Apache CloudStack 4.20.1 introduces automatic SystemVM template seeding for ARM64 Hosts. When the first ARM64 host is added to a zone, CloudStack downloads and registers the aarch64 template automatically. Combined with the new system.vm.preferred.architecture setting and architecture-aware filters in the UI/API, this feature streamlines mixed-architecture deployments and removes the need for manual template management.

Automatic Seeding for ARM SystemVM Templates

One of the key additions in 4.20.1 is improved logic for SystemVM template seeding. When a zone contains aarch64 (ARM) hosts, CloudStack now automatically downloads and registers the appropriate aarch64 SystemVM template—reducing the need for manual intervention.

Unlike x86_64 templates, the aarch64 version is not bundled with installation packages (RPM/DEB) and is downloaded on demand. In air-gapped or restricted environments, administrators still have the option to manually register the template.

This enhancement simplifies deployment for ARM-based infrastructure and improves the out-of-the-box experience for multi-architecture zones.

Configuring SystemVM Architecture per Zone

A new global configuration key has been introduced to allow Administrators to control the architecture used by System VMs, including Virtual Routers:

system.vm.preferred.architecture

This setting lets Administrators define the target architecture (e.g., x86_64 or aarch64) for System VMs in a given Zone. CloudStack will then deploy these VMs using Templates that match the selected architecture, maintaining consistency across the environment.

This is especially relevant in Zones where both x86_64 and ARM Hosts may be present, enabling Administrators to control System VM placement according to the architecture of the underlying infrastructure.

Architecture-Aware APIs

This improvement introduces architecture attributes across multiple API calls. Resource-related APIs—including those for Clusters, Hosts, Templates, Instances, System VMs, Virtual Routers, and Kubernetes Clusters—now include the architecture information of each resource.

In addition, list* API calls support filtering by architecture, which facilitates automation and improves resource targeting in mixed-architecture environments.

Improved UI for Multi-Architecture Management

As a result of these backend improvements, the CloudStack UI now includes additional features for managing mixed-architecture environments:

• Architecture details are displayed in both list and detail views for supported resources.
• Architecture-based filters enable users to narrow down results when viewing or managing infrastructure.

These UI enhancements expose architecture information across multiple views.

Architecture shown in list view: the Instances table now includes an Arch column, allowing operators to quickly identify the architecture of each Instance:

Architecture shown in list view

 

Architecture being shown in resource information: the Instance detail view displays the architecture label (e.g., x86_64) next to key metadata:

Architecture being shown in resource information

Filtering option to filter based on architecture: the “Add Instance” form introduces a new architecture selector, enabling users to filter instance templates by target architecture:

Filtering option to filter based on architecture

 

Looking Ahead

The improvements introduced in CloudStack 4.20.1 establish baseline support for operating Zones with mixed compute architectures. These capabilities—automatic Template registration, architecture-specific SystemVM configuration, and API/UI filtering—reduce operational overhead in heterogeneous environments.

For details on previous enhancements in this area, refer to ShapeBlue’s blog on multi-architecture Zones in CloudStack.