AWS Metadata

The AWS Filter enriches logs with AWS Metadata. The plugin adds the EC2 instance ID and availability zone to log records. To use this plugin, you must be running in EC2 and have the instance metadata service enabled.

Configuration parameters

The plugin supports the following configuration parameters:

Key	Description	Default
imds_version	Specify which version of the instance metadata service to use. Valid values are v1 and v2.	v2
az	The availability zone, such as us-east-1a.	true
ec2_instance_id	The EC2 instance ID.	true
ec2_instance_type	The EC2 instance type.	false
private_ip	The EC2 instance private IP.	false
ami_id	The EC2 instance image ID.	false
account_id	The account ID for the current EC2 instance.	false
hostname	The hostname for the current EC2 instance.	false
vpc_id	The VPC ID for the current EC2 instance.	false
tags_enabled	Specifies whether to attach EC2 instance tags. The EC2 instance must have the instance-metadata-tags option enabled, which is disabled by default.	false
tags_include	Defines a list of specific EC2 tag keys to inject into the logs. Tag keys must be comma-separated (,). Tags not included in this list will be ignored. Example: Name,tag1,tag2.	none
tags_exclude	Defines a list of specific EC2 tag keys not to inject into the logs. Tag keys must be comma-separated (,). Tags not included in this list will be injected into the logs. If both tags_include and tags_exclude are specified, the configuration is invalid and the plugin fails. Example: Name,tag1,tag2	none
retry_interval_s	Defines minimum duration between retries for fetching EC2 instance tags.	300

If you run Fluent Bit in a container, you might need to use instance metadata v1. The plugin behaves the same regardless of which version is used.

Command line

Run Fluent Bit from the command line:

bin/fluent-bit -c /PATH_TO_CONF_FILE/fluent-bit.conf

You should see results like this:

[2020/01/17 07:57:17] [ info] [engine] started (pid=32744)
[0] dummy: [1579247838.000171227, {"message"=>"dummy", "az"=>"us-west-2c", "ec2_instance_id"=>"i-0c862eca9038f5aae", "ec2_instance_type"=>"t2.medium", "private_ip"=>"172.31.6.59", "vpc_id"=>"vpc-7ea11c06", "ami_id"=>"ami-0841edc20334f9287", "account_id"=>"YOUR_ACCOUNT_ID", "hostname"=>"ip-172-31-6-59.us-west-2.compute.internal"}]
[0] dummy: [1601274509.970235760, {"message"=>"dummy", "az"=>"us-west-2c", "ec2_instance_id"=>"i-0c862eca9038f5aae", "ec2_instance_type"=>"t2.medium", "private_ip"=>"172.31.6.59", "vpc_id"=>"vpc-7ea11c06", "ami_id"=>"ami-0841edc20334f9287", "account_id"=>"YOUR_ACCOUNT_ID", "hostname"=>"ip-172-31-6-59.us-west-2.compute.internal"}]

Configuration file

The following is an example of a configuration file:

[INPUT]
    Name dummy
    Tag dummy

[FILTER]
    Name aws
    Match *
    imds_version v1
    az true
    ec2_instance_id true
    ec2_instance_type true
    private_ip true
    ami_id true
    account_id true
    hostname true
    vpc_id true
    tags_enabled true

[OUTPUT]
    Name stdout
    Match *

EC2 tags

EC2 Tags let you label and organize your EC2 instances by creating custom-defined key-value pairs. These tags are commonly used for resource management, cost allocation, and automation. Including them in the Fluent Bit-generated logs is almost essential.

To achieve this, AWS Filter can be configured with tags_enabled true to enable the tagging of logs with the relevant EC2 instance tags. This setup ensures that logs are appropriately tagged, making it easier to manage and analyze them based on specific criteria.

Requirements

To use the tags_enabled true feature in Fluent Bit, the instance-metadata-tags option must be enabled on the EC2 instance where Fluent Bit is running. Without this option enabled, Fluent Bit won't be able to retrieve the tags associated with the EC2 instance. However, this doesn't mean that Fluent Bit will fail or stop working altogether. Instead, if instance-metadata-tags option isn't enabled, Fluent Bit will continue to operate normally and capture other values, such as the EC2 instance ID or availability zone, based on its configuration.

Example

tags_include

Assume the EC2 instance has many tags, some of which have lengthy values that are irrelevant to the logs you want to collect. Only two tags, department and project, are valuable for your purpose. The following configuration reflects this requirement:

[FILTER]
    Name aws
    Match *
    tags_enabled true
    tags_include department,project

If you run Fluent Bit logs might look like the following:

{"log"=>"fluentbit is awesome", "az"=>"us-east-1a", "ec2_instance_id"=>"i-0e66fc7f9809d7168", "department"=>"it", "project"=>"fluentbit"}

tags_exclude

Suppose the EC2 instance has three tags: Name:fluent-bit-docs-example, project:fluentbit, and department:it. In this example, the department tag is redundant and will be excluded. All of the projects belong to the it department, and you don't want to waste storage space on redundant labels.

Here is an example configuration that achieves this:

[FILTER]
    Name aws
    Match *
    tags_enabled true
    tags_exclude department

The resulting logs might look like this:

{"log"=>"aws is awesome", "az"=>"us-east-1a", "ec2_instance_id"=>"i-0e66fc7f9809d7168", "Name"=>"fluent-bit-docs-example", "project"=>"fluentbit"}