Using etcd for Distributed Locking

Introduction to etcd

etcd is a popular distributed key/value store. It stores keys and values and replicates them on several nodes which can be used to query or update the keys. To keep its members in sync, etcd implements the Raft algorithm. Raft solves the consensus issue in distributed systems by electing a leader who is responsible for maintaining consistency across nodes. In short, Raft makes sure that data stored by etcd are consistent across all nodes, and that if a node crashes, the etcd cluster can continue to operate until its failed node comes back to life.

In that regard, etcd allows implementing a distributed lock. The basic idea behind the lock algorithm is to write some value in a predetermined key. All the services in the cluster would pick, for example, the key lock1 and would try to write the value acquired in it. As etcd supports transactions, this operation would be executed in a ...