Support Policy

Container-Optimized OS is tested and qualified for running various container workloads on Google Cloud Platform (GCP). It is actively patched with security updates (CVEs) and bug-fixes to address issues that impact GCP users. Users get access to these fixes via our image releases in cos-cloud project.

Release Support Duration

A major version on Container-Optimized OS corresponds to a new Release Milestone as explained in Release Channels. Each such Release Milestone (or major version) stays actively supported for approximately 22 weeks. During these 22 weeks, the release milestone will get features, bug fixes, security updates with varying frequency depending on what stage it is in.

After 22 weeks, the release milestone is deprecated. Specifically, we set the DEPRECATED flag on the image and it stops showing in the active list of images in cos-cloud project.

Under this state, the image is still usable but new patches or fixes will not be made to it. Users may see a warning as well if they are using the gcloud command-line tool while accessing such images.

Users must upgrade to one of the newer active releases in order to continue to receive bug fixes and security patches.

Release Quality

Every major release milestone goes through dev, beta and stable phases (also described in detail in Release Channels). These correspond to cos-dev, cos-beta and cos-stable image families in the cos-cloud project.

You can identify the stage (and the image-family) a release is at by looking at the image name (example: cos-stable-54-8743-71-0) or by looking at the image family it belongs to (example: cos-stable) as listed by gcloud compute images list --project=cos-cloud --no-standard-images command.

Users can always expect to see at least 1 image for each of the three image families. Thus, we have at-least 3 actively supported major versions at any given time.

Release Milestone Progression

Progression of a Release Milestone

Please refer to Release Channels for a detailed explanation of these stages. Each stage receives varying degree of attention with respect to our support policy. This is explained below.

Image Family Duration (Soak Period) Release Frequency Properties
cos-dev ~6 weeks Weekly
  • A new major version is always introduced in `cos-dev` family first.
  • The new major version stays in `cos-dev` for approximately 6 weeks (soak period)
  • New images are released once a week
  • Gets bug fixes, package upgrades and new features
  • May introduce breaking changes compared to previous major version.
  • After the soak period, the major version is promoted to `cos-beta` family
cos-beta ~4 weeks On-demand
  • Feature set is frozen and no major version changes of packages. So breaking changes are not expected.
  • New images are released at most once week, mostly on as-needed basis.
  • Get security fixes and other major bug fixes affecting already built-in features and majority of users
  • Approximately 6 weeks of soak period, after which the major version is promoted to `cos-stable` family
cos-stable ~12 weeks on-demand
  • New images are released only for critical bug fixes and security fixes
  • A major version is available on `cos-stable` for approximately 12 weeks

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