postcli

postcli

CLI tool for PoST initialization

Getting it

Go to the https://github.com/spacemeshos/post/releases and take the most recent release for your platform. In case if you want to build it from source, follow the instructions below.

git clone https://github.com/spacemeshos/post
cd post
make postcli

Usage

./postcli --help

Get OpenCL working

You need to have OpenCL support on your system. OpenCL usually comes with your graphics drivers. On Windows it should work out of the box on linux you will need to install them separately.

You can always list the providers by using

clinfo -l

That's separate command NOT shipped with post implementation. Please refer to your system installation manual of clinfo for installation instructions.

Nvidia

apt install nvidia-opencl-icd 

AMD

https://amdgpu-install.readthedocs.io/en/latest/install-script.html

Intel

https://github.com/intel/compute-runtime/releases

Print the list of compute providers

./postcli -printProviders

Print the number of files that would be initialized

./postcli -numUnits 100 -printNumFiles
1600

Print the used config and options

./postcli -printConfig

Initialize

Example

./postcli -provider=2 -id=c230c51669d1fcd35860131e438e234726b2bd5f9adbbd91bd88a718e7e98ecb -commitmentAtxId=c230c51669d1fcd35860131e438e234726b2bd5f9adbbd91bd88a718e7e98ecb -genproof

Initialize subset

It is possible to initialize only subset of the files. It's useful if one wants to split initialization between many machines.

Example - split initialization between 2 machines

Let's assume one wants to initialize 100 units and split the process of initialization to machine A and B.

First let's see how many files it would be:

./postcli -numUnits 100 -printNumFiles
1600

Next, on machine A:

./postcli -numUnits 100 -id <id> -commitmentAtxId <id> -toFile 799 -datadir ./dataA

We get the first half - 800 binary files

ls -la ./dataA/*.bin | wc -l
800

Next, on machine B:

./postcli -numUnits 100 -id <id> -commitmentAtxId <id> -fromFile 800 -datadir ./dataB

We get the second half - 800 binary files

ls -la ./dataB/*.bin | wc -l
800

Finally we can combine both sets together. A dummy example to get the feeling. Realisticly it would probably be copying over the network

cp ./dataA/* ./data/
cp ./dataB/* ./data/
ls -la ./data/*.bin | wc -l
1600

An optional step to select best possible VRF nonce Normally, when postcliinitializates from the start to the end it will automatically pick the best VRF nonce. The best means pointing to the label with the smallest value. This will avoid a longer initialization time when a node increases their PoST size in the future (not supported yet).

Now, when postcli initializes in chunks, each subset will find a valid vrf nonce, which represents the local minimum in the inititalized subset. It is recommended to select the best one (the global minimum).

The values of nonces are 128bit, represented as a 16B binary array in big endian. Given two nonces:

NonceA = 12345
NonceValueA = 0000ffda94993723a980bf557509773e
NonceB = 98765
NonceValueB = 0000488e171389cce69344d68b66f6b4

NonceB is the global minimum since its value is smaller than the one of NonceA.

The nonce (index) and noncevalue (the label) is included in the post_metadata.json. It is up to the operator to find the best VRF nonce manually and copy the Nonce and NonceValue to the postdata_metadata.json on the target machine.

Remarks

• -id and -commitmentAtxId are required because they are committed to the generated data.
• If -id isn't provided, the id (public key) will be auto-generated, while saving key.bin in -datadir.
• If postcli is called multiple times on a given -datadir, config mismatch error is likely to occur. In this case, the -reset flag can be used to easily clean the previous instance.

How to set the required options

• -commitmentAtxId: At the moment, there is no easy way to get that programaticaly. If you start to initialize before first 2 epochs finish then it's safe to use goldenATX value here. Later the best way to get it is to use grpc api of the node and call ActivationService::Highest() to get that value.
• -id: There are two options there, you can autogenerate it (do not provide it as an option) then there will be key.bin file in the -datadir folder which will have private key REMEMBER to copy it also. The other option is to provide the -id flag with the public key you want to use. In this case, the key.bin file will be NOT craeted. Make sure that you put the binary representation of the key there.