New c4 CCC parameters for allowing multiple subnets in an Exasol environment.
Details
| Detail name | Value |
|---|---|
| Changelog Number | 26757 |
| Type | New Feature |
| Status | Resolved |
| Fix Versions | C4 4.29.0, Exasol 2025.2.0 |
| Resolution Date | 2025-11-18 |
Background
Earlier by default internal component “cored” filtered network packets from different subnets when handling interconnect messages. This meant that all nodes in a cluster needed to be on the same IP subnet. For SDDC use cases (see Synchronous Dual Data Center (SDDC)) one may want to do L3 routing, meaning that the two sides of the cluster will be on different subnets.
Usage of two different subnets required manual modification of configuration files.
New Feature
Two new c4 CCC parameters have been added:
- CCC_PLAY_CORED_ALLOW_ONLY_SAME_SUBNET: when enabled, it filters internal cluster messages by subnet.
- CCC_PLAY_CORED_SUBNETS: this parameter is only used when CCC_PLAY_CORED_ALLOW_ONLY_SAME_SUBNET is enabled and specifies an array of subnets the cluster can receive internal messages from. An empty value means the interface’s subnet will be used.
Examples
CCC_PLAY_ALLOW_ONLY_SAME_SUBNET=true #The CCC_PLAY_CORED_SUBNETS value can be omitted, this is the default behaviour. CCC_PLAY_ALLOW_ONLY_SAME_SUBNET=true CCC_PLAY_CORED_SUBNETS="192.168.1.0/24 2001:db8::/32" CCC_PLAY_ALLOW_ONLY_SAME_SUBNET=false #The CCC_PLAY_CORED_SUBNETS value won't matter in this case, since CCC_PLAY_ALLOW_ONLY_SAME_SUBNET is false
