Stable Release Updates (SRU)

For each upstream cloud-init release, a backport is performed to previous Ubuntu releases via a “Stable Release Update” (SRU). Each SRU ensures that new versions of cloud-init on existing releases of Ubuntu will not experience breaking changes. Breaking changes are allowed when transitioning from one Ubuntu series to the next (Noble -> Resolute).

SRU supported releases

Cloud-init will provide SRU support for the current active interim releases and the most recent 2 long-term support (LTS) releases as documented in the Ubuntu Release Cycle

Security Updates

The Ubuntu CVE policy governs how Ubuntu mitigates CVEs in upstream and the standard support Ubuntu releases and releases covered by Expanded Security Maintenance.

SRU package version

Ubuntu cloud-init packages follow the SRU release version format.

SRU testing for cloud-init

The cloud-init project follows a specific process to validate a cloud-init SRU.

An SRU test of cloud-init performs the following:

For each Ubuntu SRU, the Ubuntu Server team validates the new version of cloud-init on these platforms: Amazon EC2, Azure, GCE, OpenStack, Oracle, Softlayer (IBM), LXD using the integration test suite.

Test process:

The integration test suite used for validation follows these steps:

• Install a pre-release version of cloud-init from the -proposed APT pocket (e.g., resolute-proposed).

• Upgrade cloud-init and attempt a clean run of cloud-init to assert that the new version works properly on the specific platform and Ubuntu series.

• Check for tracebacks and errors in behavior.