[](https://travis-ci.org/status-im/nim-beacon-chain)
[](https://dev.azure.com/nimbus-dev/nim-beacon-chain/_build/latest?definitionId=3&branchName=master)
* [ethereum/eth2.0-specs](https://github.com/ethereum/eth2.0-specs/blob/v0.9.2/specs/core/0_beacon-chain.md): Serenity specification that this project implements
Nimbus connects to any of the testnets published in the [eth2-clients/eth2-testnets repo](https://github.com/eth2-clients/eth2-testnets/tree/master/nimbus).
After installing the [prerequisites](#prerequisites)
To run the Nimbus state transition, we provide the `ncli` tool:
* [ncli](ncli)
The interop scripts have been moved in a common repo, the interop relied on 0.8.3 specs which had seen significant changes. The interop branch still exist but is unmaintained.
* [multinet](https://github.com/status-im/nim-beacon-chain/tree/master/multinet) - a set of scripts to build and run several Eth2 clients locally
The state transition simulator can quickly run the Beacon chain state transition function in isolation and output JSON snapshots of the state. The simulation runs without networking and blocks are processed without slot time delays.
```bash
# build and run the state simulator, then display its help ("-d:release" speeds it
# up substantially, allowing the simulation of longer runs in reasonable time)
The local network simulation will create a full peer-to-peer network of beacon nodes and validators on a single machine, and run the beacon chain in real time.
Parameters such as shard, validator counts, and data folders are configured [vars.sh](tests/simulation/vars.sh). They can be set in as environment variables before launching the simulation.
# In another terminal, get a shell with the right environment variables set:
./env.sh bash
# In the above example, the network is prepared for 7 beacon nodes but one of
# them is not started by default (`USER_NODES`) - this is useful to test
# catching up to the consensus. The following command will start the missing node.
./tests/simulation/run_node.sh 0 # (or the index (0-based) of the missing node)
# Running a separate node allows you to test sync as well as see what the action
# looks like from a single nodes' perspective.
```
You can also separate the output from each beacon node in its own panel, using [multitail](http://www.vanheusden.com/multitail/):
```bash
make USE_MULTITAIL="yes" eth2_network_simulation
```
You can find out more about it in the [development update](https://our.status.im/nimbus-development-update-2018-12-2/).
_Alternatively, fire up our [experimental Vagrant instance with Nim pre-installed](https://our.status.im/setting-up-a-local-vagrant-environment-for-nim-development/) and give us yout feedback about the process!_
### Visualising simulation metrics
The [generic instructions from the Nimbus repo](https://github.com/status-im/nimbus/#metric-visualisation) apply here as well.
Specific steps:
```bash
# This will generate the Prometheus config and the Grafana dashboard on the fly,
# based on the number of nodes (which you can control by passing something like NODES=6 to `make`).
make VALIDATORS=192 NODES=6 USER_NODES=0 eth2_network_simulation
Install Mingw-w64 for your architecture using the "[MinGW-W64 Online
Installer](https://sourceforge.net/projects/mingw-w64/files/)" (first link
under the directory listing). Run it and select your architecture in the setup
menu ("i686" on 32-bit, "x86\_64" on 64-bit), set the threads to "win32" and
the exceptions to "dwarf" on 32-bit and "seh" on 64-bit. Change the
installation directory to "C:\mingw-w64" and add it to your system PATH in "My
Computer"/"This PC" -> Properties -> Advanced system settings -> Environment
Variables -> Path -> Edit -> New -> C:\mingw-w64\mingw64\bin (it's "C:\mingw-w64\mingw32\bin" on 32-bit)
Install [Git for Windows](https://gitforwindows.org/) and use a "Git Bash" shell to clone and build nim-beacon-chain.
If you don't want to compile RocksDB and SQLite separately, you can fetch pre-compiled DLLs with:
```bash
mingw32-make # this first invocation will update the Git submodules
mingw32-make fetch-dlls # this will place the right DLLs for your architecture in the "build/" directory
```
You can now follow those instructions in the previous section by replacing `make` with `mingw32-make` (regardless of your 32-bit or 64-bit architecture):
