Mackerel is a server monitoring service that also supports AWS cloud products. Using the CloudWatch (an AWS monitoring service) API, various AWS cloud products (such as ELB, RDS, and ElastiCache) can be monitored with Mackerel. The only required configurations for Mackerel are registering the read-only access key and making a simple selection. In this post I'll show how to configure mackerel to monitor ELB and RDS. 

IAM User Creation

We need an AWS IAM user with the following policy.

• CloudWatchReadOnlyAccess

You can create the user from AWS Console or AWS CLI.

From AWS Console

• Login to the AWS IAM console and go to the Users section. 
• Select Add user. 
• Fill out the form.
  • Input an username for Mackerel-agent. e.g- mackerel-agent.
  • Select AWS access type- Programmatic access.
• Select Next: Permissions to go to the next page. 
• Attach the policies for the user
  • Select Attach existing policies directly underneath Set permissions for YOUR-USERNAME
  • Search for CloudWatchReadOnly on the filter section.
  • Check CloudWatchReadOnlyAccess
• Select Next: Review to go to the next page. 
• Select Create user
• You’ll get a success message. 
• Select Download .csv to downlod the user credentials and don’t lose it. Alternatively, you can copy the Access key IDand Secret access key which we’ll use in next.

From AWS CLI

$ USER=mackerel-agent
# Create IAM User
$ aws iam create-user --user-name $USER
{
    "User": {
        "UserName": "mackerel-agent",
        "Path": "/",
        "CreateDate": "2018-01-15T10:04:13.381Z",
        "UserId": "XXXXXXXXXXXXXXXXXXXXX",
        "Arn": "arn:aws:iam::999999999999:user/mackerel-agent"
    }
}
# Attach Access Policy
$ aws iam attach-user-policy --user-name $USER --policy-arn arn:aws:iam::aws:policy/CloudWatchReadOnlyAccess
# Generate AccessKey
$ aws iam create-access-key --user-name $USER
{
    "AccessKey": {
        "UserName": "mackerel-agent",
        "Status": "Active",
        "CreateDate": "2018-01-15T10:06:33.644Z",
        "SecretAccessKey": "YYYYYYYYYYYYYYYYYYYYYYYYYYYY/zzzzzzzzzzz",
        "AccessKeyId": "WWWWWWWWWWWWWWWWWWWW"
    }
}

Mackerel plugins configuration

I’m writing the commands as Amazon Linux. The commands may be different based on operating system.

• Install mackerel-plugins with the following command.

  sudo yum install mackerel-plugins
  

ELB

• Open config file and enable plugin

  sudo vi /etc/mackerel-agent/mackerel-agent.conf    
  

• Add the following code on the config file.

  # /etc/mackerel-agent/mackerel-agent.conf
  # mackerel-plugin-aws-elb [-lbname=] [-region=] [-access-key-id=] [-secret-access-key=] [-tempfile=]
  [plugin.metrics.aws-elb]
  command = "/usr/local/bin/mackerel-plugin-aws-elb -lbname=ELB_NAME -region=REGION -access-key-id=AWS_ACCESS_KEY_ID -secret-access-key=AWS_SECRET_ACCESS_KEY"
  

• Restart mackerel

  sudo service mackerel-agent restart
  

RDS

• Open config file and enable plugin

  sudo vi /etc/mackerel-agent/mackerel-agent.conf    
  

• Add the following code on the config file.

  # /etc/mackerel-agent/mackerel-agent.conf
  # mackerel-plugin-aws-rds -identifier= [-region=] [-access-key-id=] [-secret-access-key=] [-tempfile=] [-metric-key-prefix=] [-metric-label-prefix=]
  [plugin.metrics.aws-rds]
  command = "/usr/local/bin/mackerel-plugin-aws-rds -identifier=DBIDENTIFIER -region=REGION -access-key-id=AWS_ACCESS_KEY_ID -secret-access-key=AWS_SECRET_ACCESS_KEY"
  

• Restart mackerel

  sudo service mackerel-agent restart