vitessio/vitess · error

Error setting tablet to read-only: %w

Error message

Error setting tablet to read-only: %w

What it means

SetReadOnly calls vtctld SetWritable(writable=false) on the tablet; if that RPC fails, VTAdmin wraps the error with this message. The tablet remains in its prior writability state and the caller receives the wrapped underlying error.

Source

Thrown at go/vt/vtadmin/api.go:2375

	}, nil
}

// SetReadOnly is part of the vtadminpb.VTAdminServer interface.
func (api *API) SetReadOnly(ctx context.Context, req *vtadminpb.SetReadOnlyRequest) (*vtadminpb.SetReadOnlyResponse, error) {
	span, ctx := trace.NewSpan(ctx, "API.SetReadOnly")
	defer span.Finish()

	tablet, c, err := api.getTabletForAction(ctx, span, rbac.ManageTabletWritabilityAction, req.Alias, req.ClusterIds)
	if err != nil {
		return nil, err
	}

	err = c.SetWritable(ctx, &vtctldatapb.SetWritableRequest{
		TabletAlias: tablet.Tablet.Alias,
		Writable:    false,
	})
	if err != nil {
		return nil, fmt.Errorf("Error setting tablet to read-only: %w", err)
	}

	return &vtadminpb.SetReadOnlyResponse{}, nil
}

// SetReadWrite is part of the vtadminpb.VTAdminServer interface.
func (api *API) SetReadWrite(ctx context.Context, req *vtadminpb.SetReadWriteRequest) (*vtadminpb.SetReadWriteResponse, error) {
	span, ctx := trace.NewSpan(ctx, "API.SetReadWrite")
	defer span.Finish()

	tablet, c, err := api.getTabletForAction(ctx, span, rbac.ManageTabletWritabilityAction, req.Alias, req.ClusterIds)
	if err != nil {
		return nil, err
	}

	err = c.SetWritable(ctx, &vtctldatapb.SetWritableRequest{
		TabletAlias: tablet.Tablet.Alias,
		Writable:    true,

View on GitHub (pinned to 01a25a7d17)

Solutions

1. Check the wrapped error for the failing tablet and verify the tablet is up (vtctld GetTablet / tablet status page)
2. Verify vtadmin can reach the cluster's vtctld and retry SetReadOnly
3. If the tablet is gone, correct the alias or remove it from use

// confirm the tablet is reachable via topo before calling
// e.g. tablet, err := client.GetTablet(ctx, alias); require tablet != nil and state healthy

resp, err := client.SetReadOnly(ctx, req)
if err != nil {
    if strings.Contains(err.Error(), "Error setting tablet to read-only") {
        return fmt.Errorf("tablet %s not set read-only: %w — check vtctld/tablet health", alias, err)
    }
    return err
}

When it happens

Trigger: Calling API.SetReadOnly when the cluster's SetWritable RPC to vtctld fails — vtctld unreachable, tablet down, or the tablet rejects the command.

Common situations: Tablet already drained/in a transitional state; vtctld service down; network timeout between vtadmin and vtctld; tablet alias belongs to a retired tablet.

Related errors

• Error setting tablet to read-write: %w
• invalid key:value pair
• failed to delete tablet: %w
• ReloadSchemas(cluster = %s) failed: %w
• GetKeyspaces(cluster = %s) failed: %w

AI-assisted analysis of vitessio/vitess@01a25a7d17 (2026-09-01). Data as JSON: /api/errors/15bd56acc1d5018e. Report an issue: GitHub.