Install Hyper-Converged Database (HCD) using the binary tarball

Use this installation method to run Hyper-Converged Database (HCD) on bare metal or a virtual machine (VM). The following steps set up HCD in a compact installation in a single directory. By default, the installation stores binaries, data, and logs in the installation directory. For production deployments, configure separate locations for data and logs before you start HCD. You can run the installation on Linux or Mac.

An HCD binary tarball enables:

Running HCD as a standalone process.
Storing binaries, data, and logs in a single directory.
Installing HCD with or without root permissions.

Important considerations before installation

When you install HCD, it creates a cassandra superuser role in the database, and HCD runs as this user. Don’t use the default cassandra role in production because it is a security risk. Instead, create a new superuser role for running HCD.

When you install HCD from the binary tarball, it runs as a standalone process.
This procedure installs HCD only. It doesn’t install developer-related tools, such as Cassandra drivers or Mission Control.

Prerequisites

An HCD 1.1 tarball download link.

Contact IBM Support to request a tarball download link.
Install a supported Java 11 runtime: OpenJDK 11 (recommended) or Oracle Java SE 11.0.x (JDK).

If you install multiple Java versions, set your $JAVA_HOME environment variable to Java 11.
For production installations and simulated production test environments, review the recommended settings.

Some settings can be applied before installing HCD. For settings that require a running HCD instance, plan to apply them after the installation.

Set data and log directory locations

You can use the default data and logging directory locations, or you can define your own locations. Configure your preferred locations before you start HCD.

Use default directory locations

To use the default data and logging directory locations, you must create and set ownership for the following:

/var/lib/cassandra
/var/log/cassandra

sudo mkdir -p /var/lib/cassandra; sudo chown -R $USER:$GROUP /var/lib/cassandra &&
sudo mkdir -p /var/log/cassandra; sudo chown -R $USER:$GROUP /var/log/cassandra

Use custom directory locations

In your HCD installation directory, create directories for data and logging:

mkdir hcd-data &&
cd hcd-data &&
mkdir data &&
mkdir commitlog &&
mkdir saved_caches &&
mkdir hints &&
mkdir cdc_raw

Change to your HCD installation directory, and then change to the directory containing the cassandra.yaml file:
```
cd ../resources/cassandra/conf
```

Update the following lines in the cassandra.yaml file to match your custom locations:

data_file_directories:
  - full_path_to_installation_location/hcd-data/data
  commitlog_directory: full_path_to_installation_location/hcd-data/commitlog
  saved_caches_directory: full_path_to_installation_location/hcd-data/saved_caches
  hints_directory: full_path_to_installation_location/hcd-data/hints
  cdc_raw_directory: full_path_to_installation_location/hcd-data/cdc_raw

Install HCD using a tarball

Unpack the tarball into your desired installation directory:
```
tar xvzf hcd-VERSION_NUMBER-bin.tar.gz
```
Replace VERSION_NUMBER with your installation’s version number. For example, 1.2.7.

HCD unpacks its files into the hcd-VERSION_NUMBER subdirectory.
Start HCD from the installation directory:
```
cd hcd-VERSION_NUMBER
bin/hcd cassandra
```
Replace VERSION_NUMBER with your installation’s version number. For example, 1.2.7.

If HCD doesn’t start, check your Java version, and make sure that the $JAVA_HOME environment variable is set to the latest HCD supported Java version that you have installed.
Optional: To store logs in a custom location, set the CASSANDRA_LOG_DIR environment variable inline at start-up:
```
cd hcd-VERSION_NUMBER
CASSANDRA_LOG_DIR=INSTALLATION_DIRECTORY/logs bin/hcd cassandra
```
Replace the following:
- VERSION_NUMBER: Your installation’s version number
- INSTALLATION_DIRECTORY: The full path to your installation directory
  
  This sets a process-level override for the current invocation only. It does not persist across restarts. To permanently redirect logs, configure the log directory in cassandra.yaml before starting HCD.
For multi-node installations, repeat the install process and start HCD on each node.