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Cosmos Hub 4, v6-Vega Upgrade Instructions

This document describes the steps for validator and full node operators for the successful execution of the Vega Upgrade, which contains the following main new features:

TOC:

On-chain governance proposal attains consensus​

Proposal #59 is the reference on-chain governance proposal for this upgrade, which has passed with overwhelming community support. Neither core developers nor core funding entities control the governance, and this governance proposal has passed in a fully decentralized way.

Upgrade will take place December 14, 2021​

The upgrade will take place at a block height of 8695000. At the time of writing, and at current block times (around 7s/block), this block height corresponds approximately to Tuesday, 14-Dec-21 14:49:50 UTC. This date/time is approximate as blocks are not generated at a constant interval. You can stay up-to-date using this live countdown page.

Chain-id will remain the same​

The chain-id of the network will remain the same, cosmoshub-4. This is because an in-place migration of state will take place, i.e., this upgrade does not export any state.

Preparing for the upgrade​

System requirement​

32GB RAM is recommended to ensure a smooth upgrade.

If you have less than 32GB RAM, you might try creating a swapfile to swap an idle program onto the hard disk to free up memory. This can allow your machine to run the binary than it could run in RAM alone.

sudo fallocate -l 16G /swapfile
sudo chmod 600 /swapfile
sudo mkswap /swapfile
sudo swapon /swapfile

Backups​

Prior to the upgrade, validators are encouraged to take a full data snapshot. Snapshotting depends heavily on infrastructure, but generally this can be done by backing up the .gaia directory. If you use Cosmovisor to upgrade, by default, Cosmovisor will backup your data upon upgrade. See below upgrade by cosmovisor section.

It is critically important for validator operators to back-up the .gaia/data/priv_validator_state.json file after stopping the gaiad process. This file is updated every block as your validator participates in consensus rounds. It is a critical file needed to prevent double-signing, in case the upgrade fails and the previous chain needs to be restarted.

Testing​

For those validator and full node operators that are interested in ensuring preparedness for the impending upgrade, you can join in our Vega public-testnet or run a Vega local testnet.

Current runtime, cosmoshub-4 (pre-Vega upgrade) is running Gaia v5.0.0​

The Cosmos Hub mainnet network, cosmoshub-4, is currently running Gaia v5.0.0. We anticipate that operators who are running on v5.0.x, will be able to upgrade successfully; however, this is untested and it is up to operators to ensure that their systems are capable of performing the upgrade.

Target runtime, cosmoshub-4 (post-Vega upgrade) will run Gaia v6.0.4​

The Comsos Hub mainnet network, cosmoshub-4, will run Gaia v6.0.4. Operators MUST use this version post-upgrade to remain connected to the network.

Vega upgrade steps​

There are 2 major ways to upgrade a node:

  • Manual upgrade
  • Upgrade using Cosmovisor
    • Either by manually preparing the new binary
    • Or by using the auto-download functionality (this is not yet recommended)

If you prefer to use Cosmovisor to upgrade, some preparation work is needed before upgrade.

Method I: manual upgrade​

Run Gaia v5.0.x till upgrade height, the node will panic:

ERR UPGRADE "Vega" NEEDED at height: 8695000

panic: UPGRADE "Vega" NEEDED at height: 8695000

Stop the node, and install Gaia v6.0.4 and re-start by gaiad start.

It may take 20 min to a few hours until validators with a total sum voting power > 2/3 to complete their nodes upgrades. After that, the chain can continue to produce blocks.

Method II: upgrade using Cosmovisor by manually preparing the Gaia v6.0.4 binary​

Preparation​

Install the latest version of Cosmovisor:

go install github.com/cosmos/cosmos-sdk/cosmovisor/cmd/cosmovisor@latest

Create a cosmovisor folder:

create a Cosmovisor folder inside $GAIA_HOME and move Gaia v5.0.0 into $GAIA_HOME/cosmovisor/genesis/bin

mkdir -p $GAIA_HOME/cosmovisor/genesis/bin
cp $(which gaiad) $GAIA_HOME/cosmovisor/genesis/bin

build Gaia v6.0.4, and move gaiad v6.0.4 to $GAIA_HOME/cosmovisor/upgrades/Vega/bin

mkdir -p  $GAIA_HOME/cosmovisor/upgrades/Vega/bin
cp $(which gaiad) $GAIA_HOME/cosmovisor/upgrades/Vega/bin

Then you should get the following structure:

.
├── current -> genesis or upgrades/<name>
├── genesis
│   └── bin
│       └── gaiad  #v5.0.x
└── upgrades
└── Vega
└── bin
    └── gaiad  #v6.0.4

Export the environmental variables:

export DAEMON_NAME=gaiad
# please change to your own gaia home dir
export DAEMON_HOME= $GAIA_HOME
export DAEMON_RESTART_AFTER_UPGRADE=true

Start the node:

cosmovisor start --x-crisis-skip-assert-invariants

Skipping the invariant checks is strongly encouraged since it decreases the upgrade time significantly and since there are some other improvements coming to the crisis module in the next release of the Cosmos SDK.

Expected upgrade result​

When the upgrade block height is reached, you can find the following information in the log:

ERR UPGRADE "Vega" NEEDED at height: 8695000: upgrade to Vega and applying upgrade "Vega" at height:8695000.

This may take 20 min to a few hours. After this, the chain will continue to produce blocks when validators with a total sum voting power > 2/3 complete their nodes upgrades.

Preparation​

Install Cosmovisor v0.1

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

Create a cosmovisor folder:

create a cosmovisor folder inside gaia home and move gaiad v5.0.0 into $GAIA_HOME/cosmovisor/genesis/bin

mkdir -p $GAIA_HOME/cosmovisor/genesis/bin
cp $(which gaiad) $GAIA_HOME/cosmovisor/genesis/bin
.
├── current -> genesis or upgrades/<name>
└── genesis
     └── bin
        └── gaiad  #v5.0.x

Export the environmental variables:

export DAEMON_NAME=gaiad
# please change to your own gaia home dir
export DAEMON_HOME= $GAIA_HOME
export DAEMON_RESTART_AFTER_UPGRADE=true
export DAEMON_ALLOW_DOWNLOAD_BINARIES=true

Start the node:

cosmovisor start --x-crisis-skip-assert-invariants

Skipping the invariant checks is strongly encouraged since it decreases the upgrade time significantly and since there are some other improvements coming to the crisis module in the next release of the Cosmos SDK.

Expected result​

When the upgrade block height is reached, you can find the following information in the log:

ERR UPGRADE "Vega" NEEDED at height: 8695000: upgrade to Vega and applying upgrade "Vega" at height:8695000

Then the Cosmovisor will create $GAIA_HOME/cosmovisor/upgrades/Vega/bin and download Gaia v6.0.4 binary to this folder according to links in the --info field of the upgrade proposal 59. This may take 20 min to a few hours, afterwards, the chain will continue to produce blocks once validators with a total sum voting power > 2/3 complete their nodes upgrades.

Please Note:

Auto-download the new binary is not recommended for the following reasons:

  • In general, auto-download comes with the risk that the verification of correct download is done automatically. If you want to have the highest guarantee you should confirm the check-sum manually. We hope more node operators will use the auto-download for this release but please be aware this is a risk you should take at your own discretion.
  • For the Vega upgrade, Gaia will upgrade its dependency on Cosmos SDK v0.42 to Cosmos SDK v0.44, this will require Cosmovisor v0.1. Later versions of Cosmovisor do not support Cosmos SDK v0.42 or earlier if the auto-download option is enabled.
  • By using Cosmovisor v0.1 you might experience a node hanging issue when querying a result with a large output size. For example, gaiad q gov proposals will hang the node being queried, this issue will not appear for Cosmovisor versions newer than v0.1.

Upgrade duration​

The upgrade may take several hours to complete because cosmoshub-4 participants operate globally with differing operating hours and it may take some time for operators to upgrade their binaries and connect to the network.

Rollback plan​

During the network upgrade, core Cosmos teams will be keeping an ever vigilant eye and communicating with operators on the status of their upgrades. During this time, the core teams will listen to operator needs to determine if the upgrade is experiencing unintended challenges. In the event of unexpected challenges, the core teams, after conferring with operators and attaining social consensus, may choose to declare that the upgrade will be skipped.

Steps to skip this upgrade proposal are simply to resume the cosmoshub-4 network with the (downgraded) v5.0.x binary using the following command:

gaiad start --unsafe-skip-upgrade 8695000

Note: There is no particular need to restore a state snapshot prior to the upgrade height, unless specifically directed by core Cosmos teams.

Important: A social consensus decision to skip the upgrade will be based solely on technical merits, thereby respecting and maintaining the decentralized governance process of the upgrade proposal's successful YES vote.

Communications​

Operators are encouraged to join the #validators-verified channel of the Cosmos Community Discord. This channel is the primary communication tool for operators to ask questions, report upgrade status, report technical issues, and to build social consensus should the need arise. This channel is restricted to known operators and requires verification beforehand. Requests to join the #validators-verified channel can be sent to the #general-support channel.

Risks​

As a validator performing the upgrade procedure on your consensus nodes carries a heightened risk of double-signing and being slashed. The most important piece of this procedure is verifying your software version and genesis file hash before starting your validator and signing.

The riskiest thing a validator can do is discover that they made a mistake and repeat the upgrade procedure again during the network startup. If you discover a mistake in the process, the best thing to do is wait for the network to start before correcting it.

Reference​

cosmos/vega-test

Delta upgrade instruction