diff --git a/lib/galaxy/jobs/runners/kubernetes.py b/lib/galaxy/jobs/runners/kubernetes.py
index dffcfeda8cb..0e9095acae0 100644
--- a/lib/galaxy/jobs/runners/kubernetes.py
+++ b/lib/galaxy/jobs/runners/kubernetes.py
@@ -76,9 +76,9 @@ class KubernetesJobRunner(AsynchronousJobRunner):
             k8s_job_metadata=dict(map=str, default=None),
             k8s_supplemental_group_id=dict(map=str),
             k8s_pull_policy=dict(map=str, default="Default"),
-            k8s_run_as_user_id=dict(map=str, valid=lambda s: s == "$uid" or s.isdigit()),
-            k8s_run_as_group_id=dict(map=str, valid=lambda s: s == "$gid" or s.isdigit()),
-            k8s_fs_group_id=dict(map=int),
+            k8s_run_as_user_id=dict(map=str, valid=lambda s: s == "$uid" or isinstance(s, int) or s.isdigit()),
+            k8s_run_as_group_id=dict(map=str, valid=lambda s: s == "$gid" or isinstance(s, int) or s.isdigit()),
+            k8s_fs_group_id=dict(map=str, valid=lambda s: s == "$gid" or isinstance(s, int) or s.isdigit()),
             k8s_cleanup_job=dict(map=str, valid=lambda s: s in {"onsuccess", "always", "never"}, default="always"),
             k8s_pod_retries=dict(map=int, valid=lambda x: int(x) >= 0, default=3),
             k8s_walltime_limit=dict(map=int, valid=lambda x: int(x) >= 0, default=172800),