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Elastic Docs ›Filebeat Reference [8.17] ›Configure Filebeat ›Configure inputs

Journald input

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Journald input

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This functionality is in technical preview and may be changed or removed in a future release. Elastic will work to fix any issues, but features in technical preview are not subject to the support SLA of official GA features.

journald is a system service that collects and stores logging data. The journald input reads this log data and the metadata associated with it. To read this log data Filebeat calls journalctl to read from the journal, therefore Filebeat needs permission to execute journalctl.

If the journalctl process exits unexpectedly the journald input will terminate with an error and Filebeat will need to be restarted to start reading from the jouranl again.

The simplest configuration example is one that reads all logs from the default journal.

filebeat.inputs:
- type: journald
  id: everything

You may wish to have separate inputs for each service. You can use include_matches to specify filtering expressions. A good way to list the journald fields that are available for filtering messages is to run journalctl -o json to output logs and metadata as JSON. This example collects logs from the vault.service systemd unit.

filebeat.inputs:
- type: journald
  id: service-vault
  include_matches.match:
    - _SYSTEMD_UNIT=vault.service

This example collects kernel logs where the message begins with iptables. Note that include_matches is more efficient than Beat processors because that are applied before the data is passed to the Filebeat so prefer them where possible.

filebeat.inputs:
- type: journald
  id: iptables
  include_matches.match:
    - _TRANSPORT=kernel
  processors:
    - drop_event:
        when.not.regexp.message: '^iptables'

Each example adds the id for the input to ensure the cursor is persisted to the registry with a unique ID. The ID should be unique among journald inputs. If you don’t specify and id then one is created for you by hashing the configuration. So when you modify the config this will result in a new ID and a fresh cursor.

Configuration options

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The journald input supports the following configuration options plus the Common options described later.

id

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An unique identifier for the input. By providing a unique id you can operate multiple inputs on the same journal. This allows each input’s cursor to be persisted independently in the registry file. Each journald input must have an unique ID.

filebeat.inputs:
- type: journald
  id: consul.service
  include_matches.match:
    - _SYSTEMD_UNIT=consul.service

- type: journald
  id: vault.service
  include_matches.match:
    - _SYSTEMD_UNIT=vault.service

paths

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A list of paths that will be crawled and fetched. Each path can be a directory path (to collect events from all journals in a directory), or a file path. If you specify a directory, Filebeat merges all journals under the directory into a single journal and reads them.

If no paths are specified, Filebeat reads from the default journal.

seek

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The position to start reading the journal from. Valid settings are:

  • head: Starts reading at the beginning of the journal. After a restart, Filebeat resends all log messages in the journal.
  • tail: Starts reading at the end of the journal. This means that no events will be sent until a new message is written.
  • since: Use the since option to determine where to start reading from.

Regardless of the value of seek if Filebeat has a state (cursor) for this input, the seek value is ignored and the current cursor is used. To reset the cursor, just change the id of the input, this will start from a fresh state.

since

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A time offset from the current time to start reading from. To use since, seek option must be set to since.

This example demonstrates how to resume from the persisted cursor when it exists, or otherwise begin reading logs from the last 24 hours.

seek: since
since: -24h

units

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Iterate only the entries of the units specified in this option. The iterated entries include messages from the units, messages about the units by authorized daemons and coredumps. However, it does not match systemd user units.

syslog_identifiers

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Read only the entries with the selected syslog identifiers.

transports

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Collect the messages using the specified transports. Example: syslog.

Valid transports:

  • audit: messages from the kernel audit subsystem
  • driver: internally generated messages
  • syslog: messages received via the local syslog socket with the syslog protocol
  • journal: messages received via the native journal protocol
  • stdout: messages from a service’s standard output or error output
  • kernel: messages from the kernel

facilities

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Filter entries by facilities, facilities must be specified using their numeric code.

include_matches

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A collection of filter expressions used to match fields. The format of the expression is field=value. Filebeat fetches all events that exactly match the expressions. Pattern matching is not supported.

If you configured a filter expression, only entries with this field set will be iterated by the journald reader of Filebeat. If the filter expressions apply to different fields, only entries with all fields set will be iterated. If they apply to the same fields, only entries where the field takes one of the specified values will be iterated.

match: List of filter expressions to match fields.

Please note that these expressions are limited. You can build complex filtering, but full logical expressions are not supported.

The following include matches configuration will ingest entries that contain journald.process.name: systemd and systemd.transport: syslog.

include_matches:
  match:
    - "journald.process.name=systemd"
    - "systemd.transport=syslog"

The following include matches configuration will ingest entries that contain systemd.transport: systemd or systemd.transport: kernel.

include_matches:
  match:
    - "systemd.transport=kernel"
    - "systemd.transport=syslog"

To reference fields, use one of the following:

  • The field name used by the systemd journal. For example, CONTAINER_TAG=redis.
  • The translated field name used by Filebeat. For example, container.image.tag=redis. Filebeat does not translate all fields from the journal. For custom fields, use the name specified in the systemd journal.

Translated field names

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You can use the following translated names in filter expressions to reference journald fields:

Journald field name

Translated name

COREDUMP_UNIT

journald.coredump.unit

COREDUMP_USER_UNIT

journald.coredump.user_unit

OBJECT_AUDIT_LOGINUID

journald.object.audit.login_uid

OBJECT_AUDIT_SESSION

journald.object.audit.session

OBJECT_CMDLINE

journald.object.cmd

OBJECT_COMM

journald.object.name

OBJECT_EXE

journald.object.executable

OBJECT_GID

journald.object.gid

OBJECT_PID

journald.object.pid

OBJECT_SYSTEMD_OWNER_UID

journald.object.systemd.owner_uid

OBJECT_SYSTEMD_SESSION

journald.object.systemd.session

OBJECT_SYSTEMD_UNIT

journald.object.systemd.unit

OBJECT_SYSTEMD_USER_UNIT

journald.object.systemd.user_unit

OBJECT_UID

journald.object.uid

_AUDIT_LOGINUID

process.audit.login_uid

_AUDIT_SESSION

process.audit.session

_BOOT_ID

host.boot_id

_CAP_EFFECTIVE

process.capabilites

_CMDLINE

process.cmd

_CODE_FILE

journald.code.file

_CODE_FUNC

journald.code.func

_CODE_LINE

journald.code.line

_COMM

process.name

_EXE

process.executable

_GID

process.uid

_HOSTNAME

host.name

_KERNEL_DEVICE

journald.kernel.device

_KERNEL_SUBSYSTEM

journald.kernel.subsystem

_MACHINE_ID

host.id

_MESSAGE

message

_PID

process.pid

_PRIORITY

syslog.priority

_SYSLOG_FACILITY

syslog.facility

_SYSLOG_IDENTIFIER

syslog.identifier

_SYSLOG_PID

syslog.pid

_SYSTEMD_CGROUP

systemd.cgroup

_SYSTEMD_INVOCATION_ID

systemd.invocation_id

_SYSTEMD_OWNER_UID

systemd.owner_uid

_SYSTEMD_SESSION

systemd.session

_SYSTEMD_SLICE

systemd.slice

_SYSTEMD_UNIT

systemd.unit

_SYSTEMD_USER_SLICE

systemd.user_slice

_SYSTEMD_USER_UNIT

systemd.user_unit

_TRANSPORT

systemd.transport

_UDEV_DEVLINK

journald.kernel.device_symlinks

_UDEV_DEVNODE

journald.kernel.device_node_path

_UDEV_SYSNAME

journald.kernel.device_name

_UID

process.uid

The following translated fields for Docker are also available:

CONTAINER_ID

container.id_truncated

CONTAINER_ID_FULL

container.id

CONTAINER_NAME

container.name

CONTAINER_PARTIAL_MESSAGE

container.partial

CONTAINER_TAG

container.log.tag

IMAGE_NAME

container.image.name

Common options

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The following configuration options are supported by all inputs.

enabled
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Use the enabled option to enable and disable inputs. By default, enabled is set to true.

tags
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A list of tags that Filebeat includes in the tags field of each published event. Tags make it easy to select specific events in Kibana or apply conditional filtering in Logstash. These tags will be appended to the list of tags specified in the general configuration.

Example:

filebeat.inputs:
- type: journald
  . . .
  tags: ["json"]
fields
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Optional fields that you can specify to add additional information to the output. For example, you might add fields that you can use for filtering log data. Fields can be scalar values, arrays, dictionaries, or any nested combination of these. By default, the fields that you specify here will be grouped under a fields sub-dictionary in the output document. To store the custom fields as top-level fields, set the fields_under_root option to true. If a duplicate field is declared in the general configuration, then its value will be overwritten by the value declared here.

filebeat.inputs:
- type: journald
  . . .
  fields:
    app_id: query_engine_12
fields_under_root
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If this option is set to true, the custom fields are stored as top-level fields in the output document instead of being grouped under a fields sub-dictionary. If the custom field names conflict with other field names added by Filebeat, then the custom fields overwrite the other fields.

processors
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A list of processors to apply to the input data.

See Processors for information about specifying processors in your config.

pipeline
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The ingest pipeline ID to set for the events generated by this input.

The pipeline ID can also be configured in the Elasticsearch output, but this option usually results in simpler configuration files. If the pipeline is configured both in the input and output, the option from the input is used.

keep_null
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If this option is set to true, fields with null values will be published in the output document. By default, keep_null is set to false.

index
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If present, this formatted string overrides the index for events from this input (for elasticsearch outputs), or sets the raw_index field of the event’s metadata (for other outputs). This string can only refer to the agent name and version and the event timestamp; for access to dynamic fields, use output.elasticsearch.index or a processor.

Example value: "%{[agent.name]}-myindex-%{+yyyy.MM.dd}" might expand to "filebeat-myindex-2019.11.01".

publisher_pipeline.disable_host
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By default, all events contain host.name. This option can be set to true to disable the addition of this field to all events. The default value is false.

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