The success of a GBase 8a cluster installation often hinges not on the install commands themselves, but on the pre‑installation environment preparation and post‑installation validation. This guide focuses on critical prerequisites — networking, SSH, system limits, and firewall settings — and walks through a verified workflow for verifying cluster state and distribution configuration.
1. Node Planning and Component Roles
A GBase 8a cluster consists of three component types: gcware (management nodes, 3 or 5 recommended), gcluster (coordinators), and gnode (data nodes). Plan the roles of each node before starting. Here is a sample 3‑node layout:
198.51.100.21 management + coordinator + data node
198.51.100.22 management + coordinator + data node
198.51.100.23 management + coordinator + data node
2. System Prerequisites to Address Before Installation
Nodes must use static IPs, have full network connectivity between them, and have hostname resolution properly configured.
Network and SSH Checks
# Node connectivity
ping 198.51.100.22
ping 198.51.100.23
# SSH connectivity
ssh root@198.51.100.22
ssh root@198.51.100.23
Firewall and SELinux Checks
systemctl status firewalld
sestatus
3. Handling Non‑Default SSH Ports
If SSH is not running on port 22, specify the custom port either through user‑level SSH configuration or the installation options file.
Option A: User‑level SSH config
cat ~/.ssh/config
Host 198.51.100.22 198.51.100.23
Port 22022
Option B: Install options file
# install.options
sshPort = 22022
4. Adjust ulimit and systemd Limits Early
Insufficient file handles or process limits will cause instability under concurrency and batch workloads. Address this across systemd, profile, and limits simultaneously.
# /etc/systemd/system.conf
DefaultLimitNOFILE=655350
DefaultLimitNPROC=655350
systemctl daemon-reexec
systemctl restart sshd
# Also update /etc/profile and /etc/security/limits.conf with appropriate nofile settings
5. Key Installation Steps
- Create the operating system user and directories
useradd gbaseadm
passwd gbaseadm
mkdir -p /data/gbase8a
chown -R gbaseadm:gbaseadm /data/gbase8a
chown gbaseadm:gbaseadm /tmp
- Extract the package and run the environment setup script
cd /data
tar xfj GBase8a_MPP_Cluster-NoLicense-FREE-9.5.3-demo-redhat7-x86_64.tar.bz2
python SetSysEnv.py --dbaUser=gbaseadm --installPrefix=/data/gbase8a --cgroup
Write the installation configuration file
install.options, specifying the install directory, coordinator hosts, data hosts, management hosts, user credentials, and SSH port.Run the silent installation
./gcinstall.py --silent=install.options
6. Validate Cluster Health Immediately After Installation
A completed install script does not guarantee a healthy cluster. Always run gcadmin to verify that the cluster state is ACTIVE and that all gcware, coordinator, and data node roles show OPEN.
7. Configure and Verify Distribution Settings
Prepare a distribution XML file, apply it with gcadmin distribution, and inspect the result with gcadmin showdistribution node. This step directly determines how data is placed across nodes and how the load is balanced.
8. Parameter Tuning Recommendations
Avoid changing many parameters at once. Prioritise based on symptom category: for connection and timeout issues, check max_connections and connect_timeout first; for concurrency and thread pool pressure, look at gbase_parallel_degree; for loading bottlenecks, examine gcluster_loader_max_data_processors.
A smooth GBase 8a installation relies on getting the basics right before running any installer. When the network, SSH, system limits, and cluster health checks are all solid, the rest of the gbase database operations become far more predictable.
