add service_mgmt (#15927)

Adding yang model for CONFIG_DB table MUX_LINKMGR|SERVICE_MGMT.

sign-off: Jing Zhang zhangjing@microsoft.com

src/sonic-yang-models/doc/Configuration.md

@@ -1223,6 +1223,9 @@ The **MUX_LINKMGR** table is used for dualtor device configuration.
         },
         "MUXLOGGER": {
             "log_verbosity": "debug"
+        },
+        "SERVICE_MGMT": {
+            "kill_radv": "True"
         }
     }
 }

src/sonic-yang-models/tests/files/sample_config_db.json

@@ -1947,6 +1947,9 @@
             },
             "MUXLOGGER": {
                 "log_verbosity": "debug"
+            },
+            "SERVICE_MGMT": {
+                "kill_radv": "False"
             }
         },
 

src/sonic-yang-models/tests/yang_model_tests/tests/mux-linkmgr.json

@@ -7,5 +7,8 @@
     },
     "MUX_LINKMGR_MUXLOGGER_CHANGE_VERBOSITY_LEVEL": {
         "desc": "Consume verbosity level config changes. "
+    },
+    "MUX_LINKMGR_SERVICE_MGMT_KILL_RADV_DISABLED": {
+        "desc": "Disable feature to kill radv."
     }
 }

src/sonic-yang-models/tests/yang_model_tests/tests_config/mux-linkmgr.json

@@ -32,5 +32,15 @@
                     }
             }
         }
+    },
+    "MUX_LINKMGR_SERVICE_MGMT_KILL_RADV_DISABLED": {
+        "sonic-mux-linkmgr:sonic-mux-linkmgr": {
+            "sonic-mux-linkmgr:MUX_LINKMGR": {
+                "sonic-mux-linkmgr:SERVICE_MGMT": 
+                    {
+                        "kill_radv": "False"
+                    }
+            }
+        }
     }
 }

src/sonic-yang-models/yang-models/sonic-mux-linkmgr.yang

@@ -98,6 +98,20 @@ module sonic-mux-linkmgr {
                     description "Linkmgrd log verbosity level. ";
                 }
             }
+
+            container SERVICE_MGMT {
+
+                leaf kill_radv {
+                    type enumeration {
+                        enum True;
+                        enum False;
+                    }
+
+                    default True;
+
+                    description "Kill radv service instead of gracefully stopping it. ";
+                }
+            }
         }
     }
 }