Cronos Gravity Bridge Testnet

This is a detailed documentation for setting up a full node on Cronos gravity bridge testnet - Pioneer 11 pioneereleventestnet_340-1.

{% hint style="info" %} Remarks:

Cronos gravity bridge testnet - Pioneer 11 (pioneereleventestnet_340-1) is distinct from the official "Cronos testnet" (cronostestnet_338-3) which is used by app developers to test their Dapps. The Pioneer 11 testnet is a dedicated testnet created specifically for the purpose of testing the Cronos Gravity Bridge. {% endhint %}

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 operating systems after we have stabilised our current architecture.

Prepare your machine

To run Cronos gravity bridge 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 0 : Notes on testnet Network upgrade

This is a detailed documentation for setting up a full node on Crypto.org Cronos testnet pioneereleventestnet_340-1.

Before we start, please note that there are three binary upgrades along with the testnet:

Block Height	Binary Version	Instruction
~ `991350`	v0.8.0-gravity-alpha0	Follow Step 1 to Step 3 and start the node with the older binary version `v0.8.0-gravity-alpha0`; Sync-up with the blockchain until it reaches the target upgrade block height `991350`; Please note that `panic: UPGRADE "v0.7.0-hotfix" NEEDED at height:` `991350` is the expected error message when we hit that block.
`991350`	v0.8.0-gravity-alpha1-patch	After it reaches the block height `991350`, update the binary to v0.8.0-gravity-alpha1-patch; Start the node again
`1995388`	v0.8.0-gravity-alpha2	After it reaches the block height `1995388`, update the binary to v0.8.0-gravity-alpha2; Start the node again
`2083888`	v0.8.0-gravity-alpha3	After it reaches the block height `2083888`, update the binary to v0.8.0-gravity-alpha3; Start the node again

Step 1. Get the Cronos gravity bridge testnet binary

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.

To install released Cronos Cronos Pioneer 11 testnet binaries from github:

$ curl -LOJ https://github.com/crypto-org-chain/cronos/releases/download/v0.8.0-gravity-alpha0/cronos_0.8.0-gravity-alpha0-testnet_Linux_x86_64.tar.gz
$ tar -zxvf cronos_0.8.0-gravity-alpha0-testnet_Linux_x86_64.tar.gz

Afterward, you can check the version of cronosd by

$ ./cronosd version
v0.8.0

Step 2. Configure `cronosd`

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

If you have joined other Cronos gravity bridge testnet 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 gravity bridge testnet:

Step 2-1 Initialize `cronosd`

First of all, you can initialize cronosd by:
```
  $ ./cronosd init [moniker] --chain-id pioneereleventestnet_340-1
```
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 pioneereleventestnet_340-1
```

{% hint style="info" %} 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 {% endhint %}

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/pioneereleventestnet_340-1/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}') = "350b4d14d38d37b1f60b340bcb6c05cc1e0980811e2153fdef29a6530bd3d952" ]]; then echo "OK"; else echo "MISMATCHED"; fi;

OK!

{% hint style="info" %} 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

{% endhint %}

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"0d5cf1394a1cfde28dc8f023567222abc0f47534@52.74.82.209:26656,04f43116b4c6c70054d9c2b7485383df5b1ed1da@52.76.110.186:26656"#' ~/.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

{% hint style="info" %} For Mac environment, if jq is missing, you may install it by: brew install jq {% endhint %}

Step 3. Run everything

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

Start cronosd, e.g.:

  $ ./cronosd start --unsafe-experimental

{% hint style="info" %} 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

{% endhint %}

(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 --unsafe-experimental
  # view log
  $ journalctl -u cronosd -f

{% hint style="info" %} 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  --unsafe-experimental --home /home/ubuntu/.cronos
Restart=on-failure
RestartSec=10
LimitNOFILE=50000

[Install]
WantedBy=multi-user.target

{% endhint %}

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://rpc-p11.cronos.org/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'