Run a Validator

Learn how to run a validator node.

Prerequisite Readings

• Validator Overview
• Validator Security

tip

If you plan to use a Key Management System (KMS), you should go through these steps first: Using a KMS.

danger

⚠️ WARNING: Make sure your server timezone configuration is UTC. Having a different timezone configuration may cause a LastResultsHash mismatch error. This will take down your node!

Create Your Validator

Your node consensus public key (evmosvalconspub...) can be used to create a new validator by staking EVMOS tokens. You can find your validator pubkey by running:

evmosd tendermint show-validator

danger

🚨 DANGER: Never create your mainnet validator keys using a test keying backend. Doing so might result in a loss of funds by making your funds remotely accessible via the eth_sendTransaction JSON-RPC endpoint.

Ref: Security Advisory: Insecurely configured geth can make funds remotely accessible

To create your validator on testnet, just use the following command:

evmosd tx staking create-validator \
  --amount=1000000atevmos \
  --pubkey=$(evmosd tendermint show-validator) \
  --moniker="choose a moniker" \
  --chain-id=<chain_id> \
  --commission-rate="0.05" \
  --commission-max-rate="0.10" \
  --commission-max-change-rate="0.01" \
  --min-self-delegation="1000000" \
  --gas="auto" \
  --gas-prices="0.025atevmos" \
  --from=<key_name>

tip

When specifying commission parameters, the commission-max-change-rate is used to measure % point change over the commission-rate, e.g. 1% to 2% is a 100% rate increase, but only 1 percentage point.

tip

Min-self-delegation is a strictly positive integer that represents the minimum amount of self-delegated voting power your validator must always have. A min-self-delegation of 1000000 means your validator will never have a self-delegation lower than 1 atevmos.

You can confirm that you are in the validator set by using a third party explorer.

Edit Validator Description

You can edit your validator's public description. This info is to identify your validator, and will be relied on by delegators to decide which validators to stake to. Make sure to provide input for every flag below. If a flag is not included in the command the field will default to empty (--moniker defaults to the machine name) if the field has never been set or remain the same if it has been set in the past.

The <key_name> specifies which validator you are editing. If you choose to not include certain flags, remember that the --from flag must be included to identify the validator to update.

The --identity can be used as to verify identity with systems like Keybase or UPort. When using with Keybase --identity should be populated with a 16-digit string that is generated with a keybase.io account. It's a cryptographically secure method of verifying your identity across multiple online networks. The Keybase API allows us to retrieve your Keybase avatar. This is how you can add a logo to your validator profile.

evmosd tx staking edit-validator
  --moniker="choose a moniker" \
  --website="https://evmos.org" \
  --identity=6A0D65E29A4CBC8E \
  --details="To infinity and beyond!" \
  --chain-id=<chain_id> \
  --gas="auto" \
  --gas-prices="0.025atevmos" \
  --from=<key_name> \
  --commission-rate="0.10"

Note: The commission-rate value must adhere to the following invariants:

• Must be between 0 and the validator's commission-max-rate
• Must not exceed the validator's commission-max-change-rate which is maximum % point change rate per day. In other words, a validator can only change its commission once per day and within commission-max-change-rate bounds.

View Validator Description

View the validator's information with this command:

evmosd query staking validator <account_cosmos>

Track Validator Signing Information

In order to keep track of a validator's signatures in the past you can do so by using the signing-info command:

evmosd query slashing signing-info <validator-pubkey>\
  --chain-id=<chain_id>

Unjail Validator

When a validator is "jailed" for downtime, you must submit an Unjail transaction from the operator account in order to be able to get block proposer rewards again (depends on the zone fee distribution).

evmosd tx slashing unjail \
  --from=<key_name> \
  --chain-id=<chain_id>

Confirm Your Validator is Running

Your validator is active if the following command returns anything:

evmosd query tendermint-validator-set | grep "$(evmosd tendermint show-address)"

You should now see your validator in one of Evmos explorers. You are looking for the bech32 encoded address in the ~/.evmosd/config/priv_validator.json file.

Note

To be in the validator set, you need to have more total voting power than the 100th validator.

Halting Your Validator

When attempting to perform routine maintenance or planning for an upcoming coordinated upgrade, it can be useful to have your validator systematically and gracefully halt. You can achieve this by either setting the halt-height to the height at which you want your node to shutdown or by passing the --halt-height flag to evmosd. The node will shutdown with a zero exit code at that given height after committing the block.

Common Problems

Problem #1: My validator has voting_power: 0

Your validator has become jailed. Validators get jailed, i.e. get removed from the active validator set, if they do not vote on 500 of the last 10000 blocks, or if they double sign.

If you got jailed for downtime, you can get your voting power back to your validator. First, if evmosd is not running, start it up again:

evmosd start

Wait for your full node to catch up to the latest block. Then, you can unjail your validator

Lastly, check your validator again to see if your voting power is back.

evmosd status

You may notice that your voting power is less than it used to be. That's because you got slashed for downtime!

Problem #2: My node crashes because of too many open files

The default number of files Linux can open (per-process) is 1024. evmosd is known to open more than 1024 files. This causes the process to crash. A quick fix is to run ulimit -n 4096 (increase the number of open files allowed) and then restart the process with evmosd start. If you are using systemd or another process manager to launch evmosd this may require some configuration at that level. A sample systemd file to fix this issue is below:

# /etc/systemd/system/evmosd.service
[Unit]
Description=Evmos Node
After=network.target

[Service]
Type=simple
User=ubuntu
WorkingDirectory=/home/ubuntu
ExecStart=/home/ubuntu/go/bin/evmosd start
Restart=on-failure
RestartSec=3
LimitNOFILE=4096

[Install]
WantedBy=multi-user.target