Lock-Free Decentralized Storage for Transactional Upgrade Rollback

Installing and upgrading software may introduce conflicts and errors into a system. Transactional Rollback allows the system to return back to a previous, stable and known state. However, to perform such a rollback, it is necessary to store a large amount of information including configuration and installation logs, as well as different versions of software packages. Nevertheless, much of this information is common to several users using the same software and performing the same operations. We can reduce the total amount of storage by having a decentralized architecture using a Distributed Hash Table (DHT) to localise shared resources. We propose a lock-free key/value-set protocol to add and remove data from the DHT. The lock-free protocol is not limited to transactional rollback, and it can be used by other applications that also need value-sets as part of their stored data.