# Cronos Testnet: Running Nodes

The latest Crypto.org EVM Chain Testnet has been named as Cronos.

This is a detailed documentation for setting up a Validator or a full node on Crypto.org Cronos testnet cronostestnet_338-3.

Before we start, please note that there are 3 binary upgrade along with the testnet:

Follow Step 1 to Step 3 and start the node with the older binary version v0.6.0;
- Sync-up with the blockchain until it reaches the target upgrade block height 1553700;
- Please note that panic: UPGRADE "v0.7.0" NEEDED at height: 1553700 is the expected error message when we hit that block.
cronos_0.7.0-rc1 upgrade:
- After it reaches the block height 1553700, update the binary to cronos_0.7.0-rc1-testnet (opens new window);
- Then update the default ~/.cronos/config/app.toml(given there are some new parameter introduced in the upgrade), either by manually replace the local app.toml with this new app.toml (opens new window), or by:
```
$ curl https://raw.githubusercontent.com/crypto-org-chain/cronos-testnets/main/cronostestnet_338-3/app.toml > ~/.cronos/config/app.toml
```
- Continue to sync from block 1553700;
cronos_0.7.0-rc2 upgrade:
- After it reaches the block height 1869000, update the binary to cronos_0.7.0-rc2-testnet (opens new window);
- Start the node again
- Continue to sync from block 1869000;
cronos_0.7.0-rc3 upgrade:
- After it reaches the block height 2483600, update the binary to cronos_0.7.0-rc3-testnet (opens new window);
- Start the node again

#

# Pre-requisites

# 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

To run Cronos testnet nodes, you will need a machine with the following minimum requirements:
- 4-core, x86_64/ARM architecture processor;
- 16 GB RAM;
- 1 TB of storage space.

# Step 1. Get the Cronos testnet binary

Remarks:

The following is the minimal setup for a full node.

To simplify the following step, we will be using Linux (Intel x86) for illustration. Binary for

Mac Intel x86 as Darwin_x86_64, Mac M1 as arm64 and Windows as Windows_x86_64 are also available here (opens new window). Please check the required node version here (opens new window).

To install released Cronos testnet binaries from github:

$ curl -LOJ https://github.com/crypto-org-chain/cronos/releases/download/v0.6.0-testnet/cronos_0.6.0-testnet_Linux_x86_64.tar.gz
$ tar -zxvf cronos_0.6.0-testnet_Linux_x86_64.tar.gz

Afterward, you can check the version of cronosd by

$ ./cronosd version
v0.6.0-testnet

# Step 2. Configure `cronosd`

# Step 2-0 (Optional) Clean up the old blockchain data

If you have joined cronostestnet_338-2 before, you would have to clean up the old blockchain data and start over again, it can be done by running:
```
$ ./cronosd unsafe-reset-all
```
and remove the old genesis file by
```
$ rm ~/.cronos/config/genesis.json
```

Before kick-starting your node, we will have to configure your node so that it connects to the Cronos testnet:

# Step 2-1 Initialize `cronosd`

First of all, you can initialize cronosd by:
```
  $ ./cronosd init [moniker] --chain-id cronostestnet_338-3
```
This moniker will be the displayed id of your node when connected to the Cronos network. When providing the moniker value, make sure you drop the square brackets since they are not needed. The example below shows how to initialize a node named pegasus-node :
```
  $ ./cronosd init pegasus-node --chain-id cronostestnet_338-3
```
NOTE
- Depending on your cronosd home setting, the cronosd configuration will be initialized to that home directory. To simply the following steps, we will use the default cronosd home directory ~/.cronos/ for illustration.
- You can also put the cronosd to your binary path and run it by cronosd

# Step 2-2 Configure cronosd

Download and replace the Cronos Testnet genesis.json by:

$ curl https://raw.githubusercontent.com/crypto-org-chain/cronos-testnets/main/cronostestnet_338-3/genesis.json > ~/.cronos/config/genesis.json

Verify sha256sum checksum of the downloaded genesis.json. You should see OK! if the sha256sum checksum matches.

$ if [[ $(sha256sum ~/.cronos/config/genesis.json | awk '{print $1}') = "7d898ad75b3e2e1fa182d928ca10a284c1dd252e12d17ad6dab76551b29d1a59" ]]; then echo "OK"; else echo "MISMATCHED"; fi;

OK!

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
```

(Validator node only) In ~/.cronos/config/app.toml, update minimum gas price to avoid transaction spamming (opens new window)

$ sed -i.bak -E 's#^(minimum-gas-prices[[:space:]]+=[[:space:]]+).*$#\1"5000000000000basetcro"#' ~/.cronos/config/app.toml

For network configuration, in ~/.cronos/config/config.toml, validator nodes need to modify the configurations of persistent_peers, create_empty_blocks_interval and timeout_commit. For non-validator full nodes, only persistent_peers modification is required:

$ sed -i.bak -E 's#^(persistent_peers[[:space:]]+=[[:space:]]+).*$#\1"[email protected]:26656,[email protected]:26656"#' ~/.cronos/config/config.toml
$ sed -i.bak -E 's#^(create_empty_blocks_interval[[:space:]]+=[[:space:]]+).*$#\1"5s"#' ~/.cronos/config/config.toml
$ sed -i.bak -E 's#^(timeout_commit[[:space:]]+=[[:space:]]+).*$#\1"5s"#' ~/.cronos/config/config.toml

NOTE

For Mac environment, if jq is missing, you may install it by: brew install jq

# Step 3. Run everything

CAUTION

This page only shows the minimal setup for validator / full node.

Furthermore, you may want to run full nodes as sentries (see Tendermint (opens new window)), restrict your validator connections to only connect to your full nodes, test secure storage of validator keys etc.

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

Start cronosd, e.g.:

  $ ./cronosd start

Remarks:

If you see errors saying too many files opened..., then you need to set a higher number for maximum open file descriptors in your OS.

If you are on OSX or Linux, then the following could be useful:

# Check current max fd
$ ulimit -n
# Set a new max fd
$ ulimit -Sn [NEW_MAX_FILE_DESCRIPTOR]
# Example
$ ulimit -Sn 4096

(Optional for Linux) Start cronosd with systemd service, e.g.:

  $ curl -s https://raw.githubusercontent.com/crypto-org-chain/cronos-docs/master/systemd/create-service.sh -o create-service.sh && curl -s https://raw.githubusercontent.com/crypto-org-chain/cronos-docs/master/systemd/cronosd.service.template -o cronosd.service.template
  $ chmod +x ./create-service.sh && ./create-service.sh
  $ sudo systemctl start cronosd
  # view log
  $ journalctl -u cronosd -f

Example: /etc/systemd/system/cronosd.service created by script

# /etc/systemd/system/cronosd.service
[Unit]
Description=cronosd
ConditionPathExists=/usr/local/bin/cronosd
After=network.target

[Service]
Type=simple
User=ubuntu
WorkingDirectory=/usr/local/bin
ExecStart=/usr/local/bin/cronosd start --home /home/ubuntu/.cronos
Restart=on-failure
RestartSec=10
LimitNOFILE=50000

[Install]
WantedBy=multi-user.target

It should begin fetching blocks from the other peers. Please wait until it is fully synced before moving onto the next step.

You can query the node syncing status by
```
$ ./cronosd status 2>&1 | jq '.SyncInfo.catching_up'
```
If the above command returns false, It means that your node is fully synced; otherwise, it returns true and implies your node is still catching up.

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

curl -s https://evm-t3.cronos.org/:26657/commit | jq "{height: .result.signed_header.header.height}"

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

$ ./cronosd status 2>&1 | jq '.SyncInfo.latest_block_height'

# Cronos testnet faucet and explorer

You can lookup data within the cronostestnet_338-3 network by the explorer (opens new window);
To interact with the blockchain, simply use the test-token faucet (opens new window) to obtain test CRO tokens for performing transactions on the Cronos testnet.
- Users can use the faucet (opens new window) to obtain test tokens, please note that you would need a Ethereum type address 0x... that can be obtained by Using metamask.

In case you have reached the daily limit on faucet , you can simply send a message on Discord (opens new window) #request-tcro channel , stating who you are and your 0x... address.

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