# Chain Upgrade Guide to v0.44

This document provides guidelines for a chain upgrade from v0.42 to v0.44 and an example of the upgrade process using simapp.

You must upgrade to Stargate v0.42 before upgrading to v0.44. If you have not done so, please see Chain Upgrade Guide to v0.42. Please note, v0.43 was discontinued shortly after being released and all chains should upgrade directly to v0.44 from v0.42.

# Prerequisite Readings

Cosmos SDK v0.44 introduces a new way of handling chain upgrades that no longer requires exporting state to JSON, making the necesssary changes, and then creating a new chain with the modified JSON as the new genesis file.

Instead of starting a new chain, the upgrade binary will read the existing database and perform in-place store migrations. This new way of handling chain upgrades can be used alongside Cosmovisor to make the upgrade process seamless.

# In-Place Store Migrations

We recommend using In-Place Store Migrations to upgrade your chain from v0.42 to v0.44. The first step is to make sure all your modules follow the Module Upgrade Guide. The second step is to add an upgrade handler to app.go.

In this document, we'll provide an example of what the upgrade handler looks like for a chain upgrading module versions for the first time. It's critical to note that the initial consensus version of each module must be set to 1 rather than 0 or else the upgrade handler will re-initialize each module.

In addition to migrating existing modules, the upgrade handler also performs store upgrades for new modules. In the example below, we'll be adding store migrations for two new modules made available in v0.44: x/authz and x/feegrant.

# Using Cosmovisor

We recommend validators use Cosmovisor, which is a process manager for running application binaries. For security reasons, we recommend validators build their own upgrade binaries rather than enabling the auto-download option. Validators may still choose to use the auto-download option if the necessary security guarantees are in place (i.e. the URL provided in the upgrade proposal for the downloadable upgrade binary includes a proper checksum).

If validators would like to enable the auto-download option, and they are currently running an application using Cosmos SDK v0.42, they will need to use Cosmovisor v0.1 (opens new window). Later versions of Cosmovisor do not support Cosmos SDK v0.42 or earlier if the auto-download option is enabled.

Validators can use the auto-restart option to prevent unnecessary downtime during the upgrade process. The auto-restart option will automatically restart the chain with the upgrade binary once the chain has halted at the proposed upgrade height. With the auto-restart option, validators can prepare the upgrade binary in advance and then relax at the time of the upgrade.

# Migrating app.toml

With the update to v0.44, new server configuration options have been added to app.toml. The updates include new configuration sections for Rosetta and gRPC Web as well as a new configuration option for State Sync. Check out the default app.toml (opens new window) file in the latest version of v0.44 for more information.

# Example: Simapp Upgrade

The following example will walk through the upgrade process using simapp as our blockchain application. We will be upgrading simapp from v0.42 to v0.44. We will be building the upgrade binary ourselves and enabling the auto-restart option.

In the following example, we start a new chain from v0.42. The binary for this version will be the genesis binary. For validators using Cosmovisor for the first time on an existing chain, either the binary for the current version of the chain should be used as the genesis binary (i.e. the starting binary) or validators should update the current symbolic link to point to the upgrade directory. For more information, see Cosmovisor.

# Initial Setup

From within the cosmos-sdk repository, check out the latest v0.42.x release:

Copy git checkout release/v0.42.x

Build the simd binary for the latest v0.42.x release (the genesis binary):

Copy make build

Reset ~/.simapp (never do this in a production environment):

Copy ./build/simd unsafe-reset-all

Configure the simd binary for testing:

Copy ./build/simd config chain-id test ./build/simd config keyring-backend test ./build/simd config broadcast-mode block

Initialize the node and overwrite any previous genesis file (never do this in a production environment):

Copy ./build/simd init test --chain-id test --overwrite

Set the minimum gas price to 0stake in ~/.simapp/config/app.toml:

Copy minimum-gas-prices = "0stake"

For the purpose of this demonstration, change voting_period in genesis.json to a reduced time of 20 seconds (20s):

Copy cat <<< $(jq '.app_state.gov.voting_params.voting_period = "20s"' $HOME/.simapp/config/genesis.json) > $HOME/.simapp/config/genesis.json

Create a new key for the validator, then add a genesis account and transaction:

Copy ./build/simd keys add validator ./build/simd add-genesis-account validator 5000000000stake --keyring-backend test ./build/simd gentx validator 1000000stake --chain-id test ./build/simd collect-gentxs

Now that our node is initialized and we are ready to start a new simapp chain, let's set up cosmovisor and the genesis binary.

# Cosmovisor Setup

Install the cosmovisor binary:

Copy go install github.com/cosmos/cosmos-sdk/cosmovisor/cmd/cosmovisor@v0.1.0

If you are using go v1.15 or earlier, you will need to change out of the cosmos-sdk directory, run go get instead of go install, and then change back into the cosmos-sdk repository.

Set the required environment variables:

Copy export DAEMON_NAME=simd export DAEMON_HOME=$HOME/.simapp

Set the optional environment variable to trigger an automatic restart:

Copy export DAEMON_RESTART_AFTER_UPGRADE=true

Create the folder for the genesis binary and copy the v0.42.x binary:

Copy mkdir -p $DAEMON_HOME/cosmovisor/genesis/bin cp ./build/simd $DAEMON_HOME/cosmovisor/genesis/bin

Now that cosmovisor is installed and the genesis binary has been added, let's add the upgrade handler to simapp/app.go and prepare the upgrade binary.

# Chain Upgrade

Check out release/v0.44.x:

Copy git checkout release/v0.44.x

Add the following to simapp/app.go inside NewSimApp and after app.UpgradeKeeper:

Copy app.registerUpgradeHandlers()

Add the following to simapp/app.go after NewSimApp (to learn more about the upgrade handler, see the In-Place Store Migrations):

Copy func (app *SimApp) registerUpgradeHandlers() { app.UpgradeKeeper.SetUpgradeHandler("v0.44", func(ctx sdk.Context, plan upgradetypes.Plan, _ module.VersionMap) (module.VersionMap, error) { // 1st-time running in-store migrations, using 1 as fromVersion to // avoid running InitGenesis. fromVM := map[string]uint64{ "auth": 1, "bank": 1, "capability": 1, "crisis": 1, "distribution": 1, "evidence": 1, "gov": 1, "mint": 1, "params": 1, "slashing": 1, "staking": 1, "upgrade": 1, "vesting": 1, "ibc": 1, "genutil": 1, "transfer": 1, } return app.mm.RunMigrations(ctx, app.configurator, fromVM) }) upgradeInfo, err := app.UpgradeKeeper.ReadUpgradeInfoFromDisk() if err != nil { panic(err) } if upgradeInfo.Name == "v0.44" && !app.UpgradeKeeper.IsSkipHeight(upgradeInfo.Height) { storeUpgrades := storetypes.StoreUpgrades{ Added: []string{"authz", "feegrant"}, } // configure store loader that checks if version == upgradeHeight and applies store upgrades app.SetStoreLoader(upgradetypes.UpgradeStoreLoader(upgradeInfo.Height, &storeUpgrades)) } }

Add storetypes to imports:

Copy storetypes "github.com/cosmos/cosmos-sdk/store/types"

Build the simd binary for v0.44.x (the upgrade binary):

Copy make build

Create the folder for the upgrade binary and copy the v0.44.x binary:

Copy mkdir -p $DAEMON_HOME/cosmovisor/upgrades/v0.44/bin cp ./build/simd $DAEMON_HOME/cosmovisor/upgrades/v0.44/bin

Now that we have added the upgrade handler and prepared the upgrade binary, we are ready to start cosmovisor and simulate the upgrade proposal process.

# Upgrade Proposal

Start the node using cosmovisor:

Copy cosmovisor start

Open a new terminal window and submit an upgrade proposal along with a deposit and a vote (these commands must be run within 20 seconds of each other):

Copy ./build/simd tx gov submit-proposal software-upgrade v0.44 --title upgrade --description upgrade --upgrade-height 20 --from validator --yes ./build/simd tx gov deposit 1 10000000stake --from validator --yes ./build/simd tx gov vote 1 yes --from validator --yes

Confirm the chain automatically upgrades at height 20.