{"source":"semconv","version":"1.44.0","attribute":{"id":"k8s.cluster.uid","type":"string","stability":"stable","brief":"A pseudo-ID for the cluster, set to the UID of the `kube-system` namespace.","note":"K8s doesn't have support for obtaining a cluster ID. If this is ever\nadded, we will recommend collecting the `k8s.cluster.uid` through the\nofficial APIs. In the meantime, we are able to use the `uid` of the\n`kube-system` namespace as a proxy for cluster ID. Read on for the\nrationale.\n\nEvery object created in a K8s cluster is assigned a distinct UID. The\n`kube-system` namespace is used by Kubernetes itself and will exist\nfor the lifetime of the cluster. Using the `uid` of the `kube-system`\nnamespace is a reasonable proxy for the K8s ClusterID as it will only\nchange if the cluster is rebuilt. Furthermore, Kubernetes UIDs are\nUUIDs as standardized by\n[ISO/IEC 9834-8 and ITU-T X.667](https://www.itu.int/ITU-T/studygroups/com17/oid.html).\nWhich states:\n\n> If generated according to one of the mechanisms defined in Rec.\n> ITU-T X.667 | ISO/IEC 9834-8, a UUID is either guaranteed to be\n> different from all other UUIDs generated before 3603 A.D., or is\n> extremely likely to be different (depending on the mechanism chosen).\n\nTherefore, UIDs between clusters should be extremely unlikely to\nconflict.","examples":["218fc5a9-a5f1-4b54-aa05-46717d0ab26d"],"namespace":"k8s","definedIn":"model/k8s/registry.yaml","usedBy":[{"groupId":"entity.k8s.cluster","groupType":"entity","signalName":"k8s.cluster","requirementLevel":"recommended"}]},"history":[{"version":"1.30.0","publishedAt":"2025-01-24T19:11:42Z","kind":"first-seen","detail":"Already present at v1.30.0, the oldest release tracked here (experimental)."},{"version":"1.31.0","publishedAt":"2025-03-11T00:53:13Z","kind":"stability-changed","detail":"Stability label respelled from experimental to development.","severity":"informational"},{"version":"1.39.0","publishedAt":"2026-01-12T22:11:41Z","kind":"stability-changed","detail":"Stability label respelled from development to alpha.","severity":"informational"},{"version":"1.40.0","publishedAt":"2026-02-19T17:50:21Z","kind":"stability-changed","detail":"Stability label respelled from alpha to beta.","severity":"informational"},{"version":"1.41.0","publishedAt":"2026-04-28T04:57:50Z","kind":"stability-changed","detail":"Promoted to release_candidate.","severity":"notable"},{"version":"1.42.0","publishedAt":"2026-06-12T21:03:17Z","kind":"stability-changed","detail":"Promoted to stable.","severity":"notable"}],"replaces":[]}