Elastic Logging Plugin configuration options

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Elastic Logging Plugin configuration options

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Use the following options to configure the Elastic Logging Plugin for Docker. You can pass these options with the --log-opt flag when you start a container, or you can set them in the daemon.json file for all containers.

Usage examples

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To set configuration options when you start a container:

docker run --log-driver=elastic/elastic-logging-plugin:8.9.2 \
           --log-opt hosts="https://myhost:9200" \
           --log-opt user="myusername" \
           --log-opt password="mypassword" \
           -it debian:jessie /bin/bash

To set configuration options for all containers in the daemon.json file:

{
  "log-driver" : "elastic/elastic-logging-plugin:8.9.2",
  "log-opts" : {
    "hosts" : "https://myhost:9200",
    "user" : "myusername",
    "password" : "mypassword"
  }
}

For more examples, see Usage examples.

Elastic Cloud options

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Option Description

cloud_id

The Cloud ID found in the Elastic Cloud web console. This ID is used to resolve the Elastic Stack URLs when connecting to Elasticsearch Service on Elastic Cloud.

cloud_auth

The username and password combination for connecting to Elasticsearch Service on Elastic Cloud. The format is "username:password".

Elasticsearch output options

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Option Default Description

hosts

"localhost:9200"

The list of Elasticsearch nodes to connect to. Specify each node as a URL or IP:PORT. For example: http://192.0.2.0, https://myhost:9230 or 192.0.2.0:9300. If no port is specified, the default is 9200.

user

The basic authentication username for connecting to Elasticsearch.

password

The basic authentication password for connecting to Elasticsearch.

index

A format string value that specifies the index to write events to when you’re using daily indices. For example: "dockerlogs-%{+yyyy.MM.dd}".

Advanced:

name

testbeat

A custom value that will be inserted into the document as agent.name. If not set, it will be the hostname of Docker host.

backoff_init

1s

The number of seconds to wait before trying to reconnect to Elasticsearch after a network error. After waiting backoff.init seconds, the Elastic Logging Plugin tries to reconnect. If the attempt fails, the backoff timer is increased exponentially up to backoff.max. After a successful connection, the backoff timer is reset.

backoff_max

60s

The maximum number of seconds to wait before attempting to connect to Elasticsearch after a network error.

api_key

Instead of using usernames and passwords, you can use API keys to secure communication with Elasticsearch.

pipeline

A format string value that specifies the Elasticsearch ingest pipeline to write events to.

timeout

90

The http request timeout in seconds for the Elasticsearch request.

proxy_url

The URL of the proxy to use when connecting to the Elasticsearch servers. The value may be either a complete URL or a host[:port], in which case the http scheme is assumed. If a value is not specified through the configuration file then proxy environment variables are used. See the Go documentation for more information about the environment variables.

Configuring the local log

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This plugin fully supports docker logs, and it maintains a local copy of logs that can be read without a connection to Elasticsearch. The plugin mounts the /var/lib/docker directory on the host to write logs to /var/log/containers on the host. If you want to change the log location on the host, you must change the mount inside the plugin:

  1. Disable the plugin:

    docker plugin disable elastic/elastic-logging-plugin:8.9.2
  2. Set the bindmount directory:

    docker plugin set elastic/elastic-logging-plugin:8.9.2 LOG_DIR.source=NEW_LOG_LOCATION
  3. Enable the plugin:

    docker plugin enable elastic/elastic-logging-plugin:8.9.2

The local log also supports the max-file, max-size and compress options that are a part of the Docker default file logger. For example:

docker run --log-driver=elastic/elastic-logging-plugin:8.9.2 \
           --log-opt hosts="myhost:9200" \
           --log-opt user="myusername" \
           --log-opt password="mypassword" \
           --log-opt max-file=10 \
           --log-opt max-size=5M \
           --log-opt compress=true \
           -it debian:jessie /bin/bash

In situations where logs can’t be easily managed, for example, you can also configure the plugin to remove log files when a container is stopped. This will prevent you from reading logs on a stopped container, but it will rotate logs without user intervention. To enable removal of logs for stopped containers, you must change the DESTROY_LOGS_ON_STOP environment variable:

  1. Disable the plugin:

    docker plugin disable elastic/elastic-logging-plugin:8.9.2
  2. Enable log removal:

    docker plugin set elastic/elastic-logging-plugin:8.9.2 DESTROY_LOGS_ON_STOP=true
  3. Enable the plugin:

    docker plugin enable elastic/elastic-logging-plugin:8.9.2