Container-Optimized OS イメージのメジャー バージョンは、マイルストーンという機能を使用して識別されます。Container-Optimized OS マイルストーンは、単調増加整数です。新しいマイルストーンごとに、新しい開発サイクルの開始（コードのブランチ）を示し、新しい機能や他の主要な変更が導入されることがあります。
Container-Optimized OS マイルストーンの期間中に、バグ修正やセキュリティ修正などの変更を含むいくつかの更新がリリースされることがあります。これらのマイルストーンの増分リリースは、ビルド番号を使用して識別できます。
使用している Container-Optimized OS のマイルストーンとビルド番号は、/etc/os-release ファイルで確認できます。このファイルでは、VERSION_ID の値（例: VERSION_ID=81）は、マイルストーンを表し、BUILD_ID フィールドの値（例: BUILD_ID=12871.1160.0）はビルド番号を表します。マイルストーンとビルド番号は、Container-Optimized OS イメージ名の一部としても表示されます。たとえば、イメージ cos-81-12871-1160-0 には、マイルストーン 81 とビルド番号 12871-1160-0 があります。
[[["わかりやすい","easyToUnderstand","thumb-up"],["問題の解決に役立った","solvedMyProblem","thumb-up"],["その他","otherUp","thumb-up"]],[["わかりにくい","hardToUnderstand","thumb-down"],["情報またはサンプルコードが不正確","incorrectInformationOrSampleCode","thumb-down"],["必要な情報 / サンプルがない","missingTheInformationSamplesINeed","thumb-down"],["翻訳に関する問題","translationIssue","thumb-down"],["その他","otherDown","thumb-down"]],["最終更新日 2025-03-06 UTC。"],[[["\u003cp\u003eContainer-Optimized OS uses milestones (major versions) and build numbers (incremental releases) to identify images, with milestones representing new development cycles and build numbers representing updates.\u003c/p\u003e\n"],["\u003cp\u003eYou can find the milestone and build number for your Container-Optimized OS by checking the \u003ccode\u003eVERSION_ID\u003c/code\u003e and \u003ccode\u003eBUILD_ID\u003c/code\u003e values within the \u003ccode\u003e/etc/os-release\u003c/code\u003e file, or from within the image name.\u003c/p\u003e\n"],["\u003cp\u003eLong Term Supported (LTS) milestones, intended for production, are supported for two years, receive security fixes and bug fixes, and are identified by the \u003ccode\u003ecos-[MILESTONE]-lts\u003c/code\u003e and \u003ccode\u003ecos-arm64-[MILESTONE]-lts\u003c/code\u003e image families.\u003c/p\u003e\n"],["\u003cp\u003eContainer-Optimized OS images are available in several image families, such as \u003ccode\u003ecos-dev\u003c/code\u003e, \u003ccode\u003ecos-beta\u003c/code\u003e, \u003ccode\u003ecos-stable\u003c/code\u003e, and \u003ccode\u003ecos-[MILESTONE]-lts\u003c/code\u003e which correspond to development, stabilization, latest production, and long term support releases, respectively.\u003c/p\u003e\n"],["\u003cp\u003eFor production deployments, it is highly recommended to use an image from an LTS family, and to perform tiered testing in conjunction with the image family API to ensure smoother major version rollouts.\u003c/p\u003e\n"]]],[],null,["# Versioning scheme\n\nMilestones and Build Numbers\n----------------------------\n\nMajor versions of Container-Optimized OS images are identified using\nwhat we call **milestones**. Container-Optimized OS milestones are\nmonotonically increasing integers. Each new milestone indicates the start of a new\ndevelopment cycle (a branch in our code) and may introduce new features and other\nmajor changes.\n\nOver the lifetime of a Container-Optimized OS milestone, we may release\nseveral updates containing bug fixes, security fixes and other changes. These\nincremental releases on a milestone can be identified using the **build number**.\n\nThe milestone and build number of the Container-Optimized OS you are using\ncan be identified by inspecting the `/etc/os-release` file. In this file, the\nvalue of the `VERSION_ID` (for example, `VERSION_ID=81`) represents the milestone\nand the value of the `BUILD_ID` field (for example, `BUILD_ID=12871.1160.0`)\nrepresents the build number. The milestone and build number are also present as\npart of the Container-Optimized OS image name. For example, image\n`cos-81-12871-1160-0` has milestone `81` and build number `12871-1160-0`.\n\nLong Term Supported (LTS) milestones\n------------------------------------\n\nMilestones that are intended for production use and supported for longer duration\nare labelled as LTS (for Long Term Supported). On Compute Engine, we use the\n[image families](/compute/docs/images#image_families) feature to label and identify\nour LTS releases.\n\n\nThe following table provides a summary of Container-Optimized OS releases available on\nCompute Engine: \n\n### Active Milestones\n\n### Deprecated Milestones\n\n1.\n COS 77 LTS and COS 81 LTS, when bundled with GKE, have slightly longer support durations.\n GKE users should consult the\n [GKE release schedule](/kubernetes-engine/docs/release-schedule) for details.\n [↩](#fnref1)\n\n### Development Release Notes\n\nFor release notes related to the milestone under development, see the [Development Release Notes](/container-optimized-os/docs/release-notes/dev) page. \nFor release notes related to cos-dev before M93, see the [Legacy Release Notes](/container-optimized-os/docs/legacy-release-notes) page.\n\nThere may be multiple active LTS milestones at any time. For example, the\nfollowing command shows currently active LTS image families: \n\n gcloud compute images list --no-standard-images --project=cos-cloud | grep lts\n cos-101-17162-40-16 cos-cloud cos-101-lts READY\n cos-89-16108-766-3 cos-cloud cos-89-lts READY\n cos-93-16623-295-5 cos-cloud cos-93-lts READY\n cos-97-16919-189-3 cos-cloud cos-97-lts READY\n cos-arm64-101-17162-40-16 cos-cloud cos-arm64-101-lts READY\n\nLifecycle of an LTS milestone\n-----------------------------\n\nA new Container-Optimized OS LTS milestone is introduced approximately\nevery 6 months on its own image family named `cos-[MILESTONE]-lts` (x86) and\n`cos-arm64-[MILESTONE]-lts` (Arm).\nBefore being labeled as LTS, the milestone undergoes approximately 6 months of\nfeature development and 2 months of extensive testing and stabilization.\n\nThe lifecycle of a Container-Optimized OS LTS milestone looks as follows:\n\n\nOnce promoted to the LTS family, the LTS milestone provides the following benefits:\n\n- A support duration of 2 years\n- Security fixes for the entire support duration\n- Fixes for any production issues\n- A dedicated [release notes](/container-optimized-os/docs/release-notes#lts_image_families) page listing every change going into the image.\n\n**For all of your production deployments, we recommend that you use an image\nfrom one of the LTS families.**\n\nAfter the LTS support duration is over for a LTS milestone, the corresponding\nimage family will no longer receive any security or bug fixes. In addition, the\ncorresponding `cos-[MILESTONE]-lts` and `cos-arm64-[MILESTONE]-lts` image\nfamilies will be marked as deprecated.\n| **Warning:** Any [image family API](/compute/docs/reference/rest/v1/images/getFromFamily) references to the deprecated image family will return errors and break any workflows depending on it. You should not use this API to create production instances.\n\nPlease refer to the\n[Support Policy](/container-optimized-os/docs/resources/support-policy) to\nlearn more about support commitments for these families.\n\n### LTS Refresh releases\n\nOn-demand releases are made on LTS milestones in response to high priority bug\nand security fixes. Every three months, a release is made that includes medium and\nlow priority bug and security fixes. We call these releases \"LTS Refresh\"\nreleases. These releases are made less frequently to help users manage update\nrisks.\n\nThe release notes page for the milestone will indicate which releases are\nLTS Refresh releases. Users should take extra care when rolling out these\nreleases, because medium and low priority bug and security fixes might introduce\nregressions.\n\nChoosing the right Container-Optimized OS version\n-------------------------------------------------\n\nOn Compute Engine, the image families for Container-Optimized OS can\nguide you in selecting the correct image for your intended purpose. We strongly\nrecommend that you set up tiered testing alongside your production environment\nutilizing the convenience offered by the image family api.\n| **Warning:** We recommend using the [Image Family API](/compute/docs/reference/rest/v1/images/getFromFamily) only for testing to automatically pick the latest images released on the image families. We do not recommend using it for creating production instances. You should always refer to a specific image you have qualified for use in production. This prevents any potential disruption due to the image being updated and rolled out to your production environment without being qualified first.\n\nA tiered testing setup like this should help to minimize issues when rolling\nout newer major versions of Container-Optimized OS images to your\nproduction environment."]]
