Changelog entry, doc, and only pass KUBECONFIG_FILE

app/models/project_services/kubernetes_service.rb

@@ -102,8 +102,7 @@ class KubernetesService < DeploymentService
       { key: 'KUBE_URL', value: api_url, public: true },
       { key: 'KUBE_TOKEN', value: token, public: false },
       { key: 'KUBE_NAMESPACE', value: actual_namespace, public: true },
-      { key: 'KUBECONFIG', value: config, public: false },
-      { key: 'KUBECONFIG_FILE', value: config, public: false, file: true },
+      { key: 'KUBECONFIG_FILE', value: config, public: false, file: true }
     ]
 
     if ca_pem.present?

changelogs/unreleased/33360-generate-kubeconfig.yml

+---
+title: Provide KUBECONFIG_FILE from KubernetesService for runners
+merge_request: 12223
+author:

doc/user/project/integrations/kubernetes.md

@@ -55,6 +55,7 @@ GitLab CI build environment:
 - `KUBE_CA_PEM_FILE` - only present if a custom CA bundle was specified. Path
   to a file containing PEM data.
 - `KUBE_CA_PEM` (deprecated)- only if a custom CA bundle was specified. Raw PEM data.
+- `KUBECONFIG_FILE` - Path to a file containing kubeconfig for this deployment. CA bundle would be embedded if specified.
 
 ## Web terminals
 

spec/models/project_services/kubernetes_service_spec.rb

@@ -221,7 +221,6 @@ describe KubernetesService, models: true, caching: true do
           { key: 'KUBE_URL', value: 'https://kube.domain.com', public: true },
           { key: 'KUBE_TOKEN', value: 'token', public: false },
           { key: 'KUBE_NAMESPACE', value: namespace, public: true },
-          { key: 'KUBECONFIG', value: kubeconfig, public: false },
           { key: 'KUBECONFIG_FILE', value: kubeconfig, public: false, file: true },
           { key: 'KUBE_CA_PEM', value: 'CA PEM DATA', public: true },
           { key: 'KUBE_CA_PEM_FILE', value: 'CA PEM DATA', public: true, file: true }