10 of Cups: Partition
The 10th card of a suit is the principle of that suit exhausted, divorced from its purpose and foundations. In Computing, the suit of cups represents the network - the things that surround your program, that drive and depend on it. The 10th card in the suit of networking is partition - when connected machines cannot reach one another, when a single network is fragmented by a failure. A cable is cut, and one network is now two networks.
Partitions may not be permanent, and may not be obvious. A common side effect of partitions is a split brain, where both parts of the network believe they are the whole. When the partition is repaired, which side of the repair represents the “real” history of the network? How can we reconcile the two experiences?
Where is the heart of your system? If your system is well designed, that heart may be in many places, or everywhere. If that is the case, what happens when those hearts differ?