ifenslave is no more needed when configuring bonding under Linux. There are situations when we could have no network link without bonding, because of specific switch configuration and we do not have ifenslave package installed. We can configure bonding manually via Sysfs.
Here are the steps to configure bond0 in adaptive load balancing with two network cards in slave mode:

modprobe bonding
echo balance-alb > /sys/class/net/bond0/bonding/mode
echo +eth0 > /sys/class/net/bond0/bonding/slaves
echo +eth1 > /sys/class/net/bond0/bonding/slaves
ifconfig bond0 192.168.1.1 netmask 255.255.255.0 up

The adaptive load balancing does not require any special network setup. On the contrary, the mode “802.3ad” could be used only if you enable bonding of the interfaces of your server to have a network link.

echo 802.3ad > /sys/class/net/bond0/bonding/mode

For more detailed explanation:

https://www.kernel.org/doc/Documentation/networking/bonding.txt

If the “/sys/class/net/bond0” is missing you should do:

echo +bond0 > /sys/class/net/bonding_masters