solana/docs/src/running-validator/validator-start.md

title
Starting a Validator

Configure Solana CLI

The solana cli includes get and set configuration commands to automatically set the --url argument for cli commands. For example:

solana config set --url http://devnet.solana.com

While this section demonstrates how to connect to the Devnet cluster, the steps are similar for the other Solana Clusters.

Confirm The Cluster Is Reachable

Before attaching a validator node, sanity check that the cluster is accessible to your machine by fetching the transaction count:

solana transaction-count

View the metrics dashboard for more detail on cluster activity.

Confirm your Installation

Try running following command to join the gossip network and view all the other nodes in the cluster:

solana-gossip spy --entrypoint devnet.solana.com:8001
# Press ^C to exit

Enabling CUDA

If your machine has a GPU with CUDA installed Linux-only currently, include the --cuda argument to solana-validator.

When your validator is started look for the following log message to indicate that CUDA is enabled: "[<timestamp> solana::validator] CUDA is enabled"

System Tuning

For Linux validators, the solana repo includes a daemon to adjust system settings to optimize performance (namely by increasing the OS UDP buffer limits, and scheduling PoH with realtime policy).

The daemon (solana-sys-tuner) is included in the solana binary release.

To run it:

sudo solana-sys-tuner --user $(whoami) > sys-tuner.log 2>&1 &

Generate identity

Create an identity keypair for your validator by running:

solana-keygen new -o ~/validator-keypair.json

The identity public key can now be viewed by running:

solana-keygen pubkey ~/validator-keypair.json

Note: The "validator-keypair.json” file is also your ed25519 private key.

Paper Wallet identity

You can create a paper wallet for your identity file instead of writing the keypair file to disk with:

solana-keygen new --no-outfile

The corresponding identity public key can now be viewed by running:

solana-keygen pubkey ASK

and then entering your seed phrase.

See Paper Wallet Usage for more info.

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Vanity Keypair

You can generate a custom vanity keypair using solana-keygen. For instance:

solana-keygen grind --starts-with e1v1s

Depending on the string requested, it may take days to find a match...

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Your validator identity keypair uniquely identifies your validator within the network. It is crucial to back-up this information.

If you don’t back up this information, you WILL NOT BE ABLE TO RECOVER YOUR VALIDATOR if you lose access to it. If this happens, YOU WILL LOSE YOUR ALLOCATION OF SOL TOO.

To back-up your validator identify keypair, back-up your "validator-keypair.json” file or your seed phrase to a secure location.

More Solana CLI Configuration

Now that you have a keypair, set the solana configuration to use your validator keypair for all following commands:

solana config set --keypair ~/validator-keypair.json

You should see the following output:

Wallet Config Updated: /home/solana/.config/solana/wallet/config.yml
* url: http://devnet.solana.com
* keypair: /home/solana/validator-keypair.json

Airdrop & Check Validator Balance

Airdrop yourself some SOL to get started:

solana airdrop 10

Note that airdrops are only available on Devnet. Testnet SOL can be obtained by participating in the Tour de SOL program.

To view your current balance:

solana balance

Or to see in finer detail:

solana balance --lamports

Read more about the difference between SOL and lamports here.

Create Vote Account

If you haven’t already done so, create a vote-account keypair and create the vote account on the network. If you have completed this step, you should see the “vote-account-keypair.json” in your Solana runtime directory:

solana-keygen new -o ~/vote-account-keypair.json

Create your vote account on the blockchain:

solana create-vote-account ~/vote-account-keypair.json ~/validator-keypair.json

Trusted validators

If you know and trust other validator nodes, you can specify this on the command line with the --trusted-validator <PUBKEY> argument to solana-validator. You can specify multiple ones by repeating the argument --trusted-validator <PUBKEY1> --trusted-validator <PUBKEY2>. This has two effects, one is when the validator is booting with --no-untrusted-rpc, it will only ask that set of trusted nodes for downloading genesis and snapshot data. Another is that in combination with the --halt-on-trusted-validator-hash-mismatch option, it will monitor the merkle root hash of the entire accounts state of other trusted nodes on gossip and if the hashes produce any mismatch, the validator will halt the node to prevent the validator from voting or processing potentially incorrect state values. At the moment, the slot that the validator publishes the hash on is tied to the snapshot interval. For the feature to be effective, all validators in the trusted set should be set to the same snapshot interval value or multiples of the same.

It is highly recommended you use these options to prevent malicious snapshot state download or account state divergence.

Connect Your Validator

Connect to the cluster by running:

solana-validator \
  --identity ~/validator-keypair.json \
  --vote-account ~/vote-account-keypair.json \
  --ledger ~/validator-ledger \
  --rpc-port 8899 \
  --entrypoint devnet.solana.com:8001 \
  --limit-ledger-size
  --log ~/solana-validator.log

Lastly, to configure log rotation, please run the following:

# Setup log rotation

cat > logrotate.sol <<EOF
~/solana-validator.log {
  rotate 7
  daily
  missingok
  postrotate
    systemctl kill -s USR1 sol.service
  endscript
}
EOF
sudo cp logrotate.sol /etc/logrotate.d/sol
systemctl restart logrotate.service

To force validator logging to the console add a --log - argument, otherwise the validator will automatically log to a file.

Note: You can use a paper wallet seed phrase for your --identity and/or --vote-account keypairs. To use these, pass the respective argument as solana-validator --identity ASK ... --vote-account ASK ... and you will be prompted to enter your seed phrases and optional passphrase.

Confirm your validator connected to the network by opening a new terminal and running:

solana-gossip spy --entrypoint devnet.solana.com:8001

If your validator is connected, its public key and IP address will appear in the list.

Controlling local network port allocation

By default the validator will dynamically select available network ports in the 8000-10000 range, and may be overridden with --dynamic-port-range. For example, solana-validator --dynamic-port-range 11000-11010 ... will restrict the validator to ports 11000-11010.

Limiting ledger size to conserve disk space

The --limit-ledger-size argument will instruct the validator to only retain the last couple hours of ledger. To retain the full ledger, simply remove that arg.