diff --git a/src/ai/backend/manager/models/kernel.py b/src/ai/backend/manager/models/kernel.py
index b9cf03e545..c3f8f88033 100644
--- a/src/ai/backend/manager/models/kernel.py
+++ b/src/ai/backend/manager/models/kernel.py
@@ -70,7 +70,6 @@
     URLColumn,
     batch_multiresult,
     batch_result,
-    mapper_registry,
 )
 from .group import groups
 from .image import ImageNode, ImageRow
@@ -373,110 +372,134 @@ async def handle_kernel_exception(
         raise
 
 
-kernels = sa.Table(
-    "kernels",
-    mapper_registry.metadata,
+class KernelRow(Base):
+    __tablename__ = "kernels"
+
     # The Backend.AI-side UUID for each kernel
     # (mapped to a container in the docker backend and a pod in the k8s backend)
-    KernelIDColumn(),
+    id = KernelIDColumn()
     # session_id == id when the kernel is the main container in a multi-container session or a
     # single-container session.
     # Otherwise, it refers the kernel ID of the main container of the belonged multi-container session.
-    sa.Column(
+    session_id = sa.Column(
         "session_id",
         SessionIDColumnType,
         sa.ForeignKey("sessions.id"),
         unique=False,
         index=True,
         nullable=False,
-    ),
-    sa.Column("session_creation_id", sa.String(length=32), unique=False, index=False),
-    sa.Column("session_name", sa.String(length=64), unique=False, index=True),  # previously sess_id
-    sa.Column(
+    )
+    session_creation_id = sa.Column(
+        "session_creation_id", sa.String(length=32), unique=False, index=False
+    )
+    session_name = sa.Column(
+        "session_name", sa.String(length=64), unique=False, index=True
+    )  # previously sess_id
+    session_type = sa.Column(
         "session_type",
         EnumType(SessionTypes),
         index=True,
         nullable=False,  # previously sess_type
         default=SessionTypes.INTERACTIVE,
         server_default=SessionTypes.INTERACTIVE.name,
-    ),
-    sa.Column(
+    )
+    cluster_mode = sa.Column(
         "cluster_mode",
         sa.String(length=16),
         nullable=False,
         default=ClusterMode.SINGLE_NODE,
         server_default=ClusterMode.SINGLE_NODE.name,
-    ),
-    sa.Column("cluster_size", sa.Integer, nullable=False, default=1),
-    sa.Column(
+    )
+    cluster_size = sa.Column("cluster_size", sa.Integer, nullable=False, default=1)
+    cluster_role = sa.Column(
         "cluster_role", sa.String(length=16), nullable=False, default=DEFAULT_ROLE, index=True
-    ),
-    sa.Column("cluster_idx", sa.Integer, nullable=False, default=0),
-    sa.Column("local_rank", sa.Integer, nullable=False, default=0),
-    sa.Column("cluster_hostname", sa.String(length=64), nullable=False, default=default_hostname),
+    )
+    cluster_idx = sa.Column("cluster_idx", sa.Integer, nullable=False, default=0)
+    local_rank = sa.Column("local_rank", sa.Integer, nullable=False, default=0)
+    cluster_hostname = sa.Column(
+        "cluster_hostname", sa.String(length=64), nullable=False, default=default_hostname
+    )
     # Resource ownership
-    sa.Column("scaling_group", sa.ForeignKey("scaling_groups.name"), index=True, nullable=True),
-    sa.Column("agent", sa.String(length=64), sa.ForeignKey("agents.id"), nullable=True),
-    sa.Column("agent_addr", sa.String(length=128), nullable=True),
-    sa.Column("domain_name", sa.String(length=64), sa.ForeignKey("domains.name"), nullable=False),
-    sa.Column("group_id", GUID, sa.ForeignKey("groups.id"), nullable=False),
-    sa.Column("user_uuid", GUID, sa.ForeignKey("users.uuid"), nullable=False),
-    sa.Column("access_key", sa.String(length=20), sa.ForeignKey("keypairs.access_key")),
+    scaling_group = sa.Column(
+        "scaling_group", sa.ForeignKey("scaling_groups.name"), index=True, nullable=True
+    )
+    agent = sa.Column("agent", sa.String(length=64), sa.ForeignKey("agents.id"), nullable=True)
+    agent_addr = sa.Column("agent_addr", sa.String(length=128), nullable=True)
+    domain_name = sa.Column(
+        "domain_name", sa.String(length=64), sa.ForeignKey("domains.name"), nullable=False
+    )
+    group_id = sa.Column("group_id", GUID, sa.ForeignKey("groups.id"), nullable=False)
+    user_uuid = sa.Column("user_uuid", GUID, sa.ForeignKey("users.uuid"), nullable=False)
+    access_key = sa.Column("access_key", sa.String(length=20), sa.ForeignKey("keypairs.access_key"))
     # `image` is a string shaped "<REGISTRY>/<IMAGE>:<TAG>". it is identical to images.name column
-    sa.Column("image", sa.String(length=512)),
-    # ForeignKeyIDColumn("image_id", "images.id"),
-    sa.Column("architecture", sa.String(length=32), default="x86_64"),
-    sa.Column("registry", sa.String(length=512)),
-    sa.Column("tag", sa.String(length=64), nullable=True),
+    image = sa.Column("image", sa.String(length=512))
+    # ForeignKeyIDColumn("image_id", "images.id")
+    architecture = sa.Column("architecture", sa.String(length=32), default="x86_64")
+    registry = sa.Column("registry", sa.String(length=512))
+    tag = sa.Column("tag", sa.String(length=64), nullable=True)
     # Resource occupation
-    sa.Column("container_id", sa.String(length=64)),
-    sa.Column("occupied_slots", ResourceSlotColumn(), nullable=False),
-    sa.Column("requested_slots", ResourceSlotColumn(), nullable=False, default=ResourceSlot()),
-    sa.Column("occupied_shares", pgsql.JSONB(), nullable=False, default={}),  # legacy
-    sa.Column("environ", sa.ARRAY(sa.String), nullable=True),
-    sa.Column("mounts", sa.ARRAY(sa.String), nullable=True),  # list of list; legacy since 22.03
-    sa.Column("mount_map", pgsql.JSONB(), nullable=True, default={}),  # legacy since 22.03
-    sa.Column("vfolder_mounts", StructuredJSONObjectListColumn(VFolderMount), nullable=True),
-    sa.Column("attached_devices", pgsql.JSONB(), nullable=True, default={}),
-    sa.Column("resource_opts", pgsql.JSONB(), nullable=True, default={}),
-    sa.Column("bootstrap_script", sa.String(length=16 * 1024), nullable=True),
+    container_id = sa.Column("container_id", sa.String(length=64))
+    occupied_slots = sa.Column("occupied_slots", ResourceSlotColumn(), nullable=False)
+    requested_slots = sa.Column(
+        "requested_slots", ResourceSlotColumn(), nullable=False, default=ResourceSlot()
+    )
+    occupied_shares = sa.Column(
+        "occupied_shares", pgsql.JSONB(), nullable=False, default={}
+    )  # legacy
+    environ = sa.Column("environ", sa.ARRAY(sa.String), nullable=True)
+    mounts = sa.Column(
+        "mounts", sa.ARRAY(sa.String), nullable=True
+    )  # list of list; legacy since 22.03
+    mount_map = sa.Column(
+        "mount_map", pgsql.JSONB(), nullable=True, default={}
+    )  # legacy since 22.03
+    vfolder_mounts = sa.Column(
+        "vfolder_mounts", StructuredJSONObjectListColumn(VFolderMount), nullable=True
+    )
+    attached_devices = sa.Column("attached_devices", pgsql.JSONB(), nullable=True, default={})
+    resource_opts = sa.Column("resource_opts", pgsql.JSONB(), nullable=True, default={})
+    bootstrap_script = sa.Column("bootstrap_script", sa.String(length=16 * 1024), nullable=True)
     # Port mappings
     # If kernel_host is NULL, it is assumed to be same to the agent host or IP.
-    sa.Column("kernel_host", sa.String(length=128), nullable=True),
-    sa.Column("repl_in_port", sa.Integer(), nullable=False),
-    sa.Column("repl_out_port", sa.Integer(), nullable=False),
-    sa.Column("stdin_port", sa.Integer(), nullable=False),  # legacy for stream_pty
-    sa.Column("stdout_port", sa.Integer(), nullable=False),  # legacy for stream_pty
-    sa.Column("service_ports", pgsql.JSONB(), nullable=True),
-    sa.Column("preopen_ports", sa.ARRAY(sa.Integer), nullable=True),
-    sa.Column("use_host_network", sa.Boolean(), default=False, nullable=False),
+    kernel_host = sa.Column("kernel_host", sa.String(length=128), nullable=True)
+    repl_in_port = sa.Column("repl_in_port", sa.Integer(), nullable=False)
+    repl_out_port = sa.Column("repl_out_port", sa.Integer(), nullable=False)
+    stdin_port = sa.Column("stdin_port", sa.Integer(), nullable=False)  # legacy for stream_pty
+    stdout_port = sa.Column("stdout_port", sa.Integer(), nullable=False)  # legacy for stream_pty
+    service_ports = sa.Column("service_ports", pgsql.JSONB(), nullable=True)
+    preopen_ports = sa.Column("preopen_ports", sa.ARRAY(sa.Integer), nullable=True)
+    use_host_network = sa.Column("use_host_network", sa.Boolean(), default=False, nullable=False)
     # Lifecycle
-    sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now(), index=True),
-    sa.Column(
+    created_at = sa.Column(
+        "created_at", sa.DateTime(timezone=True), server_default=sa.func.now(), index=True
+    )
+    terminated_at = sa.Column(
         "terminated_at", sa.DateTime(timezone=True), nullable=True, default=sa.null(), index=True
-    ),
-    sa.Column("starts_at", sa.DateTime(timezone=True), nullable=True, default=sa.null()),
-    sa.Column(
+    )
+    starts_at = sa.Column("starts_at", sa.DateTime(timezone=True), nullable=True, default=sa.null())
+    status = sa.Column(
         "status",
         EnumType(KernelStatus),
         default=KernelStatus.PENDING,
         server_default=KernelStatus.PENDING.name,
         nullable=False,
         index=True,
-    ),
-    sa.Column(
+    )
+    role = sa.Column(
         "role",
         EnumType(KernelRole),
         default=KernelRole.COMPUTE,
         server_default=KernelRole.COMPUTE.name,
         nullable=False,
         index=True,
-    ),
-    sa.Column("status_changed", sa.DateTime(timezone=True), nullable=True, index=True),
-    sa.Column("status_info", sa.Unicode(), nullable=True, default=sa.null()),
+    )
+    status_changed = sa.Column(
+        "status_changed", sa.DateTime(timezone=True), nullable=True, index=True
+    )
+    status_info = sa.Column("status_info", sa.Unicode(), nullable=True, default=sa.null())
     # status_info contains a kebab-cased string that expresses a summary of the last status change.
     # Examples: "user-requested", "self-terminated", "predicate-checks-failed", "no-available-instances"
-    sa.Column("status_data", pgsql.JSONB(), nullable=True, default=sa.null()),
+    status_data = sa.Column("status_data", pgsql.JSONB(), nullable=True, default=sa.null())
     # status_data contains a JSON object that contains detailed data for the last status change.
     # During scheduling (as PENDING + ("no-available-instances" | "predicate-checks-failed")):
     # {
@@ -512,43 +535,43 @@ async def handle_kernel_exception(
     #         // used to prevent duplication of SessionTerminatedEvent
     #   }
     # }
-    sa.Column("status_history", pgsql.JSONB(), nullable=True, default=sa.null()),
-    sa.Column("callback_url", URLColumn, nullable=True, default=sa.null()),
-    sa.Column("startup_command", sa.Text, nullable=True),
-    sa.Column(
+    status_history = sa.Column("status_history", pgsql.JSONB(), nullable=True, default=sa.null())
+    callback_url = sa.Column("callback_url", URLColumn, nullable=True, default=sa.null())
+    startup_command = sa.Column("startup_command", sa.Text, nullable=True)
+    result = sa.Column(
         "result",
         EnumType(SessionResult),
         default=SessionResult.UNDEFINED,
         server_default=SessionResult.UNDEFINED.name,
         nullable=False,
         index=True,
-    ),
-    sa.Column("internal_data", pgsql.JSONB(), nullable=True),
-    sa.Column("container_log", sa.LargeBinary(), nullable=True),
+    )
+    internal_data = sa.Column("internal_data", pgsql.JSONB(), nullable=True)
+    container_log = sa.Column("container_log", sa.LargeBinary(), nullable=True)
     # Resource metrics measured upon termination
-    sa.Column("num_queries", sa.BigInteger(), default=0),
-    sa.Column("last_stat", pgsql.JSONB(), nullable=True, default=sa.null()),
-    sa.Index("ix_kernels_sess_id_role", "session_id", "cluster_role", unique=False),
-    sa.Index("ix_kernels_status_role", "status", "cluster_role"),
-    sa.Index(
-        "ix_kernels_updated_order",
-        sa.func.greatest("created_at", "terminated_at", "status_changed"),
-        unique=False,
-    ),
-    sa.Index(
-        "ix_kernels_unique_sess_token",
-        "access_key",
-        "session_name",
-        unique=True,
-        postgresql_where=sa.text(
-            "status NOT IN ('TERMINATED', 'CANCELLED') and cluster_role = 'main'"
+    num_queries = sa.Column("num_queries", sa.BigInteger(), default=0)
+    last_stat = sa.Column("last_stat", pgsql.JSONB(), nullable=True, default=sa.null())
+
+    __table_args__ = (
+        # indexing
+        sa.Index("ix_kernels_sess_id_role", "session_id", "cluster_role", unique=False),
+        sa.Index("ix_kernels_status_role", "status", "cluster_role"),
+        sa.Index(
+            "ix_kernels_updated_order",
+            sa.func.greatest("created_at", "terminated_at", "status_changed"),
+            unique=False,
         ),
-    ),
-)
-
+        sa.Index(
+            "ix_kernels_unique_sess_token",
+            "access_key",
+            "session_name",
+            unique=True,
+            postgresql_where=sa.text(
+                "status NOT IN ('TERMINATED', 'CANCELLED') and cluster_role = 'main'"
+            ),
+        ),
+    )
 
-class KernelRow(Base):
-    __table__ = kernels
     session = relationship("SessionRow", back_populates="kernels")
     image_row = relationship(
         "ImageRow",
@@ -715,6 +738,9 @@ async def _update() -> bool:
         return await execute_with_retry(_update)
 
 
+# For compatibility
+kernels = KernelRow.__table__
+
 DEFAULT_KERNEL_ORDERING = [
     sa.desc(
         sa.func.greatest(