Genesis Block (Starting a New Blockchain Instance)

Fuzzybear edited this page Mar 19, 2015 · 23 revisions

Last edited Fri, 25 Apr 2014 16:29:42 GMT, by pennybreaker

This guide outlines the steps to manually generate a genesis block and start a new blockchain. Once the genesis block is generated, two nodes must be used to start the blockchain. This guide will show you how to do this on one machine, using two data directories and two instances of the daemon. Please note that it is also possible to do this using two physical or virtual machines.

Install Dependencies and Mini-UPnP

If Peershares has never been run on your machine, be sure to follow the Dependency and Mini-UPnP installation steps, located on the Linux wiki page: https://github.com/Peershares/Peershares/wiki/Linux

Clean-up Prior Work

If you have already been using your machine to test Peershares builds, it's a good idea to delete your prior working folders and start fresh.

$ rm -r ~/.peershares
$ rm -r ~/Peershares

Clone the Peershares Github Repository

$ git clone https://github.com/Peershares/Peershares.git

Get the current unix epoch time from the command line, or, from using a site like Epoch Converter.

$ date +%s

We'll use this in a few minutes, so copy it down.

Edit main.cpp

$ cd ~/Peershares/src/
$ (text editor) main.cpp

Be sure to turn on line numbering in your text editor. Edit the following lines ...

Main.cpp:L2260 - Change the value for the constant, pszTimestamp, to something unique, up to 91 characters:

const char* pszTimestamp = "YOUR CUSTOM, VERIFIABLE TIMESTAMP GOES HERE";

Main.cpp:L2261 - Change nTimeGenesis value to current epoch time (captured in the previous step). For example, when this guide was written, the epoch time was 1395169964, so it would be inserted as so:

unsigned int nTimeGenesis=1395169964;

Main.cpp:L2262 - Make sure that nNonceGenesis=0

Main.cpp:L2266 - For the TestNet genesis block, change the value for the constant, pszTimestamp, to something unique (same length rules apply as the previous timestamp string):

Main.cpp:L2267 - Change nTimeGenesis value to current epoch time stamp. This can match the value you used for the previous nTimeGenesis variable, or you can use the epoch time for when you modified this step, either is appropriate.

Main.cpp:L2268 - Make sure that nNonceGenesis=0

Complete set of changes from the previous steps:

if (fTestNet)
  {
    pszTimestamp="YOUR CUSTOM, VERIFIABLE TESTNET TIMESTAMP GOES HERE";
    nTimeGenesis=1395170250;
    nNonceGenesis=0;
  }

Save the file and exit.

Compile the daemon

$ make -f makefile.unix

Run the daemon

$ ./peersharesd --daemon

It should start and run for a few seconds then stop with an error. This error is our notification that the new genesis block has been generated. That was for real-net. Now lets generate one for testnet.

$ ./peersharesd --daemon -testnet

It will start and run for a few seconds then stop with an error like the first one. We now have two debug.log files located at: ~/.peershares/debug.log and ~/.peershares/testnet/debug.log. You will find an entry in both of these files starting with 'PPCoin Found Genesis Block:'. Under that entry, you will find values for 'genesis hash=', 'merkle root=' and 'nNonce=' ... We need those three values from both real-net and testnet debug.log files.

Edit main.cpp and kernel.cpp

$ cd ~/Peershares/src/
$ (text editor) main.cpp

Edit the following lines ...

Main.cpp:L24 - Change the value for the constant, hashGenesisBlockOfficial, to the new genesis hash value from debug.log. Paste the value in-between the quotation marks, after the leading 0x :

static const uint256 hashGenesisBlockOfficial("0x00000053229d58cdda911f4188240d4843f6bca1d8978d3349d87c38976463dd");

Main.cpp:L25 - Change the value for the constant, hashGenesisBlockTestNet, to the new genesis hash value from TestNet debug.log. Paste the value in-between the quotation marks, after the leading 0x :

static const uint256 hashGenesisBlockTestNet ("0x00000053229d58cdda911f4188240d4843f6bca1d8978d3349d87c38976463dd");

Main.cpp:L2262 - Change the value for nNonceGenesis to the new nNonce value from debug.log:

unsigned int nNonceGenesis=236800;

Main.cpp:L2268 - Change the value for nNonceGenesis to the new nNonce value from the TestNet debug.log:

unsigned int nNonceGenesis=236800;

Main.cpp:L2312 - Change the value for block.hashMerkleRoot == uint256, to the new merkle root hash value from debug.log. Paste the value in-between the quotation marks, after the leading 0x :

assert(block.hashMerkleRoot == uint256("0xf0e9ac2cef9820c036e397c738ae5cea91df3724f5418eb6a7450350f2702278"));

Main.cpp:L2314 - Change the value for block.hashMerkleRoot == uint256, to the new merkle root hash value from TestNet debug.log. Paste the value in-between the quotation marks, after the leading 0x :

assert(block.hashMerkleRoot == uint256("0xf0e9ac2cef9820c036e397c738ae5cea91df3724f5418eb6a7450350f2702278"));

Save and exit main.cpp ... Open kernel.cpp:

$ (text editor) kernel.cpp

nProtocolV03SwitchTime and nProtocolV03TestSwitchTime need to be set to a time in the future, after PoS starts. So just set these to several days in advance. Use the Epoch Converter to get the correct value.

Kernel.cpp:L14 - Change the value for nProtocolV03SwitchTime to the to the correct future time. Edit the number after the '=' sign and update the comment to reflect what it was changed to:

unsigned int nProtocolV03SwitchTime     = 1394841600; // 2014-03-15 00:00:00 UTC

Kernel.cpp:L15 - Change the value for nProtocolV03TestSwitchTime to the to the correct future time. Edit the number after the '=' sign and update the comment to reflect what it was changed to:

unsigned int nProtocolV03TestSwitchTime = 1396224000; // 2014-03-31 00:00:00 UTC

Save and exit kernel.cpp

Recompile the daemon

$ make -f makefile.unix BDB_INCLUDE_PATH="/usr/local/BerkeleyDB.4.8/include" BDB_LIB_PATH="/usr/local/BerkeleyDB.4.8/lib"

Remove and recreate working folder

Add a 2nd working folder for instance2, which is needed to start the blockchain.

$ rm -r ~/.peershares/
$ mkdir ~/.peershares/
$ mkdir ~/.peershares2/

Move the newly recompiled daemon to working folder

$ mv ppcoind ~/.peershares

Create conf file and start instance 1

$ cd ~/.peershares 
$ touch peershares.conf
$ (text editor) peershares.conf

Add the following lines to the conf file and save:

server=1
rpcallowip=127.0.0.1
listen=1
rpcuser=<anything>
rpcpassword=<anything>
dnsseed=0
port=9090
rpcport=9091
gen=1

Run the daemon

$ ./ppcoind --daemon

If it stops with an error about blkindex.dat when it is run for the first time, simply run it again and it should work. This is a known issue on the first run attempt.

Copy and rename daemon to 2nd instance

$ cp ppcoind ~/.peershares2/ppcoind2

Create conf file for 2nd instance

$ cd ~/.peershares2
$ touch peershares.conf
$ (text editor) peershares.conf

Add the following lines to the conf file and save:

server=1
rpcuser=<anything>
rpcpassword=<anything>
port=19090
rpcport=19091
gen=1

Run the 2nd instance of the daemon

We must specify the data directory so that the 2nd instance doesn't try to use '~/.peershares' and we must also specify that we want to connect to the IP address of our first instance, which, in this case, is localhost. Be sure to replace with your username. Note that datadir and connect commands can be added to your conf file to simplify things.

$ ./ppcoind2 --daemon -datadir=/home/<user>/.peershares2 -connect=127.0.0.1:9090

If either instance stops with an error about blkindex.dat when it is run for the first time, kill the instance and run again with the same command. It should work on the 2nd try. This is a known issue.

At this point, your new blockchain should be started and both instances should be generating PoW blocks. Check status with:

$ ./ppcoind getinfo
$ ./ppcoind getmininginfo
$ (text editor) debug.log

Or from the 2nd instance dir

$ ./ppcoind2 getinfo
$ ./ppcoind2 getmininginfo

If you wish to start a testnet, add testnet=1 to your conf files, stop and restart the daemons.

Note: If difficulty settings are changed in Main.cpp:L37 and Main.cpp:L38, you'll need to recreate the genesis block because the nonce/hash/merkel root will change.

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