code: func (m *Mercury) AddContainer(ctx context.Context, container *types.Container) error {
  	return m.doOpsContainer(ctx, container, true)
  }
docs: // AddContainer add a container
  // mainly record its relationship on pod and node
  // actually if we already know its node, we will know its pod
  // but we still store it
  // storage path in etcd is `/container/:containerid`