elasticsearch filebeat mapper_parsing_exception when using decode_json_fields - elasticsearch

Question

I have ECK setup and im using filebeat to ship logs from Kubernetes to elasticsearch.
Ive recently added decode_json_fields processor to my configuration, so that im able decode the json that is usually in the message field.
- decode_json_fields:
fields: ["message"]
process_array: false
max_depth: 10
target: "log"
overwrite_keys: true
add_error_key: true
However logs have stopped appearing since adding it.
example log:
{
"_index": "filebeat-7.9.1-2020.10.01-000001",
"_type": "_doc",
"_id": "wF9hB3UBtUOF3QRTBcts",
"_score": 1,
"_source": {
"#timestamp": "2020-10-08T08:43:18.672Z",
"kubernetes": {
"labels": {
"controller-uid": "9f3f9d08-cfd8-454d-954d-24464172fa37",
"job-name": "stream-hatchet-cron-manual-rvd"
},
"container": {
"name": "stream-hatchet-cron",
"image": "<redacted>.dkr.ecr.us-east-2.amazonaws.com/stream-hatchet:v0.1.4"
},
"node": {
"name": "ip-172-20-32-60.us-east-2.compute.internal"
},
"pod": {
"uid": "041cb6d5-5da1-4efa-b8e9-d4120409af4b",
"name": "stream-hatchet-cron-manual-rvd-bh96h"
},
"namespace": "default"
},
"ecs": {
"version": "1.5.0"
},
"host": {
"mac": [],
"hostname": "ip-172-20-32-60",
"architecture": "x86_64",
"name": "ip-172-20-32-60",
"os": {
"codename": "Core",
"platform": "centos",
"version": "7 (Core)",
"family": "redhat",
"name": "CentOS Linux",
"kernel": "4.9.0-11-amd64"
},
"containerized": false,
"ip": []
},
"cloud": {
"instance": {
"id": "i-06c9d23210956ca5c"
},
"machine": {
"type": "m5.large"
},
"region": "us-east-2",
"availability_zone": "us-east-2a",
"account": {
"id": "<redacted>"
},
"image": {
"id": "ami-09d3627b4a09f6c4c"
},
"provider": "aws"
},
"stream": "stdout",
"message": "{\"message\":{\"log_type\":\"cron\",\"status\":\"start\"},\"level\":\"info\",\"timestamp\":\"2020-10-08T08:43:18.670Z\"}",
"input": {
"type": "container"
},
"log": {
"offset": 348,
"file": {
"path": "/var/log/containers/stream-hatchet-cron-manual-rvd-bh96h_default_stream-hatchet-cron-73069980b418e2aa5e5dcfaf1a29839a6d57e697c5072fea4d6e279da0c4e6ba.log"
}
},
"agent": {
"type": "filebeat",
"version": "7.9.1",
"hostname": "ip-172-20-32-60",
"ephemeral_id": "6b3ba0bd-af7f-4946-b9c5-74f0f3e526b1",
"id": "0f7fff14-6b51-45fc-8f41-34bd04dc0bce",
"name": "ip-172-20-32-60"
}
},
"fields": {
"#timestamp": [
"2020-10-08T08:43:18.672Z"
],
"suricata.eve.timestamp": [
"2020-10-08T08:43:18.672Z"
]
}
}
In the filebeat logs i can see the following error:
2020-10-08T09:25:43.562Z WARN [elasticsearch] elasticsearch/client.go:407 Cannot
index event
publisher.Event{Content:beat.Event{Timestamp:time.Time{wall:0x36b243a0,
ext:63737745936, loc:(*time.Location)(nil)}, Meta:null,
Fields:{"agent":{"ephemeral_id":"5f8afdba-39c3-4fb7-9502-be7ef8f2d982","hostname":"ip-172-20-32-60","id":"0f7fff14-6b51-45fc-8f41-34bd04dc0bce","name":"ip-172-20-32-60","type":"filebeat","version":"7.9.1"},"cloud":{"account":{"id":"700849607999"},"availability_zone":"us-east-2a","image":{"id":"ami-09d3627b4a09f6c4c"},"instance":{"id":"i-06c9d23210956ca5c"},"machine":{"type":"m5.large"},"provider":"aws","region":"us-east-2"},"ecs":{"version":"1.5.0"},"host":{"architecture":"x86_64","containerized":false,"hostname":"ip-172-20-32-60","ip":["172.20.32.60","fe80::af:9fff:febe:dc4","172.17.0.1","100.96.1.1","fe80::6010:94ff:fe17:fbae","fe80::d869:14ff:feb0:81b3","fe80::e4f3:b9ff:fed8:e266","fe80::1c19:bcff:feb3:ce95","fe80::fc68:21ff:fe08:7f24","fe80::1cc2:daff:fe84:2a5a","fe80::3426:78ff:fe22:269a","fe80::b871:52ff:fe15:10ab","fe80::54ff:cbff:fec0:f0f","fe80::cca6:42ff:fe82:53fd","fe80::bc85:e2ff:fe5f:a60d","fe80::e05e:b2ff:fe4d:a9a0","fe80::43a:dcff:fe6a:2307","fe80::581b:20ff:fe5f:b060","fe80::4056:29ff:fe07:edf5","fe80::c8a0:5aff:febd:a1a3","fe80::74e3:feff:fe45:d9d4","fe80::9c91:5cff:fee2:c0b9"],"mac":["02:af:9f:be:0d:c4","02:42:1b:56:ee:d3","62:10:94:17:fb:ae","da:69:14:b0:81:b3","e6:f3:b9:d8:e2:66","1e:19:bc:b3:ce:95","fe:68:21:08:7f:24","1e:c2:da:84:2a:5a","36:26:78:22:26:9a","ba:71:52:15:10:ab","56:ff:cb:c0:0f:0f","ce:a6:42:82:53:fd","be:85:e2:5f:a6:0d","e2:5e:b2:4d:a9:a0","06:3a:dc:6a:23:07","5a:1b:20:5f:b0:60","42:56:29:07:ed:f5","ca:a0:5a:bd:a1:a3","76:e3:fe:45:d9:d4","9e:91:5c:e2:c0:b9"],"name":"ip-172-20-32-60","os":{"codename":"Core","family":"redhat","kernel":"4.9.0-11-amd64","name":"CentOS
Linux","platform":"centos","version":"7
(Core)"}},"input":{"type":"container"},"kubernetes":{"container":{"image":"700849607999.dkr.ecr.us-east-2.amazonaws.com/stream-hatchet:v0.1.4","name":"stream-hatchet-cron"},"labels":{"controller-uid":"a79daeac-b159-4ba7-8cb0-48afbfc0711a","job-name":"stream-hatchet-cron-manual-c5r"},"namespace":"default","node":{"name":"ip-172-20-32-60.us-east-2.compute.internal"},"pod":{"name":"stream-hatchet-cron-manual-c5r-7cx5d","uid":"3251cc33-48a9-42b1-9359-9f6e345f75b6"}},"log":{"level":"info","message":{"log_type":"cron","status":"start"},"timestamp":"2020-10-08T09:25:36.916Z"},"message":"{"message":{"log_type":"cron","status":"start"},"level":"info","timestamp":"2020-10-08T09:25:36.916Z"}","stream":"stdout"},
Private:file.State{Id:"native::30998361-66306", PrevId:"",
Finished:false, Fileinfo:(*os.fileStat)(0xc001c14dd0),
Source:"/var/log/containers/stream-hatchet-cron-manual-c5r-7cx5d_default_stream-hatchet-cron-4278d956fff8641048efeaec23b383b41f2662773602c3a7daffe7c30f62fe5a.log",
Offset:539, Timestamp:time.Time{wall:0xbfd7d4a1e556bd72,
ext:916563812286, loc:(*time.Location)(0x607c540)}, TTL:-1,
Type:"container", Meta:map[string]string(nil),
FileStateOS:file.StateOS{Inode:0x1d8ff59, Device:0x10302},
IdentifierName:"native"}, TimeSeries:false}, Flags:0x1,
Cache:publisher.EventCache{m:common.MapStr(nil)}} (status=400):
{"type":"mapper_parsing_exception","reason":"failed to parse field
[log.message] of type [keyword] in document with id
'56aHB3UBLgYb8gz801DI'. Preview of field's value: '{log_type=cron,
status=start}'","caused_by":{"type":"illegal_state_exception","reason":"Can't
get text on a START_OBJECT at 1:113"}}
It throws an error because apparently log.message is of type "keyword" however this does not exist in the index mapping.
I thought this maybe an issue with the "target": "log" so ive tried changing this to something arbitrary like "my_parsed_message" or "m_log" or "mlog" and i get the same error for all of them.
{"type":"mapper_parsing_exception","reason":"failed to parse field
[mlog.message] of type [keyword] in document with id
'J5KlDHUB_yo5bfXcn2LE'. Preview of field's value: '{log_type=cron,
status=end}'","caused_by":{"type":"illegal_state_exception","reason":"Can't
get text on a START_OBJECT at 1:217"}}
Elastic version: 7.9.2

Answer 1

The problem is that some of your JSON messages contain a message field that is sometimes a simple string and other times a nested JSON object (like in the case you're showing in your question).
After this index was created, the very first message that was parsed was probably a string and hence the mapping has been modified to add the following field (line 10553):
"mlog": {
"properties": {
...
"message": {
"type": "keyword",
"ignore_above": 1024
},
}
}
You'll find the same pattern for my_parsed_message (line 10902), my_parsed_logs (line 10742), etc...
Hence the next message that comes with message being a JSON object, like
{"message":{"log_type":"cron","status":"start"}, ...
will not work because it's an object, not a string...
Looking at the fields of your custom JSON, it seems you don't really have the control over either their taxonomy (i.e. naming) or what they contain...
If you're serious about willing to search within those custom fields (which I think you are since you're parsing the field, otherwise you'd just store the stringified JSON), then I can only suggest to start figuring out a proper taxonomy in order to make sure that they all get a standard type.
If all you care about is logging your data, then I suggest to simply disable the indexing of that message field. Another solution is to set dynamic: false in your mapping to ignore those fields, i.e. not modify your mapping.