Like any peer to peer system, Ethereum network health and proper functioning relies on the total number of nodes (which are currently about 10-15K nodes). The majority of these nodes are x86 based servers or desktops, and an important number of them depend on cloud computing services. This may represent a centralization issue as a significant part of the infrastructure depends on a centralized service. As stated on “Mastering Ethereum” by Andreas Antonopoulos and Gavin Wood:
“The health, resilience, and censorship resistance of blockchains depend on having many independently operated and geographically dispersed full nodes. Each full node can help other new nodes obtain the block data to bootstrap their operation, as well as offer the operator an authoritative and independent verification of all transactions and contracts”.