SONiC Yang model support for Kdump (#10786)

#### Why I did it
Created SONiC Yang model for Kdump
Tables: KDUMP

#### How I did it
Defined Yang models for NAT based on Guideline doc:
https://github.com/Azure/SONiC/blob/master/doc/mgmt/SONiC_YANG_Model_Guidelines.md
and
https://github.com/Azure/sonic-utilities/blob/master/doc/Command-Reference.md

#### How to verify it
Added test cases to verify it.

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

@@ -25,6 +25,7 @@ Table of Contents
          * [Device neighbor metada](#device-neighbor-metada)  
          * [DSCP_TO_TC_MAP](#dscp_to_tc_map)  
          * [FLEX_COUNTER_TABLE](#flex_counter_table)  
+         * [KDUMP](#kdump)
          * [L2 Neighbors](#l2-neighbors)  
          * [Loopback Interface](#loopback-interface)  
          * [LOSSLESS_TRAFFIC_PATTERN](#LOSSLESS_TRAFFIC_PATTERN)  
@@ -861,6 +862,20 @@ instance is supported in SONiC.
 
 ```
 
+### KDUMP
+
+```
+{
+    "KDUMP": {
+        "config": {
+            "enabled": "true",
+            "num_dumps": "3",
+            "memory": "0M-2G:256M,2G-4G:256M,4G-8G:384M,8G-:448M"
+         }
+     }
+}
+
+```
 
 ### L2 Neighbors
 

src/sonic-yang-models/setup.py

@@ -105,6 +105,7 @@ setup(
                          './yang-models/sonic-flex_counter.yang',
                          './yang-models/sonic-feature.yang',
                          './yang-models/sonic-interface.yang',
+                         './yang-models/sonic-kdump.yang',
                          './yang-models/sonic-loopback-interface.yang',
                          './yang-models/sonic-mgmt_interface.yang',
                          './yang-models/sonic-mgmt_port.yang',
@@ -164,6 +165,7 @@ setup(
                          './cvlyang-models/sonic-flex_counter.yang',
                          './cvlyang-models/sonic-feature.yang',
                          './cvlyang-models/sonic-interface.yang',
+                         './cvlyang-models/sonic-kdump.yang',
                          './cvlyang-models/sonic-loopback-interface.yang',
                          './cvlyang-models/sonic-mgmt_interface.yang',
                          './cvlyang-models/sonic-mgmt_port.yang',

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

@@ -1792,6 +1792,14 @@
                 "rrclient": "0",
                 "admin_status": "up"
             }
+        },
+
+        "KDUMP": {
+            "config": {
+                "enabled": "true",
+                "num_dumps": "3",
+                "memory": "0M-2G:256M,2G-4G:256M,4G-8G:384M,8G-:448M"
+             }
          }
     },
     "SAMPLE_CONFIG_DB_UNKNOWN": {

src/sonic-yang-models/tests/yang_model_tests/tests/kdump.json

@@ -0,0 +1,19 @@
+{
+    "KDUMP_WITH_VALID_VALUES": {
+        "desc": "Configuring the kdump with valid values."
+    },
+    "KDUMP_WITH_VALID_VALUES_2": {
+        "desc": "Configuring the kdump with valid values."
+    },
+    "KDUMP_WITH_VALID_VALUES_3": {
+        "desc": "Configuring the kdump with valid values."
+    },
+    "KDUMP_WITH_INVALID_NUM_DUMPS": {
+        "desc": "Configuring kdump config with a invalid number of allowed kdumps.",
+        "eStr": ["pattern", "does not satisfy"]
+    },
+    "KDUMP_WITH_INVALID_MEMORY": {
+        "desc": "Configuring kdump config with invalid memory config.",
+        "eStr": ["pattern", "does not satisfy"]
+    }
+}

src/sonic-yang-models/tests/yang_model_tests/tests_config/kdump.json

@@ -0,0 +1,57 @@
+{
+    "KDUMP_WITH_VALID_VALUES": {
+        "sonic-kdump:sonic-kdump": {
+            "sonic-kdump:KDUMP": {
+                "config": {
+                    "enabled": "true",
+                    "num_dumps": "3",
+                    "memory": "0M-2G:256M,2G-4G:256M,4G-8G:384M,8G-:448M"
+                }
+            }
+        }
+    },
+    "KDUMP_WITH_VALID_VALUES_2": {
+        "sonic-kdump:sonic-kdump": {
+            "sonic-kdump:KDUMP": {
+                "config": {
+                    "enabled": "true",
+                    "num_dumps": "9",
+                    "memory": "512M"
+                }
+            }
+        }
+    },
+    "KDUMP_WITH_VALID_VALUES_3": {
+        "sonic-kdump:sonic-kdump": {
+            "sonic-kdump:KDUMP": {
+                "config": {
+                    "enabled": "false",
+                    "num_dumps": "1",
+                    "memory": "512M"
+                }
+            }
+        }
+    },
+    "KDUMP_WITH_INVALID_NUM_DUMPS": {
+        "sonic-kdump:sonic-kdump": {
+            "sonic-kdump:KDUMP": {
+                "config": {
+                    "enabled": "true",
+                    "num_dumps": "100",
+                    "memory": "0M-2G:256M,2G-4G:256M,4G-8G:384M,8G-:448M"
+                }
+            }
+        }
+    },
+    "KDUMP_WITH_INVALID_MEMORY": {
+        "sonic-kdump:sonic-kdump": {
+            "sonic-kdump:KDUMP": {
+                "config": {
+                    "enabled": "true",
+                    "num_dumps": "3",
+                    "memory": "666"
+                }
+            }
+        }
+    }
+}

src/sonic-yang-models/yang-models/sonic-kdump.yang

@@ -0,0 +1,60 @@
+module sonic-kdump {
+    namespace "http://github.com/Azure/sonic-kdump";
+    prefix kdump;
+    yang-version 1.1;
+
+    organization
+        "SONiC";
+
+    contact
+        "SONiC";
+
+    description
+        "This module contains a collection of YANG definitions for the
+         Linux Kernel crash dumping (Kdump) mechanism. The Kdump feature
+         is used to detect and record Linux kernel crash events.";
+
+    revision 2022-05-09 {
+        description
+            "Initial revision.";
+    }
+
+    container sonic-kdump {
+        container KDUMP {
+            description
+                "Kdump configuration parameters";
+            container config {
+                description "Top level grouping for attributes for Kdump.";
+                leaf enabled {
+                    type boolean;
+                    description
+                        "Enable or Disable the Kdump mechanism";
+                }
+
+                leaf memory {
+                    type string {
+                        pattern "(((([0-9]+[MG])?(-([0-9]+[MG])?):)?[0-9]+[MG],?)+)";
+                    }
+                    description
+                        "Memory reserved for loading the crash handler kernel. The amount
+                        of reserved memory can be variable, depending on the total amount
+                        of installed memory. The syntax for variable memory reservation is
+                        <range1>:<size1>,<range2>:<size2>. For example, 512M-2G:64M,2G-:128M,
+                        where a memory of 64MB is reserved for the crash kernel for systems
+                        with installed memory between 512MB and 2GB, 128MB is reserved for
+                        systems that have more than 2GB installed memory. An absolute memory
+                        value can also be specified in the format <size>M or <size>G.
+                        For example, 512M.";
+                }
+
+                leaf num_dumps {
+                    type uint8 {
+                        range "1 .. 9";
+                    }
+                    description
+                        "Maximum number of Kernel Core files Stored";
+                }
+            }
+        }
+    }
+}