diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index eddd1329..7fd70f1f 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -9,6 +9,7 @@ on:
   schedule:
     - cron: "53 0 * * *" # Daily at 00:53 UTC
   workflow_dispatch:
+  workflow_call:
 
 jobs:
   pre-commit:
diff --git a/single_kernel_mongo/abstract_charm.py b/single_kernel_mongo/abstract_charm.py
index 789cee7a..e278ea8d 100644
--- a/single_kernel_mongo/abstract_charm.py
+++ b/single_kernel_mongo/abstract_charm.py
@@ -8,6 +8,7 @@
 from ops.charm import CharmBase
 
 from single_kernel_mongo.config.literals import Substrates
+from single_kernel_mongo.config.relations import PeerRelationNames
 from single_kernel_mongo.core.operator import OperatorProtocol
 from single_kernel_mongo.core.structured_config import MongoConfigModel
 from single_kernel_mongo.events.lifecycle import LifecycleEventsHandler
@@ -35,7 +36,7 @@ class AbstractMongoCharm(Generic[T, U], CharmBase):
     config_type: type[T]
     operator_type: type[U]
     substrate: ClassVar[Substrates]
-    peer_rel_name: ClassVar[str]
+    peer_rel_name: ClassVar[PeerRelationNames]
     name: ClassVar[str]
 
     def __init__(self, *args):
diff --git a/single_kernel_mongo/config/relations.py b/single_kernel_mongo/config/relations.py
index c502f7bd..5d98ba3c 100644
--- a/single_kernel_mongo/config/relations.py
+++ b/single_kernel_mongo/config/relations.py
@@ -6,12 +6,17 @@
 from enum import Enum
 
 
+class PeerRelationNames(str, Enum):
+    """The peer relation names."""
+
+    PEERS = "database-peers"  # check.
+    ROUTER_PEERS = "router-peers"
+
+
 class RelationNames(str, Enum):
     """The different relations."""
 
     DATABASE = "database"  # In progress
-    PEERS = "database-peers"  # check.
-    ROUTER_PEERS = "router-peers"
     SHARDING = "sharding"
     CONFIG_SERVER = "config-server"
     CLUSTER = "cluster"
diff --git a/single_kernel_mongo/events/lifecycle.py b/single_kernel_mongo/events/lifecycle.py
index df27329a..9920efb9 100644
--- a/single_kernel_mongo/events/lifecycle.py
+++ b/single_kernel_mongo/events/lifecycle.py
@@ -25,6 +25,7 @@
 from ops.framework import Object
 
 from single_kernel_mongo.config.literals import Substrates
+from single_kernel_mongo.config.relations import PeerRelationNames
 from single_kernel_mongo.core.operator import OperatorProtocol
 from single_kernel_mongo.exceptions import (
     ContainerNotReadyError,
@@ -42,7 +43,7 @@ class LifecycleEventsHandler(Object):
     In charge of handling the lifecycle events such as install, start, pebble ready, etc.
     """
 
-    def __init__(self, dependent: OperatorProtocol, rel_name: str):
+    def __init__(self, dependent: OperatorProtocol, rel_name: PeerRelationNames):
         super().__init__(parent=dependent, key=dependent.name)
         self.dependent = dependent
         self.charm = dependent.charm
@@ -60,9 +61,15 @@ def __init__(self, dependent: OperatorProtocol, rel_name: str):
         self.framework.observe(getattr(self.charm.on, "update_status"), self.on_update_status)
         self.framework.observe(getattr(self.charm.on, "secret_changed"), self.on_secret_changed)
 
-        self.framework.observe(self.charm.on[rel_name].relation_joined, self.on_relation_joined)
-        self.framework.observe(self.charm.on[rel_name].relation_changed, self.on_relation_changed)
-        self.framework.observe(self.charm.on[rel_name].relation_departed, self.on_relation_departed)
+        self.framework.observe(
+            self.charm.on[rel_name.value].relation_joined, self.on_relation_joined
+        )
+        self.framework.observe(
+            self.charm.on[rel_name.value].relation_changed, self.on_relation_changed
+        )
+        self.framework.observe(
+            self.charm.on[rel_name.value].relation_departed, self.on_relation_departed
+        )
 
         self.framework.observe(
             getattr(self.charm.on, "mongodb_storage_attached"), self.on_storage_attached
diff --git a/single_kernel_mongo/state/charm_state.py b/single_kernel_mongo/state/charm_state.py
index e44514d8..00b330c7 100644
--- a/single_kernel_mongo/state/charm_state.py
+++ b/single_kernel_mongo/state/charm_state.py
@@ -24,6 +24,7 @@
 from single_kernel_mongo.config.models import Role
 from single_kernel_mongo.config.relations import (
     ExternalRequirerRelations,
+    PeerRelationNames,
     RelationNames,
 )
 from single_kernel_mongo.core.secrets import SecretCache
@@ -86,11 +87,11 @@ def __init__(self, charm: AbstractMongoCharm[T, U], substrate: Substrates, charm
 
         self.peer_app_interface = DataPeerData(
             self.model,
-            relation_name=RelationNames.PEERS.value,
+            relation_name=PeerRelationNames.PEERS.value,
         )
         self.peer_unit_interface = DataPeerUnitData(
             self.model,
-            relation_name=RelationNames.PEERS.value,
+            relation_name=PeerRelationNames.PEERS.value,
             additional_secret_fields=SECRETS_UNIT,
         )
 
@@ -99,7 +100,7 @@ def __init__(self, charm: AbstractMongoCharm[T, U], substrate: Substrates, charm
     @property
     def peer_relation(self) -> Relation | None:
         """The replica set peer relation."""
-        return self.model.get_relation(RelationNames.PEERS.value)
+        return self.model.get_relation(PeerRelationNames.PEERS.value)
 
     @property
     def peers_units(self) -> set[Unit]:
@@ -260,7 +261,7 @@ def peer_units_data_interfaces(self) -> dict[Unit, DataPeerOtherUnitData]:
         """The cluster peer relation."""
         return {
             unit: DataPeerOtherUnitData(
-                model=self.model, unit=unit, relation_name=RelationNames.PEERS.value
+                model=self.model, unit=unit, relation_name=PeerRelationNames.PEERS.value
             )
             for unit in self.peers_units
         }
diff --git a/tests/unit/mongodb_test_charm/src/charm.py b/tests/unit/mongodb_test_charm/src/charm.py
index 01829538..4214fb41 100755
--- a/tests/unit/mongodb_test_charm/src/charm.py
+++ b/tests/unit/mongodb_test_charm/src/charm.py
@@ -7,7 +7,7 @@
 
 from single_kernel_mongo.abstract_charm import AbstractMongoCharm
 from single_kernel_mongo.config.literals import Substrates
-from single_kernel_mongo.config.relations import RelationNames
+from single_kernel_mongo.config.relations import PeerRelationNames
 from single_kernel_mongo.core.structured_config import MongoDBCharmConfig
 from single_kernel_mongo.managers.mongodb_operator import MongoDBOperator
 
@@ -16,7 +16,7 @@ class MongoTestCharm(AbstractMongoCharm[MongoDBCharmConfig, MongoDBOperator]):
     config_type = MongoDBCharmConfig
     operator_type = MongoDBOperator
     substrate = Substrates.VM
-    peer_rel_name = RelationNames.PEERS.value
+    peer_rel_name = PeerRelationNames.PEERS
     name = "mongodb-test"
 
 
diff --git a/tests/unit/test_charm_state.py b/tests/unit/test_charm_state.py
index 62be7c93..7756abf5 100644
--- a/tests/unit/test_charm_state.py
+++ b/tests/unit/test_charm_state.py
@@ -2,7 +2,7 @@
 from ops.testing import Harness
 
 from single_kernel_mongo.config.literals import Scope
-from single_kernel_mongo.config.relations import RelationNames
+from single_kernel_mongo.config.relations import PeerRelationNames
 from single_kernel_mongo.core.structured_config import MongoDBRoles
 from single_kernel_mongo.utils.mongodb_users import BackupUser, MonitorUser, OperatorUser
 
@@ -14,7 +14,7 @@
 
 @patch_network_get(private_address="1.1.1.1")
 def test_app_hosts(harness: Harness[MongoTestCharm]):
-    rel_id = harness.charm.model.get_relation(RelationNames.PEERS.value).id  # type: ignore
+    rel_id = harness.charm.model.get_relation(PeerRelationNames.PEERS.value).id  # type: ignore
     harness.add_relation_unit(rel_id, "test-mongodb/1")
     harness.update_relation_data(rel_id, "test-mongodb/1", PEER_ADDR)
     resulting_ips = harness.charm.operator.state.app_hosts
@@ -29,14 +29,14 @@ def test_config(harness: Harness[MongoTestCharm]):
 
 
 def test_peer_units(harness: Harness[MongoTestCharm]):
-    rel = harness.charm.model.get_relation(RelationNames.PEERS.value)
+    rel = harness.charm.model.get_relation(PeerRelationNames.PEERS.value)
     harness.add_relation_unit(rel.id, "test-mongodb/1")  # type: ignore
     assert harness.charm.operator.state.peer_relation.id == rel.id  # type: ignore
     assert {unit.name for unit in harness.charm.operator.state.peers_units} == {"test-mongodb/1"}
 
 
 def test_users_secrets(harness: Harness[MongoTestCharm]):
-    rel = harness.charm.model.get_relation(RelationNames.PEERS.value)
+    rel = harness.charm.model.get_relation(PeerRelationNames.PEERS.value)
     harness.add_relation_unit(rel.id, "test-mongodb/1")  # type: ignore
 
     harness.set_leader(True)
@@ -51,7 +51,7 @@ def test_users_secrets(harness: Harness[MongoTestCharm]):
 
 
 def test_app_peer_data(harness: Harness[MongoTestCharm]):
-    rel = harness.charm.model.get_relation(RelationNames.PEERS.value)
+    rel = harness.charm.model.get_relation(PeerRelationNames.PEERS.value)
     harness.add_relation_unit(rel.id, "test-mongodb/1")  # type: ignore
     harness.set_leader(True)
     state = harness.charm.operator.state
@@ -83,7 +83,7 @@ def test_app_peer_data(harness: Harness[MongoTestCharm]):
 
 @patch_network_get(private_address="1.1.1.1")
 def test_unit_peer_data(harness: Harness[MongoTestCharm]):
-    rel = harness.charm.model.get_relation(RelationNames.PEERS.value)
+    rel = harness.charm.model.get_relation(PeerRelationNames.PEERS.value)
     harness.add_relation_unit(rel.id, "test-mongodb/1")  # type: ignore
     harness.set_leader(True)
     state = harness.charm.operator.state