root.component.html

<table mat-table [dataSource]="[{ id: 0 }]">
  <ng-container matColumnDef="actions">
    <th mat-header-cell *matHeaderCellDef></th>
    <td mat-cell *matCellDef="let cluster">
      <button mat-fab [matMenuTriggerFor]="rowPopupMenu" [matMenuTriggerData]="{ items: rowPopupMenuItems() }">...</button>
    </td>
  </ng-container>

  <tr mat-header-row *matHeaderRowDef="['actions']"></tr>
  <tr mat-row *matRowDef="let cluster; columns: ['actions']"></tr>
</table>

<mat-menu #rowPopupMenu="matMenu"></mat-menu>

<button>Hello World</button>