Replace free for all collation in cumulus runtimes (#1251)

Partially fixes #103 

This PR removes instances of "free for all" collation in the `glutton`,
`shell`, and `seedling` runtimes and replaces them with Aura instances.
Aura is configured without a session manager, so the initial authority
set cannot be changed later on.

---------

Signed-off-by: georgepisaltu <george.pisaltu@parity.io>

cumulus/parachains/runtimes/glutton/glutton-kusama/Cargo.toml

@@ -16,10 +16,13 @@ frame-system = { path = "../../../../../substrate/frame/system", default-feature
 frame-system-rpc-runtime-api = { path = "../../../../../substrate/frame/system/rpc/runtime-api", default-features = false}
 frame-system-benchmarking = { path = "../../../../../substrate/frame/system/benchmarking", default-features = false, optional = true}
 frame-try-runtime = { path = "../../../../../substrate/frame/try-runtime", default-features = false, optional = true}
+pallet-aura = { path = "../../../../../substrate/frame/aura", default-features = false}
 pallet-glutton = { path = "../../../../../substrate/frame/glutton", default-features = false, optional = true}
 pallet-sudo = { path = "../../../../../substrate/frame/sudo", default-features = false, optional = true}
+pallet-timestamp = { path = "../../../../../substrate/frame/timestamp", default-features = false }
 sp-api = { path = "../../../../../substrate/primitives/api", default-features = false}
 sp-block-builder = { path = "../../../../../substrate/primitives/block-builder", default-features = false}
+sp-consensus-aura = { path = "../../../../../substrate/primitives/consensus/aura", default-features = false }
 sp-core = { path = "../../../../../substrate/primitives/core", default-features = false}
 sp-inherents = { path = "../../../../../substrate/primitives/inherents", default-features = false}
 sp-offchain = { path = "../../../../../substrate/primitives/offchain", default-features = false}
@@ -36,9 +39,11 @@ xcm-builder = { package = "staging-xcm-builder", path = "../../../../../polkadot
 xcm-executor = { package = "staging-xcm-executor", path = "../../../../../polkadot/xcm/xcm-executor", default-features = false}
 
 # Cumulus
+cumulus-pallet-aura-ext = { path = "../../../../pallets/aura-ext", default-features = false }
 cumulus-pallet-parachain-system = { path = "../../../../pallets/parachain-system", default-features = false, features = ["parameterized-consensus-hook",] }
 cumulus-pallet-xcm = { path = "../../../../pallets/xcm", default-features = false }
 cumulus-primitives-core = { path = "../../../../primitives/core", default-features = false }
+cumulus-primitives-timestamp = { path = "../../../../primitives/timestamp", default-features = false }
 parachain-info = { path = "../../../pallets/parachain-info", default-features = false }
 parachains-common = { path = "../../../common", default-features = false }
 
@@ -55,6 +60,7 @@ runtime-benchmarks = [
 	"frame-system/runtime-benchmarks",
 	"pallet-glutton/runtime-benchmarks",
 	"pallet-sudo?/runtime-benchmarks",
+	"pallet-timestamp/runtime-benchmarks",
 	"parachains-common/runtime-benchmarks",
 	"sp-runtime/runtime-benchmarks",
 	"xcm-builder/runtime-benchmarks",
@@ -62,9 +68,11 @@ runtime-benchmarks = [
 ]
 std = [
 	"codec/std",
+	"cumulus-pallet-aura-ext/std",
 	"cumulus-pallet-parachain-system/std",
 	"cumulus-pallet-xcm/std",
 	"cumulus-primitives-core/std",
+	"cumulus-primitives-timestamp/std",
 	"frame-benchmarking?/std",
 	"frame-executive/std",
 	"frame-support/std",
@@ -72,13 +80,16 @@ std = [
 	"frame-system-rpc-runtime-api/std",
 	"frame-system/std",
 	"frame-try-runtime?/std",
+	"pallet-aura/std",
 	"pallet-glutton/std",
 	"pallet-sudo/std",
+	"pallet-timestamp/std",
 	"parachain-info/std",
 	"parachains-common/std",
 	"scale-info/std",
 	"sp-api/std",
 	"sp-block-builder/std",
+	"sp-consensus-aura/std",
 	"sp-core/std",
 	"sp-inherents/std",
 	"sp-offchain/std",
@@ -93,14 +104,19 @@ std = [
 	"xcm/std",
 ]
 try-runtime = [
+	"cumulus-pallet-aura-ext/try-runtime",
 	"cumulus-pallet-parachain-system/try-runtime",
 	"cumulus-pallet-xcm/try-runtime",
 	"frame-executive/try-runtime",
 	"frame-support/try-runtime",
 	"frame-system/try-runtime",
 	"frame-try-runtime/try-runtime",
+	"pallet-aura/try-runtime",
 	"pallet-glutton/try-runtime",
 	"pallet-sudo/try-runtime",
+	"pallet-timestamp/try-runtime",
 	"parachain-info/try-runtime",
 	"sp-runtime/try-runtime",
 ]
+
+experimental = [ "pallet-aura/experimental" ]

cumulus/parachains/runtimes/glutton/glutton-kusama/src/lib.rs

@@ -46,11 +46,12 @@ include!(concat!(env!("OUT_DIR"), "/wasm_binary.rs"));
 pub mod weights;
 pub mod xcm_config;
 
-use cumulus_pallet_parachain_system::RelayNumberStrictlyIncreases;
+use cumulus_pallet_parachain_system::RelayNumberMonotonicallyIncreases;
 use sp_api::impl_runtime_apis;
-use sp_core::OpaqueMetadata;
+pub use sp_consensus_aura::sr25519::AuthorityId as AuraId;
+use sp_core::{crypto::KeyTypeId, OpaqueMetadata};
 use sp_runtime::{
-	create_runtime_str, generic,
+	create_runtime_str, generic, impl_opaque_keys,
 	traits::{AccountIdLookup, BlakeTwo256, Block as BlockT},
 	transaction_validity::{TransactionSource, TransactionValidity},
 	ApplyExtrinsicResult,
@@ -64,24 +65,37 @@ pub use frame_support::{
 	construct_runtime,
 	dispatch::DispatchClass,
 	parameter_types,
-	traits::{Everything, IsInVec, Randomness},
+	traits::{
+		ConstBool, ConstU32, ConstU64, ConstU8, EitherOfDiverse, Everything, IsInVec, Randomness,
+	},
 	weights::{
 		constants::{
 			BlockExecutionWeight, ExtrinsicBaseWeight, RocksDbWeight, WEIGHT_REF_TIME_PER_SECOND,
 		},
 		IdentityFee, Weight,
 	},
-	StorageValue,
+	PalletId, StorageValue,
 };
 use frame_system::{
 	limits::{BlockLength, BlockWeights},
 	EnsureRoot,
 };
-use parachains_common::{AccountId, Signature};
+use parachains_common::{
+	kusama::consensus::{
+		BLOCK_PROCESSING_VELOCITY, RELAY_CHAIN_SLOT_DURATION_MILLIS, UNINCLUDED_SEGMENT_CAPACITY,
+	},
+	AccountId, Signature, SLOT_DURATION,
+};
 #[cfg(any(feature = "std", test))]
 pub use sp_runtime::BuildStorage;
 pub use sp_runtime::{Perbill, Permill};
 
+impl_opaque_keys! {
+	pub struct SessionKeys {
+		pub aura: Aura,
+	}
+}
+
 #[sp_version::runtime_version]
 pub const VERSION: RuntimeVersion = RuntimeVersion {
 	spec_name: create_runtime_str!("glutton"),
@@ -178,12 +192,35 @@ impl cumulus_pallet_parachain_system::Config for Runtime {
 	type ReservedDmpWeight = ReservedDmpWeight;
 	type XcmpMessageHandler = ();
 	type ReservedXcmpWeight = ();
-	type CheckAssociatedRelayNumber = RelayNumberStrictlyIncreases;
-	type ConsensusHook = cumulus_pallet_parachain_system::consensus_hook::ExpectParentIncluded;
+	type CheckAssociatedRelayNumber = RelayNumberMonotonicallyIncreases;
+	type ConsensusHook = cumulus_pallet_aura_ext::FixedVelocityConsensusHook<
+		Runtime,
+		RELAY_CHAIN_SLOT_DURATION_MILLIS,
+		BLOCK_PROCESSING_VELOCITY,
+		UNINCLUDED_SEGMENT_CAPACITY,
+	>;
 }
 
 impl parachain_info::Config for Runtime {}
 
+impl cumulus_pallet_aura_ext::Config for Runtime {}
+
+impl pallet_timestamp::Config for Runtime {
+	type Moment = u64;
+	type OnTimestampSet = Aura;
+	type MinimumPeriod = ConstU64<{ SLOT_DURATION / 2 }>;
+	type WeightInfo = weights::pallet_timestamp::WeightInfo<Runtime>;
+}
+
+impl pallet_aura::Config for Runtime {
+	type AuthorityId = AuraId;
+	type DisabledValidators = ();
+	type MaxAuthorities = ConstU32<100_000>;
+	type AllowMultipleBlocksPerSlot = ConstBool<false>;
+	#[cfg(feature = "experimental")]
+	type SlotDuration = pallet_aura::MinimumPeriodTimesTwo<Self>;
+}
+
 impl pallet_glutton::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type WeightInfo = weights::pallet_glutton::WeightInfo<Runtime>;
@@ -204,6 +241,7 @@ construct_runtime! {
 			Pallet, Call, Config<T>, Storage, Inherent, Event<T>, ValidateUnsigned,
 		} = 1,
 		ParachainInfo: parachain_info::{Pallet, Storage, Config<T>} = 2,
+		Timestamp: pallet_timestamp::{Pallet, Call, Storage, Inherent} = 3,
 
 		// DMP handler.
 		CumulusXcm: cumulus_pallet_xcm::{Pallet, Call, Storage, Event<T>, Origin} = 10,
@@ -211,6 +249,10 @@ construct_runtime! {
 		// The main stage.
 		Glutton: pallet_glutton::{Pallet, Call, Storage, Event, Config<T>} = 20,
 
+		// Collator support
+		Aura: pallet_aura::{Pallet, Storage, Config<T>} = 30,
+		AuraExt: cumulus_pallet_aura_ext::{Pallet, Storage, Config<T>} = 31,
+
 		// Sudo.
 		Sudo: pallet_sudo::{Pallet, Call, Storage, Event<T>, Config<T>} = 255,
 	}
@@ -295,6 +337,16 @@ impl_runtime_apis! {
 		}
 	}
 
+	impl sp_consensus_aura::AuraApi<Block, AuraId> for Runtime {
+		fn slot_duration() -> sp_consensus_aura::SlotDuration {
+			sp_consensus_aura::SlotDuration::from_millis(Aura::slot_duration())
+		}
+
+		fn authorities() -> Vec<AuraId> {
+			Aura::authorities().into_inner()
+		}
+	}
+
 	impl sp_block_builder::BlockBuilder<Block> for Runtime {
 		fn apply_extrinsic(
 			extrinsic: <Block as BlockT>::Extrinsic,
@@ -332,12 +384,14 @@ impl_runtime_apis! {
 	}
 
 	impl sp_session::SessionKeys<Block> for Runtime {
-		fn decode_session_keys(_: Vec<u8>) -> Option<Vec<(Vec<u8>, sp_core::crypto::KeyTypeId)>> {
-			Some(Vec::new())
+		fn generate_session_keys(seed: Option<Vec<u8>>) -> Vec<u8> {
+			SessionKeys::generate(seed)
 		}
 
-		fn generate_session_keys(_: Option<Vec<u8>>) -> Vec<u8> {
-			Vec::new()
+		fn decode_session_keys(
+			encoded: Vec<u8>,
+		) -> Option<Vec<(Vec<u8>, KeyTypeId)>> {
+			SessionKeys::decode_into_raw_public_keys(&encoded)
 		}
 	}
 
@@ -402,5 +456,5 @@ impl_runtime_apis! {
 
 cumulus_pallet_parachain_system::register_validate_block! {
 	Runtime = Runtime,
-	BlockExecutor = Executive,
+	BlockExecutor = cumulus_pallet_aura_ext::BlockExecutor::<Runtime, Executive>,
 }

cumulus/parachains/runtimes/glutton/glutton-kusama/src/weights/mod.rs

@@ -15,3 +15,4 @@
 // along with Cumulus.  If not, see <http://www.gnu.org/licenses/>.
 
 pub mod pallet_glutton;
+pub mod pallet_timestamp;

cumulus/parachains/runtimes/glutton/glutton-kusama/src/weights/pallet_timestamp.rs

@@ -0,0 +1,75 @@
+// Copyright Parity Technologies (UK) Ltd.
+// This file is part of Cumulus.
+
+// Cumulus is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Cumulus is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Cumulus.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Autogenerated weights for `pallet_timestamp`
+//!
+//! THIS FILE WAS AUTO-GENERATED USING THE SUBSTRATE BENCHMARK CLI VERSION 4.0.0-dev
+//! DATE: 2023-07-31, STEPS: `50`, REPEAT: `20`, LOW RANGE: `[]`, HIGH RANGE: `[]`
+//! WORST CASE MAP SIZE: `1000000`
+//! HOSTNAME: `runner-ynta1nyy-project-238-concurrent-0`, CPU: `Intel(R) Xeon(R) CPU @ 2.60GHz`
+//! EXECUTION: ``, WASM-EXECUTION: `Compiled`, CHAIN: `Some("asset-hub-kusama-dev")`, DB CACHE: 1024
+
+// Executed Command:
+// ./target/production/polkadot-parachain
+// benchmark
+// pallet
+// --chain=asset-hub-kusama-dev
+// --wasm-execution=compiled
+// --pallet=pallet_timestamp
+// --no-storage-info
+// --no-median-slopes
+// --no-min-squares
+// --extrinsic=*
+// --steps=50
+// --repeat=20
+// --json
+// --header=./file_header.txt
+// --output=./parachains/runtimes/assets/asset-hub-kusama/src/weights/
+
+#![cfg_attr(rustfmt, rustfmt_skip)]
+#![allow(unused_parens)]
+#![allow(unused_imports)]
+#![allow(missing_docs)]
+
+use frame_support::{traits::Get, weights::Weight};
+use core::marker::PhantomData;
+
+/// Weight functions for `pallet_timestamp`.
+pub struct WeightInfo<T>(PhantomData<T>);
+impl<T: frame_system::Config> pallet_timestamp::WeightInfo for WeightInfo<T> {
+	/// Storage: `Timestamp::Now` (r:1 w:1)
+	/// Proof: `Timestamp::Now` (`max_values`: Some(1), `max_size`: Some(8), added: 503, mode: `MaxEncodedLen`)
+	/// Storage: `Aura::CurrentSlot` (r:1 w:0)
+	/// Proof: `Aura::CurrentSlot` (`max_values`: Some(1), `max_size`: Some(8), added: 503, mode: `MaxEncodedLen`)
+	fn set() -> Weight {
+		// Proof Size summary in bytes:
+		//  Measured:  `86`
+		//  Estimated: `1493`
+		// Minimum execution time: 9_313_000 picoseconds.
+		Weight::from_parts(9_775_000, 0)
+			.saturating_add(Weight::from_parts(0, 1493))
+			.saturating_add(T::DbWeight::get().reads(2))
+			.saturating_add(T::DbWeight::get().writes(1))
+	}
+	fn on_finalize() -> Weight {
+		// Proof Size summary in bytes:
+		//  Measured:  `57`
+		//  Estimated: `0`
+		// Minimum execution time: 3_322_000 picoseconds.
+		Weight::from_parts(3_577_000, 0)
+			.saturating_add(Weight::from_parts(0, 0))
+	}
+}

cumulus/parachains/runtimes/starters/seedling/Cargo.toml

@@ -12,10 +12,13 @@ scale-info = { version = "2.9.0", default-features = false, features = ["derive"
 frame-executive = { path = "../../../../../substrate/frame/executive", default-features = false}
 frame-support = { path = "../../../../../substrate/frame/support", default-features = false}
 frame-system = { path = "../../../../../substrate/frame/system", default-features = false}
+pallet-aura = { path = "../../../../../substrate/frame/aura", default-features = false}
 pallet-balances = { path = "../../../../../substrate/frame/balances", default-features = false}
 pallet-sudo = { path = "../../../../../substrate/frame/sudo", default-features = false}
+pallet-timestamp = { path = "../../../../../substrate/frame/timestamp", default-features = false }
 sp-api = { path = "../../../../../substrate/primitives/api", default-features = false}
 sp-block-builder = { path = "../../../../../substrate/primitives/block-builder", default-features = false}
+sp-consensus-aura = { path = "../../../../../substrate/primitives/consensus/aura", default-features = false }
 sp-core = { path = "../../../../../substrate/primitives/core", default-features = false}
 sp-inherents = { path = "../../../../../substrate/primitives/inherents", default-features = false}
 sp-offchain = { path = "../../../../../substrate/primitives/offchain", default-features = false}
@@ -26,11 +29,13 @@ sp-transaction-pool = { path = "../../../../../substrate/primitives/transaction-
 sp-version = { path = "../../../../../substrate/primitives/version", default-features = false}
 
 # Cumulus
+cumulus-pallet-aura-ext = { path = "../../../../pallets/aura-ext", default-features = false }
 cumulus-pallet-parachain-system = { path = "../../../../pallets/parachain-system", default-features = false, features = ["parameterized-consensus-hook",] }
 cumulus-pallet-solo-to-para = { path = "../../../../pallets/solo-to-para", default-features = false }
+cumulus-primitives-core = { path = "../../../../primitives/core", default-features = false }
+cumulus-primitives-timestamp = { path = "../../../../primitives/timestamp", default-features = false }
 parachain-info = { path = "../../../pallets/parachain-info", default-features = false }
 parachains-common = { path = "../../../common", default-features = false }
-cumulus-primitives-core = { path = "../../../../primitives/core", default-features = false }
 
 [build-dependencies]
 substrate-wasm-builder = { path = "../../../../../substrate/utils/wasm-builder", optional = true }
@@ -39,19 +44,24 @@ substrate-wasm-builder = { path = "../../../../../substrate/utils/wasm-builder",
 default = [ "std" ]
 std = [
 	"codec/std",
+	"cumulus-pallet-aura-ext/std",
 	"cumulus-pallet-parachain-system/std",
 	"cumulus-pallet-solo-to-para/std",
 	"cumulus-primitives-core/std",
+	"cumulus-primitives-timestamp/std",
 	"frame-executive/std",
 	"frame-support/std",
 	"frame-system/std",
+	"pallet-aura/std",
 	"pallet-balances/std",
 	"pallet-sudo/std",
+	"pallet-timestamp/std",
 	"parachain-info/std",
 	"parachains-common/std",
 	"scale-info/std",
 	"sp-api/std",
 	"sp-block-builder/std",
+	"sp-consensus-aura/std",
 	"sp-core/std",
 	"sp-inherents/std",
 	"sp-offchain/std",
@@ -62,3 +72,5 @@ std = [
 	"sp-version/std",
 	"substrate-wasm-builder",
 ]
+
+experimental = [ "pallet-aura/experimental" ]

cumulus/parachains/runtimes/starters/seedling/src/lib.rs

@@ -27,11 +27,12 @@
 #[cfg(feature = "std")]
 include!(concat!(env!("OUT_DIR"), "/wasm_binary.rs"));
 
-use cumulus_pallet_parachain_system::RelayNumberStrictlyIncreases;
+use cumulus_pallet_parachain_system::RelayNumberMonotonicallyIncreases;
 use sp_api::impl_runtime_apis;
-use sp_core::OpaqueMetadata;
+pub use sp_consensus_aura::sr25519::AuthorityId as AuraId;
+use sp_core::{crypto::KeyTypeId, OpaqueMetadata};
 use sp_runtime::{
-	create_runtime_str, generic,
+	create_runtime_str, generic, impl_opaque_keys,
 	traits::{AccountIdLookup, BlakeTwo256, Block as BlockT},
 	transaction_validity::{TransactionSource, TransactionValidity},
 	ApplyExtrinsicResult,
@@ -46,7 +47,7 @@ pub use frame_support::{
 	construct_runtime,
 	dispatch::DispatchClass,
 	parameter_types,
-	traits::{IsInVec, Randomness},
+	traits::{ConstBool, ConstU32, ConstU64, ConstU8, EitherOfDiverse, IsInVec, Randomness},
 	weights::{
 		constants::{
 			BlockExecutionWeight, ExtrinsicBaseWeight, RocksDbWeight, WEIGHT_REF_TIME_PER_SECOND,
@@ -61,6 +62,12 @@ use parachains_common::{AccountId, Signature};
 pub use sp_runtime::BuildStorage;
 pub use sp_runtime::{Perbill, Permill};
 
+impl_opaque_keys! {
+	pub struct SessionKeys {
+		pub aura: Aura,
+	}
+}
+
 /// This runtime version.
 #[sp_version::runtime_version]
 pub const VERSION: RuntimeVersion = RuntimeVersion {
@@ -80,6 +87,15 @@ pub fn native_version() -> NativeVersion {
 	NativeVersion { runtime_version: VERSION, can_author_with: Default::default() }
 }
 
+/// Maximum number of blocks simultaneously accepted by the Runtime, not yet included
+/// into the relay chain.
+const UNINCLUDED_SEGMENT_CAPACITY: u32 = 1;
+/// How many parachain blocks are processed by the relay chain per parent. Limits the
+/// number of blocks authored per slot.
+const BLOCK_PROCESSING_VELOCITY: u32 = 1;
+/// Relay chain slot duration, in milliseconds.
+const RELAY_CHAIN_SLOT_DURATION_MILLIS: u32 = 6000;
+
 /// We assume that ~10% of the block weight is consumed by `on_initialize` handlers.
 /// This is used to limit the maximal weight of a single extrinsic.
 const AVERAGE_ON_INITIALIZE_RATIO: Perbill = Perbill::from_percent(10);
@@ -174,23 +190,49 @@ impl cumulus_pallet_parachain_system::Config for Runtime {
 	type ReservedDmpWeight = ();
 	type XcmpMessageHandler = ();
 	type ReservedXcmpWeight = ();
-	type CheckAssociatedRelayNumber = RelayNumberStrictlyIncreases;
-	type ConsensusHook = cumulus_pallet_parachain_system::consensus_hook::ExpectParentIncluded;
+	type CheckAssociatedRelayNumber = RelayNumberMonotonicallyIncreases;
+	type ConsensusHook = cumulus_pallet_aura_ext::FixedVelocityConsensusHook<
+		Runtime,
+		RELAY_CHAIN_SLOT_DURATION_MILLIS,
+		BLOCK_PROCESSING_VELOCITY,
+		UNINCLUDED_SEGMENT_CAPACITY,
+	>;
 }
 
 impl parachain_info::Config for Runtime {}
 
+impl cumulus_pallet_aura_ext::Config for Runtime {}
+
+impl pallet_aura::Config for Runtime {
+	type AuthorityId = AuraId;
+	type DisabledValidators = ();
+	type MaxAuthorities = ConstU32<100_000>;
+	type AllowMultipleBlocksPerSlot = ConstBool<false>;
+	#[cfg(feature = "experimental")]
+	type SlotDuration = pallet_aura::MinimumPeriodTimesTwo<Self>;
+}
+
+impl pallet_timestamp::Config for Runtime {
+	type Moment = u64;
+	type OnTimestampSet = Aura;
+	type MinimumPeriod = ConstU64<0>;
+	type WeightInfo = ();
+}
+
 construct_runtime! {
 	pub enum Runtime
 	{
 		System: frame_system::{Pallet, Call, Storage, Config<T>, Event<T>},
 		Sudo: pallet_sudo::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Timestamp: pallet_timestamp::{Pallet, Call, Storage, Inherent},
 
 		ParachainSystem: cumulus_pallet_parachain_system::{
 			Pallet, Call, Config<T>, Storage, Inherent, Event<T>, ValidateUnsigned,
 		},
 		ParachainInfo: parachain_info::{Pallet, Storage, Config<T>},
 		SoloToPara: cumulus_pallet_solo_to_para::{Pallet, Call, Storage, Event},
+		Aura: pallet_aura::{Pallet, Storage, Config<T>},
+		AuraExt: cumulus_pallet_aura_ext::{Pallet, Storage, Config<T>},
 	}
 }
 
@@ -233,6 +275,16 @@ pub type Executive = frame_executive::Executive<
 >;
 
 impl_runtime_apis! {
+	impl sp_consensus_aura::AuraApi<Block, AuraId> for Runtime {
+		fn slot_duration() -> sp_consensus_aura::SlotDuration {
+			sp_consensus_aura::SlotDuration::from_millis(Aura::slot_duration())
+		}
+
+		fn authorities() -> Vec<AuraId> {
+			Aura::authorities().into_inner()
+		}
+	}
+
 	impl sp_api::Core<Block> for Runtime {
 		fn version() -> RuntimeVersion {
 			VERSION
@@ -298,12 +350,14 @@ impl_runtime_apis! {
 	}
 
 	impl sp_session::SessionKeys<Block> for Runtime {
-		fn decode_session_keys(_: Vec<u8>) -> Option<Vec<(Vec<u8>, sp_core::crypto::KeyTypeId)>> {
-			Some(Vec::new())
+		fn generate_session_keys(seed: Option<Vec<u8>>) -> Vec<u8> {
+			SessionKeys::generate(seed)
 		}
 
-		fn generate_session_keys(_: Option<Vec<u8>>) -> Vec<u8> {
-			Vec::new()
+		fn decode_session_keys(
+			encoded: Vec<u8>,
+		) -> Option<Vec<(Vec<u8>, KeyTypeId)>> {
+			SessionKeys::decode_into_raw_public_keys(&encoded)
 		}
 	}
 
@@ -316,5 +370,5 @@ impl_runtime_apis! {
 
 cumulus_pallet_parachain_system::register_validate_block! {
 	Runtime = Runtime,
-	BlockExecutor = Executive,
+	BlockExecutor = cumulus_pallet_aura_ext::BlockExecutor::<Runtime, Executive>,
 }

cumulus/parachains/runtimes/starters/shell/Cargo.toml

@@ -13,8 +13,11 @@ frame-executive = { path = "../../../../../substrate/frame/executive", default-f
 frame-support = { path = "../../../../../substrate/frame/support", default-features = false}
 frame-system = { path = "../../../../../substrate/frame/system", default-features = false}
 frame-try-runtime = { path = "../../../../../substrate/frame/try-runtime", default-features = false, optional = true }
+pallet-aura = { path = "../../../../../substrate/frame/aura", default-features = false}
+pallet-timestamp = { path = "../../../../../substrate/frame/timestamp", default-features = false }
 sp-api = { path = "../../../../../substrate/primitives/api", default-features = false}
 sp-block-builder = { path = "../../../../../substrate/primitives/block-builder", default-features = false}
+sp-consensus-aura = { path = "../../../../../substrate/primitives/consensus/aura", default-features = false }
 sp-core = { path = "../../../../../substrate/primitives/core", default-features = false}
 sp-inherents = { path = "../../../../../substrate/primitives/inherents", default-features = false}
 sp-offchain = { path = "../../../../../substrate/primitives/offchain", default-features = false}
@@ -30,6 +33,7 @@ xcm-builder = { package = "staging-xcm-builder", path = "../../../../../polkadot
 xcm-executor = { package = "staging-xcm-executor", path = "../../../../../polkadot/xcm/xcm-executor", default-features = false}
 
 # Cumulus
+cumulus-pallet-aura-ext = { path = "../../../../pallets/aura-ext", default-features = false }
 cumulus-pallet-parachain-system = { path = "../../../../pallets/parachain-system", default-features = false, features = ["parameterized-consensus-hook",] }
 cumulus-pallet-xcm = { path = "../../../../pallets/xcm", default-features = false }
 cumulus-primitives-core = { path = "../../../../primitives/core", default-features = false }
@@ -43,6 +47,7 @@ substrate-wasm-builder = { path = "../../../../../substrate/utils/wasm-builder",
 default = [ "std" ]
 std = [
 	"codec/std",
+	"cumulus-pallet-aura-ext/std",
 	"cumulus-pallet-parachain-system/std",
 	"cumulus-pallet-xcm/std",
 	"cumulus-primitives-core/std",
@@ -50,11 +55,14 @@ std = [
 	"frame-support/std",
 	"frame-system/std",
 	"frame-try-runtime?/std",
+	"pallet-aura/std",
+	"pallet-timestamp/std",
 	"parachain-info/std",
 	"parachains-common/std",
 	"scale-info/std",
 	"sp-api/std",
 	"sp-block-builder/std",
+	"sp-consensus-aura/std",
 	"sp-core/std",
 	"sp-inherents/std",
 	"sp-offchain/std",
@@ -69,12 +77,17 @@ std = [
 	"xcm/std",
 ]
 try-runtime = [
+	"cumulus-pallet-aura-ext/try-runtime",
 	"cumulus-pallet-parachain-system/try-runtime",
 	"cumulus-pallet-xcm/try-runtime",
 	"frame-executive/try-runtime",
 	"frame-support/try-runtime",
 	"frame-system/try-runtime",
 	"frame-try-runtime/try-runtime",
+	"pallet-aura/try-runtime",
+	"pallet-timestamp/try-runtime",
 	"parachain-info/try-runtime",
 	"sp-runtime/try-runtime",
 ]
+
+experimental = [ "pallet-aura/experimental" ]

cumulus/parachains/runtimes/starters/shell/src/lib.rs

@@ -32,13 +32,14 @@ include!(concat!(env!("OUT_DIR"), "/wasm_binary.rs"));
 pub mod xcm_config;
 
 use codec::{Decode, Encode};
-use cumulus_pallet_parachain_system::RelayNumberStrictlyIncreases;
+use cumulus_pallet_parachain_system::RelayNumberMonotonicallyIncreases;
 use frame_support::unsigned::TransactionValidityError;
 use scale_info::TypeInfo;
 use sp_api::impl_runtime_apis;
-use sp_core::OpaqueMetadata;
+pub use sp_consensus_aura::sr25519::AuthorityId as AuraId;
+use sp_core::{crypto::KeyTypeId, OpaqueMetadata};
 use sp_runtime::{
-	create_runtime_str, generic,
+	create_runtime_str, generic, impl_opaque_keys,
 	traits::{AccountIdLookup, BlakeTwo256, Block as BlockT, DispatchInfoOf},
 	transaction_validity::{TransactionSource, TransactionValidity},
 	ApplyExtrinsicResult,
@@ -53,7 +54,7 @@ pub use frame_support::{
 	construct_runtime,
 	dispatch::DispatchClass,
 	parameter_types,
-	traits::{Everything, IsInVec, Randomness},
+	traits::{ConstBool, ConstU32, ConstU64, ConstU8, EitherOfDiverse, IsInVec, Randomness},
 	weights::{
 		constants::{
 			BlockExecutionWeight, ExtrinsicBaseWeight, RocksDbWeight, WEIGHT_REF_TIME_PER_SECOND,
@@ -68,6 +69,12 @@ use parachains_common::{AccountId, Signature};
 pub use sp_runtime::BuildStorage;
 pub use sp_runtime::{Perbill, Permill};
 
+impl_opaque_keys! {
+	pub struct SessionKeys {
+		pub aura: Aura,
+	}
+}
+
 /// This runtime version.
 #[sp_version::runtime_version]
 pub const VERSION: RuntimeVersion = RuntimeVersion {
@@ -87,6 +94,15 @@ pub fn native_version() -> NativeVersion {
 	NativeVersion { runtime_version: VERSION, can_author_with: Default::default() }
 }
 
+/// Maximum number of blocks simultaneously accepted by the Runtime, not yet included
+/// into the relay chain.
+const UNINCLUDED_SEGMENT_CAPACITY: u32 = 1;
+/// How many parachain blocks are processed by the relay chain per parent. Limits the
+/// number of blocks authored per slot.
+const BLOCK_PROCESSING_VELOCITY: u32 = 1;
+/// Relay chain slot duration, in milliseconds.
+const RELAY_CHAIN_SLOT_DURATION_MILLIS: u32 = 6000;
+
 /// We assume that ~10% of the block weight is consumed by `on_initialize` handlers.
 /// This is used to limit the maximal weight of a single extrinsic.
 const AVERAGE_ON_INITIALIZE_RATIO: Perbill = Perbill::from_percent(10);
@@ -177,16 +193,41 @@ impl cumulus_pallet_parachain_system::Config for Runtime {
 	type ReservedDmpWeight = ReservedDmpWeight;
 	type XcmpMessageHandler = ();
 	type ReservedXcmpWeight = ();
-	type CheckAssociatedRelayNumber = RelayNumberStrictlyIncreases;
-	type ConsensusHook = cumulus_pallet_parachain_system::consensus_hook::ExpectParentIncluded;
+	type CheckAssociatedRelayNumber = RelayNumberMonotonicallyIncreases;
+	type ConsensusHook = cumulus_pallet_aura_ext::FixedVelocityConsensusHook<
+		Runtime,
+		RELAY_CHAIN_SLOT_DURATION_MILLIS,
+		BLOCK_PROCESSING_VELOCITY,
+		UNINCLUDED_SEGMENT_CAPACITY,
+	>;
 }
 
 impl parachain_info::Config for Runtime {}
 
+impl cumulus_pallet_aura_ext::Config for Runtime {}
+
+impl pallet_aura::Config for Runtime {
+	type AuthorityId = AuraId;
+	type DisabledValidators = ();
+	type MaxAuthorities = ConstU32<100_000>;
+	type AllowMultipleBlocksPerSlot = ConstBool<false>;
+	#[cfg(feature = "experimental")]
+	type SlotDuration = pallet_aura::MinimumPeriodTimesTwo<Self>;
+}
+
+impl pallet_timestamp::Config for Runtime {
+	type Moment = u64;
+	type OnTimestampSet = Aura;
+	type MinimumPeriod = ConstU64<0>;
+	type WeightInfo = ();
+}
+
 construct_runtime! {
 	pub enum Runtime
 	{
 		System: frame_system::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Timestamp: pallet_timestamp::{Pallet, Call, Storage, Inherent},
+
 		ParachainSystem: cumulus_pallet_parachain_system::{
 			Pallet, Call, Config<T>, Storage, Inherent, Event<T>, ValidateUnsigned,
 		},
@@ -194,6 +235,9 @@ construct_runtime! {
 
 		// DMP handler.
 		CumulusXcm: cumulus_pallet_xcm::{Pallet, Call, Storage, Event<T>, Origin},
+
+		Aura: pallet_aura::{Pallet, Storage, Config<T>},
+		AuraExt: cumulus_pallet_aura_ext::{Pallet, Storage, Config<T>},
 	}
 }
 
@@ -263,6 +307,16 @@ pub type Executive = frame_executive::Executive<
 >;
 
 impl_runtime_apis! {
+	impl sp_consensus_aura::AuraApi<Block, AuraId> for Runtime {
+		fn slot_duration() -> sp_consensus_aura::SlotDuration {
+			sp_consensus_aura::SlotDuration::from_millis(Aura::slot_duration())
+		}
+
+		fn authorities() -> Vec<AuraId> {
+			Aura::authorities().into_inner()
+		}
+	}
+
 	impl sp_api::Core<Block> for Runtime {
 		fn version() -> RuntimeVersion {
 			VERSION
@@ -328,12 +382,14 @@ impl_runtime_apis! {
 	}
 
 	impl sp_session::SessionKeys<Block> for Runtime {
-		fn decode_session_keys(_: Vec<u8>) -> Option<Vec<(Vec<u8>, sp_core::crypto::KeyTypeId)>> {
-			Some(Vec::new())
+		fn generate_session_keys(seed: Option<Vec<u8>>) -> Vec<u8> {
+			SessionKeys::generate(seed)
 		}
 
-		fn generate_session_keys(_: Option<Vec<u8>>) -> Vec<u8> {
-			Vec::new()
+		fn decode_session_keys(
+			encoded: Vec<u8>,
+		) -> Option<Vec<(Vec<u8>, KeyTypeId)>> {
+			SessionKeys::decode_into_raw_public_keys(&encoded)
 		}
 	}
 
@@ -346,5 +402,5 @@ impl_runtime_apis! {
 
 cumulus_pallet_parachain_system::register_validate_block! {
 	Runtime = Runtime,
-	BlockExecutor = Executive,
+	BlockExecutor = cumulus_pallet_aura_ext::BlockExecutor::<Runtime, Executive>,
 }