[SIMPL-30451] Mount shared storage in step pods

Configure Kubernetes executor step pods with the shared Dagster home and persistent volume used by the code location.

Changelog: fixed

src/distributed_execution/tightly_coupled/jobs.py

@@ -31,13 +31,31 @@ COMMON_TAGS = {
 # Per-step pod shape. Only honoured by k8s_job_executor.
 STEP_K8S_CONFIG = {
     "container_config": {
+        "env": [
+            {
+                "name": "DAGSTER_HOME",
+                "value": "/dagster/shared/distributed-execution",
+            }
+        ],
         "resources": {
             "requests": {"cpu": "100m", "memory": "128Mi"},
             "limits": {"cpu": "500m", "memory": "512Mi"},
         },
+        "volume_mounts": [
+            {
+                "name": "dagster-shared-storage",
+                "mount_path": "/dagster/shared",
+            }
+        ],
     },
     "pod_spec_config": {
         "restart_policy": "Never",
+        "volumes": [
+            {
+                "name": "dagster-shared-storage",
+                "persistent_volume_claim": {"claim_name": "dagster-shared-pvc"},
+            }
+        ],
     },
 }