What causes "can only delete one instance group at a time" in kubernetes/kops?

Delete groups one at a time: run the command once per instance group.

can only delete one instance group at a time

Error message

can only delete one instance group at a time

What it means

The Args validator accepts exactly one instance group per invocation. If more than one positional argument is passed, the command refuses with this error; each group must be deleted in a separate command run.

Source

Thrown at cmd/kops/delete_instancegroup.go:82

		Aliases: []string{"instancegroups", "ig"},
		Short:   deleteInstanceGroupShort,
		Long:    deleteInstanceGroupLong,
		Example: deleteInstanceGroupExample,
		Args: func(cmd *cobra.Command, args []string) error {
			options.ClusterName = rootCommand.ClusterName(true)

			if options.ClusterName == "" {
				return fmt.Errorf("--name is required")
			}

			if len(args) == 0 {
				return fmt.Errorf("must specify the name of the instance group to delete")
			}

			options.GroupName = args[0]

			if len(args) != 1 {
				return fmt.Errorf("can only delete one instance group at a time")
			}

			return nil
		},
		ValidArgsFunction: completeInstanceGroup(f, nil, &[]string{kops.InstanceGroupRoleControlPlane.ToLowerString()}),
		RunE: func(cmd *cobra.Command, args []string) error {
			ctx := cmd.Context()

			if !options.Yes {
				message := fmt.Sprintf("Do you really want to delete instance group %q? This action cannot be undone.", options.GroupName)

				c := &ui.ConfirmArgs{
					Out:     out,
					Message: message,
					Default: "no",
					Retries: 2,
				}

View on GitHub (pinned to 4c8573c808)

Solutions

Delete groups one at a time: run the command once per instance group.
Loop in shell: `for g in groupA groupB; do kops delete instancegroup --name "$CLUSTER" "$g"; done`.
Quote or disable globs so extra files aren't passed as arguments.

Example fix

// before
$ kops delete instancegroup --name prod.example.com workers spot-workers
error: can only delete one instance group at a time
// after
$ kops delete instancegroup --name prod.example.com workers
$ kops delete instancegroup --name prod.example.com spot-workers

Defensive patterns

Strategy: validation

Validate before calling

[ $# -eq 1 ] || { echo "pass exactly one instance group" >&2; exit 1; }

Prevention

Loop over groups instead of passing multiple arguments.
Quote globs ("$@", set -f) to avoid accidental extra positional args.
Read `kops delete instancegroup --help` to confirm single-argument arity.

When it happens

Trigger: Running `kops delete instancegroup --name <cluster> groupA groupB` or passing extra positional words (e.g. a stray filename from shell glob expansion).

Common situations: Assuming multi-arg support like `kubectl delete` resources; accidental glob expansion (*.yaml matching files); copy-pasting multiple group names from notes.

Related errors

AI-assisted analysis of kubernetes/kops@4c8573c808 (2026-09-05). Data as JSON: /api/errors/76f1f228c1024219. Report an issue: GitHub.