Running nodes locally

Starting a Corda node from the command line

Run a node by opening a terminal window in the node’s folder and running:

java -jar corda.jar

By default, the node will look for a configuration file called node.conf and a CorDapps folder called cordapps in the current working directory. You can override the configuration file and workspace paths on the command line (e.g. ./corda.jar --config-file=test.conf --base-directory=/opt/corda/nodes/test).

$ java -jar corda.jar --config-obfuscation-seed my-seed --config-obfuscation-passphrase my-passphrase

$ export CONFIG_OBFUSCATION_SEED=my-seed; export CONFIG_OBFUSCATION_PASSPHRASE=my-passphrase; java -jar corda.jar

Setting JVM arguments

There are several ways of setting JVM arguments for the node process (particularly the garbage collector and the memory settings). They are listed here in order of increasing priority, i.e. if the same flag is set in a way later in this list, it will override anything set earlier.

• Default arguments in capsule: The capsuled Corda node has default flags set to -Xmx512m -XX:+UseG1GC - this gives the node (a relatively low) 512 MB of heap space and turns on the G1 garbage collector, ensuring low pause times for garbage collection.

When devMode is explicitly set to false the default node memory size will be enlarged to 4G: -Xmx4G -XX:+UseG1GC.

• Node configuration: The node configuration file can specify custom default JVM arguments by adding a section like:

custom = {
   jvmArgs: [ "-Xmx1G", "-XX:+UseG1GC" ]
}

Note that this will completely replace any defaults set by capsule above, not just the flags that are set here, so if you use this to set e.g. the memory, you also need to set the garbage collector, or it will revert to whatever default your JVM is using.

• Capsule specific system property: You can use a special system property that Capsule understands to set JVM arguments only for the Corda process, not the launcher that actually starts it:

java -Dcapsule.jvm.args="-Xmx1G" -jar corda.jar

Setting a property like this will override any value for this property, but not interfere with any other JVM arguments that are configured in any way mentioned above. In this example, it would reset the maximum heap memory to -Xmx1G but not touch the garbage collector settings. This is particularly useful for either setting large memory allowances that you don’t want to give to the launcher or for setting values that can only be set on one process at a time, e.g. a debug port.

• Command line flag: You can set JVM args on the command line that apply to the launcher process and the node process as in the example above. This will override any value for the same flag set any other way, but will leave any other JVM arguments alone.

• OutOfMemoryError handling: In addition to the JVM arguments listed above, the capsuled Corda node has two flags that cause the node to stop on out-of-memory error and generate the corresponding diagnostic files:

-XX:+HeapDumpOnOutOfMemoryError -XX:+CrashOnOutOfMemoryError

With CrashOnOutOfMemoryError the node which is running out of memory is expected to stop immediately (fail-fast) to preserve ledger consistency and avoid flaws in operations.

Unlike for arguments related to memory and GC, to completely replace the default out-of-memory error args, you must explicitly add at least one out-of-memory error related argument into the custom.jvmArgs section. For example, the following config turns off HeapDumpOnOutOfMemoryError and doesn’t invoke CrashOnOutOfMemoryError option:

custom = {
   jvmArgs: [ "-Xmx1G", "-XX:+UseG1GC", "-XX:-HeapDumpOnOutOfMemoryError" ]
}

Command-line options

The node can optionally be started with the following command-line options:

• --base-directory, -b: The node working directory where all the files are kept (default: .).
• --config-file, -f: The path to the config file. Defaults to node.conf.
• --dev-mode, -d: Runs the node in development mode. Unsafe in production. Defaults to true on MacOS and desktop versions of Windows. False otherwise.
• --no-local-shell, -n: Do not start the embedded shell locally.
• --on-unknown-config-keys <[FAIL,INFO]>: How to behave on unknown node configuration. Defaults to FAIL.
• --sshd: Enables SSH server for node administration.
• --sshd-port: Sets the port for the SSH server. If not supplied and SSH server is enabled, the port defaults to 2222.
• --verbose, --log-to-console, -v: If set, prints logging to the console as well as to a file.
• --logging-level=<loggingLevel>: Enable logging at this level and higher. Possible values: ERROR, WARN, INFO, DEBUG, TRACE. Default: INFO.
• --help, -h: Show this help message and exit.
• --version, -V: Print version information and exit.

Sub-commands

clear-network-cache: Clears local copy of network map, on node startup it will be restored from server or file system.

initial-registration: Starts initial node registration with the compatibility zone to obtain a certificate from the Doorman.

Parameters:

• --network-root-truststore, -t required: Network root trust store obtained from network operator.
• --network-root-truststore-password, -p: Network root trust store password obtained from network operator.
• • --skip-schema-creation: Skips the default database migration step.

generate-node-info: Performs the node start-up tasks necessary to generate the nodeInfo file, saves it to disk, then exits.

generate-rpc-ssl-settings: Generates the SSL keystore and truststore for a secure RPC connection.

install-shell-extensions: Install corda alias and auto completion for bash and zsh. See cli-application-shell-extensions for more info.

validate-configuration: Validates the actual configuration without starting the node.

Enabling remote debugging

To enable remote debugging of the node, run the node with the following JVM arguments:

java -Dcapsule.jvm.args="-agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=5005" -jar corda.jar

This will allow you to attach a debugger to your node on port 5005.

Starting a node with JMX monitoring enabled

To enable export of JMX metrics over HTTP via Jolokia, run the following from the terminal window:

java -Dcapsule.jvm.args="-javaagent:drivers/jolokia-jvm-1.3.7-agent.jar=port=7005" -jar corda.jar

This command line will start the node with JMX metrics accessible via HTTP on port 7005.

See Monitoring via Jolokia for further details.

Starting all nodes at once on a local machine from the command line

Native

If you created your nodes using deployNodes, a runnodes shell script (or batch file on Windows) will have been generated to allow you to quickly start up all nodes and their webservers. runnodes should only be used for testing purposes.

Start the nodes with runnodes by running the following command from the root of the project:

• Linux/macOS: build/nodes/runnodes
• Windows: call build\nodes\runnodes.bat

If you receive an OutOfMemoryError exception when interacting with the nodes, you need to increase the amount of Java heap memory available to them, which you can do when running them individually. See Starting a Corda node from the command line.

docker-compose

If you created your nodes using Dockerform, the docker-compose.yml file and corresponding Dockerfile for nodes has been created and configured appropriately. Navigate to build/nodes directory and run docker-compose up command. This will startup nodes inside new, internal network. After the nodes are started up, you can use docker ps command to see how the ports are mapped.

Starting all nodes at once on a remote machine from the command line

By default, Cordform expects the nodes it generates to be run on the same machine where they were generated. In order to run the nodes remotely, the nodes can be deployed locally and then copied to a remote server. If after copying the nodes to the remote machine you encounter errors related to localhost resolution, you will additionally need to follow the steps below.

To create nodes locally and run on a remote machine perform the following steps:

• Configure Cordform task and deploy the nodes locally as described in Creating nodes locally.
• Copy the generated directory structure to a remote machine using e.g. Secure Copy.
• Optionally, add database configuration settings if they weren’t specified in the first step.This step needs to be performed if the local machine doesn’t have access to the remote database (a database couldn’t be configured in the first step). In each top level [NODE NAME]_node.conf configuration file add the database settings and copy the JDBC driver JAR (if required). Edit the top level [NODE NAME]_node.conf files only and not the files (node.conf) inside the node subdirectories.
• Optionally, bootstrap the network on the remote machine.This is optional step when a remote machine doesn’t accept localhost addresses, or the generated nodes are configured to run on another host’s IP address.If required change host addresses in top level configuration files [NODE NAME]_node.conf for entries p2pAddress , rpcSettings.address and rpcSettings.adminAddress.Run the network bootstrapper tool to regenerate the nodes network map (see for more explanation network-bootstrapper):java -jar corda-tools-network-bootstrapper-Master.jar --dir <nodes-root-dir>
• Run nodes on the remote machine using runnodes command.

The above steps create a test deployment as deployNodes Gradle task would do on a local machine.

Database migrations

Depending on the versions of Corda and of the CorDapps used, database migration scripts might need to run before a node is able to start. For more information refer to database-management.

Stability of the Corda Node

There are a number of critical resources necessary for Corda Node to operate to ensure transactional consistency of the ledger. These critical resources include:

• Connection to a database;
• Connection to Artemis Broker for P2P communication;
• Connection to Artemis Broker for RPC communication.

Should any of those critical resources become not available, Corda Node will be getting into an unstable state and as a safety precaution it will shut itself down reporting the cause as an error message to the Node’s log file.