CloudHub Static IP Addresses with Multiple Workers

Horizontal scaling in CloudHub can require more than increasing the worker count. Applications that connect to external systems protected by IP allowlists may also need predictable outbound IP addresses.

When this article was written, CloudHub's documented static-IP behavior appeared to be limited to single-worker applications. In practice, MuleSoft had begun enabling multiple static IPs for organizations using multiple workers, subject to subscription and capacity requirements.

Version context: This article documents CloudHub behavior observed in 2017. CloudHub networking, worker models, private spaces/VPC capabilities, and static-IP options have evolved since then. Verify current MuleSoft documentation before designing a new network architecture.

Original Workflow

The observed sequence was:

1. Open the application's Static IPs configuration in Runtime Manager.
2. Enable Use Static IP.
3. Return to the runtime configuration.
4. Increase the number of workers.
5. Apply the deployment changes.

CloudHub then allocated static IP addresses for the multi-worker deployment. The limitation was that the complete set of addresses could not necessarily be pre-allocated before deployment.

Preconditions Observed at the Time

The feature depended on sufficient subscription capacity and platform capabilities, including enough vCores, enough static-IP capacity, support for multiple workers, and the Cloud Fabric capability used by the deployment model at that time.

Architectural Takeaway

Scaling an integration runtime can affect network identity as well as compute capacity. If downstream systems rely on IP allowlisting, static egress requirements should be considered before changing worker topology. Treat network egress, capacity, availability, and scaling as one deployment design rather than independent settings.