# Installing Matcher on Ubuntu From Deb-package

Waves.Exchange Matcher executes orders on buying/selling an asset. Everyone can deploy matcher and start getting a reward from executing orders.

Let's review the order execution process.

Matcher receives an order to buy/sell some asset pair. The order contains information about asset A amount and its price, expressed in asset B amount.
Matcher accumulates the orders in the order book. When a new order is received, the matcher matches it with the present orders and tries to find mutually satisfying orders.
If mutually satisfying orders are found, then the matcher sends the exchange transaction to the blockchain. As a result, the mentioned orders are being executed. If the mutually satisfying orders are not found, then the new order is sent to the order book.
Matcher gets a matcher fee from each sender of the executed orders.
Matcher repays exchange transaction fee to the miner. Matcher reward is the difference between the matcher fee and the exchange transaction fee.

The current article considers deploying matcher from deb-package. Because matcher is a node extension, the node must be deployed prior to the matcher activation.

# System Requirements

2 core CPU
4 GB RAM
50 GB HDD

# Checking the Version of the Installed OpenJDK

Make sure that you have OpenJDK version 8 installed. To do so, execute the following command in the console:

java -version 2>&1 | grep "openjdk version \"1.8" | wc -l

If 0 is being displayed, then proceed to OpenJDK version 8 installation step.

If 1 is being displayed, then proceed to Node installation.

# OpenJDK Version 8 Installation

To install OpenJDK version 8, execute in the console:

sudo apt-get update
sudo apt-get install openjdk-8-jre

# Node installation

Download the latest version of waves_<version>_all.deb file from https://github.com/wavesplatform/Waves/releases.

Execute in the console

sudo dpkg -i /path/to/waves_<version>_all.deb

Move to /var/lib/waves folder by executing
```
cd /var/lib/waves
```

# Node setup

Open the /usr/share/waves/conf/waves.conf file using the following command:
```
sudo nano /usr/share/waves/conf/waves.conf
```

Decide whether the existing or new account should be used for the node. Use the existing account if you plan to use your node as a mining node.

To use a new account, uncomment in wallet section the password parameter and set a value for it. Example:

wallet {
  # Password to protect wallet file
  password = iAmGoingToUseAnewAccount
  # Wallet seed as BASE58 string
  # seed =
}

To use an existing account, input in wallet section the password and, in base58 encoding, the seed.

wallet {
  # Password to protect wallet file
  password = iAmGoingToUseAnExistingAccount
  # Wallet seed as BASE58 string
  seed = 35S7EzKMHMN4JQyWnwpp84Zot1yqLoP2Q46RsbYRzgFq7n8AiV8L6skeGPq93P2NU4pGcZFeNTAT2TKJTa2XvqRwSdCmBR556MBmtZ3ggAkBtd3CCZFvZwZufz1ZqfzJQ
}

Add to /usr/share/waves/conf/waves.conf file the section:

waves.extensions = ["com.wavesplatform.dex.Matcher"]

Set in /usr/share/waves/conf/waves.conf file in rest_api section the following parameters:
- enable = yes
- api_key_hash = " "
```
rest-api {
  # Disable node’s REST API
  enable = yes
  …
  api_key_hash = " "
}
```
Start node by executing the following command:
```
sudo systemctl start waves
```

Generate non-empty api_key_hash value. Execute command:

curl -X POST --header 'Content-Type: application/json' --header 'Accept: application/json' -d '<YOUR_ARBITRARY_STRING>' '127.0.0.1:6869/utils/hash/secure'

Please use your own value instead of <YOUR_ARBITRARY_STRING>. It is recommended to store it. As a result, you will see the following output:

{"message": "YOUR_ARBITRARY_STRING", "hash": "3QbuM9nJP9GZQDekgfGboPGDQe4g1nsH4kmK2jbCLAFJ"}

Set in the /usr/share/waves/conf/waves.conf file in the rest_api section the value of api_key_hash parameter:
```
rest-api {
  …
  api_key_hash = “3QbuM9nJP9GZQDekgfGboPGDQe4g1nsH4kmK2jbCLAFJ”
}
```
Restart the node by executing the following command:
```
sudo systemctl restart waves
```
Make sure that blockchain is downloaded. Execute the following command:
```
sudo journalctl -u waves -f
```
As a result, the blockchain download log will be displayed. If "microblock appended" entries started to appear in the log, then blockchain is completely downloaded.
Press Ctrl-C to close the log.
Discover the node account address. To do so, execute the following command:

curl 127.0.0.1:6869/addresses

As a result, the node account address will be displayed, for example, 3PAbvhnSesJGUd1Ry6YM1qCALTSD4pYGxG.

Execute the following steps in /usr/share/waves/conf/waves.conf file:
1. Create a waves.dex section.
2. Set the node account address for matcher. To do so, assign in waves.dex section the value obtained in the previous step to account parameter.
```
waves.dex {
  account = "3PAbvhnSesJGUd1Ry6YM1qCALTSD4pYGxG"
  # bind-address = "0.0.0.0" # uncomment this line to accept connections from any host
}
```

Other node parameters are out of the scope of the current article. To get more information about node parameters, refer to Node Configuration.

# Installing matcher

Download the latest version of dex_<version>_all.deb file from https://github.com/wavesplatform/dex/releases.

Execute the following command in the console:

sudo dpkg -i /path/to/dex_<version>_all.deb

Restart the node by executing:
```
sudo systemctl restart waves
```
Make sure that matcher is successfully started. To do so, execute:
```
curl 127.0.0.1:6886/matcher
```

As a result, the matcher account address will be displayed. Congratulations, you've successfully installed the matcher.