Originating a Smart Rollup

This blog post will assume that you have access to the octez-smart-rollup-client-PtMumbai and the octez-client binaries, you can install them by following this documentation.

$ curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

$ git clone git@gitlab.com:tezos/kernel-gallery.git

You will notice a file rust-toolchain that forces the rust to use the version 1.66.0. To make sure you have the correct installed Rust version you can use this command:

$ rustup --version
> rustup 1.26.0 (5af9b9484 2023-04-05)
> info: This is the version for the rustup toolchain manager, not the rustc compiler.
> info: The currently active `rustc` version is `rustc 1.66.0 (69f9c33d7 2022-12-12)

The kernels are compile to Wasm, to compile some Rust code to Wasm you need to add the wasm32-unknown-unknown to the Rust compiler

$ rustup target add wasm32-unknown-unknown
> info: downloading component 'rust-std' for 'wasm32-unknown-unknown'
> info: installing component 'rust-std' for 'wasm32-unknown-unknown'

$ cargo build --target wasm32-unknown-unknown
> ...
> Finished dev [unoptimized + debuginfo] target(s) in 8.61s

On Macos you may have some troubles when compiling the Kernel Gallery, so we added a section in the readme of the Kernel Gallery to help you solve the issue

$ cd 00_debug_kernel
$ cargo build --release --target wasm32-unknown-unknown
> Finished release [optimized] target(s) in 0.16s

A wasm file should be present under ../target/wasm32-unknown-unknown/release/debug_kernel.wasm

$ cd ../
$ ls -lh target/wasm32-unknown-unknown/release/debug_kernel.wasm

To reduce the size of the kernel, you can use wasm-strip. Be careful, wasm-strip will replace the existing kernel.

$ wasm-strip target/wasm32-unknown-unknown/release/debug_kernel.wasm

$ xxd -ps -c 0 target/wasm32-unknown-unknown/release/debug_kernel.wasm | tr -d '\n' > kernel.hex

A kernel.hex should be present on your computer then.

$ octez-client --endpoint https://ghostnet.tezos.marigold.dev config update
$ octez-client originate smart rollup "my-rollup" \
  from "bob" \
  of kind wasm_2_0_0 \
  of type unit \
  with kernel "file:kernel.hex" \
  --burn-cap 999 \
  --force
> Estimated gas: 2748.229 units (will add 100 for safety)
> Estimated storage: 6552 bytes added (will add 20 for safety)
> Operation successfully injected in the node
> ...
> Smart rollup sr1xxxxxx memorized as "my-rollup"

No need to remember the name of your rollup, we will use the alias "my-rollup" in the next step.

Finally, you can start your rollup. The --data-dir represents the data directory of your rollup.

$ octez-smart-rollup-node-PtNairob run operator \
    for "my-rollup" \
    with operators "bob" \
    --data-dir "rollup"

But it might happen that your kernel is bigger than 24KB even after using wasm-strip. Because a Tezos operation size is limited to 32Kb, you can't directly originate your kernel on the layer 1.

Let use the debug kernel without using wasm-stripas a big kernel.

$ cd 00_debug_kernel
$ cargo build --release --target wasm32-unknown-unknown
$ cd ../

To originate this kernel, we will use the data reveal channel of the rollup, the name of the data reveal channel folder is wasm_2_0_0, and it is located under the data directory of your rollup.

$ cargo install tezos-smart-rollup-installer

$ smart-rollup-installer get-reveal-installer \
    --upgrade-to target/wasm32-unknown-unknown/release/debug_kernel.wasm \
    --output kernel.hex \
    --preimages-dir rollup/wasm_2_0_0

A folder rollup should be present on your machine. This folder is the data directory of your rollup, the folder that interest us the most is the subfolder wasm_2_0_0, it's the data reveal directory, it contains your kernel splitted into different chunks of 4Kb.

The command should have also created a kernel.hex . This kernel will install your kernel by reading the data reveal channel.

$ octez-client originate smart rollup "my-rollup" \
  from "bob" \
  of kind wasm_2_0_0 \
  of type unit \
  with kernel "file:kernel.hex" \
  --burn-cap 999 \
  --force

Finally, you can start your rollup. Be careful, the --data-dir should point to the folder generated previously by the get-reveal-installer command.

$ octez-smart-rollup-node-PtNairob run operator \
    for "my-rollup" \
    with operators "bob" \
    --data-dir "rollup"