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Created November 25, 2018 20:30
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Revisions

  1. Philidor Green revised this gist Aug 8, 2018. 1 changed file with 6 additions and 0 deletions.
    6 changes: 6 additions & 0 deletions PrivateEthereumCluster.md
    View file
    Original file line number Diff line number Diff line change
    @@ -387,3 +387,9 @@ References:
    > :exclamation: you use the howto at your own risk..
    <sub>P.S. forgive me my bad English, it’s not my native language.</sub>

    ### Donation
    Are you like this tutorial? Buy me a beer and I'll write more tutorials like this one:

    BTC - 19SYMA2hqRZHRSL4di35Uf7jV87KBKc9bf
    ETH - 0xD7cc10f0d70Fd8f9fB83D4eF9250Fc9201981e3a
  2. Philidor Green revised this gist Jan 6, 2018. 1 changed file with 7 additions and 7 deletions.
    14 changes: 7 additions & 7 deletions PrivateEthereumCluster.md
    View file
    Original file line number Diff line number Diff line change
    @@ -163,14 +163,14 @@ Note about the command line options to `geth`:

    - ` — identity` must be unique identifier of the node
    - `— networkid` must be the same on the both nodes
    - `—verbosity` there is many levels `0=silent, 1=error, 2=warn, 3=info, 4=core, 5=debug, 6=detail` (default: 3)
    - `—verbosity` there are many levels `0=silent, 1=error, 2=warn, 3=info, 4=core, 5=debug, 6=detail` (default: 3)
    - `— mine` enable minning
    - `— rpc` enable RPC
    - `— rpcport=8546` change the (default: 8545) RPC port in order to reach container from the host machine

    Documentation for all other command line options you can find [here](https://github.com/ethereum/go-ethereum/wiki/Command-Line-Options)
    The documentation for all other command line options you can find [here](https://github.com/ethereum/go-ethereum/wiki/Command-Line-Options)

    Let’s run some command to check the state of our nodes.
    Let’s run some command and check the state of our nodes.

    node_one:
    ```js
    @@ -180,7 +180,7 @@ node_one:
    0
    ```

    If both commands return zero, don’t worry, the DAG is generated. Wait some time and check again, you must see results(your output might be different):
    If both commands returns zero, don’t worry, the DAG is generated. Wait some time and check again, you must see the result(your output might be different):
    ```js
    > eth.hashrate
    23458
    @@ -199,7 +199,7 @@ node_one:
    > admin.nodeInfo.enode
    "enode://2468b878bb87****072fae1362fd3448@[::]:30303"
    ```
    I omit most of the enode, your enode url will be other, except last part `[::]:30303`.
    I omit a most part of the enode, your enode url will be other, except the last part `[::]:30303`.
    - `[::]`  — means localhost, that’s the enode url of node_one.

    Let’s get the second enode from another container:
    @@ -208,7 +208,7 @@ node_two:
    > admin.nodeInfo.enode
    "enode://4f3c1f87914a68255f9b736aa**ac754d7558ba@[::]:30303"
    ```
    Ok, we have enode urls of both containers, let’s add its to each other. In order to do that, we need container IP address, which we have from the output of the `docker network inspect ETH` command, `IPv4Address`.
    Ok, at this point we're having enode urls of both containers, let’s add its to each other. In order to do that, we need container IP address, which we have from the output of the `docker network inspect ETH` command, `IPv4Address`.

    node_one:
    ```
    @@ -374,7 +374,7 @@ NODE_TWO coinbase: 0x648a4b24cf769da5467bf9b008dace89d9f65a80
    NODE_TWO blocknumber: 1533
    NODE_ONE coinbase: 0x718cb4a34cac0fa4e9a37f249340078896b4dfa0
    ```
    We have builded private ethereum network cluster with the script writen on Ruby and Nodejs, those scripts able to communicate with our cluster using JSON-RPC protocol.
    We have builded private ethereum network cluster with the script writen on Ruby and Nodejs, these scripts able to communicate with our cluster using JSON-RPC protocol.
    It’s a good start to create your blockchain project based on Ethereum. 

    References:
  3. Philidor Green revised this gist Dec 29, 2017. 1 changed file with 2 additions and 2 deletions.
    4 changes: 2 additions & 2 deletions PrivateEthereumCluster.md
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    Original file line number Diff line number Diff line change
    @@ -73,7 +73,7 @@ eth_user@node_one:~$ ls -a
    eth_user@node_one:~$
    ```

    First one is ready(*don’t close terminal*), now second, open an another terminal and run:
    First one are ready(*don’t close terminal*), now second one, open an another terminal and run:

    ```bash
    docker run --rm -it -p 8546:8546 --net=ETH node_two
    @@ -117,7 +117,7 @@ Inspect docker network(remember `IPv4Address`, we’ll use it later), run comman
    ]
    ```

    Now we have two docker containers connected each other. Need to generate coinbase account, in order to mine ether we must provide an address [to receive reward for found blocks](http://www.ethdocs.org/en/latest/mining.html#mining-rewards).
    At this point we have two docker containers connected each other. Need to generate coinbase account, in order to mine ether we must provide an address [to receive reward for found blocks](http://www.ethdocs.org/en/latest/mining.html#mining-rewards).

    node_one:
    ```bash
  4. Philidor Green revised this gist Dec 29, 2017. 1 changed file with 3 additions and 3 deletions.
    6 changes: 3 additions & 3 deletions PrivateEthereumCluster.md
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    @@ -6,7 +6,7 @@
    This is a step-by-step guide, how to setup *private* Ethereum network. 

    We’ll set up network and write two simple JSON-RPC clients in order to communicate with our Ethereum nodes.
    We’ll set up a network and create two simple JSON-RPC clients in order to communicate with our Ethereum nodes.

    > Private blockchains: a fully private blockchain is a blockchain where write permissions are kept centralized to one organization. Read permissions may
    > be public or restricted to an arbitrary extent. Likely applications include database management, auditing, etc internal to a single company, and so
    @@ -20,7 +20,7 @@ I assume you have got hand-on experience with Docker, also you’re knowing Ruby
    Copy the source code from my [Github repository.](https://github.com/fishbullet/Ethereum-Private-Network)

    Let’s get started from the Docker container, here is a Dockerfile for our ethereum nodes, we’ll use the geth (go-ethereum):
    Let’s get started from the Docker container, here is the Dockerfile for our ethereum nodes, we’ll use the geth (go-ethereum):

    ```Dockerfile
    FROM ubuntu:16.04
    @@ -45,7 +45,7 @@ RUN geth init eth_common/genesis.json
    ENTRYPOINT bash
    ```

    In order to create *private* network we need a [genesis file](https://github.com/ethereum/go-ethereum/wiki/Private-network#creating-the-genesis-block) which must be on both nodes(look in the `eth_common/`).
    In order to create *private* network we need the [genesis file](https://github.com/ethereum/go-ethereum/wiki/Private-network#creating-the-genesis-block) which must be on both nodes(look in the `eth_common/`).

    To allow nodes to _talk_ to each other, we must create the network between containers, with the `docker network` it’s pretty easy:

  5. Philidor Green revised this gist Oct 25, 2017. 1 changed file with 2 additions and 0 deletions.
    2 changes: 2 additions & 0 deletions PrivateEthereumCluster.md
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    Original file line number Diff line number Diff line change
    @@ -16,6 +16,8 @@ To get the difference between Public and Private networks [read this article by

    I assume you have got hand-on experience with Docker, also you’re knowing Ruby or Nodejs a little. 

    > You can ask why docker? I don't want to install `geth` locally.
    Copy the source code from my [Github repository.](https://github.com/fishbullet/Ethereum-Private-Network)

    Let’s get started from the Docker container, here is a Dockerfile for our ethereum nodes, we’ll use the geth (go-ethereum):
  6. Philidor Green revised this gist Oct 24, 2017. 1 changed file with 1 addition and 1 deletion.
    2 changes: 1 addition & 1 deletion PrivateEthereumCluster.md
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    Original file line number Diff line number Diff line change
    @@ -382,6 +382,6 @@ References:
    - https://github.com/ethereum/go-ethereum/wiki

    ### Disclaimer
    > :exclamation: This is just a note for me, is provided “as is," and you use the howto at your own risk..
    > :exclamation: you use the howto at your own risk..
    <sub>P.S. forgive me my bad English, it’s not my native language.</sub>
  7. Philidor Green revised this gist Oct 24, 2017. 1 changed file with 2 additions and 2 deletions.
    4 changes: 2 additions & 2 deletions PrivateEthereumCluster.md
    View file
    Original file line number Diff line number Diff line change
    @@ -93,7 +93,7 @@ Inspect docker network(remember `IPv4Address`, we’ll use it later), run comman
    ```json
    [
    {
    # ..... ommited ....
    # ..... omitted ....
    "Containers": {
    "50e624e9481765443216eebaa4d0d7ae1dda3497f64eb55d6160632c7b7d0cce": {
    "Name": "cocky_mccarthy",
    @@ -110,7 +110,7 @@ Inspect docker network(remember `IPv4Address`, we’ll use it later), run comman
    "IPv6Address": ""
    }
    },
    # ..... ommited ....
    # ..... omitted ....
    }
    ]
    ```
  8. Philidor Green revised this gist Oct 24, 2017. 1 changed file with 3 additions and 3 deletions.
    6 changes: 3 additions & 3 deletions PrivateEthereumCluster.md
    View file
    Original file line number Diff line number Diff line change
    @@ -18,7 +18,7 @@ I assume you have got hand-on experience with Docker, also you’re knowing Ruby

    Copy the source code from my [Github repository.](https://github.com/fishbullet/Ethereum-Private-Network)

    Let’s get started from the Docker container creation, here is a Dockerfile for our ethereum nodes, we’ll be using geth:
    Let’s get started from the Docker container, here is a Dockerfile for our ethereum nodes, we’ll use the geth (go-ethereum):

    ```Dockerfile
    FROM ubuntu:16.04
    @@ -55,10 +55,10 @@ Now let’s build two containers:

    ```bash
    docker build -t node_one .
    # Output ommited
    # Output omitted
    # ...
    docker build -t node_two .
    # Output ommited
    # Output omitted
    # ....
    ```

  9. Philidor Green revised this gist Oct 24, 2017. 1 changed file with 1 addition and 1 deletion.
    2 changes: 1 addition & 1 deletion PrivateEthereumCluster.md
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    Original file line number Diff line number Diff line change
    @@ -32,7 +32,7 @@ RUN add-apt-repository ppa:ethereum/ethereum
    RUN apt-get update && apt-get install --yes geth

    RUN adduser --disabled-login --gecos "" eth_user
    WORKDIR /home/eth_user

    COPY eth_common /home/eth_user/eth_common
    RUN chown -R eth_user:eth_user /home/eth_user/eth_common
    USER eth_user
  10. Philidor Green revised this gist Oct 24, 2017. 1 changed file with 3 additions and 3 deletions.
    6 changes: 3 additions & 3 deletions PrivateEthereumCluster.md
    View file
    Original file line number Diff line number Diff line change
    @@ -43,7 +43,7 @@ RUN geth init eth_common/genesis.json
    ENTRYPOINT bash
    ```

    In order to create *private* network we need a [genesis file](https://github.com/ethereum/go-ethereum/wiki/Private-network#creating-the-genesis-block) whom must be on both nodes(look in the `eth_common/`).
    In order to create *private* network we need a [genesis file](https://github.com/ethereum/go-ethereum/wiki/Private-network#creating-the-genesis-block) which must be on both nodes(look in the `eth_common/`).

    To allow nodes to _talk_ to each other, we must create the network between containers, with the `docker network` it’s pretty easy:

    @@ -85,7 +85,7 @@ Second one is also ready.
    Note about `docker run` command line options:

    - `-p 8545:8545` in the node_one expose the default RPC port of geth.
    - `-p 8546:8546` in the node_two expose port, whom will be used later in geth.
    - `-p 8546:8546` in the node_two expose port, which will be used later in geth.
    - `— net=ETH` is a custom docker network, to allow containers communicate each other(because we’re building the cluster).

    Inspect docker network(remember `IPv4Address`, we’ll use it later), run command `docker network inspect ETH`:
    @@ -206,7 +206,7 @@ node_two:
    > admin.nodeInfo.enode
    "enode://4f3c1f87914a68255f9b736aa**ac754d7558ba@[::]:30303"
    ```
    Ok, we have enode urls of both containers, let’s add its to each other. In order to do that, we need container IP address, whom we have from the output of the `docker network inspect ETH` command, `IPv4Address`.
    Ok, we have enode urls of both containers, let’s add its to each other. In order to do that, we need container IP address, which we have from the output of the `docker network inspect ETH` command, `IPv4Address`.

    node_one:
    ```
  11. Philidor Green revised this gist Oct 24, 2017. 1 changed file with 3 additions and 0 deletions.
    3 changes: 3 additions & 0 deletions PrivateEthereumCluster.md
    View file
    Original file line number Diff line number Diff line change
    @@ -381,4 +381,7 @@ References:
    - https://github.com/ethereum/wiki/wiki
    - https://github.com/ethereum/go-ethereum/wiki

    ### Disclaimer
    > :exclamation: This is just a note for me, is provided “as is," and you use the howto at your own risk..
    <sub>P.S. forgive me my bad English, it’s not my native language.</sub>
  12. Philidor Green created this gist Oct 24, 2017.
    384 changes: 384 additions & 0 deletions PrivateEthereumCluster.md
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,384 @@
    # Setup private Ethereum network with Docker

    > Ethereum is a decentralized platform that runs smart contracts:
    > applications that run exactly as programmed without any possibility of downtime,
    > censorship, fraud or third party interference.
    This is a step-by-step guide, how to setup *private* Ethereum network. 

    We’ll set up network and write two simple JSON-RPC clients in order to communicate with our Ethereum nodes.

    > Private blockchains: a fully private blockchain is a blockchain where write permissions are kept centralized to one organization. Read permissions may
    > be public or restricted to an arbitrary extent. Likely applications include database management, auditing, etc internal to a single company, and so
    > public readability may not be necessary in many cases at all, though in other cases public auditability is desired.
    To get the difference between Public and Private networks [read this article by V. Buterin the author of Ethereum](https://blog.ethereum.org/2015/08/07/on-public-and-private-blockchains/).

    I assume you have got hand-on experience with Docker, also you’re knowing Ruby or Nodejs a little. 

    Copy the source code from my [Github repository.](https://github.com/fishbullet/Ethereum-Private-Network)

    Let’s get started from the Docker container creation, here is a Dockerfile for our ethereum nodes, we’ll be using geth:

    ```Dockerfile
    FROM ubuntu:16.04

    LABEL version="1.0"
    LABEL maintainer="shindu666@gmail.com"

    ENV DEBIAN_FRONTEND=noninteractive
    RUN apt-get update && apt-get install --yes software-properties-common
    RUN add-apt-repository ppa:ethereum/ethereum
    RUN apt-get update && apt-get install --yes geth

    RUN adduser --disabled-login --gecos "" eth_user
    WORKDIR /home/eth_user
    COPY eth_common /home/eth_user/eth_common
    RUN chown -R eth_user:eth_user /home/eth_user/eth_common
    USER eth_user
    WORKDIR /home/eth_user

    RUN geth init eth_common/genesis.json

    ENTRYPOINT bash
    ```

    In order to create *private* network we need a [genesis file](https://github.com/ethereum/go-ethereum/wiki/Private-network#creating-the-genesis-block) whom must be on both nodes(look in the `eth_common/`).

    To allow nodes to _talk_ to each other, we must create the network between containers, with the `docker network` it’s pretty easy:

    ```bash
    docker network create ETH
    ```

    Now let’s build two containers:

    ```bash
    docker build -t node_one .
    # Output ommited
    # ...
    docker build -t node_two .
    # Output ommited
    # ....
    ```

    OK, containers are builded:

    ```bash
    docker run --rm -it -p 8545:8545 --net=ETH node_one
    eth_user@node_one:~$ ls -a
    . .. .bash_logout .bashrc .ethereum .profile eth_common
    eth_user@node_one:~$
    ```

    First one is ready(*don’t close terminal*), now second, open an another terminal and run:

    ```bash
    docker run --rm -it -p 8546:8546 --net=ETH node_two
    eth_user@node_two:~$ ls -a
    . .. .bash_logout .bashrc .ethereum .profile eth_common
    eth_user@node_two:~$
    ```

    Second one is also ready.

    Note about `docker run` command line options:

    - `-p 8545:8545` in the node_one expose the default RPC port of geth.
    - `-p 8546:8546` in the node_two expose port, whom will be used later in geth.
    - `— net=ETH` is a custom docker network, to allow containers communicate each other(because we’re building the cluster).

    Inspect docker network(remember `IPv4Address`, we’ll use it later), run command `docker network inspect ETH`:

    ```json
    [
    {
    # ..... ommited ....
    "Containers": {
    "50e624e9481765443216eebaa4d0d7ae1dda3497f64eb55d6160632c7b7d0cce": {
    "Name": "cocky_mccarthy",
    "EndpointID": "15a34c3bf61f85cd1e705bf72470e2ac46d370159db59d07715e428518533bba",
    "MacAddress": "02:42:ac:12:00:03",
    "IPv4Address": "172.18.0.3/16",
    "IPv6Address": ""
    },
    "54d6fecd407b586bd4d0e20422923dd7355a691ce4de8a2050d649d7c9318526": {
    "Name": "nostalgic_raman",
    "EndpointID": "64fdd19a2f50e5fd184afa839b271c122a22d8b965ea7c72240624804c73cf3b",
    "MacAddress": "02:42:ac:12:00:02",
    "IPv4Address": "172.18.0.2/16",
    "IPv6Address": ""
    }
    },
    # ..... ommited ....
    }
    ]
    ```

    Now we have two docker containers connected each other. Need to generate coinbase account, in order to mine ether we must provide an address [to receive reward for found blocks](http://www.ethdocs.org/en/latest/mining.html#mining-rewards).

    node_one:
    ```bash
    eth_user@node_one:~$ ./eth_common/setup_account
    Address: {9b40d576bfaa7781e0826a4024b6300566113ce1}
    eth_user@node_one:~$
    ```
    node_two:
    ```bash
    eth_user@node_two:~$ ./eth_common/setup_account
    Address: {648a4b24cf769da5467bf9b008dace89d9f65a80}
    eth_user@node_two:~$
    ```

    Here we’re using `setup_account` shell script, which has been copied early to the docker container. 
    Time to start minning.

    node_one:
    ```bash
    eth_user@node_one:~$ geth --identity="NODE_ONE" --networkid="500" --verbosity=1 --mine --minerthreads=1 --rpc --rpcaddr 0.0.0.0 console
    Welcome to the Geth JavaScript console!
    instance: Geth/NODE_ONE/v1.7.2-stable-1db4ecdc/linux-amd64/go1.9
    coinbase: 0x9b40d576bfaa7781e0826a4024b6300566113ce1
    at block: 0 (Thu, 01 Jan 1970 00:00:00 UTC)
    datadir: /home/eth_user/.ethereum
    modules: admin:1.0 debug:1.0 eth:1.0 miner:1.0 net:1.0 personal:1.0 rpc:1.0 txpool:1.0 web3:1.0
    >
    ```

    node_two:
    ```bash
    eth_user@node_two:~$ geth --identity="NODE_TWO" --networkid="500" --verbosity=1 --mine --minerthreads=1 --rpc --rpcport=8546 --rpcaddr 0.0.0.0 console
    Welcome to the Geth JavaScript console!
    instance: Geth/NODE_TWO/v1.7.2-stable-1db4ecdc/linux-amd64/go1.9
    coinbase: 0x648a4b24cf769da5467bf9b008dace89d9f65a80
    at block: 0 (Thu, 01 Jan 1970 00:00:00 UTC)
    datadir: /home/eth_user/.ethereum
    modules: admin:1.0 debug:1.0 eth:1.0 miner:1.0 net:1.0 personal:1.0 rpc:1.0 txpool:1.0 web3:1.0
    >
    ```

    Note about the command line options to `geth`:

    - ` — identity` must be unique identifier of the node
    - `— networkid` must be the same on the both nodes
    - `—verbosity` there is many levels `0=silent, 1=error, 2=warn, 3=info, 4=core, 5=debug, 6=detail` (default: 3)
    - `— mine` enable minning
    - `— rpc` enable RPC
    - `— rpcport=8546` change the (default: 8545) RPC port in order to reach container from the host machine

    Documentation for all other command line options you can find [here](https://github.com/ethereum/go-ethereum/wiki/Command-Line-Options)

    Let’s run some command to check the state of our nodes.

    node_one:
    ```js
    > eth.hashrate
    0
    > eth.blockNumber
    0
    ```

    If both commands return zero, don’t worry, the DAG is generated. Wait some time and check again, you must see results(your output might be different):
    ```js
    > eth.hashrate
    23458
    > eth.blockNumber
    20
    ```
    Let’s check peers, our nodes must detect each other:
    ```js
    > admin.peers
    []
    ```
    Peers are empty, in order to add peers we must provide a full enode url to the `admin.addPeer()` method, to get the enode url run command:

    node_one:
    ```js
    > admin.nodeInfo.enode
    "enode://2468b878bb87****072fae1362fd3448@[::]:30303"
    ```
    I omit most of the enode, your enode url will be other, except last part `[::]:30303`.
    - `[::]`  — means localhost, that’s the enode url of node_one.

    Let’s get the second enode from another container:
    node_two:
    ```
    > admin.nodeInfo.enode
    "enode://4f3c1f87914a68255f9b736aa**ac754d7558ba@[::]:30303"
    ```
    Ok, we have enode urls of both containers, let’s add its to each other. In order to do that, we need container IP address, whom we have from the output of the `docker network inspect ETH` command, `IPv4Address`.

    node_one:
    ```
    #
    # enode from node_two with IP address of node_two container
    > enode = "enode://4f3c1f87914a68255f9b736aa**ac754d7558ba@172.18.0.3:30303"
    > admin.addPeer(enode)
    > admin.peers
    [{
    caps: ["eth/63"],
    id: "4f3c1f87914a68255f9b736aa**ac754d7558ba",
    name: "Geth/NODE_TWO/v1.7.2-stable-1db4ecdc/linux-amd64/go1.9",
    network: {
    localAddress: "172.18.0.2:41760",
    remoteAddress: "172.18.0.3:30303"
    },
    protocols: {
    eth: {
    difficulty: 70077493,
    head: "0x2d1a50604ea00163728a9ff80824c66105dcfb129a66d218f709ce6bab285249",
    version: 63
    }
    }
    }]
    ```
    node_two:
    ```
    # enode from node_one with IP address of node_one container
    enode = "enode://2468b878bb87****072fae1362fd3448@172.18.0.2:30303
    > admin.addPeer(enode)
    > admin.peers
    [{
    caps: ["eth/63"],
    id: "2468b878bb87****072fae1362fd3448",
    name: "Geth/NODE_ONE/v1.7.2-stable-1db4ecdc/linux-amd64/go1.9",
    network: {
    localAddress: "172.18.0.3:30303",
    remoteAddress: "172.18.0.2:41760"
    },
    protocols: {
    eth: {
    difficulty: 76191910,
    head: "0x1eca2ed57825c8840eca54cf807228f15473e120f65fbaaf6e3b5b79d6d5203d",
    version: 63
    }
    }
    }]
    ```

    That’s good, nodes are seeing each other. Let’s check the block number it must be the same on both nodes(+\- 1–2 blocks, because the mining is going fast, your output might be different):

    node_one:
    ```js
    > eth.blockNumber
    750
    > eth.hashrate
    60757
    ```

    node_two:
    ```js
    > eth.blockNumber
    753
    > eth.hashrate
    61494
    ```
    *Don’t close docker containers* it’s time to create a script to run commands in our nodes by `JSON-RPC`.

    Here is an example of Ruby script:

    ```ruby
    #!/usr/bin/env ruby
    require "bundler/setup"
    require 'json-rpc-client'
    EM.run {
    EventMachine.add_periodic_timer(5) { # 5 seconds timeout
    node_one = JsonRpcClient.new('http://localhost:8545/')
    node_two = JsonRpcClient.new('http://localhost:8546/')
    [
    { name: "NODE_ONE", node: node_one },
    { name: "NODE_TWO", node: node_two }
    ].each do |node|
    rpc_coinbase = node[:node].eth_coinbase
    rpc_blockNumber = node[:node].eth_blockNumber
    rpc_coinbase.callback do |result|
    puts "#{node[:name]} coinbase: #{result}"
    end
    rpc_coinbase.errback do |error|
    puts error
    end
    rpc_blockNumber.callback do |result|
    puts "#{node[:name]} blocknumber: #{Integer(result)}"
    end
    rpc_blockNumber.errback do |error|
    puts error
    end
    end
    }
    }
    ```
    And a Nodejs example:
    ```js
    var rpc = require('node-json-rpc');

    var nodeOne = {
    port: 8545,
    host: 'localhost',
    path: '/',
    strict: true
    };
    var nodeTwo = {
    port: 8546,
    host: 'localhost',
    path: '/',
    strict: true
    };

    var clientNodeOne = new rpc.Client(nodeOne);
    var clientNodeTwo = new rpc.Client(nodeTwo);

    setInterval(()=> {
    // Coinbase
    clientNodeOne.call({"jsonrpc": "2.0", "method": "eth_coinbase", "params": [], "id": 0 },
    function(err, res) {
    if (err) console.log(err)
    console.log("NODE ONE coinbase: " + res.result )
    })
    // blockNumber
    clientNodeTwo.call({"jsonrpc": "2.0", "method": "eth_blockNumber", "params": [], "id": 1 },
    function(err, res) {
    if (err) console.log(err)
    console.log("NODE TWO block number: " + parseInt(res.result, 16) )
    })

    // Coinbase
    clientNodeOne.call({"jsonrpc": "2.0", "method": "eth_coinbase", "params": [], "id": 0 },
    function(err, res) {
    if (err) console.log(err)
    console.log("NODE ONE coinbase: " + res.result )
    })

    // blockNumber
    clientNodeTwo.call({"jsonrpc": "2.0", "method": "eth_blockNumber", "params": [], "id": 1 },
    function(err, res) {
    if (err) console.log(err)
    console.log("NODE TWO block number: " + parseInt(res.result, 16) )
    })
    }, 5000) // 5 seconds timeout
    ```

    Now run scripts and check out the results(note about 5 seconds timeout):
    ```bash
    $> node index.js
    NODE ONE coinbase: 0x718cb4a34cac0fa4e9a37f249340078896b4dfa0
    NODE ONE block number: 1467
    NODE TWO coinbase: 0x648a4b24cf769da5467bf9b008dace89d9f65a80
    NODE TWO block number: 1467
    ```
    ```bash
    $> ruby client.rb
    NODE_ONE blocknumber: 1533
    NODE_TWO coinbase: 0x648a4b24cf769da5467bf9b008dace89d9f65a80
    NODE_TWO blocknumber: 1533
    NODE_ONE coinbase: 0x718cb4a34cac0fa4e9a37f249340078896b4dfa0
    ```
    We have builded private ethereum network cluster with the script writen on Ruby and Nodejs, those scripts able to communicate with our cluster using JSON-RPC protocol.
    It’s a good start to create your blockchain project based on Ethereum. 

    References:
    - https://ethereum.gitbooks.io/frontier-guide/content/index.html
    - http://www.ethdocs.org/en/latest/introduction/index.html
    - https://github.com/ethereum/wiki/wiki
    - https://github.com/ethereum/go-ethereum/wiki

    <sub>P.S. forgive me my bad English, it’s not my native language.</sub>