Upgrade a Running Network

Illustrates ways you can update a running node.

PreviousSimulate Network NextBuild Application Logic

Last updated 1 year ago

Upgrade a Running Network

Illustrates ways you can update a running node.

Unlike many blockchains, the Substrate development framework supports forkless upgrades to the runtime that is the core of the blockchain. Most blockchain projects require a of the code base to support ongoing development of new features or enhancements to existing features. With Substrate, you can deploy enhanced runtime capabilities—including breaking changes—without a hard fork. Because the definition of the runtime is itself an element in the state of a Substrate-based chain, network participants can update this value by calling the function in a transaction. Because updates to the runtime state are validated using the blockchain's consensus mechanisms and cryptographic guarantees, network participants can use the blockchain itself to distribute updated or extended runtime logic without needing to fork the chain or release a new blockchain client.

This tutorial illustrates how to upgrade the runtime without creating a fork of the code base or stopping the progress of the chain. In this tutorial, you'll make the following changes to a Substrate runtime on a running network node:

Increase the spec_version of the runtime.
Add the Utility pallet to the runtime.
Increase the minimum balance for network accounts.

Before you begin

Before you begin, verify the following:

You have configured your environment for Substrate development by installing .
You have completed and have the Substrate node template installed locally.
You have reviewed for an introduction to adding a new pallet to the runtime.

Tutorial objectives

By completing this tutorial, you will accomplish the following objectives:

Use the Sudo pallet to simulate governance for a chain upgrade.
Upgrade the runtime for a running node to include a new pallet.
Submit a transaction to upload the modified runtime onto a running node.

Authorize an upgrade with Sudo

Typically, runtime upgrades are managed through governance with community members voting to approve or reject upgrade proposals. In place of governance, this tutorial uses the Sudo pallet and the Root origin to identify the runtime administrator with permission to upgrade the runtime. Only this root-level administrator can update the runtime by calling the set_code function. The Sudo pallet enables you to invoke the set_code function using the Root origin by specifying the account that has root-level administrative permissions.

By default, the chain specification file for the node template specifies that the alice development account is the owner of the Sudo administrative account. Therefore, this tutorial uses the alice account to perform runtime upgrades.

Resource accounting for runtime upgrades

The weight annotation for the set_code function also specifies that the function is in the Operational class because it provides network capabilities. Function calls that are identified as operational:

Can consume the entire weight limit of a block.
Are given maximum priority.
Are exempt from paying transaction fees.

Managing resource accounting

Add the Utility pallet to the runtime

Start the local node

This tutorial illustrates how to update a running node, so the first step is to start the local node with the current runtime.

To start the node with the current runtime:

Open a terminal shell on your computer.
Change to the root directory where you compiled the Substrate node template.
Start the previously-compiled local node in development mode by running the following command:
```
cargo run --release -- --dev
```
Leave this node running. You can edit and re-compile to upgrade the runtime without stopping or restarting the running node.
Click the left-most dropdown menu to select the network.
Under Development, select Local Node, then click Switch.
In the upper left, notice the node template version is the default version 100.

Add the Utility pallet to the runtime dependencies

To update the dependencies for the runtime to include the Utility pallet:

Open a second terminal shell window or tab.
Change to the root directory where you compiled the Substrate node template.
Open the runtime/Cargo.toml file in a text editor.

Locate the [dependencies] section.

For example:

[dependencies]
codec = { package = "parity-scale-codec", version = "3.0.0", default-features = false, features = ["derive"] }
scale-info = { version = "2.1.1", default-features = false, features = ["derive"] }

pallet-aura = { version = "4.0.0-dev", default-features = false, git = "https://github.com/paritytech/polkadot-sdk.git", branch = "polkadot-v1.0.0" }

Add the Utility pallet as a dependency.

For example, add a single line with the following fields:

pallet-utility = {
   version = "4.0.0-dev",
   default-features = false,
   git = "https://github.com/paritytech/polkadot-sdk.git",
   branch = "polkadot-v1.0.0"
}

Locate the [features] section and the list of the default features for the standard binary.

For example:

[features]
default = ["std"]
std = [
   "frame-try-runtime?/std",
   "frame-system-benchmarking?/std",
   "frame-benchmarking?/std",
   "codec/std",
   "scale-info/std",

Add the Utility pallet to the list.
```
"pallet-utility/std",
```
Save your changes and close the Cargo.toml file.

Add the Utility pallet configuration

To add the Utility types and configuration trait:

Open the runtime/src/lib.rs file in a text editor.

Add the implementation for the Config trait for the Utility pallet.

impl pallet_utility::Config for Runtime {
   type RuntimeEvent = RuntimeEvent;
   type RuntimeCall = RuntimeCall;
   type PalletsOrigin = OriginCaller;
   type WeightInfo = pallet_utility::weights::SubstrateWeight<Runtime>;
}

Locate the construct_runtime! macro.

construct_runtime!(
  pub struct Runtime
  where
     Block = Block,
     NodeBlock = opaque::Block,
     UncheckedExtrinsic = UncheckedExtrinsic
  {
         System: frame_system,
         RandomnessCollectiveFlip: pallet_randomness_collective_flip,
         Timestamp: pallet_timestamp,
         Aura: pallet_aura,

Add the Utility pallet inside the construct_runtime! macro.
```
Utility: pallet_utility,
```

Locate the runtime_version macro.

#[sp_version::runtime_version]
pub const VERSION: RuntimeVersion = RuntimeVersion {
     spec_name: create_runtime_str!("node-template"),
     impl_name: create_runtime_str!("node-template"),
     authoring_version: 1,
     spec_version: 100,
     impl_version: 1,
     apis: RUNTIME_API_VERSIONS,
     transaction_version: 1,
     state_version: 1,
};

Update the value for the EXISTENTIAL_DEPOSIT for the Balances pallet.
```
pub const EXISTENTIAL_DEPOSIT: u128 = 1000 // Update this value.
```
```
spec_version: 101,  // Change the spec_version from 100 to 101
```
The fields for the runtime_version specify the following information:
- spec_name specifies the name of the runtime.
- impl_name specifies the name of the outer node client.
- spec_version specifies the version of the runtime.
- impl_version specifies the version of the outer node client.
- apis specifies the list of supported APIs.
- state_version specifies the version of the key-value trie data structure that the runtime uses.
Save your changes and close the runtime/src/lib.rs file.

Recompile and connect to the local node

Verify that the local node continues to run in the first terminal.
In the second terminal where you updated the runtime Cargo.toml and lib.rs files, recompile the runtime by running the following command
```
cargo build --release --package node-template-runtime
```
The --release command-line option requires a longer compile time. However, it generates a smaller build artifact that is better suited for submitting to the blockchain network. Storage optimization is critical for any blockchain. With this command, the build artifacts are output to the target/release directory. The WebAssembly build artifacts are in the target/release/wbuild/node-template-runtime directory. For example, you should see the following WebAssembly artifacts:
```
node_template_runtime.compact.compressed.wasm
node_template_runtime.compact.wasm
node_template_runtime.wasm
```

Execute a runtime upgrade

You now have a WebAssembly artifact that describes the modified runtime logic. However, the running node isn't using the upgraded runtime yet. To complete the upgrade, you need to submit a transaction that updates the node to use the upgraded runtime.

To update the network with the upgraded runtime:

Click Developer and select Extrinsics to submit a transaction for the runtime to use the new build artifact.
Select the administrative Alice account.
Select the sudo pallet and the sudoUncheckedWeight(call, weight) function.
Select system and setCode(code) as the call to make using the Alice account.
Click file upload, then select or drag and drop the compact and compressed WebAssembly file—node_template_runtime.compact.compressed.wasm—that you generated for the updated runtime.
For example, navigate to the target/release/wbuild/node-template-runtime directory and select node_template_runtime.compact.compressed.wasm as the file to upload.
Leave both of the weight parameters set to the default value of 0.
Click Submit Transaction.
Review the authorization, then click Sign and Submit.
Click Network and select Explorer to see that there has been a successful sudo.Sudid event.
After the transaction is included in a block, the node template version number indicates that the runtime version is now 101. For example:
If your local node is producing blocks in the terminal that match what is displayed in the browser, you have completed a successful runtime upgrade.
Click Developer and select Extrinsics. Click on submit the following extrinsic and scroll to the bottom of the list. You will see utility as an option.
- Click Developer and select Chain state.
- Click Constants.
- Select the balances pallet.
- Select existentialDeposit as the constant value as the value to query.

Where to go next

PreviousSimulate Network NextBuild Application Logic

Last updated 1 year ago