# Starting a relay node

After downloading the cardano-node software from the [Github Releases page](https://github.com/input-output-hk/cardano-node/releases) (or building it from the source code, if you prefer: [building instructions](https://github.com/input-output-hk/cardano-node/blob/master/doc/getting-started/install.md/)) and copying the `cardano-node` and `cardano-cli` binaries to `/usr/local/bin`, the next step is to create a dedicated user for running the cardano-node service, create the required folders and download the configuration files.

I am usually creating a user named "cardano", without any extra privileges (and without a password), for this purpose.

```bash
sudo useradd -m -s /bin/bash cardano
```

To login as this user, after connecting with ssh with an user with sudo rights, I am switching to cardano using the command:

```bash
sudo su - cardano
```

As the cardano user, I am creating the following folders:

```bash
mkdir ~/cardano-node ~/cardano-node/bin ~/cardano-node/config ~/cardano-node/db
```

The next step is to download the configuration files for the selected network (mainnet, preprod or preview) from here: <https://book.world.dev.cardano.org/environments.html>

This can be done like this for mainnet (and similar for preview or preprod, but downloading their similar config files):

```bash
cd ~/cardano-node/config
wget https://book.world.dev.cardano.org/environments/mainnet/config.json
wget https://book.world.dev.cardano.org/environments/mainnet/topology.json
wget https://book.world.dev.cardano.org/environments/mainnet/byron-genesis.json
wget https://book.world.dev.cardano.org/environments/mainnet/shelley-genesis.json
wget https://book.world.dev.cardano.org/environments/mainnet/alonzo-genesis.json
wget https://book.world.dev.cardano.org/environments/mainnet/conway-genesis.json
```

These files are all the configuration files required for running the cardano node.

After downloading them, the next step is to create a startup script inside the `~/cardano-node/bin` folder:

```bash
cd ~/cardano-node/bin
cat >startNode.sh<<EOF
#!/bin/bash

DIRECTORY=/home/cardano/cardano-node
PORT=6000
HOSTADDR=0.0.0.0
TOPOLOGY=\${DIRECTORY}/config/topology.json
DB_PATH=\${DIRECTORY}/db
SOCKET_PATH=\${DIRECTORY}/db/node.socket
CONFIG=\${DIRECTORY}/config/config.json

cardano-node +RTS -N -RTS run \\
--topology \${TOPOLOGY} \\
--database-path \${DB_PATH} \\
--socket-path \${SOCKET_PATH} \\
--host-addr \${HOSTADDR} \\
--port \${PORT} \\
--config \${CONFIG}
EOF
chmod 755 startNode.sh
```

This will create the `startNode.sh` file with the content above starting with `#!/bin/bash` and ending before the `EOF` towards the end of the code, and `chmod 755 startNode.sh` will make the file executable.

Using this file, you can already start the node in relay mode, but you need to let it run inside the console. If you close the console, it will stop. The initial sync will take a long time (probably hours, because the `~/cardano-node/db` folder has close to 100 GB that need to be downloaded. After the initial setup, the node needs to run permanently, to sync the new blocks.

The better way of starting the node is as a systemd service. For this, a systemd service needs to be defined, activated and started. As root (`sudo -i` as an user with `sudo` rights to become root), run the following commands:

```bash
cd /etc/systemd/system
cat >cardano-node.service<<EOF
# The Cardano node service (part of systemd)
# file: /etc/systemd/system/cardano-node.service 

[Unit]
Description      = Cardano node service
Wants            = network-online.target
After            = network-online.target 

[Service]
User             = cardano
Type             = simple
WorkingDirectory = /home/cardano/cardano-node
ExecStart        = /bin/bash -c '/home/cardano/cardano-node/bin/startNode.sh'
KillSignal       = SIGINT
TimeoutStopSec   = 300
LimitNOFILE      = 32768
Restart          = always
RestartSec       = 5

[Install]
WantedBy         = multi-user.target
EOF
systemctl daemon-reload
systemctl enable cardano-node.service
systemctl start cardano-node.service
```

This will create the `cardano-node.service` file, enable it (make it start automatically at boot) and start it.

To see and follow the logs, type the following command (as root):

```bash
journalctl -f -u cardano-node.service -n 50
```

If everything is fine, you should see the node syncing the blocks.

To see the progress of the sync, you can run the query tip command (as the `cardano` user):

```
cardano-cli query tip --mainnet
```

The response will be like this (with different numbers and block hash, and a percent lower than 100 while the node is still not in sync):

```json
{
    "block": 9470184,
    "epoch": 444,
    "era": "Babbage",
    "hash": "25add230783281b0be4337dbf36bafe18897bf451eb211cbe5977ca14f61c92f",
    "slot": 106842959,
    "slotInEpoch": 398159,
    "slotsToEpochEnd": 33841,
    "syncProgress": "100.00"
}
```

If this command is not running, then you need to set the `CARDANO_NODE_SOCKET_PATH` environment variable, pointing to the node socket (defined in the `startNode.sh` file above):

```bash
export CARDANO_NODE_SOCKET_PATH=/home/cardano/cardano-node/db/node.socket
```

To make it set automatically at the login, put it in the `.bashrc` file (in the `cardano` user's home):

```bash
echo "export CARDANO_NODE_SOCKET_PATH=/home/cardano/cardano-node/db/node.socket" >>~/.bashrc
```

In case you did not do it already, also set the `LD_LIBRARY_PATH` environment variable in the \~/.bashrc\` file:

```bash
echo 'export LD_LIBRARY_PATH="/usr/local/lib:$LD_LIBRARY_PATH"' >>~/.bashrc
```

In case the `cardano-node` or/and `cardano-cli` files are not found, make sure you copy them to `/usr/local/bin` or another folder which is in your $PATH environment variable. I prefer having them in `usr/local/bin`.


---

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