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pezkuwi-subxt/polkadot
Sergei Shulepov 47810dcac9 pvf-precheck: Integrate PVF pre-checking into paras module (#4457)
* pvf-precheck: Integrate PVF pre-checking into paras module

Closes #4009

This is the most of the runtime-side change needed for #3211.

Here is how it works.

The PVF pre-checking can be triggered either by an upgrade or by
onboarding (i.e. calling `schedule_para_initialize`). The PVF
pre-checking process is identified by the PVF code hash that is being
voted on. If there is already PVF pre-checking process running, then no
new PVF pre-checking process will be started. Instead, we just subscribe
to the existing one.

If there is no PVF pre-checking process running but the PVF code hash
was already saved in the storage, that necessarily means (I invite the
reviewers to double-check this invariant) that the PVF already passed
pre-checking. This is equivalent to instant approving of the PVF.

The pre-checking process can be concluded either by obtaining a
supermajority or if it expires.

Each validator checks the list of PVFs available for voting. The vote is
binary, i.e. accept or reject a given PVF. As soon as the supermajority
of votes are collected for one of the sides of the vote, the voting is
concluded in that direction and the effects of the voting are enacted.

Only validators from the active set can participate in the vote. The set
of active validators can change each session. That's why we reset the
votes each session. A voting that observed a certain number of sessions
will be rejected.

The effects of the PVF accepting depend on the operations requested it:

1. All onboardings subscribed to the approved PVF pre-checking process will
get scheduled and after passing 2 session boundaries they will be onboarded.
2. All upgrades subscribed to the approved PVF pre-checking process will
get scheduled very similarly to the existing process. Upgrades with
pre-checking are really the same process that is just delayed by the
time required for pre-checking voting. In case of instant approval the
mechanism is exactly the same. This is important from parachains
compatibility standpoint since following the delayed upgrade requires
the parachain to implement
https://github.com/paritytech/cumulus/pull/517.

In case, PVF pre-checking process was concluded with rejection, then all
the requesting operations get cancelled. For onboarding it means it gets
without movement: the lifecycle of such parachain is terminated on the
`Onboarding` state and after rejection the lifecycle is none. That in
turn means that the caller can attempt registering the parachain once
more. For upgrading it means that the upgrade process is aborted: that
flashes go-ahead signal with `Abort` flag.

Rejection leads to removing the allegedly bad validation code from the
chain storage. Among other things, this implies that the operation can
be re-requested. That allows for retrying an operation in case there was
some bug. At the same time it does not look as a DoS vector due to the
caching performed by the nodes.

PVF pre-checking can be enabled and disabled. Initially, according to
the changes in #4420, this mechanism is disabled. Triggering the PVF
pre-checking when it is disabled just means that we insta approve the
requesting operation. This should lead to the behavior being unchanged.

Follow-ups:

- expose runtime APIs

* cargo run --quiet --release --features=runtime-benchmarks -- benchmark --chain=polkadot-dev --steps=50 --repeat=20 --pallet=runtime_parachains::paras --extrinsic=* --execution=wasm --wasm-execution=compiled --heap-pages=4096 --header=./file_header.txt --output=./runtime/polkadot/src/weights/runtime_parachains_paras.rs

* cargo run --quiet --release --features=runtime-benchmarks -- benchmark --chain=westend-dev --steps=50 --repeat=20 --pallet=runtime_parachains::paras --extrinsic=* --execution=wasm --wasm-execution=compiled --heap-pages=4096 --header=./file_header.txt --output=./runtime/westend/src/weights/runtime_parachains_paras.rs

* cargo run --quiet --release --features=runtime-benchmarks -- benchmark --chain=kusama-dev --steps=50 --repeat=20 --pallet=runtime_parachains::paras --extrinsic=* --execution=wasm --wasm-execution=compiled --heap-pages=4096 --header=./file_header.txt --output=./runtime/kusama/src/weights/runtime_parachains_paras.rs

* cargo run --quiet --release --features runtime-benchmarks -- benchmark --chain=rococo-dev --steps=50 --repeat=20 --pallet=runtime_parachains::paras --extrinsic=* --execution=wasm --wasm-execution=compiled --heap-pages=4096 --header=./file_header.txt --output=./runtime/rococo/src/weights/runtime_parachains_paras.rs

* Review fixes

Co-authored-by: Parity Bot <admin@parity.io>
2021-12-16 17:14:40 +01:00
..
2021-12-13 12:20:49 +01:00

Polkadot

Implementation of a https://polkadot.network node in Rust based on the Substrate framework.

NOTE: In 2018, we split our implementation of "Polkadot" from its development framework "Substrate". See the Substrate repo for git history prior to 2018.

This repo contains runtimes for the Polkadot, Kusama, and Westend networks. The README provides information about installing the polkadot binary and developing on the codebase. For more specific guides, like how to be a validator, see the Polkadot Wiki.

Installation

If you just wish to run a Polkadot node without compiling it yourself, you may either run the latest binary from our releases page, or install Polkadot from one of our package repositories.

Installation from the Debian or rpm repositories will create a systemd service that can be used to run a Polkadot node. This is disabled by default, and can be started by running systemctl start polkadot on demand (use systemctl enable polkadot to make it auto-start after reboot). By default, it will run as the polkadot user. Command-line flags passed to the binary can be customized by editing /etc/default/polkadot. This file will not be overwritten on updating polkadot. You may also just run the node directly from the command-line.

Debian-based (Debian, Ubuntu)

Currently supports Debian 10 (Buster) and Ubuntu 20.04 (Focal), and derivatives. Run the following commands as the root user.

# Import the security@parity.io GPG key
gpg --recv-keys --keyserver hkps://keys.mailvelope.com 9D4B2B6EB8F97156D19669A9FF0812D491B96798
gpg --export 9D4B2B6EB8F97156D19669A9FF0812D491B96798 > /usr/share/keyrings/parity.gpg
# Add the Parity repository and update the package index
echo 'deb [signed-by=/usr/share/keyrings/parity.gpg] https://releases.parity.io/deb release main' > /etc/apt/sources.list.d/parity.list
apt update
# Install the `parity-keyring` package - This will ensure the GPG key
# used by APT remains up-to-date
apt install parity-keyring
# Install polkadot
apt install polkadot

RPM-based (Fedora, CentOS)

Currently supports Fedora 32 and CentOS 8, and derivatives.

# Install dnf-plugins-core (This might already be installed)
dnf install dnf-plugins-core
# Add the repository and enable it
dnf config-manager --add-repo https://releases.parity.io/rpm/polkadot.repo
dnf config-manager --set-enabled polkadot
# Install polkadot (You may have to confirm the import of the GPG key, which
# should have the following fingerprint: 9D4B2B6EB8F97156D19669A9FF0812D491B96798)
dnf install polkadot

Building

Install via Cargo

Make sure you have the support software installed from the Build from Source section below this section.

If you want to install Polkadot in your PATH, you can do so with with:

cargo install --git https://github.com/paritytech/polkadot --tag <version> polkadot --locked

Build from Source

If you'd like to build from source, first install Rust. You may need to add Cargo's bin directory to your PATH environment variable. Restarting your computer will do this for you automatically.

curl https://sh.rustup.rs -sSf | sh

If you already have Rust installed, make sure you're using the latest version by running:

rustup update

Once done, finish installing the support software:

sudo apt install build-essential git clang libclang-dev pkg-config libssl-dev

Build the client by cloning this repository and running the following commands from the root directory of the repo:

git checkout <latest tagged release>
./scripts/init.sh
cargo build --release

Note that compilation is a memory intensive process. We recommend having 4 GiB of physical RAM or swap available (keep in mind that if a build hits swap it tends to be very slow).

Build from Source with Docker

You can also build from source using Parity CI docker image:

git checkout <latest tagged release>
docker run --rm -it -w /shellhere/polkadot \
                    -v $(pwd):/shellhere/polkadot \
                    paritytech/ci-linux:production cargo build --release
sudo chown -R $(id -u):$(id -g) target/

If you want to reproduce other steps of CI process you can use the following guide.

Networks

This repo supports runtimes for Polkadot, Kusama, and Westend.

Connect to Polkadot Mainnet

Connect to the global Polkadot Mainnet network by running:

./target/release/polkadot --chain=polkadot

You can see your node on telemetry (set a custom name with --name "my custom name").

Connect to the "Kusama" Canary Network

Connect to the global Kusama canary network by running:

./target/release/polkadot --chain=kusama

You can see your node on telemetry (set a custom name with --name "my custom name").

Connect to the Westend Testnet

Connect to the global Westend testnet by running:

./target/release/polkadot --chain=westend

You can see your node on telemetry (set a custom name with --name "my custom name").

Obtaining DOTs

If you want to do anything on Polkadot, Kusama, or Westend, then you'll need to get an account and some DOT, KSM, or WND tokens, respectively. See the claims instructions for Polkadot if you have DOTs to claim. For Westend's WND tokens, see the faucet instructions on the Wiki.

Hacking on Polkadot

If you'd actually like to hack on Polkadot, you can grab the source code and build it. Ensure you have Rust and the support software installed. This script will install or update Rust and install the required dependencies (this may take up to 30 minutes on Mac machines):

curl https://getsubstrate.io -sSf | bash -s -- --fast

Then, grab the Polkadot source code:

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

Then build the code. You will need to build in release mode (--release) to start a network. Only use debug mode for development (faster compile times for development and testing).

./scripts/init.sh   # Install WebAssembly. Update Rust
cargo build # Builds all native code

You can run the tests if you like:

cargo test --all

You can start a development chain with:

cargo run -- --dev

Detailed logs may be shown by running the node with the following environment variables set:

RUST_LOG=debug RUST_BACKTRACE=1 cargo run----dev

Development

You can run a simple single-node development "network" on your machine by running:

polkadot --dev

You can muck around by heading to https://polkadot.js.org/apps and choose "Local Node" from the Settings menu.

Local Two-node Testnet

If you want to see the multi-node consensus algorithm in action locally, then you can create a local testnet. You'll need two terminals open. In one, run:

polkadot --chain=polkadot-local --alice -d /tmp/alice

And in the other, run:

polkadot --chain=polkadot-local --bob -d /tmp/bob --port 30334 --bootnodes '/ip4/127.0.0.1/tcp/30333/p2p/ALICE_BOOTNODE_ID_HERE'

Ensure you replace ALICE_BOOTNODE_ID_HERE with the node ID from the output of the first terminal.

Using Docker

Using Docker

Shell Completion

Shell Completion

Contributing

Contributing Guidelines

Contribution Guidelines

Contributor Code of Conduct

Code of Conduct

License

Polkadot is GPL 3.0 licensed.