## 4 Development of Blockchain-Based Cloud Manufacturing System
### Blockchain and Cloud Manufacturing for SCM  
The move from on-premise data centres to cloud services has created a plethora of opportunities for collaboration in business and new sustainable value creation through digitization. Utilizing serverless computing, a multiple provider-managed cloud service offering triggered by events is deployed [75]. Therefore, cloud services for the manufacturer are built on K8s, which is a platform for large enterprise applications, to allow for multiple container orchestration. There are no execution costs in a permissioned ledger [80], making it favourable for use amongst SMEs. The Hyperledger Fabric is built on a Kubernetes platform. Both systems are built for enterprise applications and are open-source and modular architectures.  
An AIS is centralized as it is the core module of business operations, integrating multiple applications to perform various business processes, and hence the AIS system design and analysis is arduous [72]. Consequently, a permissioned blockchain with centralized authority was adopted for hierarchical SCM. Blockchain is event-driven due to its asynchronous characteristics, as latency is incurred whilst awaiting confirmation of transactions [81]. K8s' command line interface kubect is used to run commands and orchestrate resources. The microservices are deployed onto a pod, which is the smallest executable unit in K8s. The pod encapsulates the loosely coupled microservices to operate as a single unit with a shared IP address. K8s has different controllers, however, in this study, StatefulSets controllers were utilized for stateful pods [82]. Statefulness is critical in SCM systems, as pods are ephemeral and data need to be traced along the IS.  
The supply chain is built around a hierarchical information system interface through identity management access. Fabric is a permissioned DLT with pluggable consensus mechanisms [69], enabling information sharing whilst maintaining privacy amongst multi-stakeholders, which can easily be revoked dependent on supplier performance. In a manufacturing enterprise, product specifications include CAD files, material information, invoices, etc., which are shared as smart contracts with the supplier. Since the manufacturer has multiple suppliers for its multiple components and parts, it offers various contract conditions to its supplier based on its discretion. The channels create ledgers inside ledgers, which are private to other peers within the network, allowing for private communication [69]. As such, multiple channels are created and interlinked between various departments and suppliers, which are also private to other participants based on their identity and role.  
Fabric uses an execute-order-validate architecture [69] in its transactions. As such, the parallel execution of multiple transactions occurs within Fabric concurrently and are shared across related multiple collections. A chaincode is created once a transaction has been accepted and is used in tracing transactions that occur within Fabric. Since the world state is immutable, records are stored in the ledger, which consists of various aspects of transactional and supply chain documentation. The world state database is shared with an external party, an auditing firm to perform an audit of the financial transactions and inventory of stock, that occur during an annual year.