Stable Release Updates (SRU)#
Once upstream cloud-init has released a new version, the Ubuntu Server team backports cloud-init to previous releases via a special procedure called a “Stable Release Update” (SRU). This helps ensure 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 (Focal -> Jammy).
SRU package version#
Ubuntu cloud-init packages follow the SRU release version format.
SRU testing for cloud-init#
The cloud-init project has a specific process it follows when validating a cloud-init SRU, which is documented in the CloudinitUpdates wiki page.
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.
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., jammy-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 behaviour.