corda/docs/source/generating-a-node.rst

Creating nodes locally

Node structure

Each Corda node has the following structure:

.
├── certificates            // The node's certificates
├── corda-webserver.jar     // The built-in node webserver
├── corda.jar               // The core Corda libraries
├── logs                    // The node logs
├── node.conf               // The node's configuration files
├── persistence.mv.db       // The node's database
└── cordapps                // The CorDapps jars installed on the node

The node is configured by editing its node.conf file. You install CorDapps on the node by dropping the CorDapp JARs into the cordapps folder.

In development mode (i.e. when devMode = true, see corda-configuration-file for more information), the certificates directory is filled with pre-configured keystores if the required keystores do not exist. This ensures that developers can get the nodes working as quickly as possible. However, these pre-configured keystores are not secure, to learn more see permissioning.

Node naming

A node's name must be a valid X.500 distinguished name. In order to be compatible with other implementations (particularly TLS implementations), we constrain the allowed X.500 name attribute types to a subset of the minimum supported set for X.509 certificates (specified in RFC 3280), plus the locality attribute:

• Organization (O)
• State (ST)
• Locality (L)
• Country (C)
• Organizational-unit (OU)
• Common name (CN)

Note that the serial number is intentionally excluded in order to minimise scope for uncertainty in the distinguished name format. The distinguished name qualifier has been removed due to technical issues; consideration was given to "Corda" as qualifier, however the qualifier needs to reflect the compatibility zone, not the technology involved. There may be many Corda namespaces, but only one R3 namespace on Corda. The ordering of attributes is important.

State should be avoided unless required to differentiate from other localities with the same or similar names at the country level. For example, London (GB) would not need a state, but St Ives would (there are two, one in Cornwall, one in Cambridgeshire). As legal entities in Corda are likely to be located in major cities, this attribute is not expected to be present in the majority of names, but is an option for the cases which require it.

The name must also obey the following constraints:

• The organisation, locality and country attributes are present

  • The state, organisational-unit and common name attributes are optional

• The fields of the name have the following maximum character lengths:

  • Common name: 64
  • Organisation: 128
  • Organisation unit: 64
  • Locality: 64
  • State: 64

• The country attribute is a valid ISO 3166-1 two letter code in upper-case

• All attributes must obey the following constraints:

  • Upper-case first letter
  • Has at least two letters
  • No leading or trailing whitespace
  • Does not include the following characters: , , = , $ , " , ' , \
  • Is in NFKC normalization form
  • Does not contain the null character
  • Only the latin, common and inherited unicode scripts are supported

• The organisation field of the name also obeys the following constraints:

  • No double-spacing

    • This is to avoid right-to-left issues, debugging issues when we can't pronounce names over the phone, and character confusability attacks

External identifiers

Mappings to external identifiers such as Companies House nos., LEI, BIC, etc. should be stored in custom X.509 certificate extensions. These values may change for operational reasons, without the identity they're associated with necessarily changing, and their inclusion in the distinguished name would cause significant logistical complications. The OID and format for these extensions will be described in a further specification.

The Cordform task

Corda provides a gradle plugin called Cordform that allows you to automatically generate and configure a set of nodes for testing and demos. Here is an example Cordform task called deployNodes that creates three nodes, defined in the Kotlin CorDapp Template:

task deployNodes(type: net.corda.plugins.Cordform, dependsOn: ['jar']) {
    directory "./build/nodes"
    node {
        name "O=Notary,L=London,C=GB"
        // The notary will offer a validating notary service.
        notary = [validating : true]
        p2pPort  10002
        rpcPort  10003
        // No webport property, so no webserver will be created.
        h2Port   10004
        // Includes the corda-finance CorDapp on our node.
        cordapps = ["$corda_release_distribution:corda-finance:$corda_release_version"]
    }
    node {
        name "O=PartyA,L=London,C=GB"
        p2pPort  10005
        rpcPort  10006
        webPort  10007
        h2Port   10008
        cordapps = ["$corda_release_distribution:corda-finance:$corda_release_version"]
        // Grants user1 all RPC permissions.
        rpcUsers = [[ user: "user1", "password": "test", "permissions": ["ALL"]]]
    }
    node {
        name "O=PartyB,L=New York,C=US"
        p2pPort  10009
        rpcPort  10010
        webPort  10011
        h2Port   10012
        cordapps = ["$corda_release_distribution:corda-finance:$corda_release_version"]
        // Grants user1 the ability to start the MyFlow flow.
        rpcUsers = [[ user: "user1", "password": "test", "permissions": ["StartFlow.net.corda.flows.MyFlow"]]]
    }
}

Running this task will create three nodes in the build/nodes folder:

• A Notary node that:
  • Offers a validating notary service
  • Will not have a webserver (since webPort is not defined)
  • Is running the corda-finance CorDapp
• PartyA and PartyB nodes that:
  • Are not offering any services
  • Will have a webserver (since webPort is defined)
  • Are running the corda-finance CorDapp
  • Have an RPC user, user1, that can be used to log into the node via RPC

Additionally, all three nodes will include any CorDapps defined in the project's source folders, even though these CorDapps are not listed in each node's cordapps entry. This means that running the deployNodes task from the template CorDapp, for example, would automatically build and add the template CorDapp to each node.

You can extend deployNodes to generate additional nodes.

Warning

When adding nodes, make sure that there are no port clashes!

Specifying a custom webserver

By default, any node listing a webport will use the default development webserver, which is not production-ready. You can use your own webserver JAR instead by using the webserverJar argument in a Cordform node configuration block:

node {
    name "O=PartyA,L=New York,C=US"
    webPort 10005
    webserverJar "lib/my_webserver.jar"
}

The webserver JAR will be copied into the node's build folder with the name corda-webserver.jar.

Warning

This is an experimental feature. There is currently no support for reading the webserver's port from the node's node.conf file.

Running deployNodes

To create the nodes defined in our deployNodes task, run the following command in a terminal window from the root of the project where the deployNodes task is defined:

• Linux/macOS: ./gradlew deployNodes
• Windows: gradlew.bat deployNodes

This will create the nodes in the build/nodes folder. There will be a node folder generated for each node defined in the deployNodes task, plus a runnodes shell script (or batch file on Windows) to run all the nodes at once for testing and development purposes. If you make any changes to your CorDapp source or deployNodes task, you will need to re-run the task to see the changes take effect.

You can now run the nodes by following the instructions in Running a node <running-a-node>.