タダです.

CloudWatch Agent は EC2 から CPU,メモリなどのメトリクスをとったり,CloudWatch Logs にログを出力できますし,AWS Compute Optimizer を有効活用するためにも役立てることができます.今回は,procstat プラグインを使って Nginx のプロセス監視できるように CloudWatch メトリクスに送る検証をしました.多くの方が CloudWatch Agent でのプロセス監視設定を記事にされているのですが,自分も試してみたため記事にします.

CloudWatch Agent の導入

予め CloudWatchAgentServerPolicy をアタッチした IAM ロールを適用した Amazon Linux 2 の環境に CloudWatch Agent を導入します.

sudo yum install amazon-cloudwatch-agent

プロセス数を設定ファイルを編集する

手動で設定ファイルを定義し,CloudWatch メトリクスをおくります.

docs.aws.amazon.com

/opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.jsonを編集してきます.

{
    "metrics": {
        "metrics_collected": {
            "procstat": [
                {
                    "exe": "nginx",
                    "measurement": [
                        "pid_count"
                    ],
                    "metrics_collection_interval": 60
                }
            ]
        }
    }
}

編集後,CloudWatch Agent に設定ファイルを読み込ませます./opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.toml に inputs.procstat セクションが追加されていて,CloudWatch Agent が起動できていれば CloudWatch メトリクスに送れているはずなので確認してきます.

$ sudo /opt/aws/amazon-cloudwatch-agent/bin/amazon-cloudwatch-agent-ctl  -a fetch-config -m ec2 -c file:/opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.json -s

/opt/aws/amazon-cloudwatch-agent/bin/config-downloader --output-dir /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.d --download-source file:/opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.json --mode ec2 --config /opt/aws/amazon-cloudwatch-agent/etc/common-config.toml --multi-config default
Successfully fetched the config and saved in /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.d/file_amazon-cloudwatch-agent.json.tmp
Start configuration validation...
/opt/aws/amazon-cloudwatch-agent/bin/config-translator --input /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.json --input-dir /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.d --output /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.toml --mode ec2 --config /opt/aws/amazon-cloudwatch-agent/etc/common-config.toml --multi-config default
2020/11/26 23:02:31 Reading json config file path: /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.d/file_amazon-cloudwatch-agent.json.tmp ...
Valid Json input schema.
I! Detecting runasuser...
No csm configuration found.
No log configuration found.
Configuration validation first phase succeeded
/opt/aws/amazon-cloudwatch-agent/bin/amazon-cloudwatch-agent -schematest -config /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.toml
Configuration validation second phase succeeded
Configuration validation succeeded
Redirecting to /bin/systemctl stop amazon-cloudwatch-agent.service
Redirecting to /bin/systemctl restart amazon-cloudwatch-agent.service
$ cat /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.toml
~中略~
[inputs]

  [[inputs.procstat]]
    exe = "nginx"
    fieldpass = ["pid_count"]
    interval = "60s"
    pid_finder = "native"
    tagexclude = ["user", "result"]
    [inputs.procstat.tags]
      metricPath = "metrics"
~中略~
$ sudo /opt/aws/amazon-cloudwatch-agent/bin/amazon-cloudwatch-agent-ctl -m ec2 -a status
{
  "status": "running",
  "starttime": "2020-11-26T23:02:31+0000",
  "version": "1.247345.35"
}