## Setting Up a Local FOCIL Devnet with Kurtosis
_Special thanks to [Parithosh](https://x.com/parithosh_j) for all the helps_
### Introduction
This document provides instructions for setting up and running a local devnet of Prysm and Geth prototypes using Kurtosis. We will build Docker images and use them to run Kurtosis. Docker image building scripts and Kurtosis configuration file can be found [here](https://github.com/jihoonsong/local-devnet-focil).
### Prerequisite
Before getting started, ensure that you have Docker and Kurtosis installed:
1. [Install Docker and start the Docker Daemon](https://docs.docker.com/get-docker)
2. [Install the Kurtosis CLI, or upgrade it to the latest version](https://docs.kurtosis.com/install)
### Build Prysm Docker Images
A Prysm validator client is compatible only with a Prysm CL client. We can build Docker images for both clients at the root of Prysm repository as follows:
**For AMD / x86 architecture**
```bash=
# Beacon node
bazel build //cmd/beacon-chain:oci_image_tarball --config=release
docker load -i bazel-bin/cmd/beacon-chain/oci_image_tarball/tarball.tar
# Validator client
bazel build //cmd/validator:oci_image_tarball --config=release
docker load -i bazel-bin/cmd/validator/oci_image_tarball/tarball.tar
# Retag the Docker images for Kurtosis.
docker image tag gcr.io/prysmaticlabs/prysm/beacon-chain:latest prysm-beacon-chain-focil:latest
docker image tag gcr.io/prysmaticlabs/prysm/validator:latest prysm-validator-focil:latest
# (Optional) Remove the intermediate Docker images.
docker image rm gcr.io/prysmaticlabs/prysm/beacon-chain:latest
docker image rm gcr.io/prysmaticlabs/prysm/validator:latest
```
**For ARM architecture (including Apple M1/M2/M3)**
```bash=
# Beacon node
bazel build //cmd/beacon-chain:oci_image_tarball --platforms=@io_bazel_rules_go//go/toolchain:linux_arm64_cgo --config=release
docker load -i bazel-bin/cmd/beacon-chain/oci_image_tarball/tarball.tar
# Validator client
bazel build //cmd/validator:oci_image_tarball --platforms=@io_bazel_rules_go//go/toolchain:linux_arm64_cgo --config=release
docker load -i bazel-bin/cmd/validator/oci_image_tarball/tarball.tar
# Retag the Docker images for Kurtosis.
docker image tag gcr.io/prysmaticlabs/prysm/beacon-chain:latest prysm-beacon-chain-focil:latest
docker image tag gcr.io/prysmaticlabs/prysm/validator:latest prysm-validator-focil:latest
# (Optional) Remove the intermediate Docker images.
docker image rm gcr.io/prysmaticlabs/prysm/beacon-chain:latest
docker image rm gcr.io/prysmaticlabs/prysm/validator:latest
```
For your convenience, you can place this [script](https://github.com/jihoonsong/local-devnet-focil/blob/main/prysm/build-focil.sh) in the Prysm repository and then execute it.
Please note that building Prysm Docker images is not supported on Windows. For more information, you can refer to [Prysm Documentation](https://docs.prylabs.network/docs/install/install-with-bazel#advanced-build-docker-images-from-source).
### Build Geth Docker Image
Building a Geth Docker image is simple:
```bash=
docker build . -t geth-focil:latest
```
Similarly, you can use a [script](https://github.com/jihoonsong/local-devnet-focil/blob/main/geth/build-focil.sh) instead, if you prefer.
### Run a Local FOCIL Devnet with Kurtosis
Now, we can run a local devnet using those Docker images built locally. Incorporating local changes would facilitate more effective testing.
First off, let's clone a repository:
```bash=
git clone https://github.com/jihoonsong/local-devnet-focil
```
You can launch a local devnet with Kurtosis:
```bash=
cd kurtosis
make run
```
After it's done, you should be able to see this:
### Access Dora the Explorer
To access Dora the Explorer, you can go to [localhost:65500](http://localhost:65500).
The port of Dora is currently fixed to `65500`. This is determined by the order of additional services so if you want to add other services under [`additional_services` in the Kurtosis configuration](https://github.com/jihoonsong/local-devnet-focil/blob/main/kurtosis/kurtosis.config.local.yaml#L15-L16), you might want to add them below `dora` to access Dora the Explorer at port `65500` consistently. You can find supported services [here](https://github.com/ethpandaops/ethereum-package/blob/main/README.md?plain=1#L643-L662).
You can also see the logs of Dora in the Docker app's container. The container name will be something like `dora--f95d74646f8744f58f5a09844fa92dc2`.
### Check Service Logs
It is important and helpful to see the service logs. When something goes wrong, you want to check the logs and find a problem.
To follow logs from all services:
```bash=
kurtosis service logs focil -f
```
This might be too verbose to see what each node is doing. We can specify the service name of each node to follow its logs exclusively. To get service names:
```bash=
kurtosis enclave inspect focil
```
You can see service names in the red rectangle. If you want to see logs of `snooper-engine-1-prysm-geth`:
```bash=
kurtosis service logs focil snooper-engine-1-prysm-geth -f
```
### Stop the Local Devnet
To stop the local devent:
```bash=
make stop
```
### Using Different Clients than Prysm and Geth
If you want to use different clients other than Prysm and Geth, you can replace [clients specified in the Kurtosis configuration file](https://github.com/jihoonsong/local-devnet-focil/blob/main/kurtosis/kurtosis.config.local.yaml#L2-L7) or add new ones. For example, if you want to use Teku and Geth, you can replace `participants` with:
```bash=
participants:
- el_type: geth
el_image: ethpandaops/geth:prague-devnet-5-a193537
cl_type: teku
cl_image: consensys/teku:develop
count: 2
```
### Miscellaneous
**Minimal Config**
You can set [preset to minimal](https://github.com/ethpandaops/ethereum-package/blob/main/.github/tests/deneb.yaml#L23) to use minimal config. It's mainly used for testing API compatibility, spec tests, MEV tests, etc.
However, we would want to use mainnet config for testing as minimal config often suffers from bugs outside of those use cases. Although we cannot change `slots_per_epoch` with mainnet config, setting `slots_per_second` to 3-6 seconds achieves most of what we want.
**Kurtosis CLI Completion**
Configuring [Kurtosis CLI Completion](https://docs.kurtosis.com/guides/adding-command-line-completion/) could make your life easier.
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