PostgreSQL is one of the popular relational database management systems. This article will guide you to deploy the PostgreSQL database server in a high-availability cluster that can handle any single point of failure in case one of the node is down.
Introduction: In this guide, we will walk you through the process of setting up a robust and scalable PostgreSQL cluster using Citus for sharding, Patroni for high availability, HAProxy for load balancing, and etcd for distributed coordination. This setup ensures fault tolerance and high performance for your database environment.
- A Linux-based system with root access.
- Familiarity with basic command-line operations.
Step 1: Installing Dependencies: Begin by installing the necessary dependencies. Open a terminal and run:
sudo apt-get update sudo apt-get install -y build-essential libreadline-dev zlib1g-dev flex bison
These packages are required for building PostgreSQL and its extensions.
Step 2: Installing PostgreSQL: Download, compile, and install PostgreSQL:
wget https://ftp.postgresql.org/pub/source/v15.3/postgresql-15.3.tar.gz tar xzf postgresql-15.3.tar.gz cd postgresql-15.3 ./configure --prefix=/usr/local/pgsql --with-openssl --with-libxml --with-libxslt --with-uuid=e2fs --with-system-tzdata=/usr/share/zoneinfo make sudo make install echo "export PATH=/usr/local/pgsql/bin:\$PATH" >> ~/.bashrc source ~/.bashrc
This sequence of commands downloads the PostgreSQL source code, compiles it with required options, installs it, and adds PostgreSQL’s bin directory to your PATH.
Step 3: Installing Citus Extension: Clone Citus repository and install the extension:
git clone https://github.com/citusdata/citus.git cd citus git checkout 11.3.0 sudo PATH=$PATH:/usr/local/pgsql/bin make install
Citus provides horizontal scaling capabilities for PostgreSQL.
Step 4: Installing and Configuring etcd: Download etcd and start a single-node cluster:
wget https://github.com/etcd-io/etcd/releases/download/v3.5.0/etcd-v3.5.0-linux-amd64.tar.gz tar xzf etcd-v3.5.0-linux-amd64.tar.gz sudo mv etcd-v3.5.0-linux-amd64/etcd* /usr/local/bin/ # Start etcd etcd
etcd enables distributed coordination among Patroni instances.
Step 5: Installing and Configuring Patroni: Install Patroni and create a configuration file
sudo apt-get install -y python3-pip sudo pip3 install patroni[etcd] # Create patroni.yml and configure nodes nano patroni.yml
patroni.yml file, you’ll configure settings for each node, including their roles, credentials, and failover behavior. Refer to the previous responses for an example
Troubleshooting Tip: If you encounter issues with Patroni, ensure that etcd is up and running correctly. Check its logs and status to diagnose any problems.
Step 6: Installing and Configuring HAProxy: Install HAProxy and configure load balancing:
sudo apt-get install -y haproxy sudo nano /etc/haproxy/haproxy.cfg
In the HAProxy configuration file
haproxy.cfg, you’ll define how incoming connections are distributed across your PostgreSQL nodes. Refer to the previous responses for an example
Troubleshooting Tip: If you face connection issues, verify that HAProxy is correctly forwarding requests to PostgreSQL nodes. You can check HAProxy’s logs and status to identify problems.
Step 7: Testing the Setup: Connect to the PostgreSQL cluster using HAProxy’s IP and port:
psql -h <haproxy-ip> -p 5432 -U postgres
Perform basic database operations to verify the setup.
Conclusion: By following this comprehensive guide, you’ve successfully set up a highly available PostgreSQL cluster using Citus, Patroni, HAProxy, and etcd. This setup ensures fault tolerance and scalability for your database environment. Further, you can explore additional configuration options and security measures to enhance your setup.