Installing SingleStore DB on bare metal, on virtual machines, or in the cloud can be done through the use of popular configuration management tools, such as CloudFormation, or through SingleStore’s management tools.

In this guide, you will deploy a cluster onto physical or virtual machines and connect to the cluster using our monitoring, profiling, and debugging tool, SingleStore DB Studio.

A four-node cluster is the minimal recommended cluster size for showcasing SingleStore DB as a distributed database with high availability; however, you can use the procedures in this tutorial to scale out to additional nodes for increased performance over large data sets or to handle higher concurrency loads. To learn more about SingleStore DB’s design principles and topology concepts, see Distributed Architecture.

In this tutorial, you will learn how to deploy a cluster:

• As a sudo user that can install SingleStore DB via Red Hat or Debian packages

• As a non-sudo user that can install SingleStore DB via tarball

• From the main deployment host that can connect to the Internet (online deployment) or that cannot connect to the Internet (offline deployment)

• Using individual SingleStore Tools on the command line

• Using a cluster configuration file (a.k.a. “cluster file”)

Prerequisites

For this tutorial you will need:

• One (for single host cluster-in-a-box for development) or four physical or virtual machines (“hosts”) with the following:

  • Each SingleStore node requires at least four (4) x86_64 CPU cores and eight (8) GB of RAM per host

  • Eight (8) vCPU and 32 GB of RAM are recommended for leaf nodes to align with license unit calculations

  • Running 64-bit version of RHEL/CentOS 6 or higher or Debian 8 or higher, with kernel 3.10 or higher

  • Port 3306 open on all host for intra-cluster communication. This default can be changed in the cluster file.

  • Port 8080 open on the main deployment host for the cluster

  • A non-root user with sudo privileges available on all hosts in the cluster that be used to run SingleStore DB services and own the corresponding runtime state

• SSH access to all hosts (installing and using the SSH agent is recommended for SSH keys with passwords).

  • If using SSH keys, make sure the identity key used on the main deployment host can be used to log into to the other hosts.

  • Refer to How to Setup Passwordless SSH Login for more information on using SSH without a password.

• A connection to the Internet to download required packages

• If deploying a SingleStore DB cluster in a production environment, it is highly recommended that you review and follow the host configuration recommendations for optimal cluster performance.

Duplicate Hosts

As of SingleStore DB Toolbox 1.4.4, a check for duplicate hosts is performed before SingleStore DB is deployed, and will display a message similar to the following if more than one host has the same SSH host key:

✘ Host check failed.host 172.26.212.166 has the same ssh
host keys as 172.16.212.165, toolbox doesn't support
registering the same host twice

Confirm that all specified hosts are indeed different and aren’t using identical SSH host keys. Identical host keys can be present if you have instantiated your host instances from images (AMIs, snapshots, etc.) that contain existing host keys. When a host is cloned, the host key (typically stored in /etc/ssh/ssh_host_<cipher>_key) will also be cloned.

As each cloned host will have the same host key, an SSH client cannot verify that it is connecting to the intended host. The script that deploys SingleStore DB will interpret a duplicate host key as an attempt to deploy to the same host twice, and the deployment will fail.

The CentOS 7.x steps below demonstrate a potential remedy for the “duplicate hosts” message.

$ sudo root
# ls -al /etc/ssh/
# rm /etc/ssh/<your-ssh-host-keys>
# ssh-keygen -f /etc/ssh/<ssh-host-key-filename> -N '' -t rsa1
# ssh-keygen -f /etc/ssh/<ssh-host-rsa-key-filename> -N '' -t rsa
# ssh-keygen -f /etc/ssh/<ssh-host-dsa-key-filename> -N '' -t dsa

For more information about SSH host keys, including the equivalent steps for Ubuntu-based systems, refer to Avoid Duplicating SSH Host Keys.

As of SingleStore DB Toolbox 1.5.3, sdb-deploy setup-cluster supports an --allow-duplicate-host-fingerprints option that can be used to ignore duplicate SSH host keys.

Network Configuration

Depending on the host and its function in deployment, some or all of the following port settings should be enabled on hosts in your cluster.

These routing and firewall settings must be configured to:

• Allow database clients (e.g. your application) to connect to the aggregators

• Allow all nodes in the cluster to talk to each other over the SingleStore DB protocol (3306)

• Allow you to connect to management and monitoring tools

The service port values are configurable if the default values cannot be used in your deployment environment. For more information on how to change them, see:

• The cluster file template provided in this guide

• The SingleStore DB configuration file

• The sdb-toolbox-config register-host command

• The SingleStore DB Studio Installation Guide

We also highly recommend configuring your firewall to prevent other hosts on the Internet from connecting to SingleStore DB.

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