Hazelcast is an in-memory data grid that provides distributed computing capabilities. It allows multiple nodes to work together as a single, seamless cluster, offering features like distributed caching, processing, and data storage. Hazelcast is highly scalable, resilient, and ideal for building real-time applications.
To form a Hazelcast cluster on staging virtual machines (VMs) by configuring firewalls and verifying cluster formation through Tomcat logs.
To allow communication between Hazelcast nodes, configure the firewall to open the required ports. Execute the following commands on all VMs:
ufw allow 6000:6999/tcp
ufw allow 54321/tcp
ufw reload
This ensures that Hazelcast’s default communication and cluster discovery ports are open.
Once the firewall is configured and Hazelcast is started, check the Tomcat log file (catalina.out) for cluster formation details. Typical entries in catalina.out include:
27-Dec-2024 16:13:39.260 INFO [hz.ps_sb_cs.cached.thread-11] com.hazelcast.internal.server.tcp.TcpServerConnector.null [172.21.0.63]:6501 [ps_sb_cs] [5.3.8] Connecting to /172.21.0.64:6501, timeout: 10000, bind-any: false
27-Dec-2024 16:13:39.264 INFO [hz.ps_sb_cs.IO.thread-in-1] com.hazelcast.internal.server.tcp.TcpServerConnection.null [172.21.0.63]:6501 [ps_sb_cs] [5.3.8] Initialized new cluster connection between /172.21.0.63:56675 and /172.21.0.64:6501
27-Dec-2024 16:13:44.279 INFO [hz.ps_sb_cs.priority-generic-operation.thread-0] com.hazelcast.internal.cluster.ClusterService.null [172.21.0.63]:6501 [ps_sb_cs] [5.3.8]
Members {size:6, ver:6} [
Member [172.21.0.64]:6501 - f77ec24f-c906-4b1d-b6b7-28f826446044
Member [172.21.0.62]:6501 - fe33561d-2615-41b6-84a4-5340a83c5f28
Member [172.21.0.65]:6501 - 0ad9ee40-0db6-4d16-a0b3-a2d079971f3f
Member [172.21.0.66]:6501 - 7d89d843-6929-48dd-94bb-706667cb42e1
Member [172.21.0.61]:6501 - 3be34f80-2865-4b83-97fb-5f3c70497c60
Member [172.21.0.63]:6501 - 0a01d8ae-832f-4b7e-bfb7-c05c129ef6f4 this
]
This indicates that the cluster has been successfully formed, with all members listed.
Local Data Center Nodes: 5 nodes with the following IPs:
172.21.0.61172.21.0.62172.21.0.63172.21.0.64172.21.0.65Remote Node: 1 node in the PI data center (connected via VPN):
172.21.0.66The logs confirm that all nodes are part of the Hazelcast cluster. The configuration supports 5 nodes in the local data center and 1 node in the PI data center connected via VPN. Ensure all nodes remain online and properly configured to maintain cluster integrity.
Hazelcast is an in-memory data grid that provides distributed computing capabilities. It allows multiple nodes to work together as a single, seamless cluster, offering features like distributed caching, processing, and data storage. Hazelcast is highly scalable, resilient, and ideal for building real-time applications.
To form a Hazelcast cluster on staging virtual machines (VMs) by configuring firewalls and verifying cluster formation through Tomcat logs.
To allow communication between Hazelcast nodes, configure the firewall to open the required ports. Execute the following commands on all VMs:
ufw allow 6000:6999/tcp
ufw allow 54321/tcp
ufw reload
This ensures that Hazelcast’s default communication and cluster discovery ports are open.
Once the firewall is configured and Hazelcast is started, check the Tomcat log file (catalina.out) for cluster formation details. Typical entries in catalina.out include:
27-Dec-2024 16:13:39.260 INFO [hz.ps_sb_cs.cached.thread-11] com.hazelcast.internal.server.tcp.TcpServerConnector.null [172.21.0.63]:6501 [ps_sb_cs] [5.3.8] Connecting to /172.21.0.64:6501, timeout: 10000, bind-any: false
27-Dec-2024 16:13:39.264 INFO [hz.ps_sb_cs.IO.thread-in-1] com.hazelcast.internal.server.tcp.TcpServerConnection.null [172.21.0.63]:6501 [ps_sb_cs] [5.3.8] Initialized new cluster connection between /172.21.0.63:56675 and /172.21.0.64:6501
27-Dec-2024 16:13:44.279 INFO [hz.ps_sb_cs.priority-generic-operation.thread-0] com.hazelcast.internal.cluster.ClusterService.null [172.21.0.63]:6501 [ps_sb_cs] [5.3.8]
Members {size:6, ver:6} [
Member [172.21.0.64]:6501 - f77ec24f-c906-4b1d-b6b7-28f826446044
Member [172.21.0.62]:6501 - fe33561d-2615-41b6-84a4-5340a83c5f28
Member [172.21.0.65]:6501 - 0ad9ee40-0db6-4d16-a0b3-a2d079971f3f
Member [172.21.0.66]:6501 - 7d89d843-6929-48dd-94bb-706667cb42e1
Member [172.21.0.61]:6501 - 3be34f80-2865-4b83-97fb-5f3c70497c60
Member [172.21.0.63]:6501 - 0a01d8ae-832f-4b7e-bfb7-c05c129ef6f4 this
]
This indicates that the cluster has been successfully formed, with all members listed.
Local Data Center Nodes: 5 nodes with the following IPs:
172.21.0.61172.21.0.62172.21.0.63172.21.0.64172.21.0.65Remote Node: 1 node in the PI data center (connected via VPN):
172.21.0.66The logs confirm that all nodes are part of the Hazelcast cluster. The configuration supports 5 nodes in the local data center and 1 node in the PI data center connected via VPN. Ensure all nodes remain online and properly configured to maintain cluster integrity.