Network Bootstrapper

Test deployments

Nodes within a network see each other using the network map. This is a collection of statically signed node-info files, one for each node. Most production deployments will use a highly available, secure distribution of the network map via HTTP.

For test deployments where the nodes (at least initially) reside on the same filesystem, these node-info files can be placed directly in the node’s additional-node-infos directory from where the node will pick them up and store them in its local network map cache. The node generates its own node-info file on startup.

In addition to the network map, all the nodes must also use the same set of network parameters. These are a set of constants which guarantee interoperability between the nodes. The HTTP network map distributes the network parameters which are downloaded automatically by the nodes. In the absence of this the network parameters must be generated locally.

For these reasons, test deployments can avail themselves of the network bootstrapper. This is a tool that scans all the node configurations from a common directory to generate the network parameters file, which is then copied to all the nodes’ directories. It also copies each node’s node-info file to every other node so that they can all be visible to each other.

You can find out more about network maps and network parameters from Network Map.

Bootstrapping a test network

The bootstrapper can be downloaded from https://downloads.corda.net/network-bootstrapper-VERSION.jar, where VERSION is the Corda version.

Create a directory containing a node config file, ending in “_node.conf”, for each node you want to create. Then run the following command:

java -jar network-bootstrapper-VERSION.jar --dir <nodes-root-dir>

For example running the command on a directory containing these files:

.
├── notary_node.conf             // The notary's node.conf file
├── partya_node.conf             // Party A's node.conf file
└── partyb_node.conf             // Party B's node.conf file

will generate directories containing three nodes: notary, partya and partyb. They will each use the corda.jar that comes with the bootstrapper. If a different version of Corda is required then simply place that corda.jar file alongside the configuration files in the directory.

You can also have the node directories containing their “node.conf” files already laid out. The previous example would be:

.
├── notary
│   └── node.conf
├── partya
│   └── node.conf
└── partyb
    └── node.conf

Similarly, each node directory may contain its own corda.jar, which the bootstrapper will use instead.

Providing CorDapps to the Network Bootstrapper

If you would like the Network Bootstrapper to include your CorDapps in each generated node, just place them in the directory alongside the config files. For example, if your directory has this structure:

.
├── notary_node.conf            // The notary's node.conf file
├── partya_node.conf            // Party A's node.conf file
├── partyb_node.conf            // Party B's node.conf file
├── cordapp-a.jar               // A cordapp to be installed on all nodes
└── cordapp-b.jar               // Another cordapp to be installed on all nodes

The cordapp-a.jar and cordapp-b.jar will be installed in each node directory, and any contracts within them will be added to the Contract Whitelist (see below).

Whitelisting contracts

Any CorDapps provided when bootstrapping a network will be scanned for contracts which will be used to create the Zone whitelist (see API: Contract Constraints) for the network.

Note

If you only wish to whitelist the CorDapps but not copy them to each node then run with the --no-copy flag.

The CorDapp JARs will be hashed and scanned for Contract classes. These contract class implementations will become part of the whitelisted contracts in the network parameters (see NetworkParameters.whitelistedContractImplementations Network Map).

By default the bootstrapper will whitelist all the contracts found in all the CorDapp JARs. To prevent certain contracts from being whitelisted, add their fully qualified class name in the exclude_whitelist.txt. These will instead use the more restrictive HashAttachmentConstraint.

For example:

net.corda.finance.contracts.asset.Cash
net.corda.finance.contracts.asset.CommercialPaper

Modifying a bootstrapped network

The network bootstrapper is provided as a development tool for setting up Corda networks for development and testing. There is some limited functionality which can be used to make changes to a network, but for anything more complicated consider using a Network Map server.

When running the Network Bootstrapper, each node-info file needs to be gathered together in one directory. If the nodes are being run on different machines you need to do the following:

  • Copy the node directories from each machine into one directory, on one machine
  • Depending on the modification being made (see below for more information), add any new files required to the root directory
  • Run the Network Bootstrapper from the root directory
  • Copy each individual node’s directory back to the original machine

The network bootstrapper cannot dynamically update the network if an existing node has changed something in their node-info, e.g. their P2P address. For this the new node-info file will need to be placed in the other nodes’ additional-node-infos directory. If the nodes are located on different machines, then a utility such as rsync can be used so that the nodes can share node-infos.

Adding a new node to the network

Running the bootstrapper again on the same network will allow a new node to be added and its node-info distributed to the existing nodes.

As an example, if we have an existing bootstrapped network, with a Notary and PartyA and we want to add a PartyB, we can use the network bootstrapper on the following network structure:

.
├── notary                      // existing node directories
│   ├── node.conf
│   ├── network-parameters
│   ├── node-info-notary
│   └── additional-node-infos
│       ├── node-info-notary
│       └── node-info-partya
├── partya
│   ├── node.conf
│   ├── network-parameters
│   ├── node-info-partya
│   └── additional-node-infos
│       ├── node-info-notary
│       └── node-info-partya
└── partyb_node.conf            // the node.conf for the node to be added

Then run the network bootstrapper again from the root dir:

java -jar network-bootstrapper-VERSION.jar --dir <nodes-root-dir>

Which will give the following:

.
├── notary                      // the contents of the existing nodes (keys, db's etc...) are unchanged
│   ├── node.conf
│   ├── network-parameters
│   ├── node-info-notary
│   └── additional-node-infos
│       ├── node-info-notary
│       ├── node-info-partya
│       └── node-info-partyb
├── partya
│   ├── node.conf
│   ├── network-parameters
│   ├── node-info-partya
│   └── additional-node-infos
│       ├── node-info-notary
│       ├── node-info-partya
│       └── node-info-partyb
└── partyb                      // a new node directory is created for PartyB
    ├── node.conf
    ├── network-parameters
    ├── node-info-partyb
    └── additional-node-infos
        ├── node-info-notary
        ├── node-info-partya
        └── node-info-partyb

The bootstrapper will generate a directory and the node-info file for PartyB, and will also make sure a copy of each nodes’ node-info file is in the additional-node-info directory of every node. Any other files in the existing nodes, such a generated keys, will be unaffected.

Note

The bootstrapper is provided for test deployments and can only generate information for nodes collected on the same machine. If a network needs to be updated using the bootstrapper once deployed, the nodes will need collecting back together.

Updating the contract whitelist for bootstrapped networks

If the network already has a set of network parameters defined (i.e. the node directories all contain the same network-parameters file) then the bootstrapper can be used to append contracts from new CorDapps to the current whitelist. For example, with the following pre-generated network:

.
├── notary
│   ├── node.conf
│   ├── network-parameters
│   └── cordapps
│       └── cordapp-a.jar
├── partya
│   ├── node.conf
│   ├── network-parameters
│   └── cordapps
│       └── cordapp-a.jar
├── partyb
│   ├── node.conf
│   ├── network-parameters
│   └── cordapps
│       └── cordapp-a.jar
└── cordapp-b.jar               // The new cordapp to add to the existing nodes

Then run the network bootstrapper again from the root dir:

java -jar network-bootstrapper-VERSION.jar --dir <nodes-root-dir>

To give the following:

.
├── notary
│   ├── node.conf
│   ├── network-parameters      // The contracts from cordapp-b are appended to the whitelist in network-parameters
│   └── cordapps
│       ├── cordapp-a.jar
│       └── cordapp-b.jar       // The updated cordapp is placed in the nodes cordapp directory
├── partya
│   ├── node.conf
│   ├── network-parameters      // The contracts from cordapp-b are appended to the whitelist in network-parameters
│   └── cordapps
│       ├── cordapp-a.jar
│       └── cordapp-b.jar       // The updated cordapp is placed in the nodes cordapp directory
└── partyb
    ├── node.conf
    ├── network-parameters      // The contracts from cordapp-b are appended to the whitelist in network-parameters
    └── cordapps
        ├── cordapp-a.jar
        └── cordapp-b.jar       // The updated cordapp is placed in the nodes cordapp directory

Note

The whitelist can only ever be appended to. Once added a contract implementation can never be removed.