Cronos PoS Chain Mainnet: Running a Full Node

This is detailed documentation for setting up a Full Node on the Cronos PoS Chain mainnet. Note that while anyone can set up a full node, only the top 100 validators are considered "active" and eligible to receive rewards. See FAQs for more info.

Step 0: Notes on network upgrades

For the host who would like to build a Run a Full Node with complete blockchain data from scratch, note that there were several breaking network upgrades, requiring upgrading at designated block heights below:

Block heightBinary VersionInstruction

1 - 922,363


Start the node with the older binary version

922,363 - 3,526,800


When it reaches the target block height 922,363 (Canis Major), update the binary and restart

3,526,800 - 10,073,800


When it reaches the target block height 3,526,800 (Draco II ), update the binary and restart*



When it reaches the target block height 10,073,800 (V4 upgrade ), update the binary and restart

  • *Note that as of v3.3.5 and higher, you need to modify your .chain-maind/config/app.toml and set the following params:

    • index_events = []

    • iavl-cache-size = 781250

    • iavl-disable-fastnode = false (set to true to skip IAVL migration, but keep as false when starting from a migrated snapshot. When you are on INF starting ABCI with Tendermint for a while, migration is going on and you should NOT terminate this. It might take a couple of hours, so plan well ahead for this migration, as it may incur downtime.)

  • Users can refer to the upgrade guides of


Supported OS

We officially support macOS, Windows and Linux only. Other platforms may work, but there is no guarantee. We will extend our support to other platforms after we have stabilized our current architecture.

Prepare your machine

For Cronos PoS Chain mainnet, you will need a machine with the following minimum requirements to run different types of nodes:

Archive Node (setting pruning = nothing)

  • RAM: 64GB (Rocksdb)

  • Disk: 3.4TB

  • CPU: 4 cores

Default Full Node (setting pruning = default)

  • RAM: 64GB (Rocksdb) or 16GB (goleveldb)

  • Disk: 1.2TB (From quick sync)

  • CPU: 4 cores

Pruned Node (setting pruning = everything)

  • RAM: 64GB (Rocksdb) or 16GB (goleveldb)

  • Disk: 40GB (From quick sync)

  • CPU: 4 cores

Please note that the size of snapshots from Quicksync will keep growing.

Step 1. Get the Cronos PoS Chain Mainnet binary

Remarks: The following is the minimal setup to join Cronos PoS Chain Mainnet. Furthermore, you may want to run full nodes as sentries (see Tendermint), restrict your validator connections to only connect to your full nodes, use secure storage and key management service for your validator keys etc.

To simplify the following step, we will be using Linux for illustration. Binaries for Mac and Windows are also available. There are two options to install chain-maind:

As mentioned before, in order to run a full node with complete blockchain data, we would need to begin with the older binary version 1.2.1:

Option 1 - Install chain-maind released binaries from GitHub

  • To install Cronos PoS Chain binaries from Github:

    $ curl -LOJ
    $ tar -zxvf chain-main_1.2.1_Linux_x86_64.tar.gz
  • You can verify the installation by checking the version of the chain-maind, the current version is 1.2.1.

    # check the version of chain-maind
    $ ./chain-maind version


Option 2 - Install chain-maind by homebrew

Reminder: - If you plan to play around with different networks (mainnet and testnet), we suggest you follow Option 1 to download the binary directly. - The binary downloaded from homebrew is only for interacting with the mainnet. You cannot use it to interact with testnet.

To install binaries in Homebrew for macOS X or Linux

Homebrew is a free and open-source package management system for macOS X. Install the official Chain-maind formula from the terminal.

  • First, install the crypto-org-chain tap, a repository of our Homebrew chain-maind package:

  # tap the repo
  $ brew tap crypto-org-chain/chain-maind
  • Now, install the chain-maind version 1.2.1 with crypto-org-chain/chain-maind

      # install the chain-maind CLI tool
      $ brew install chain-maind@1.2.1
  • You can verify the installation by checking the version of the chain-maind

    # check the version of chain-maind
    $ chain-maind version

Step 2. Configure chain-maind

Before kick-starting your node, we will have to configure the node so that it connects to the Cronos PoS Chain mainnet

Note: - Depending on your chain-maind home setting, the chain-maind configuration will be initialized to that home directory. To simplify the following steps, we will use the default chain-maind home directory ~/.chain-maind/ for illustration. - You can also put the chain-maind to your binary path and run it directly by chain-maind

Step 2-1. Initialize chain-maind

  • First of all, you can initialize chain-maind by:

      $ ./chain-maind init [moniker] --chain-id crypto-org-chain-mainnet-1
    • This moniker will be the displayed ID of your node when connected to the Cronos PoS Chain network. When providing the moniker value, make sure you drop the square brackets since they are not needed.

Step 2-2. Configure chain-maind

  • Download and replace the Cronos PoS Chain mainnet genesis.json by:

    $ curl > ~/.chain-maind/config/genesis.json
  • Verify sha256sum checksum of the downloaded genesis.json. You should see OK! if the sha256sum checksum matches.

    $ if [[ $(sha256sum ~/.chain-maind/config/genesis.json | awk '{print $1}') = "d299dcfee6ae29ca280006eaa065799552b88b978e423f9ec3d8ab531873d882" ]]; then echo "OK"; else echo "MISMATCHED"; fi;

    Note: For Mac environment, sha256sum was not installed by default. In this case, you may setup sha256sum with this command:

    function sha256sum() { shasum -a 256 "$@" ; } && export -f sha256sum

  • In ~/.chain-maind/config/app.toml, update minimum gas price to avoid transaction spamming

    $ sed -i.bak -E 's#^(minimum-gas-prices[[:space:]]+=[[:space:]]+)""$#\1"0.025basecro"#' ~/.chain-maind/config/app.toml

Reminder: The list of theseedis subject to change, you can also find the latest seed to connect here.

Important: When a validator is jailed because of a byzantine fault, their validator public key is added to a list of permanently banned validators and cannot re-join the network as a validator with the same public key, see staking tombstone

Step 3. Run everything

Step 3-1. Run everything

Once the chain-maind has been configured, we are ready to start the node and sync the blockchain data:

  • Start chain-maind, e.g.:

  $ ./chain-maind start


  • (Optional for Linux) If you would like to have it running in the background, you can start chain-maind with systemd service, e.g.:

  $ git clone && cd chain-main
  $ ./networks/
  $ sudo systemctl start chain-maind
  # view log
  $ journalctl -u chain-maind -f

Example: /etc/systemd/system/chain-maind.service created by script

# /etc/systemd/system/chain-maind.service

ExecStart=/usr/local/bin/chain-maind start --home /home/ubuntu/.chain-maind


It should begin fetching blocks from the other peers. Please wait until it is synced to the upgrade height 922,363 before moving onto the next step.

Remarks: Option 2 - Install chain-maind by homebrew

To install binaries in Homebrew for macOS X or Linux

  • You can query the node syncing status by

    $ ./chain-maind status 2>&1 | jq '.SyncInfo.catching_up'
  • If the above command returns false, it means that your node is synced; otherwise, it returns true and implies your node is still catching up.

Step 3-2. Upgrade the chain-maind binary to v2.1.2

At the upgrade height of 922,363, users will see the following error message on the chain-maind:

`ERR UPGRADE "v2.0.0" NEEDED at time: 2021-06-01T23:59:00Z:...`

Step 3-2-1 - Get the v2.1.2 binary

To simplify the following step, we will be using Linux for illustration. Binary for Mac and Windows are also available.

  • Terminate the chain-maind; afterwards, download the v2.1.2 released binaries from github:

    $ curl -LOJ
    $ tar -zxvf chain-main_2.1.2_Linux_x86_64.tar.gz

Remarks: If you have stated chain-maind with systemd service, kindly stop it by

$ sudo systemctl stop chain-maind

And replace the binary in the location where the ExecStart states in Systemd Unit file.

  • For homebrew users, simply run

    $ brew upgrade chain-maind

Step 3-2-2 - Verify the version

You can verify the installation by checking the version of chain-maind, the latest version is 2.0.1.

# check the version of chain-maind
$ ./chain-maind version

Step 3-2-3 - Restart chain-maind with version v2.1.2

We are ready to start the node join the network again with the new binary:

  • Start chain-maind, e.g.:

  $ ./chain-maind start

You've successfully performed the new binary upgrade! Sit back and wait for the syncing process.

  • You can query the node syncing status by

    $ ./chain-maind status 2>&1 | jq '.SyncInfo.catching_up'

If the above command returns false, it means that your node is synced; otherwise, it returns true and implies your node is still catching up.

  • You can check the current block height by querying the public full node by:

    curl -s | jq "{height: .result.signed_header.header.height}"

and you can check your node's progress (in terms of block height) by:

$ ./chain-maind status 2>&1 | jq '.SyncInfo.latest_block_height'

"DRACO II" and "V4" Network upgrades

You've successfully performed the "Canis Major" binary upgrade! Allow sometime for the node to catch up, meanwhile, you can get ready for "DRACO II," the second network upgrade ( from v2.* to v3.3.2 at block height 3,526,800 ) by following this guide, and "V4 Upgrade" (from v3.3.* to v4.2.2 at block height 10,073,800) by following this guide at a later stage. You can find the key details for all the upgrades under "Notes on network upgrades"

(Optional) QuickSync

Syncing Cronos PoS Chain could be a time-consuming process, our team has partnered with Chainlayer to provide the β€œQuickSync” service to make the process more efficient for our users.

Users can visit Chainlayer QuickSync page and download the snapshots for Cronos PoS Chain with different pruning settings (currently only levelDB downloads are available). You may refer to the following guide to implement QuickSync.

Step 1. QuickSync Download

To start with QuickSync, you need to run brew install lz4 to install lz4 in a new terminal. Then download the file with preferred pruning settings directly from

There are three versions:


  • Pruned snapshot is the quickest way to get a node running. If you only want to give it a shot, use it for a validator or sentry node, the pruned snapshot will be a good choice. Pruned snapshots have transaction index disabled to save disk/download size, which also will make API queries not work backward in time. If you still want to use a pruned snapshot to start an API node, then you can enable transaction index on your end to start indexing blocks from when you startup your node. But you will not be able to query anything earlier than that.


  • Default is a good middle choice between everything. It will work in most use cases, validator, sentry node, API nodes. It has tx index enabled, so you can query block back in time. The only thing that default nodes do not have is the full history from the start of the chain or chain upgrade.


  • For the users who would like to query the old block, you may pick the archive one for complete blockchain data. The archive node will have all the blocks from the chain start or chain upgrade with full indexing. So this is a good option for API nodes if you need to have access to the whole chain history. Archives grow fast in size and might be more sluggish to run, so if you need something simpler default or a pruned kickstarted API node might solve most of the needs out there.

Step 2. QuickSync Setup

In the following steps, we will take the version crypto-org-chain-mainnet-1-pruned.20220323.2110.tar.lz4 as an example.

(Optional) you can download an addressbook to get connected to peers faster. After downloading it, place the new addrbook.json under .chain-maind/config folder and restart your node to take effect.

Now add the crypto-org-chain-mainnet-1-pruned.20220323.2110.tar.lz4 inside .chain-maind.

Then perform the following steps:

  • Change the path under .chain-maind with cd .chain-maind

  • Decompress with lz4 first then decompress with tar by lz4 -d /Users/<username>/.chain-maind/crypto-org-chain-mainnet-1-pruned.20220323.2110.tar.lz4 | tar -xv.

Example: Decompress the QuickSync pack with lz4

x data/
x data/state.db/
x data/state.db/161915.ldb
x data/state.db/035015.ldb
x data/evidence.db/MANIFEST-000143
x data/evidence.db/000142.log
x data/priv_validator_state.json

The original data folder under .chain-maind is overwritten with the step above. It takes around a few mins to decompress the pruned version of 47GB(at the date of writing).

Step 3. Sync with QuickSync

Now direct back to the original directory and re-sync the chain again with ./chain-maind start. It starts the node and syncs the blockchain data from the height of 5055406.

Example: Restart chain-maind start with QuickSync

  $ ./chain-maind start                                                                   
  12:28PM INF starting ABCI with Tendermint
  12:28PM INF Starting multiAppConn service impl=multiAppConn module=proxy
  12:28PM INF Starting localClient service connection=query impl=localClient module=abci-client
  12:28PM INF Starting localClient service connection=snapshot impl=localClient module=abci-client
  12:28PM INF ABCI Handshake App Info hash="PΩ–}\x03G[5\x1aQi*#y-s:" height=5055406 module=consensus protocol-version=0 software-version=
  12:28PM INF ABCI Replay Blocks appHeight=5055406 module=consensus stateHeight=5055406 storeHeight=5055406

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