Outcold Solutions LLC

Forwarding Kubernetes logs to ElasticSearch and OpenSearch

Annotations

You can define annotations for namespaces, workloads, and pods. Annotations allow you to change how collector forwards data to ElasticSearch. Annotations also help collector where to discover the application logs.

The complete list of all the available annotations is available at the bottom of this page.

Default configuration uses annotationSubdomain = elasticsearch, so all the annotations should start with elasticsearch.collectord.io/. So ElasticSearch and ElasticSearch annotations are different.

Overriding datastreams

Using annotations, you can override to which datastream data should be forwarded from a specific namespace, workload, or pod. You can define one datastream for the whole object with elasticsearch.collectord.io/index or specific datastreams for container logs elasticsearch.collectord.io/logs-index, and events elasticsearch.collectord.io/events-index (can be applied only to whole namespace).

As an example, if you want to override indexes for a specific namespace

apiVersion: v1
kind: Namespace
metadata:
  name: team1
  annotations:
    elasticsearch.collectord.io/index: logs-team1

This annotation tells collectord to forward all the data from this namespace to datastream named logs-team1.

elasticsearch.collectord.io/logs-index overrides only datastream for the container logs. If you want to override logs for the application logs you should use elasticsearch.collectord.io/index or elasticsearch.collectord.io/volume.{N}-logs-index.

Overriding datastream for specific events

In the case when your container is running multiple processes, sometimes you want to override datastream just for specific events in the container (or application) logs. You can do that with the override annotations.

For example, we will use the nginx image with logs

172.17.0.1 - - [12/Oct/2018:22:38:05 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.54.0" "-"
2018/10/12 22:38:15 [error] 8#8: *2 open() "/usr/share/nginx/html/a.txt" failed (2: No such file or directory), client: 172.17.0.1, server: localhost, request: "GET /a.txt HTTP/1.1", host: "localhost:32768"
172.17.0.1 - - [12/Oct/2018:22:38:15 +0000] "GET /a.txt HTTP/1.1" 404 153 "-" "curl/7.54.0" "-"

If we want to override datastream of the web logs and keep all other logs with the predefined datastream

apiVersion: v1
kind: Pod
metadata:
  name: nginx-pod
  annotations:
    elasticsearch.collectord.io/logs-override.1-match: ^(\d{1,3}\.){3}\d{1,3}
    elasticsearch.collectord.io/logs-override.1-index: logs-nginx-web
spec:
  containers:
  - name: nginx
    image: nginx

The collector will override datastream for matched events, so with our example you will end up with events similar to

datastream       | event
------------------------------------------------------------------------------------------------------------------------
logs-nginx-web   | 172.17.0.1 - - [12/Oct/2018:22:38:05 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.54.0" "-"
logs-collectord  | 2018/10/12 22:38:15 [error] 8#8: *2 open() "/usr/share/nginx/html/a.txt" failed (2: No such file or directory), client: 172.17.0.1, server: localhost, request: "GET /a.txt HTTP/1.1", host: "localhost:32768"
logs-nginx-web   | 172.17.0.1 - - [12/Oct/2018:22:38:15 +0000] "GET /a.txt HTTP/1.1" 404 153 "-" "curl/7.54.0" "-"

Replace patterns in events

You can define replace patterns with the annotations. That allows you to hide sensitive information or drop unimportant information from the messages.

Replace patterns for container logs are configured with a pair of annotations grouped with the same number elasticsearch.collectord.io/logs-replace.1-search and elasticsearch.collectord.io/logs-replace.2-val, first specifies the search pattern as a regular expression, second a replace pattern. In replace patterns you can use placeholders for matches, like $1 or $name for named patterns.

We're using a Go regular expression library in implementation of replace pipes. You can find more information about the syntax at Package regexp and re2 syntax. We recommend to use https://regex101.com for testing your patterns (set the Flavor to golang).

Using nginx as an example, our logs have a default pattern like

172.17.0.1 - - [31/Aug/2018:21:11:26 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.54.0" "-"
172.17.0.1 - - [31/Aug/2018:21:11:32 +0000] "POST / HTTP/1.1" 405 173 "-" "curl/7.54.0" "-"
172.17.0.1 - - [31/Aug/2018:21:11:35 +0000] "GET /404 HTTP/1.1" 404 612 "-" "curl/7.54.0" "-"

Example 1. Replacing IPv4 addresses with X.X.X.X

If we want to hide an IP address from the logs by replacing all IPv4 addresses with X.X.X.X

apiVersion: v1
kind: Pod
metadata:
  name: nginx-pod
  annotations:
    elasticsearch.collectord.io/logs-replace.1-search: (\d{1,3}\.){3}\d{1,3}
    elasticsearch.collectord.io/logs-replace.1-val: X.X.X.X
spec:
  containers:
  - name: nginx
    image: nginx

The result of this replace pattern will be in ElasticSearch

X.X.X.X - - [31/Aug/2018:21:11:26 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.54.0" "-"
X.X.X.X - - [31/Aug/2018:21:11:32 +0000] "POST / HTTP/1.1" 405 173 "-" "curl/7.54.0" "-"
X.X.X.X - - [31/Aug/2018:21:11:35 +0000] "GET /404 HTTP/1.1" 404 612 "-" "curl/7.54.0" "-"

You can also keep the first part of the IPv4 with 

apiVersion: v1
kind: Pod
metadata:
  name: nginx-pod
  annotations:
    elasticsearch.collectord.io/logs-replace.1-search: (?P<IPv4p1>\d{1,3})(\.\d{1,3}){3}
    elasticsearch.collectord.io/logs-replace.1-val: ${IPv4p1}.X.X.X
spec:
  containers:
  - name: nginx
    image: nginx

That results in 

172.X.X.X - - [31/Aug/2018:21:11:26 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.54.0" "-"
172.X.X.X - - [31/Aug/2018:21:11:32 +0000] "POST / HTTP/1.1" 405 173 "-" "curl/7.54.0" "-"
172.X.X.X - - [31/Aug/2018:21:11:35 +0000] "GET /404 HTTP/1.1" 404 612 "-" "curl/7.54.0" "-"

Example 2. Dropping messages

With the replace patterns, you can drop messages that you don't want to see in ElasticSearch. With the example below we drop all log messages resulted from GET requests with 200 response

apiVersion: v1
kind: Pod
metadata:
  name: nginx-pod
  annotations:
    elasticsearch.collectord.io/logs-replace.1-search: '^.+\"GET [^\s]+ HTTP/[^"]+" 200 .+$'
    elasticsearch.collectord.io/logs-replace.1-val: ''
    elasticsearch.collectord.io/logs-replace.2-search: '(\d{1,3}\.){3}\d{1,3}'
    elasticsearch.collectord.io/logs-replace.2-val: 'X.X.X.X'
spec:
  containers:
  - name: nginx
    image: nginx

In this example, we have two replace pipes. They apply in the alphabetical order (replace.1 comes first, before the replace.2).

X.X.X.X - - [31/Aug/2018:21:11:32 +0000] "POST / HTTP/1.1" 405 173 "-" "curl/7.54.0" "-"
X.X.X.X - - [31/Aug/2018:21:11:35 +0000] "GET /404 HTTP/1.1" 404 612 "-" "curl/7.54.0" "-"

Example 3. Whitelisting the messages

With the whitelist annotation you can configure a pattern for the log messages, and only messages that match this pattern will be forwarded to ElasticSearch

apiVersion: v1
kind: Pod
metadata:
  name: nginx-pod
  annotations:
    elasticsearch.collectord.io/logs-whitelist: '((DELETE)|(POST))$'
spec:
  containers:
  - name: nginx
    image: nginx

Hashing values in logs

To hide sensitive data, you can use replace patterns or hashing functions.

apiVersion: v1
kind: Pod
metadata:
  name: nginx-pod
  annotations:
    elasticsearch.collectord.io/logs-hashing.1-match: '(\d{1,3}\.){3}\d{1,3}'
    elasticsearch.collectord.io/logs-hashing.1-function: 'fnv-1a-64'
spec:
  containers:
  - name: nginx
    image: nginx

This example will replace values that look like an IP address in the string

172.17.0.1 - - [16/Nov/2018:11:17:17 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.54.0" "-"

With the hashed value, in our example using the algorithm fnv-1a-64

gqsxydjtZL4 - - [16/Nov/2018:11:17:17 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.54.0" "-"

Collectord supports a variety of hashing functions, including cryptographic hashing functions. The list of supported functions and their performance is listed below (performance in the nanoseconds per operation to hash two IP addresses in a string source: 127.0.0.1, destination: 10.10.1.99)

| Function          | ns / op |
-------------------------------
| adler-32          |    1713 |
| crc-32-ieee       |    1807 |
| crc-32-castagnoli |    1758 |
| crc-32-koopman    |    1753 |
| crc-64-iso        |    1739 |
| crc-64-ecma       |    1740 |
| fnv-1-64          |    1711 |
| fnv-1a-64         |    1711 |
| fnv-1-32          |    1744 |
| fnv-1a-32         |    1738 |
| fnv-1-128         |    1852 |
| fnv-1a-128        |    1836 |
| md5               |    2032 |
| sha1              |    2037 |
| sha256            |    2220 |
| sha384            |    2432 |
| sha512            |    2516 |

Escaping terminal sequences, including terminal colors

Some containers don't turn off terminal colors automatically when they run inside container. For example, if you run container with attached tty and define that you want to see colors

apiVersion: v1
kind: Pod
metadata:
  name: ubuntu-shell
spec:
  containers:
  - name: ubuntu
    image: ubuntu
    tty: true
    command: [/bin/sh, -c,
             'while true; do ls --color=auto /; sleep 5; done;']

You can find messages similar to below in ElasticSearch

[01;34mboot  etc  lib   media  opt  root  sbin  sys  usr
[0mbin   dev  home  lib64  mnt  proc  run   srv  tmp  var

You can easily escape them with the annotation elasticsearch.collectord.io/logs-escapeterminalsequences='true'

apiVersion: v1
kind: Pod
metadata:
  name: ubuntu-shell
  annotations:
    elasticsearch.collectord.io/logs-escapeterminalsequences: 'true'
spec:
  containers:
  - name: ubuntu
    image: ubuntu
    tty: true
    command: [/bin/sh, -c,
             'while true; do ls --color=auto /; sleep 5; done;']

That way you will see logs in ElasticSearch as you would expect

bin   dev  home  lib64  mnt  proc  run   srv  tmp  var
boot  etc  lib   media  opt  root  sbin  sys  usr

In the collector configuration file you can find [input.files]/stripTerminalEscapeSequencesRegex and [input.files]/stripTerminalEscapeSequences that defines default regexp used for removing terminal escape sequences and default value if collector should strip terminal escape sequences (defaults to false).

Extracting fields from the container logs

You can use fields extraction, which allows you to extract timestamps from the messages, extract fields that will be indexed with ElasticSearch to speed up the search.

Using the same example with nginx we can define fields extraction for some fields.

172.17.0.1 - - [31/Aug/2018:21:11:26 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.54.0" "-"
172.17.0.1 - - [31/Aug/2018:21:11:32 +0000] "POST / HTTP/1.1" 405 173 "-" "curl/7.54.0" "-"
172.17.0.1 - - [31/Aug/2018:21:11:35 +0000] "GET /404 HTTP/1.1" 404 612 "-" "curl/7.54.0" "-"

Important note that the first unnamed pattern is used as the message for the event. If you want to override it, you can use the annotations elasticsearch.collectord.io/logs-extractionMessageField to use a specific pattern as a message field.

Nested Objects

Considering that you might want to create nested JSON objects in the events sent to ElasticSearch, when you add a named group with double underscore (__) in the name, the collector will replace it with dot (.). For example, if you've named groups in the extraction pattern (?P<obj__firstname>value1)\w+ (?P<obj__lastname>value2)\w+, the collector will create and object {"obj":{"firstname": "value", "lastname": "value"}}.

Datastreams and index templates

When you extract new fields, you might want to create a new index template for the new fields. Be sure to add elasticsearch.collectord.io/logs-datastream annotation to the pod, so the collector will send the data to a new datastream.

Example 1. Extracting the timestamp

Assuming we want to keep the whole message as it is, and extract just a timestamp. We can define the extraction pattern with the regexp. Specify that the timestampfield is timestamp and define the timestampformat.

We use Go time parsing library, that defines the format with the specific date Mon Jan 2 15:04:05 MST 2006. See Go documentation for details.

apiVersion: v1
kind: Pod
metadata:
  name: nginx-pod
  annotations:
    elasticsearch.collectord.io/logs-extraction: '^(.*\[(?P<timestamp>[^\]]+)\].+)$'
    elasticsearch.collectord.io/logs-timestampfield: timestamp
    elasticsearch.collectord.io/logs-timestampformat: '02/Jan/2006:15:04:05 -0700'
spec:
  containers:
  - name: nginx
    image: nginx

In that way, you will get messages in ElasticSearch with the exact timestamp as specified in your container logs.

Example 2. Extracting the fields

If you want to extract some fields and keep the message shorter, as an example, if you've extracted the timestamps, there is no need for you to keep the timestamp in the raw message. In the example below we extract the ip_address address as a field, timestamp and keep the rest as a raw message.

apiVersion: v1
kind: Pod
metadata:
  name: nginx-pod
  annotations:
    elasticsearch.collectord.io/logs-extraction: '^(?P<ip_address>[^\s]+) .* \[(?P<timestamp>[^\]]+)\] (.+)$'
    elasticsearch.collectord.io/logs-timestampfield: timestamp
    elasticsearch.collectord.io/logs-timestampformat: '02/Jan/2006:15:04:05 -0700'
spec:
  containers:
  - name: nginx
    image: nginx

That results in messages

ip_address | _time               | _raw
-----------|---------------------|-------------------------------------------------
172.17.0.1 | 2018-08-31 21:11:26 | "GET / HTTP/1.1" 200 612 "-" "curl/7.54.0" "-"
172.17.0.1 | 2018-08-31 21:11:32 | "POST / HTTP/1.1" 405 173 "-" "curl/7.54.0" "-"
172.17.0.1 | 2018-08-31 21:11:35 | "GET /404 HTTP/1.1" 404 612 "-" "curl/7.54.0" "-"

Defining Event pattern

With the annotation elasticsearch.collectord.io/logs-eventpattern you can define how collector should identify new events in the pipe. The default event pattern is defined by the collectord configuration as ^[^\s] (anything that does not start from a space character).

The default pattern works in most of the cases, but doesn't work in some, like Java exceptions, where the call stack of the error starts on the next line, and it doesn't start with the space character.

In example below we intentionally made a mistake in a configuration for the ElasticSearch (s-node should be a single-node) to get the error message

apiVersion: v1
kind: Pod
metadata:
  name: elasticsearch-pod
spec:
  containers:
  - name: elasticsearch
    image: docker.elastic.co/elasticsearch/elasticsearch:6.4.0
    env:
    - name: discovery.type
      value: s-node

Results in

[2018-08-31T22:44:56,433][INFO ][o.e.x.m.j.p.l.CppLogMessageHandler] [controller/92] [Main.cc@109] controller (64 bit): Version 6.4.0 (Build cf8246175efff5) Copyright (c) 2018 Elasticsearch BV
[2018-08-31T22:44:56,886][WARN ][o.e.b.ElasticsearchUncaughtExceptionHandler] [] uncaught exception in thread [main]
org.elasticsearch.bootstrap.StartupException: java.lang.IllegalArgumentException: Unknown discovery type [s-node]
    at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:140) ~[elasticsearch-6.4.0.jar:6.4.0]
    at org.elasticsearch.bootstrap.Elasticsearch.execute(Elasticsearch.java:127) ~[elasticsearch-6.4.0.jar:6.4.0]
    at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:86) ~[elasticsearch-6.4.0.jar:6.4.0]
    at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:124) ~[elasticsearch-cli-6.4.0.jar:6.4.0]
    at org.elasticsearch.cli.Command.main(Command.java:90) ~[elasticsearch-cli-6.4.0.jar:6.4.0]
    at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:93) ~[elasticsearch-6.4.0.jar:6.4.0]
    at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:86) ~[elasticsearch-6.4.0.jar:6.4.0]
Caused by: java.lang.IllegalArgumentException: Unknown discovery type [s-node]
    at org.elasticsearch.discovery.DiscoveryModule.<init>(DiscoveryModule.java:129) ~[elasticsearch-6.4.0.jar:6.4.0]
    at org.elasticsearch.node.Node.<init>(Node.java:477) ~[elasticsearch-6.4.0.jar:6.4.0]
    at org.elasticsearch.node.Node.<init>(Node.java:256) ~[elasticsearch-6.4.0.jar:6.4.0]
    at org.elasticsearch.bootstrap.Bootstrap$5.<init>(Bootstrap.java:213) ~[elasticsearch-6.4.0.jar:6.4.0]
    at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:213) ~[elasticsearch-6.4.0.jar:6.4.0]
    at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:326) ~[elasticsearch-6.4.0.jar:6.4.0]
    at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:136) ~[elasticsearch-6.4.0.jar:6.4.0]
    ... 6 more
[2018-08-31T22:44:56,892][INFO ][o.e.x.m.j.p.NativeController] Native controller process has stopped - no new native processes can be started

And with the default pattern we will not have the warning line [2018-08-31T22:44:56,886][WARN ][o.e.b.ElasticsearchUncaughtExceptionHandler] [] uncaught exception in thread [main] with the whole callstack.

We can define that every log event in this container should start with the [ character with the regular expression as

apiVersion: v1
kind: Pod
metadata:
  name: elasticsearch-pod
  annotations:
    elasticsearch.collectord.io/logs-eventpattern: '^\['
spec:
  containers:
  - name: elasticsearch
    image: docker.elastic.co/elasticsearch/elasticsearch:6.4.0
    env:
    - name: discovery.type
      value: s-node

Note: by default, collectord joins multi-line log lines that are written in the duration of 100ms, waits maximum of 1s for the next line, and combines event in the total of 100Kb. If you see that not all multi-line log lines are joined into one event as you expect, you might need to change the configuration for the collectord under [pipe.join].

Application Logs

Sometimes it is hard or just not practical to redirect all logs from the container to stdout and stderr of the container. In these cases, you keep the logs in the container. We call them application logs. With collectord you can easily pick up these logs and forward them to ElasticSearch. No additional sidecars or processes are required inside your container.

Let's take a look at the example below. We have a postgresql container, that redirects most of the logs to the path inside the container /var/log/postgresql. We define for this container a volume (emptyDir driver) with the name psql_logs and mount it to /var/log/postgresql/. With the annotation elasticsearch.collectord.io/volume.1-logs-name=psql_logs we tell collector to pick up all the logs with the default glob pattern *.log* (a default glob pattern is set in the collector configuration, and you can override it with annotation elasticsearch.collectord.io/volume.{N}-logs-glob) in the volume and forward them automatically to ElasticSearch.

When you need to forward logs from multiple volumes of the same container, you can group the settings with the same number, for example elasticsearch.collectord.io/volume.1-logs-name=psql_logs and elasticsearch.collectord.io/volume.2-logs-name=psql_logs

Example 1. Forwarding application logs

apiVersion: v1
kind: Pod
metadata:
  name: postgres-pod
  annotations:
    elasticsearch.collectord.io/volume.1-logs-name: 'logs'
spec:
  containers:
  - name: postgres
    image: postgres
    command:
      - docker-entrypoint.sh
    args:
      - postgres
      - -c
      - logging_collector=on
      - -c
      - log_min_duration_statement=0
      - -c
      - log_directory=/var/log/postgresql
      - -c
      - log_min_messages=INFO
      - -c
      - log_rotation_age=1d
      - -c
      - log_rotation_size=10MB
    volumeMounts:
      - name: data
        mountPath: /var/lib/postgresql/data
      - name: logs
        mountPath: /var/log/postgresql/
  volumes:
  - name: data
    emptyDir: {}
  - name: logs
    emptyDir: {}

Example 2. Forwarding application logs with fields extraction and time parsing

With the annotations for application logs, you can define fields extraction, replace patterns, override the datastreams.

As an example, with the extraction pattern and timestamp parsing you can do

apiVersion: v1
kind: Pod
metadata:
  name: postgres-pod
  annotations:
    elasticsearch.collectord.io/volume.1-logs-name: 'logs'
    elasticsearch.collectord.io/volume.1-logs-extraction: '^(?P<timestamp>\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}\.\d{3} [^\s]+) (.+)$'
    elasticsearch.collectord.io/volume.1-logs-timestampfield: 'timestamp'
    elasticsearch.collectord.io/volume.1-logs-timestampformat: '2006-01-02 15:04:05.000 MST'
spec:
  containers:
  - name: postgres
    image: postgres
    command:
      - docker-entrypoint.sh
    args:
      - postgres
      - -c
      - logging_collector=on
      - -c
      - log_min_duration_statement=0
      - -c
      - log_directory=/var/log/postgresql
      - -c
      - log_min_messages=INFO
      - -c
      - log_rotation_age=1d
      - -c
      - log_rotation_size=10MB
    volumeMounts:
      - name: data
        mountPath: /var/lib/postgresql/data
      - name: logs
        mountPath: /var/log/postgresql/
  volumes:
  - name: data
    emptyDir: {}
  - name: logs
    emptyDir: {}

That way you will extract the timestamps and remove them from the message

_time               | _raw
2018-08-31 23:31:02 | [133] LOG:  duration: 0.908 ms  statement: SELECT n.nspname as "Schema",
                    |     c.relname as "Name",
                    |     CASE c.relkind WHEN 'r' THEN 'table' WHEN 'v' THEN 'view' WHEN 'm' THEN 'materialized view' WHEN 'i' THEN 'index' WHEN 'S' THEN 'sequence' WHEN 's' THEN 'special' WHEN 'f' THEN 'foreign table' WHEN 'p' THEN 'table' END as "Type",
                    |     pg_catalog.pg_get_userbyid(c.relowner) as "Owner"
                    |   FROM pg_catalog.pg_class c
                    |        LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
                    |   WHERE c.relkind IN ('r','p','')
                    |         AND n.nspname <> 'pg_catalog'
                    |         AND n.nspname <> 'information_schema'
                    |         AND n.nspname !~ '^pg_toast'
                    |     AND pg_catalog.pg_table_is_visible(c.oid)
                    |   ORDER BY 1,2;
2018-08-31 23:30:53 |  UTC [124] FATAL:  role "postgresql" does not exist

Placeholder templates in a glob pattern

In the case if you're mounting the same volume to multiple Pods, and you want to differentiate the logs, you can now specify the placeholders in the glob configuration. For example, if you have a volume mounted to the Pod with the name my-pod and to the Pod with the name my-pod-2 you can specify the glob configuration like this {{kubernetes_pod_name}}.log, so the Collectord will be able to identify that files my-pod.log and my-pod-2.log are coming from different Pods.

On Volume Database for acknowledgements

Collectord has a database that stores the information about the files that were already processed. The database is stored by default on the host, where Collectord is running. In case, if one of the volumes is used on one host and then is
mounted to another host, the Collectord will start to process the files from the beginning. To avoid this, you can specify annotation elasticsearch.collectord.io/volume.{N}-logs-onvolumedatabase=true to enable the on volume database. In this case, Collectord creates a database in the volume root .collectord.db, so the data about processed files will be stored in the volume and will be available on any host.

Important details about this feature, you need to mount the /rootfs directory in the Collectord container with write access. By default, the /rootfs directory is mounted as read-only.

Volume types

Collector supports two volume types for application logs: emptyDir, hostPath and persistentVolumeClaim. Collectord configuration has two settings that helps collector to autodiscover application logs. First is the [general.kubernetes]/volumesRootDir for discovering volumes created with emptyDir, second is [input.app_logs]/root for discovering host mounts, considering that they will be mounted with a different path to collector.

Change output destination

By default, collector forwards all the data to ElasticSearch. You can configure containers to redirect data to devnull instead with annotation elasticsearch.collectord.io/logs-output=devnull.

By changing the default output for specific data, you can change how you forward data to ElasticSearch. Instead of forwarding all the logs by default, you can change configuration for collector with --env "COLLECTOR__LOGS_OUTPUT=input.files__output=devnull" to specify not forward container logs by default. And define with the containers which logs you want to see in ElasticSearch with elasticsearch.collectord.io/logs-output=elasticsearch.

For example:

apiVersion: v1
kind: Pod
metadata:
  name: nginx-pod
  labels:
    app: MyApp
  annotations:
    elasticsearch.collectord.io/logs-output: 'elasticsearch'
spec:
  containers:
  - name: nginx
    image: nginx

Additionally, if you configure multiple ElasticSearch outputs with the configuration, you can forward the data to a specific ElasticSearch Cluster as

apiVersion: v1
kind: Pod
metadata:
  name: nginx-pod
  labels:
    app: MyApp
  annotations:
    elasticsearch.collectord.io/output: 'elasticsearch::prod1'
spec:
  containers:
  - name: nginx
    image: nginx

Forwarding logs to multiple ElasticSearch clusters simultaneously

With annotation elasticsearch.collectord.io/output you can configure multiple ElasticSearch HEC endpoints, for example elasticsearch::apps and elasticsearch::security using the comma-separated list: elasticsearch.collectord.io/output=elasticsearch::apps,elasticsearch::security. Assuming you have them defined in the ConfigMap like [output.elasticsearch::apps] and [output.elasticsearch::security].

Additionally, you can configure datastreams for the endpoints in square brackets, for example elasticsearch.collectord.io/output=elasticsearch::apps[logs-team],elasticsearch::security[logs-security].

In that case, each event will be sent to both ElasticSearch Clusters.

For example, if you want to forward logs from a specific container to multiple ElasticSearch clusters, you can use the following

apiVersion: v1
kind: Pod
metadata:
  name: nginx-pod
  labels:
    app: MyApp
  annotations:
    elasticsearch.collectord.io/logs-output: 'elasticsearch::apps[logs-team],elasticsearch::security[logs-security]'
spec:
  containers:
  - name: nginx
    image: nginx

Logs sampling

Example 1. Random based sampling

When the application produces a high number of logs, in some cases, it could be enough to just on the sampled amount of the logs to understand how many failed requests the application has, or how it behaves. You can add an annotation for the logs to specify the percent number of the logs that should be forwarded to ElasticSearch.

In the following example, this application produces 300,000 log lines. Only about 60,000 log lines are going to be forwarded to ElasticSearch.

apiVersion: v1
kind: Pod
metadata:
  name: logtest
  annotations:
    elasticsearch.collectord.io/logs-sampling-percent: '20'
spec:
  restartPolicy: Never
  containers:
  - name: logtest
    image: docker.io/mffiedler/ocp-logtest:latest
    args: [python, ocp_logtest.py,
           --line-length=1024, --num-lines=300000, --rate=60000, --fixed-line]

Example 2. Hash-based sampling

In the situations where you want to look at the pattern for a specific user, you can specify that you want to sample logs based on the hash value, to be sure if the same key presents in two different log lines, both of them will be forwarded to ElasticSearch.

In the following example we define a key (should be a named submatch pattern) as an IP address. 

apiVersion: v1
kind: Pod
metadata:
  name: nginx-sampling
  annotations:
    elasticsearch.collectord.io/logs-sampling-percent: '20'
    elasticsearch.collectord.io/logs-sampling-key: '^(?P<key>(\d+\.){3}\d+)'
spec:
  containers:
  - name: nginx-sampling
    image: nginx

Thruput

You can configure the thruput specifically for the container logs as

apiVersion: v1
kind: Pod
metadata:
  name: nginx-sampling
  annotations:
    elasticsearch.collectord.io/logs-ThruputPerSecond: 128Kb
spec:
  containers:
  - name: nginx-sampling
    image: nginx

In case if this container produces more than 128kb per second collectord will throttle logs.

Time correction

If you're pre-loading a lot of logs, you might want to configure the events, that you want to skip, as they're too old or too new

apiVersion: v1
kind: Pod
metadata:
  name: nginx-sampling
  annotations:
    elasticsearch.collectord.io/logs-TooOldEvents: 168h
    elasticsearch.collectord.io/logs-TooOldEvents: 1h
spec:
  containers:
  - name: nginx-sampling
    image: nginx

Handling multiple containers

Pod can have multiple containers. You can define annotations for a specific container with the name prefixed the annotation. The format of the annotations is elasticsearch.collectord.io/{container_name}--{annotation}: {annotation-value}. As an example.

apiVersion: v1
kind: Pod
metadata:
  name: nginx-pod
  annotations:
    elasticsearch.collectord.io/web--logs-index: 'web'
    elasticsearch.collectord.io/web--logs-replace.2-search: '(?P<IPv4p1>\d{1,3})(\.\d{1,3}){3}'
    elasticsearch.collectord.io/web--logs-replace.2-val: '${IPv4p1}.X.X.X'
    elasticsearch.collectord.io/user--logs-disabled: 'true'
spec:
  containers:
  - name: web
    image: nginx
  - name: user
    image: busybox
    args: [/bin/sh, -c,
           'while true; do wget -qO- localhost:80 &> /dev/null; sleep 5; done']

Cluster level annotations

You can apply annotations to Pods on the cluster level with Configuration in api group collectord.io/v1. For example

apiVersion: "collectord.io/v1"
kind: Configuration
metadata:
  name: apply-to-all-nginx
  annotations:
    elasticsearch.collectord.io/nginx--logs-replace.1-search: '^.+\"GET [^\s]+ HTTP/[^"]+" 200 .+$'
    elasticsearch.collectord.io/nginx--logs-replace.1-val: ''
    elasticsearch.collectord.io/nginx--logs-hashing.1-match: '(\d{1,3}\.){3}\d{1,3}'
    elasticsearch.collectord.io/nginx--logs-hashing.1-function: 'fnv-1a-64'
spec:
  kubernetes.container.image: "^nginx(:.*)?$"

This configuration will be applied to all containers that use the image with nginx in the name (examples are nginx:latest or nginx:1.0).

In the spec of the Configuration you include selectors based on the meta fields that we forward to ElasticSearch, which can include fields like container.image.name, kubernetes.container.name, kubernetes.daemonset.name, kubernetes.namespace, kubernetes.pod.name, etc. When you specify multiple fields in the spec, all regexes should match.

Forcing Cluster Level Annotations

If you already have an annotation, for example, elasticsearch.collectord.io/index=foo defined on Namespace, Deployment, or Pod, and if you're trying to apply this annotation from Cluster Level Configuration as elasticsearch.collectord.io/index=bar, the one from the objects will take priority.

With the force modifier you can override those annotations, even if you have them defined on the objects.

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apiVersion: "collectord.io/v1"
kind: Configuration
metadata:
  name: apply-to-all-nginx
  annotations:
    elasticsearch.collectord.io/index=bar
spec:
  kubernetes_container_image: "^nginx(:.*)?$"
force: true

NOTE: if you have an annotation defined in the namespace as elasticsearch.collectord.io/logs-index=foo, it will still take priority over index=bar, as logs-index=foo is type specific.

Troubleshooting

Check the collector logs for warning messages about the annotations, you can find if you made a misprint in the annotations if you see warnings like

WARN 2018/08/31 21:05:33.122978 core/input/annotations.go:76: invalid annotation ...

Some pipes, like fields extraction and time-parsing pipes adds an error in the field collectord_errors, so you can identify when some events failed to be processed by this pipe.

Describe command

Please use Collectord describe command to see how annotations are applied to a specific pod or container.

See Troubleshooting -> Describe.

Reference

  • General annotations
    • elasticsearch.collectord.io/index - change the datastream for all the data forwarded for this Pod (metrics, container logs, application logs)
    • elasticsearch.collectord.io/host - change the host for all the data forwarded for this Pod (metrics, container logs, application logs)
    • elasticsearch.collectord.io/output - change the output to devnull or elasticsearch
    • elasticsearch.collectord.io/userfields.{fieldname} - attach custom fields to events
  • Annotations for container logs
    • elasticsearch.collectord.io/logs-index - change the datastream for the container logs forwarded from this Pod
    • elasticsearch.collectord.io/logs-host - change the host for the container logs forwarded from this Pod
    • elasticsearch.collectord.io/logs-eventpattern - set the regex identifying the event start pattern for Pod logs
    • elasticsearch.collectord.io/logs-replace.{N}-search - define the search pattern for the replace pipe
    • elasticsearch.collectord.io/logs-replace.{N}-val - define the replace pattern for the replace pipe
    • elasticsearch.collectord.io/logs-hashing.{N}-match - the regexp for a matched value
    • elasticsearch.collectord.io/logs-hashing.{N}-function - hash function (default is sha256, available adler-32,crc-32-ieee,crc-32-castagnoli,crc-32-koopman,crc-64-iso,crc-64-ecma,fnv-1-64,fnv-1a-64,fnv-1-32,fnv-1a-32,fnv-1-128,fnv-1a-128,md5,sha1,sha256,sha384,sha512)
    • elasticsearch.collectord.io/logs-extraction - define the regexp for fields extraction
    • elasticsearch.collectord.io/logs-extractionMessageField - specify the field name for the message (by default first unnamed ground in regexp)
    • elasticsearch.collectord.io/logs-timestampfield - define the field for timestamp (after fields extraction)
    • elasticsearch.collectord.io/logs-timestampformat - define the timestamp format
    • elasticsearch.collectord.io/logs-timestampsetmonth - define if month should be set to current for timestamp
    • elasticsearch.collectord.io/logs-timestampsetday - define if day should be set to current for timestamp
    • elasticsearch.collectord.io/logs-timestamplocation - define timestamp location if not set by format
    • elasticsearch.collectord.io/logs-joinpartial - join partial events
    • elasticsearch.collectord.io/logs-joinmultiline - join multiline logs (default value depends on [pipe.join] disabled)
    • elasticsearch.collectord.io/logs-escapeterminalsequences - escape terminal sequences (including colors)
    • elasticsearch.collectord.io/logs-override.{N}-match - match for override pattern
    • elasticsearch.collectord.io/logs-override.{N}-index - override datastream for matched events
    • elasticsearch.collectord.io/logs-output - change the output to devnull or elasticsearch (this annotation can't be specified for stderr and stdout)
    • elasticsearch.collectord.io/logs-disabled - disable any log processing for this container (this annotation can't be specified for stderr and stdout)
    • elasticsearch.collectord.io/logs-sampling-percent - specify the % value of logs that should be forwarded to ElasticSearch
    • elasticsearch.collectord.io/logs-sampling-key - regexp pattern to specify the key for the sampling based on hash values
    • elasticsearch.collectord.io/logs-ThruputPerSecond - set the thruput for this container, maximum number of logs per second, for example 128Kb, 1024b
    • elasticsearch.collectord.io/logs-TooOldEvents - duration of events from now to past that are considered too old and should be ignored, for example 168h, 24h
    • elasticsearch.collectord.io/logs-TooNewEvents - duration of events from now to the future that are considered too new and should be ignored, for example 1h, 30m
    • elasticsearch.collectord.io/logs-whitelist - allow configuring a pattern for log messages, only log messages matching this pattern will be forwarded to ElasticSearch
    • elasticsearch.collectord.io/logs-userfields.{fieldname} - attach custom fields to events
    • Specific for stdout, with the annotations below you can define configuration specific for stdout
      • elasticsearch.collectord.io/stdout-logs-index
      • elasticsearch.collectord.io/stdout-logs-host
      • elasticsearch.collectord.io/stdout-logs-eventpattern
      • elasticsearch.collectord.io/stdout-logs-replace.{N}-search
      • elasticsearch.collectord.io/stdout-logs-replace.{N}-val
      • elasticsearch.collectord.io/stdout-logs-hashing.{N}-match
      • elasticsearch.collectord.io/stdout-logs-hashing.{N}-function
      • elasticsearch.collectord.io/stdout-logs-extraction
      • elasticsearch.collectord.io/stdout-logs-extractionMessageField
      • elasticsearch.collectord.io/stdout-logs-timestampfield
      • elasticsearch.collectord.io/stdout-logs-timestampformat
      • elasticsearch.collectord.io/stdout-logs-timestampsetmonth
      • elasticsearch.collectord.io/stdout-logs-timestampsetday
      • elasticsearch.collectord.io/stdout-logs-timestamplocation
      • elasticsearch.collectord.io/stdout-logs-joinpartial
      • elasticsearch.collectord.io/stdout-logs-joinmultiline
      • elasticsearch.collectord.io/stdout-logs-escapeterminalsequences
      • elasticsearch.collectord.io/stdout-logs-override.{N}-match
      • elasticsearch.collectord.io/stdout-logs-override.{N}-index
      • elasticsearch.collectord.io/stdout-logs-sampling-percent
      • elasticsearch.collectord.io/stdout-logs-sampling-key
      • elasticsearch.collectord.io/stdout-logs-ThruputPerSecond
      • elasticsearch.collectord.io/stdout-logs-TooOldEvents
      • elasticsearch.collectord.io/stdout-logs-TooNewEvents
      • elasticsearch.collectord.io/stdout-logs-whitelist
    • Specific for stderr, with the annotations below you can define configuration specific for stderr
      • elasticsearch.collectord.io/stderr-logs-index
      • elasticsearch.collectord.io/stderr-logs-host
      • elasticsearch.collectord.io/stderr-logs-eventpattern
      • elasticsearch.collectord.io/stderr-logs-replace.{N}-search
      • elasticsearch.collectord.io/stderr-logs-replace.{N}-val
      • elasticsearch.collectord.io/stderr-logs-hashing.{N}-match
      • elasticsearch.collectord.io/stderr-logs-hashing.{N}-function
      • elasticsearch.collectord.io/stderr-logs-extraction
      • elasticsearch.collectord.io/stdout-logs-extractionMessageField
      • elasticsearch.collectord.io/stderr-logs-timestampfield
      • elasticsearch.collectord.io/stderr-logs-timestampformat
      • elasticsearch.collectord.io/stderr-logs-timestampsetmonth
      • elasticsearch.collectord.io/stderr-logs-timestampsetday
      • elasticsearch.collectord.io/stderr-logs-timestamplocation
      • elasticsearch.collectord.io/stderr-logs-joinpartial
      • elasticsearch.collectord.io/stderr-logs-joinmultiline
      • elasticsearch.collectord.io/stderr-logs-escapeterminalsequences
      • elasticsearch.collectord.io/stderr-logs-override.{N}-match
      • elasticsearch.collectord.io/stderr-logs-override.{N}-index
      • elasticsearch.collectord.io/stderr-logs-sampling-percent
      • elasticsearch.collectord.io/stderr-logs-sampling-key
      • elasticsearch.collectord.io/stderr-logs-ThruputPerSecond
      • elasticsearch.collectord.io/stderr-logs-TooOldEvents
      • elasticsearch.collectord.io/stderr-logs-TooNewEvents
      • elasticsearch.collectord.io/stderr-logs-whitelist
  • Annotations for events (can be applied only to namespaces)
    • elasticsearch.collectord.io/events-index - change the datastream for the events of specific namespace
    • elasticsearch.collectord.io/events-host - change the host for the events of specific namespace
    • elasticsearch.collectord.io/events-userfields.{fieldname} - attach custom fields to events
  • Annotations for application logs
    • elasticsearch.collectord.io/volume.{N}-logs-name - name of the volume attached to Pod
    • elasticsearch.collectord.io/volume.{N}-logs-index - target datastream for logs forwarded from the volume
    • elasticsearch.collectord.io/volume.{N}-logs-host - change the host for logs forwarded from the volume
    • elasticsearch.collectord.io/volume.{N}-logs-eventpattern - change the event pattern defining new event for logs forwarded from the volume
    • elasticsearch.collectord.io/volume.{N}-logs-replace.{N}-search - specify the regex search for replace pipe for the logs
    • elasticsearch.collectord.io/volume.{N}-logs-replace.{N}-val - specify the regex replace pattern for replace pipe for the logs
    • elasticsearch.collectord.io/volume.{N}-logs-hashing.{N}-match - the regexp for a matched value
    • elasticsearch.collectord.io/volume.{N}-logs-hashing.{N}-function - hash function (default is sha256, available adler-32,crc-32-ieee,crc-32-castagnoli,crc-32-koopman,crc-64-iso,crc-64-ecma,fnv-1-64,fnv-1a-64,fnv-1-32,fnv-1a-32,fnv-1-128,fnv-1a-128,md5,sha1,sha256,sha384,sha512)
    • elasticsearch.collectord.io/volume.{N}-logs-extraction - specify the fields extraction with the regex the logs
    • elasticsearch.collectord.io/volume.{N}-logs-extractionMessageField - specify the field name for the message (by default first unnamed ground in regexp)
    • elasticsearch.collectord.io/volume.{N}-logs-timestampfield - specify the timestamp field
    • elasticsearch.collectord.io/volume.{N}-logs-timestampformat - specify the format for timestamp field
    • elasticsearch.collectord.io/volume.{N}-logs-timestampsetmonth - define if month should be set to current for timestamp
    • elasticsearch.collectord.io/volume.{N}-logs-timestampsetday - define if day should be set to current for timestamp
    • elasticsearch.collectord.io/volume.{N}-logs-timestamplocation - define timestamp location if not set by format
    • elasticsearch.collectord.io/volume.{N}-logs-glob - set the glob pattern for matching logs
    • elasticsearch.collectord.io/volume.{N}-logs-match - set the regexp pattern for matching logs
    • elasticsearch.collectord.io/volume.{N}-logs-recursive - set if walker should walk the directory recursive
    • elasticsearch.collectord.io/volume.{N}-logs-override.{N}-match - match for override pattern
    • elasticsearch.collectord.io/volume.{N}-logs-override.{N}-index - override datastream for matched events
    • elasticsearch.collectord.io/volume.{N}-logs-sampling-percent - specify the % value of logs that should be forwarded to ElasticSearch
    • elasticsearch.collectord.io/volume.{N}-logs-sampling-key - regexp pattern to specify the key for the sampling based on hash values
    • elasticsearch.collectord.io/volume.{N}-logs-ThruputPerSecond - set the thruput for this container, maximum number of logs per second, for example 128Kb, 1024b
    • elasticsearch.collectord.io/volume.{N}-logs-TooOldEvents - duration of events from now to past that are considered too old and should be ignored, for example 168h, 24h
    • elasticsearch.collectord.io/volume.{N}-logs-TooNewEvents - duration of events from now to the future that are considered too new and should be ignored, for example 1h, 30m
    • elasticsearch.collectord.io/volume.{N}-logs-whitelist - allow configuring pattern for log messages, only log messages matching this pattern will be forwarded to ElasticSearch
    • elasticsearch.collectord.io/volume.{N}-logs-userfields.{fieldname} - attach custom fields to events
    • elasticsearch.collectord.io/volume.{N}-logs-maxholdafterclose - how long Collectord can hold file descriptors open for files in PVC after pod is terminated (duration 5s, 1800s)
    • elasticsearch.collectord.io/volume.{N}-logs-onvolumedatabase - boolean flag to enable on a volume database for this volume, in case if this volume might be used on more than one host
  • Installation
    • Forwarding container logs, application logs, host logs and audit logs
    • Test our solution with the embedded 30-days evaluation license.
  • Collectord Configuration
    • Collectord configuration reference for Kubernetes and OpenShift clusters.
  • Annotations
    • Changing a type and format of messages forwarded from namespaces, workloads and pods.
    • Forwarding application logs.
    • Multi-line container logs.
    • Fields extraction for application and container logs (including timestamp extractions).
    • Hiding sensitive data, stripping terminal escape codes and colors.
  • Troubleshooting
  • FAQ and the common questions
  • License agreement
  • Pricing
  • Contact

About Outcold Solutions

Outcold Solutions provides solutions for monitoring Kubernetes, OpenShift and Docker clusters in Splunk Enterprise and Splunk Cloud. We offer certified Splunk applications, which give you insights across all containers environments. We are helping businesses reduce complexity related to logging and monitoring by providing easy-to-use and deploy solutions for Linux and Windows containers. We deliver applications, which help developers monitor their applications and operators to keep their clusters healthy. With the power of Splunk Enterprise and Splunk Cloud, we offer one solution to help you keep all the metrics and logs in one place, allowing you to quickly address complex questions on container performance.