VMware Blockchain Release Notes 1.0

VMware Blockchain 1.0 | 19 NOV 2020 | Build 1.0.0.67 Check for additions and updates to these release notes.

What's in the Release Notes

The release notes cover the following topics:

• Introducing VMware Blockchain
• Component Versions
• Known Issues

Introducing VMware Blockchain

VMware Blockchain is an enterprise-grade blockchain platform that meets the needs of business-critical multi-party workflows. The product includes the critical blockchain platform requirements, such as:

• Consistency of data in the blockchain and system resilience and scalability.
• Maintaining privacy and a verifiable single source of truth for all.
• Deep integration with the DAML smart contract language to allow application developers access to all the features, use the versatile contract language, and the robust platform.
• Operational simplicity around deployment, observation, upgradeability, and supportability.

VMware Blockchain introduces the following new core features.

• State Machine Replication
  VMware Blockchain is a permissioned distributed trust platform that uses a Byzantine Fault Tolerant (BFT) State Machine Replication system to order and execute transactions. BFT ensures data consistency and resilience not only in crash failure scenarios but also in malicious attack scenarios. The State Machine replication is implemented by a set of Replica nodes, which form a Replica Network. The Client nodes interact with the State machine. Together, the Replica network and Client nodes constitute a VMware blockchain deployment.


• Pre-execution of commands
  To enable scalability using parallel execution, provide safety against non-determinism, and to enable long-running transactions, VMware Blockchain optimistically executes commands while committing them in total order.


• Authenticated Key-Value Ledger
  To prove facts about smart contracts on the platform and to allow access to a privacy-aware verifiable source of truth, VMware Blockchain stores the state of the blockchain (State Machine) in an authenticated key-value data structure. This structure is part of the Replica nodes in the Replica Network. The authenticated data structure is implemented as a sparse Merkle tree where the application data keys are the leaves of the tree. Application data keys have metadata that allows the Replica Network to implement privacy controls.


• Client Data Privacy
  To permit data access only to relevant parties in a multi-party workflow, the Replica Network shares a privacy-controlled subset of the state with Client nodes. Data privacy is achieved by evaluating the access control metadata embedded in the application data keys stored in the authenticated key-value ledger.


• DAML Support
  VMware Blockchain integrates with the DAML interpreter as a State Machine in the platform. This gives customers developing DAML applications a consistent, highly available, privacy-enabled blockchain platform. The DAML interpreter leverages the authenticated key-value ledger natively to ensure strong privacy and integrity for contracts deployed on the system. The standard DAML Ledger API interface and the supporting IndexDB are integrated as part of the Client nodes in VMware Blockchain.


• Backup and Restore Support
  VMware Blockchain allows the back up of a blockchain state before an upgrade. During an upgrade if problems occur, VMware Blockchain lets the user to restore to the recently backed up state.


• Deployment with VMware Orchestrator
  VMware Blockchain Orchestrator is a standalone virtual appliance designed to streamline deployment operations on a private cloud in an on-premises environment. This includes a CLI-based interface that lets the user configure the infrastructure and deployment parameters to automate several deployment tasks, hence simplifying deployment to a five-minute process.

To learn more about the core VMware Blockchain features, see the VMware Blockchain Getting Started guide.

Component Versions

The supported domain versions include:

Domain	Version
VMware Blockchain Platform	1.0.0.67
VMware Blockchain Orchestrator	1.0.0.67
DAML SDK	1.6

^{The VMware products and solutions discussed in this document are protected by U.S. and international copyright and intellectual property laws. VMware products are covered by one or more patents listed at http://www.vmware.com/go/patents. VMware is a registered trademark or trademark of VMware, Inc. and its subsidiaries in the United States and other jurisdictions. All other marks and names mentioned herein may be trademarks of their respective companies.}

Known Issues

• Possible performance degradation after continuous high transaction load for an extended time frame

  Running a blockchain deployment under a continuous high transaction load for over 30 hours could lead to an observable degradation in the throughput performance of the system.

  Workaround: None

• VMware Blockchain does not support a specific version of the ELK stack

  Environment specific configurations might be required to your default ELK stack settings to ensure that the collected metrics information is accurate.

  Workaround: Contact your VMware Blockchain technical specialist for assistance with ELK stack configurations.

• Time across the Replica and Client nodes becomes inaccurate if the NTP service is down or not synchronized

  If the NTP service is down or not synchronized, the time across Replica and Client nodes might become inaccurate leading to data discrepancies or cause errors in the DAML Ledger API.

  Workaround: To avoid any DAML Ledger API errors and data discrepancies, you must keep the NTP service up and synchronized to ensure that all the servers running VMware Blockchain reflect the accurate time.

• Cannot submit DAML transactions right after deployment

  If you submit a DAML transaction before the entire system is up and running, you receive the following error message from the DAML Ledger API,  UNAVAILABLE: The ledger configuration is not available.

  Workaround: Complete the following steps:

  1. Run the DAML transaction.
  2. Check if the transaction completes successfully.
  3. Verify that the key generation is completed successfully.
  4. Verify that in the Concord logs, all the replica node exchanged keys can start accepting messages.
  5. If the transaction fails, restart the DAML Ledger API and resubmit your DAML transaction.
• In rare cases, a Replica node might remain in an infinite state transfer loop regardless of the incoming rate

  If the Concord logs on a given node indicate to remain in the state transfer mode with a block gap up to 300, then state transfer is in an infinite loop. The blockchain system continues to function if 2f+1 Replica nodes are in consensus.

  Workaround: Complete the following steps:

  1. In the Concord logs, search for the Start fetching checkpoint entry.
     The block gap is the difference between the newCheckpoint.lastBlock:2352173 and lastReachableBlockNum:2351979.
  2. Refer to the instructions in the Backup and Restore run book to restore the state from another Replica node.
• Storage size might increase without any transactions in the system

  With time service, requests are generated every second. All the Replica nodes add seven requests even if there are no transactions in the system.

  Workaround: None

• When you disconnect and connect a Replica node from the network, the disconnected Replica node might show up in the advanced view

  When you disconnect and connect a Replica node from the network, the disconnected Replica node might show up in an advanced view. After the Replica is connected, the Replica node initiates the state transfer and remains in the previous view.

  Workaround: Complete the following steps:

  1. Use Wavefront to verify that the state transfer has been completed.
  2. If the Replica is in the advanced view, induce a view change.
  3. If the state transfer is in an infinite loop, refer to the instructions in the Backup and Restore run book to restore the state from another Replica node.