Update docs to run Rococo relay chain

[nakul1010]

Problem

The current documentation for running the Rococo locally can be found here.

The testnet is down because the relay chain is still using a very old local commit and not the newer Polkadot version. Therefore, we need to use a new relay chain version.

• Polkadot launch: We used this previously, but the CLI tool is now deprecated.

Solution

To launch using Zombienet, follow these necessary steps:

Step 1: Download and Build Polkadot-SDK

git clone https://github.com/paritytech/polkadot-sdk.git
cd polkadot-sdk

git fetch --all --tags
git checkout tags/polkadot-v1.13.0

cargo build --release

cd ..

Step 2: Download and Build InterBTC

git clone https://github.com/interlay/interbtc.git
cd interbtc

git fetch --all --tags
git checkout tags/1.25.4

cargo build --release

cd ..

Step 3: Download Zombienet

Download Zombienet for the Linux version.

• Steps to setup Zombienet can be found in this article.

mkdir deployment_config
cd deployment_config

touch config.toml

Step 4: Configure Zombienet

Copy the following into the config.toml file:

[relaychain]  
default_command =  "../polkadot-sdk/target/release/polkadot"  
default_args = [ "-lparachain=debug" ]  
  
chain = "rococo-local"  
  
[[relaychain.nodes]]  
name = "alice"  
validator = true  
  
[[relaychain.nodes]]  
name = "bob"  
validator = true  
rpc_port = 30334
  
[[parachains]]  
id = 2032  
cumulus_based = true  
  
[parachains.collator]  
name = "alice"  
command = "../interbtc/target/release/interbtc-parachain"  
validator = true  
ws_port = 9946

Step 5: Run Zombienet

To run Zombienet, use:

./zombienet-macos -p native spawn config.toml

• Zombienet configs to hardcode ports, etc.

ToDos/Known Problems

Hardcode Default Chain

• Currently, it will start the Kintsugi parachain. To start the Interlay testnet chain, update the spec here to chain_spec::testnet_interlay::staging_mainnet_config(false).
• Need to find a way to specify the chain in the config file. Zombienet itself creates a chainspec.json based on chain = "rococo-local". Adding chain as arguments creates a wrong command.

Docker Images for SDK

• Instead of compiling the repos, use Docker images instead. Didn't find any other projects using it.

---