Join a custom blockchain

Overview#

This guide assumes that the custom blockchain symbol will be foo - You should substitute foo with the relevant blockchain symbol everywhere (including all file names) as you go through this guide. The blockchain symbol (also called network symbol) is a unique symbol or acronym used to represent a blockchain (E.g. for listing on exchanges).

1. Requirements#

1.1 Machine/instance requirements#

  • A machine/instance with a publicly exposed IP address (E.g. from a cloud service provider).
  • 100GB of hard drive space is recommended (this should be enough for several years of data).
  • Port 8001 needs to be open for inbound TCP traffic.
  • All ports should be open for outbound TCP traffic.

1.2 A compatible LDEM node#

To create a custom blockchain, you first need to have an LDEM node - Any node which is based on the LDEM engine is fine; this includes a Leasehold node or a Capitalisk node. But for the purpose of this guide, it is recommended to use a Capitalisk node - So you should follow the guide Set up a new Capitalisk node to setup a node. Make sure that you also have the pm2 command installed globally on your node (sudo npm install -g pm2).

1.3 LDPoS Commander CLI#

You need to install the ldpos-commander Node.js module using the following command:

npm install -g ldpos-commander

OR (if the above fails):

sudo npm install -g ldpos-commander

Check that the installation was successful using the command:

ldpos -v

If the command outputs a version number, it means that the installation was successful.

2. Add the genesis file to your node#

You need to get a copy of the custom blockchain's genesis JSON file from existing network participants. Once you have it, paste it in the file at the following (relative) path (capitalisk-core is the directory where your node's source code is located):

capitalisk-core/genesis/mainnet/foo-genesis.json

Remember to replace foo in the filename above with the symbol of the blockchain you want to join.

3. Create a new database#

If using SQLite, the database file will be created automatically so you can skip this step.

If using Postgres, you will need to create a new database to store the blockchain data.

Create a new Postgres database. If the blockchain is called foo you may want to call it foo_main (for mainnet). The following commands may be different depending on your Postgres setup (change foo_main with an appropriate database name for the relevant chain):

postgres createdb foo_main

If using the default postgres user, the command would be:

sudo -u postgres createdb foo_main

4. Add the relevant custom module config object#

You will need to open your node's config.json file (inside your main capitalisk-core directory). Inside this file, you should find a field called modules which is an array of module objects; these objects reference the module instances which will run on your node.

You will need to add the blockchain module config object which was provided to you by existing blockchain participants to your config.json file. The object might look like this (though it will likely have some different values and properties):

"foo_chain": {
"modulePath": "node_modules/ldpos-chain",
"genesisPath": "../../genesis/mainnet/foo-genesis.json",
"components": {
"logger": {
"logFileName": "logs/mainnet/foo.log",
"consoleLogLevel": "debug",
"fileLogLevel": "error"
},
"dal": {
"libPath": "../ldpos-knex-dal",
"client": "pg",
"connection": {
"host": "127.0.0.1",
"user" : "postgres",
"password" : "password",
"database" : "capitalisk_main",
"port": "5432"
}
}
}
}

It's important that most of the properties and values in your module's config object match those of other nodes which participate in this blockchain network or else your node will not be able to reach consensus with the rest of the network.

The choice of database engine is one of the configurations which can be different on a node-by-node basis. If you want to use SQLite instead of Postgres, the object under dal should look like this instead:

"dal": {
"libPath": "../ldpos-knex-dal",
"client": "sqlite3",
"connection": {
"filename": "foo-db.sqlite3"
}
}

Remember to substitute foo with the appropriate custom chain symbol in filename.

5. Start your node#

You can start the node using PM2:

pm2 start index.js --name "ldem-node" -o "/dev/null" -e "/dev/null"

You should check the logs using the following command:

pm2 logs ldem-node

Depending on your log level, you may see a lot of messages which indicate that your node is catching up with the network. If you see a lot of error messages, it could be an indication that something went wrong. Compare your logs with existing network participants to verify that your node is running correctly.

Press Ctrl + C to stop reading the logs.