able to parse with out msg= in tex with kv
example:
POST _ingest/pipeline/_simulate
{
  "pipeline": {
    "description" : "Ravi Test",
    "processors": [
      {
        "grok": {
          "field": "message",
          "patterns": ["%{TIMESTAMP_ISO8601:date} %{GREEDYDATA:msgbody}"]
        },
          "kv": {
          "field_split" : """\s(?![-_,:()\w ]+?(\s+|$))""",
          "value_split": "=",
          "field": "msgbody",
          "ignore_failure": true,
          "trim_value": " "
        }
        
      }
    ]
  },
  "docs":[
    {
      "_source": {
        "message": 	"2020-06-02 18:35:29,582Z level=INFO, s=rio, hostname=mocklp-5cb7685fff-kc4vp, component=MockLP, site=qa-long, streamID=110, rio_system_version=rio-1.10.15,""
      }
    }
  ]
}
results which worked
{
  "docs" : [
    {
      "doc" : {
        "_index" : "_index",
        "_type" : "_doc",
        "_id" : "_id",
        "_source" : {
          "date" : "2020-06-02 18:35:29,582Z",
          "msg" : "rio_system_version=rio-1.10.15,",
          "streamID" : "110,",
          "level" : "INFO,",
          "message" : "2020-06-02 18:35:29,582Z level=INFO, s=rio, hostname=mocklp-5cb7685fff-kc4vp, component=MockLP, site=qa-long, streamID=110, rio_system_version=rio-1.10.15,",
          "hostname" : "mocklp-5cb7685fff-kc4vp,",
          "component" : "MockLP,",
          "site" : "qa-long,",
          "s" : "rio,",
          "msgbody" : "level=INFO, s=rio, hostname=mocklp-5cb7685fff-kc4vp, component=MockLP, site=qa-long, streamID=110,"
        },
        "_ingest" : {
          "timestamp" : "2020-06-02T18:58:15.336239Z"
        }
      }
    }
  ]
}
POST _ingest/pipeline/_simulate
{
  "pipeline": {
    "description" : "Ravi Test",
    "processors": [
      {
        "grok": {
          "field": "message",
          "patterns": ["%{TIMESTAMP_ISO8601:date} %{GREEDYDATA:msgbody} %{GREEDYDATA:msg}"]
        },
          "kv": {
          "field_split" : """\s(?![-_,:()\w ]+?(\s+|$))""",
          "value_split": "=",
          "field": "msgbody",
          "ignore_failure": true,
          "trim_value": " "
        }
        
      }
    ]
  },
  "docs":[
    {
      "_source": {
        "message": 	"2020-06-02 18:35:29,582Z level=INFO, s=rio, hostname=mocklp-5cb7685fff-kc4vp, component=MockLP, site=qa-long, streamID=110, rio_system_version=rio-1.10.15, msg="Advanced MPD timeline, live point is now 2020-06-02 18:35:31.173858 +0000 UTC""
      }
    }
  ]
}
results
{
  "error" : {
    "root_cause" : [
      {
        "type" : "parse_exception",
        "reason" : "Failed to parse content to map"
      }
    ],
    "type" : "parse_exception",
    "reason" : "Failed to parse content to map",
    "caused_by" : {
      "type" : "json_parse_exception",
      "reason" : "Unexpected character ('A' (code 65)): was expecting comma to separate Object entries\n at [Source: org.elasticsearch.transport.netty4.ByteBufStreamInput@63b6139f; line: 24, column: 184]"
    }
  },
  "status" : 400
}