Configure CloudWatch Log inputs for the Splunk Add-on for AWS

Complete the steps to configure CloudWatch Log inputs for the Splunk Add-on for Amazon Web Services (AWS):

1. You must manage accounts for the add-on as a prerequisite. See Manage accounts for the Splunk Add-on for AWS.
2. Configure AWS services for the CloudWatch Log input.
3. Configure AWS permissions for the CloudWatch Log input. You can skip this step and configure AWS permissions at once, if you prefer. See Configure AWS permissions for all Splunk Add-on for AWS inputs at once.
4. Configure CloudWatch Log inputs either through Splunk Web or configuration files.

Due to rate limitations, don't use the Splunk Add-on for AWS to collect CloudWatch Log data which has the source type aws:cloudwatchlogs:*. Instead, use the Splunk Add-on for Amazon Kinesis Firehose to collect CloudWatch Log and VPC Flow Logs. The Spunk Add-on for Amazon Kinesis Firehose includes index-time logic to perform the correct knowledge extraction for these events through the Kinesis input as well.

Configure AWS permissions for the CloudWatch Log input

Required permissions for Logs:

• DescribeLogGroups
• DescribeLogStreams
• GetLogEvents

See the following sample inline policy to configure CloudWatch Log input permissions:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Action": [
        "logs:DescribeLogGroups",
        "logs:DescribeLogStreams",
        "logs:GetLogEvents"
      ],
      "Effect": "Allow",
      "Resource": "*"
    }
  ]
}   

You must also ensure that your role has a trust relationship that allows the flow logs service to assume the role. While viewing the IAM role, choose Edit Trust Relationship and replace that policy with this one:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Principal": {
        "Service": "vpc-flow-logs.amazonaws.com"
      },
      "Action": "sts:AssumeRole"
    }
  ]
} 

Configure a CloudWatch Logs input using Splunk Web

To configure inputs using Splunk Web, click Splunk Add-on for AWS in the navigation bar on Splunk Web home, then choose one of the following menu paths depending on the data type you want to collect:

• Create New Input > VPC Flow Logs > CloudWatch Logs
• Create New Input > Others > CloudWatch Logs

Fill out the fields as described in the table:

Argument in configuration file	Field in Splunk Web	Description
account	AWS Account	The AWS account or EC2 IAM role the Splunk platform uses to access your CloudWatch Logs data. In Splunk Web, select an account from the drop-down list. In aws_cloudwatch_logs_tasks.conf, enter the friendly name of one of the AWS accounts that you configured on the Configuration page or the name of the automatically discovered EC2 IAM role.
region	AWS Region	The AWS region that contains the data. In aws_cloudwatch_logs_tasks.conf, enter the region ID.
groups	Log group	A comma-separated list of log group names. Do not use wildcards.
only_after	Only After	GMT time string in '%Y-%m-%dT%H:%M:%S' format. If set, only events after this time are queried and indexed. Defaults to 1970-01-01T00:00:00.
stream_matcher	Stream Matching Regex	REGEX to strictly match stream names. Defaults to .*
interval	Interval	The number of seconds to wait before the Splunk platform runs the command again. The default is 600 seconds.
sourcetype	Source type	A source type for the events. Enter aws:cloudwatchlogs:vpcflow if you are indexing VPC Flow Log data. Enter aws:cloudwatchlogs if you are collecting any other CloudWatch Logs data.
index	Index	The index name where the Splunk platform puts the CloudWatch Logs data. The default is main.

Configure a CloudWatch Logs input using configuration files

To configure the input using configuration files, create $SPLUNK_HOME/etc/apps/Splunk_TA_aws/local/aws_cloudwatch_logs_tasks.conf using the following template:

[<name>]
account = <value>
groups = <value>
index = <value>
interval = <value>
only_after = <value>
region = <value>
sourcetype = <value>
stream_matcher = <value>

Here is an example stanza that collects VPC Flow Log data from two log groups:

[splunkapp2:us-west-2]
account = splunkapp2
groups = SomeName/DefaultLogGroup, SomeOtherName/SomeOtherLogGroup
index = default
interval = 600
only_after = 1970-01-01T00:00:00
region = us-west-2
sourcetype = aws:cloudwatchlogs:vpcflow
stream_matcher = eni.*