第13章ハイブリッドマルチクラウドのデジタルソリューション開発

ML toolkits can be used for various tasks, such as scaling a computation to solve bigger problems. One approach is the SPMD model of communicating sequential processes by using the message passing interface (MPI) standard model. Another is the graph execution dataflow model, used in Spark, Flink, and the deep learning toolkits. You can write ML algorithms using either MPI or Spark. You should be aware that MPI implementations of standard ML algorithms typically perform better than the versions in Spark and Flink. Often, the differences are factors of orders of magnitude in execution time, but the MPI versions are harder to program than the Spark versions.

Blockchains use a distributed ledger system to store data and transactions in an open-source database that enables you to build applications that allow multiple parties to securely and transparently run transactions and share data without using a trusted central authority. With blockchain 2.0, developers have a mechanism that allows programmable transactions, which are modified by a condition or set of conditions. Blockchain 2.0 is not limited to supporting transactions. It can also handle microtransactions, decentralized exchange, and creating and transferring digital assets. Blockchain 2.0 also has the ability to handle smart contracts, which are scripts executed in a blockchain 2.0 environment. The codes of smart contracts are accessible to the public, and anyone can verify the correctness of code execution. The actual verification is carried out by miners in the blockchain environment, and this ensures honest execution of the “contract.” Smart contracts rely on cryptography to secure them against tampering and unauthorized revisions.

A blockchain network is a peer-to-peer network that allows people and organizations who may not know one another to trust and independently verify the records of financial and other transactions. This improves the efficiency and immutability of transactions for business processes such as international payments, supply chain management, land registration, crowdfunding, governance, financial transactions, and more.

Ethereum.org implements a blockchain 2.0 decentralized computing platform for Web3 and provides a language to write transaction scripts. Web3 applications are referred to as DApps and may be deployed on blockchain 2.0 decentralized computing platforms. Ethereum.org provides its own development environment (i.e., Remix) and programming languages, such as Solidity, to develop and deploy contracts. Public test networks such as Goerli may be used to develop and test contracts before deploying them on the Ethereum platform. Web3 APIs are available for various programming languages, such as JavaScript, Python, Haskell, Java, Scala, and PureScript, to facilitate the creation of applications that interact directly with the blockchain 2.0 platform.

Using PaaS blockchain services on AWS, Oracle, GCP, and IBM big clouds, it is possible to create a blockchain decentralized computing platform to facilitate the deployment of Web3 DApps. Big clouds provide clusters of VMs that may be leveraged as P2P nodes within a blockchain 2.0 decentralized platform implementation, such as Hyperledger. While Microsoft Azure offered PaaS services to create blockchain platforms, it has retired these services and partnered with ConsenSys and other companies to provide that support. Azure does provide products and services, Web3 developer tools, and security capabilities to help create Web3 applications and deploy them on partner platforms.

To learn more about blockchain PaaS services available in the big cloud, you can visit multiple websites and explore blockchain features. For example, you can find information about AWS blockchain (https://openstax.org/r/76AWSBlockchain) online.

AWS provides blockchain templates that help you create and deploy blockchain networks on AWS using different blockchain frameworks. AWS Managed Blockchain, which is shown in Figure 13.12, is used to configure and launch AWS CloudFormation stacks to create blockchain networks. The AWS resources and services used depend on the AWS blockchain template selected and the options to specify the fundamental components of a blockchain network.

Amazon Managed Blockchain is a fully managed service for creating and managing blockchain networks that supports the Hyperledger Fabric open-source framework. You can use Managed Blockchain to create a scalable blockchain network quickly and efficiently using the AWS Management Console, the AWS CLI, or the Managed Blockchain SDK. Managed Blockchain scales to meet the demands of thousands of applications running millions of transactions. Once the blockchain network is functional, Managed Blockchain simplifies network management tasks by managing certificates, making it easy to create proposals for a vote among network members, and tracking operational metrics such as computing resources, memory, and storage resources.

Figure 13.13 shows the basic components of a Hyperledger Fabric blockchain running on AWS. A network includes one or more members with unique identities. For example, a member might be an organization in a consortium of banks. Each member runs one or more blockchain peer nodes to run chaincode, endorse transactions, and store a local copy of the ledger. Amazon Managed Blockchain creates and manages these components for each member in a network and also creates components shared by all members in a network, such as the Hyperledger Fabric ordering service and the general networking configuration.

When creating a Managed Blockchain network, the creator chooses the blockchain framework and the edition of Amazon Managed Blockchain to use, and this determines the capacity and capabilities of the network as a whole. The creator also must create the first Managed Blockchain network member. Additional members are added through a proposal and voting process. There is no charge for the network itself, but each member pays an hourly rate (billed per second) for their network membership. Charges vary depending on the edition of the network. Each member also pays for peer nodes, peer node storage, and the amount of data that the member writes to the network. The blockchain network remains active as long as there are members. The network is deleted only when the last member deletes itself from the network. No member or AWS account, even the creator’s AWS account, can delete the network until they are the last member and delete themselves.