Single service comparison

Huawei IMS exposes a flatter image lifecycle model rather than a gallery→definition→version hierarchy. IMS classifies images by source type (public, private, shared, KooGallery) and by private image subtype (system disk, data disk, ISO, full-ECS), with lifecycle operations such as attribute edit, share, and replicate. There is no first-class image-definition grouping with semantic versioning, excludeFromLatest flags, or per-version target-region publishing profile equivalent to Azure Compute Gallery. Architects must encode gallery grouping and version lineage through naming conventions, tags, and supplemental pipelines instead of the native resource model.

Replication and scaling semantics differ materially. Azure Compute Gallery lets you declare regional replica counts and storage account type per target region and uses replica fan-out to raise concurrent VMSS creation ceilings (up to 1000 instances, ~1 replica per 20 concurrent VMs). IMS supports cross-region image replication and shared images across accounts, and it integrates with ECS/BMS provisioning and Auto Scaling, but it does not expose a declarative per-region replica count or zone-redundant storage option tied to image versions. Plan for weaker control-plane levers over regional throttling and zonal durability at the image layer.

Integration surface and responsibility boundaries shift. Azure Compute Gallery additionally hosts VM applications as a versioned package type decoupled from OS images, and offers RBAC, direct shared, and community gallery sharing across Active Directory tenants. IMS is image-only; application packaging falls to images, CCE images, ECS Custom Image pipelines, or KooGallery marketplace listings, and cross-account distribution uses image sharing plus KooGallery rather than a community gallery construct. Security posture (Trusted Launch validation, Gen2 defaults) is enforced differently, so verify Huawei ECS security features (e.g., qxsec/HCE hardening) and driver/agent compatibility rather than assuming parity.

Assessment and target choice: inventory each Azure Compute Gallery's image definitions, versions, target regions, replica counts, storage type (LRS/ZRS), sharing scope (RBAC, direct, community), and Trusted Launch/hyperVGeneration settings. Confirm the direct equivalent is IMS private and shared images; for marketplace-style distribution, map to KooGallery; for container-native workloads, consider CCE image registries instead. Verify OS support against Huawei public image catalog (Huawei Cloud EulerOS, Ubuntu, AlmaLinux, Rocky Linux) and decide whether to re-bake golden images on Huawei ECS or import external image files, since automatic cross-cloud image import is not provided.

Image and content migration: export each required Azure image version to a VHD (via managed disk snapshot or capture), upload the VHD to an Huawei Cloud OBS bucket, and register it through IMS as an external image file to produce a private system-disk image. Rebuild CI golden-image pipelines against an Huawei ECS base, reinstall Huawei Cloud agents and Cloud-Init, then create private images from the ECS or via full-ECS images. Re-establish version lineage and regional publishing intent with tags, naming standards, and a manual cross-region replication plan, because the gallery/definition/version envelope does not map natively.

Validation and cutover: provision ECS and BMS instances from the new IMS private images and validate boot, driver/agent health, Cloud-Init user-data injection, disk hot swap, and application behavior. Reproduce Auto Scaling rollout tests to check provisioning throughput under IMS's regional replication model, and confirm cross-account sharing or KooGallery publication works for your distribution scenarios. Run parallel canaries, then cut over workloads once image provisioning, restore, and rollback are proven; keep Azure galleries read-only during the transition.

Gaps and cost-model changes: Azure Compute Gallery charges only for replica snapshot storage plus first-copy inter-region egress, with no service fee; Huawei cost is driven by EVS snapshot/OBS storage for images, ECS/BMS runtime, and inter-region replication traffic, plus any CCE or KooGallery listing fees. Rebuild TCO with replica count, retention period, regional fan-out, and cross-region traffic, and confirm IMS quotas (image counts, sharing limits) before production. Budget for the loss of the VM application package type and community gallery sharing, and design compensating automation (image pipelines, CCE, ConfigMgr, KooGallery) accordingly.