=DURATION\", and \"analysis=TEMPLATE:arg1=val1:arg2=val2\"")
+
+	return func() *cell.ApplyInput {
+		spec := c.Cell.Spec.DeepCopy()
+
+		if replicas != 0 {
+			r32 := int32(replicas)
+			spec.Replicas = &r32
+		}
+
+		targetGroupSelector.MatchLabels = make(map[string]string)
+		for _, l := range matchLabels {
+			kv := strings.Split(l, "=")
+			targetGroupSelector.MatchLabels[kv[0]] = kv[1]
+		}
+
+		var cs []rolloutsv1alpha1.CanaryStep
+		for _, s := range canarySteps {
+			var kind, arg string
+
+			{
+				splits := strings.SplitN(s, "=", 2)
+
+				if len(splits) != 2 {
+					panic(fmt.Errorf("pause: unexpected number of args. got %V, wanted only one arg", splits[1:]))
+				}
+
+				kind = splits[0]
+				arg = splits[1]
+			}
+
+			var step rolloutsv1alpha1.CanaryStep
+
+			switch kind {
+			case "weight":
+				w, err := strconv.Atoi(arg)
+				if err != nil {
+					panic(fmt.Errorf("parsing weight from %s: %w", arg, err))
+				}
+
+				w32 := int32(w)
+				step.SetWeight = &w32
+			case "pause":
+				d, err := time.ParseDuration(arg)
+				if err != nil {
+					panic(fmt.Errorf("parsing duration from %s: %w", arg, err))
+				}
+
+				step.Pause = &rolloutsv1alpha1.RolloutPause{
+					Duration: &intstr.IntOrString{
+						Type:   intstr.String,
+						StrVal: d.String(),
+					},
+				}
+			case "analysis":
+				tplAndArgs := strings.Split(arg, ":")
+				tpl := tplAndArgs[0]
+
+				var args []rolloutsv1alpha1.AnalysisRunArgument
+				for _, a := range tplAndArgs[1:] {
+					kv := strings.Split(a, "=")
+
+					args = append(args, rolloutsv1alpha1.AnalysisRunArgument{
+						Name:  kv[0],
+						Value: kv[1],
+					})
+				}
+
+				step.Analysis = &rolloutsv1alpha1.RolloutAnalysis{
+					Templates: []rolloutsv1alpha1.RolloutAnalysisTemplate{
+						{
+							TemplateName: tpl,
+						},
+					},
+					Args: args,
+				}
+			default:
+				panic(fmt.Errorf("unsupported canary step kind: %s", kind))
+			}
+
+			cs = append(cs, step)
+		}
+
+		spec.UpdateStrategy = okrav1alpha1.CellUpdateStrategy{
+			Type: okrav1alpha1.CellUpdateStrategyTypeCanary,
+			Canary: &okrav1alpha1.CellUpdateStrategyCanary{
+				Steps: cs,
+			},
+		}
+
+		spec.Ingress.AWSApplicationLoadBalancer = &okrav1alpha1.CellIngressAWSApplicationLoadBalancer{
+			ListenerARN:         listenerARN,
+			TargetGroupSelector: targetGroupSelector,
+		}
+
+		input := c
+		input.Cell.Spec = *spec
+
+		return input
+	}
+}
diff --git a/pkg/cell/create.go b/pkg/cell/create.go
new file mode 100644
index 0000000..22168c0
--- /dev/null
+++ b/pkg/cell/create.go
@@ -0,0 +1,68 @@
+package cell
+
+import (
+	"context"
+
+	okrav1alpha1 "github.com/mumoshu/okra/api/v1alpha1"
+	"github.com/mumoshu/okra/pkg/clclient"
+	"k8s.io/apimachinery/pkg/runtime"
+	ctrl "sigs.k8s.io/controller-runtime"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
+)
+
+type ApplyInput struct {
+	Cell okrav1alpha1.Cell
+
+	Client  client.Client
+	Scheme  *runtime.Scheme
+	Context context.Context
+	Log     interface {
+		Info(msg string, keysAndValues ...interface{})
+	}
+}
+
+var noopLogger logger
+
+type logger struct {
+}
+
+func (_ logger) Info(msg string, keysAndValues ...interface{}) {
+
+}
+
+func CreateOrUpdate(input ApplyInput) error {
+	ctx := input.Context
+	if ctx == nil {
+		ctx = context.TODO()
+	}
+
+	logger := input.Log
+	if logger == nil {
+		logger = noopLogger
+	}
+
+	client, _, err := clclient.Init(input.Client, input.Scheme)
+	if err != nil {
+		return err
+	}
+
+	cell := okrav1alpha1.Cell{}
+	cell.SetNamespace(input.Cell.Namespace)
+	cell.SetName(input.Cell.Name)
+
+	op, err := ctrl.CreateOrUpdate(ctx, client, &cell, func() error {
+		cell.Spec = input.Cell.Spec
+
+		return nil
+	})
+	if err != nil {
+		return err
+	}
+
+	if op != controllerutil.OperationResultNone {
+		logger.Info("Reconciled Cell", "op", op)
+	}
+
+	return nil
+}