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
Release Support Duration
A major version on Container-Optimized OS corresponds to a new
as explained in
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
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.
Every major release milestone goes through
(also described in detail in
These correspond to
cos-stable image families in the
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
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|