What's?
Amazon ECSで利用できるログドライバー、AWS FireLensを使用するとAmazon ECSメタデータを付与できるそうです。
こちらの内容を、ちょっと確認してみたいなと思いまして。
AWS FireLensを使った時に付与されるメタデータ
AWS FireLensを使った時に付与されるメタデータは、以下のドキュメントに記載があります。
FireLens 設定を使用するタスク定義の作成 / Amazon ECS メタデータの使用
タスク定義においてAWS FireLensとして使うコンテナのenable-ecs-log-metadata
をtrue
にすると、以下のフィールドをログに付与するとあります。
- ecs_cluster – タスクが所属するクラスターの名前。
- ecs_task_arn – コンテナが所属するタスクの完全な ARN。
- ecs_task_definition – タスクが使用しているタスク定義名とリビジョン。
これが、Amazon ECSのメタデータです、と。
今回は、こちらの内容を実際に見てみたいと思います。
お題
なにはともあれAmazon ECSが必要なので、今回はnginxコンテナを使ったAWS Fargateクラスタを構築したいと思います。
AWS Fargateのタスク定義は、以下の2種類を試すことにします。
- nginxコンテナのみをタスク定義に含め、ログは
awslogs
ログドライバーを使用してAmazon CloudWatch Logsに出力 - nginxコンテナおよびAWS for Fluent Bitコンテナを使い、nginxのログは
firelens
ログドライバーを使用してAmazon CloudWatch Logsに出力
環境は、すべてTerraformで構築するものとします。
環境
今回の環境は、こちらです。
$ terraform version
Terraform v0.14.7
+ provider registry.terraform.io/hashicorp/aws v3.29.0
また、AWSのクレデンシャルは環境変数で設定済みとします。
$ export AWS_ACCESS_KEY_ID=...
$ export AWS_SECRET_ACCESS_KEY=...
$ export AWS_DEFAULT_REGION=ap-northeast-1
AWS Fargateクラスタのリソース定義を行う
それでは、AWS Fargateクラスタを構築していきましょう。
Terraformでデプロイするわけですが、今回は単一のmain.tf
に全部書いていきます。
まずは、TerraformやProviderのバージョン指定。
terraform {
required_version = "0.14.7"
required_providers {
aws = {
source = "hashicorp/aws"
version = "3.29.0"
}
}
}
provider "aws" {
}
VPCやALB等も必要ですが、先にAWS Fargateに関する部分だけを載せて、その他のものは最後にまとめて載せたいと思います。
とはいえ、AWS Fargateを作るにもこれらのリソースに依存する部分はあるので、そのあたりは先にローカル変数にまとめておきます。
locals {
vpc_id = module.vpc.vpc_id
private_subnets = module.vpc.private_subnets
nginx_service_security_groups = [module.nginx_service_sg.this_security_group_id]
load_balancer_target_group_arn = module.load_balancer.target_group_arns[0]
nginx_simple_container_definition = # nginxのみのタスク定義
nginx_with_fluentbit_container_definitions = # nginx+Fluent Bitのコンテナ定義
}
コメントアウトしている部分が、タスク定義で使用するコンテナの定義です。今回は、この2つ定義を切り替えてデプロイしていきたいと思います。
タスク定義に至るまでの部分を載せていきましょう。
タスク用ロールおよびタスク実行用ロール。
data "aws_iam_policy_document" "ecs_assume_role" {
statement {
actions = ["sts:AssumeRole"]
principals {
type = "Service"
identifiers = ["ecs-tasks.amazonaws.com"]
}
}
}
data "aws_iam_policy" "ecs_task_execution_role_policy" {
arn = "arn:aws:iam::aws:policy/service-role/AmazonECSTaskExecutionRolePolicy"
}
resource "aws_iam_role" "ecs_task_execution_role" {
name = "MyEcsTaskExecutionRole"
assume_role_policy = data.aws_iam_policy_document.ecs_assume_role.json
}
resource "aws_iam_role_policy_attachment" "ecs_task_execution_role_policy_attachment" {
role = aws_iam_role.ecs_task_execution_role.name
policy_arn = data.aws_iam_policy.ecs_task_execution_role_policy.arn
}
data "aws_iam_policy_document" "ecs_task_role_policy_document" {
statement {
effect = "Allow"
actions = [
"logs:DescribeLogStreams",
"logs:CreateLogGroup",
"logs:CreateLogStream",
"logs:PutLogEvents"
]
resources = ["*"]
}
}
resource "aws_iam_policy" "ecs_task_role_policy" {
name = "MyEcsTaskPolicy"
policy = data.aws_iam_policy_document.ecs_task_role_policy_document.json
}
resource "aws_iam_role" "ecs_task_role" {
name = "MyEcsTaskRole"
assume_role_policy = data.aws_iam_policy_document.ecs_assume_role.json
}
resource "aws_iam_role_policy_attachment" "ecs_task_role_policy_attachment" {
role = aws_iam_role.ecs_task_role.name
policy_arn = aws_iam_policy.ecs_task_role_policy.arn
}
タスク用ロールには、AWS for Fluent BitがAmazon CloudWatch Logsにログ出力可能なように、あらかじめAmazon CloudWatch Logs関連の権限を与えておきます。
Amazon CloudWatch Logsロググループ。各コンテナのログ出力先ですね。
AWS Fargateのクラスタ定義。
resource "aws_cloudwatch_log_group" "nginx" {
name = "/fargate/containers/nginx"
}
resource "aws_cloudwatch_log_group" "fluentbit" {
name = "/fargate/containers/fluentbit"
}
resource "aws_ecs_cluster" "nginx" {
name = "nginx-cluster"
}
resource "aws_ecs_task_definition" "nginx" {
family = "nginx-task-definition"
cpu = "512"
memory = "1024"
network_mode = "awsvpc"
requires_compatibilities = [
"FARGATE"]
execution_role_arn = aws_iam_role.ecs_task_execution_role.arn
task_role_arn = aws_iam_role.ecs_task_role.arn
container_definitions = local.nginx_simple_container_definition
# container_definitions = local.nginx_with_fluentbit_container_definitions
}
resource "aws_ecs_service" "nginx" {
name = "nginx-service"
cluster = aws_ecs_cluster.nginx.arn
task_definition = aws_ecs_task_definition.nginx.arn
desired_count = 3
launch_type = "FARGATE"
platform_version = "1.4.0"
deployment_minimum_healthy_percent = 50
network_configuration {
assign_public_ip = false
security_groups = local.nginx_service_security_groups
subnets = local.private_subnets
}
load_balancer {
target_group_arn = local.load_balancer_target_group_arn
container_name = "nginx"
container_port = 80
}
}
ここからは、container_definitions
の部分を切り替えていきます。
resource "aws_ecs_task_definition" "nginx" {
family = "nginx-task-definition"
cpu = "512"
memory = "1024"
network_mode = "awsvpc"
requires_compatibilities = [
"FARGATE"]
execution_role_arn = aws_iam_role.ecs_task_execution_role.arn
task_role_arn = aws_iam_role.ecs_task_role.arn
container_definitions = local.nginx_simple_container_definition
# container_definitions = local.nginx_with_fluentbit_container_definitions
}
AWS FireLensなしで構築してみる
最初は、AWS FireLensなしで構築してみましょう。
タスク定義で使うコンテナの定義は、こちらになります。
nginx_simple_container_definition = <<JSON
[
{
"name": "nginx",
"image": "nginx:1.19.7",
"essential": true,
"portMappings": [
{
"protocol": "tcp",
"containerPort": 80
}
],
"logConfiguration": {
"logDriver": "awslogs",
"options": {
"awslogs-group": "${aws_cloudwatch_log_group.nginx.name}",
"awslogs-region": "ap-northeast-1",
"awslogs-stream-prefix": "nginx-log-stream"
}
}
}
]
JSON
至ってシンプルです。ログ出力先はAmazon CloudWatch Logsで、先ほどリソース定義したロググループを指定しています。
では、このコンテナ定義をタスク定義で指定して
resource "aws_ecs_task_definition" "nginx" {
family = "nginx-task-definition"
cpu = "512"
memory = "1024"
network_mode = "awsvpc"
requires_compatibilities = [
"FARGATE"]
execution_role_arn = aws_iam_role.ecs_task_execution_role.arn
task_role_arn = aws_iam_role.ecs_task_role.arn
container_definitions = local.nginx_simple_container_definition
# container_definitions = local.nginx_with_fluentbit_container_definitions
}
apply
。
$ terraform apply
ロググループをtail
して待ち、
$ aws logs tail --follow /fargate/containers/nginx
クラスタが構築されてコンテナが起動したら、curl
でアクセスしてみます
$ curl [ALBのDNS名]
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>
</body>
</html>
出力されるログは、こんな感じです。
※アクセス元のIPアドレスは変えています
2021-02-22T12:47:34.424000+00:00 nginx-log-stream/nginx/df733e0802104d3890ebaad461c8d7cf 10.0.10.209 - - [22/Feb/2021:12:47:34 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.68.0" "aaa.bbb.ccc.ddd"
2021-02-22T12:47:35.754000+00:00 nginx-log-stream/nginx/df733e0802104d3890ebaad461c8d7cf 10.0.10.209 - - [22/Feb/2021:12:47:35 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.68.0" "aaa.bbb.ccc.ddd"
2021-02-22T12:47:37.315000+00:00 nginx-log-stream/nginx/df733e0802104d3890ebaad461c8d7cf 10.0.10.209 - - [22/Feb/2021:12:47:37 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.68.0" "aaa.bbb.ccc.ddd"
2021-02-22T12:47:41.261000+00:00 nginx-log-stream/nginx/163a9d4c115f4951b5cac39ef16fe60e 10.0.10.209 - - [22/Feb/2021:12:47:41 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.68.0" "aaa.bbb.ccc.ddd"
2021-02-22T12:47:43.301000+00:00 nginx-log-stream/nginx/df733e0802104d3890ebaad461c8d7cf 10.0.10.209 - - [22/Feb/2021:12:47:43 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.68.0" "aaa.bbb.ccc.ddd"
2021-02-22T12:47:45.343000+00:00 nginx-log-stream/nginx/df733e0802104d3890ebaad461c8d7cf 10.0.10.209 - - [22/Feb/2021:12:47:45 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.68.0" "aaa.bbb.ccc.ddd"
2021-02-22T12:47:47.377000+00:00 nginx-log-stream/nginx/163a9d4c115f4951b5cac39ef16fe60e 10.0.10.209 - - [22/Feb/2021:12:47:47 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.68.0" "aaa.bbb.ccc.ddd"
2021-02-22T12:47:49.408000+00:00 nginx-log-stream/nginx/df733e0802104d3890ebaad461c8d7cf 10.0.10.209 - - [22/Feb/2021:12:47:49 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.68.0" "aaa.bbb.ccc.ddd"
2021-02-22T12:47:51.435000+00:00 nginx-log-stream/nginx/7b8175f48e1244f1a41912f4af179129 10.0.10.209 - - [22/Feb/2021:12:47:51 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.68.0" "aaa.bbb.ccc.ddd"
2021-02-22T12:47:53.196000+00:00 nginx-log-stream/nginx/df733e0802104d3890ebaad461c8d7cf 10.0.10.209 - - [22/Feb/2021:12:47:53 +0000] "GET / HTTP/1.1" 200 612 "-" "ELB-HealthChecker/2.0" "-"
2021-02-22T12:47:53.196000+00:00 nginx-log-stream/nginx/7b8175f48e1244f1a41912f4af179129 10.0.10.209 - - [22/Feb/2021:12:47:53 +0000] "GET / HTTP/1.1" 200 612 "-" "ELB-HealthChecker/2.0" "-"
2021-02-22T12:47:53.468000+00:00 nginx-log-stream/nginx/163a9d4c115f4951b5cac39ef16fe60e 10.0.10.209 - - [22/Feb/2021:12:47:53 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.68.0" "aaa.bbb.ccc.ddd"
2021-02-22T12:47:55.500000+00:00 nginx-log-stream/nginx/163a9d4c115f4951b5cac39ef16fe60e 10.0.10.209 - - [22/Feb/2021:12:47:55 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.68.0" "aaa.bbb.ccc.ddd"
2021-02-22T12:47:57.541000+00:00 nginx-log-stream/nginx/7b8175f48e1244f1a41912f4af179129 10.0.10.209 - - [22/Feb/2021:12:47:57 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.68.0" "aaa.bbb.ccc.ddd"
ログとして記録されている値だけを抜粋すると、こんな感じですね。
10.0.10.209 - - [22/Feb/2021:12:47:34 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.68.0" "aaa.bbb.ccc.ddd"
ログの形式は確認できたので、リソースを破棄します。
$ terraform destroy
AWS FireLens経由でログ出力する
続いて、AWS FireLens経由でログ出力しましょう。
AWS Fargateのタスク定義は、以下のようになります。
resource "aws_ecs_task_definition" "nginx" {
family = "nginx-task-definition"
cpu = "512"
memory = "1024"
network_mode = "awsvpc"
requires_compatibilities = [
"FARGATE"]
execution_role_arn = aws_iam_role.ecs_task_execution_role.arn
task_role_arn = aws_iam_role.ecs_task_role.arn
# container_definitions = local.nginx_simple_container_definition
container_definitions = local.nginx_with_fluentbit_container_definitions
}
参照する実際のcontainer_definitions
の定義(コンテナ定義)ですが、Amazon ECSメタデータを付与する/しない設定ができるので、その両方で確認してみましょう。
Amazon ECSメタデータ付与あり
Amazon ECSのメタデータを付与する場合のコンテナ定義です。AWS for Fluent Bitと、nginxの2つのコンテナ定義があります。
nginx_with_fluentbit_container_definitions = <<JSON
[
{
"name": "log_router",
"image": "906394416424.dkr.ecr.ap-northeast-1.amazonaws.com/aws-for-fluent-bit:2.10.1",
"essential": true,
"firelensConfiguration": {
"type": "fluentbit",
"options":{
"enable-ecs-log-metadata": "true"
}
},
"logConfiguration": {
"logDriver": "awslogs",
"options": {
"awslogs-group": "${aws_cloudwatch_log_group.fluentbit.name}",
"awslogs-region": "ap-northeast-1",
"awslogs-stream-prefix": "fluentbit-log-stream"
}
}
},
{
"name": "nginx",
"image": "nginx:1.19.7",
"essential": true,
"portMappings": [
{
"protocol": "tcp",
"containerPort": 80
}
],
"logConfiguration": {
"logDriver": "awsfirelens",
"options": {
"Name": "cloudwatch",
"region": "ap-northeast-1",
"log_group_name": "${aws_cloudwatch_log_group.nginx.name}",
"log_stream_prefix": "nginx-log-stream-",
"auto_create_group": "false"
}
}
}
]
JSON
firelensConfiguration
のオプション設定として、enable-ecs-log-metadata
をtrue
に設定しています。これでAWS FireLens経由で出力するログにAmazon ECSのメタデータを付与することができるわけですが、これはデフォルトの設定です。
"firelensConfiguration": {
"type": "fluentbit",
"options":{
"enable-ecs-log-metadata": "true"
}
},
なので、以下のようにしても同義ですね。
"firelensConfiguration": {
"type": "fluentbit"
},
この状態でapply
して
$ terraform apply
先ほどと同様、ロググループをtail
しつつリソースの構築後にcurl
でアクセスしてみます。
$ aws logs tail --follow /fargate/containers/nginx
得られたログはこちらです。
2021-02-22T13:01:17.712000+00:00 nginx-log-stream-nginx-firelens-d90128b0816e4a38b34888f721bf60fb {"container_id":"d90128b0816e4a38b34888f721bf60fb-2531612879","container_name":"nginx","ecs_cluster":"nginx-cluster","ecs_task_arn":"arn:aws:ecs:ap-northeast-1:[AWSアカウントID]:task/nginx-cluster/d90128b0816e4a38b34888f721bf60fb","ecs_task_definition":"nginx-task-definition:8","log":"10.0.10.190 - - [22/Feb/2021:13:01:17 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"curl/7.68.0\" \"aaa.bbb.ccc.ddd\"","source":"stdout"}
2021-02-22T13:01:19.759000+00:00 nginx-log-stream-nginx-firelens-d90128b0816e4a38b34888f721bf60fb {"container_id":"d90128b0816e4a38b34888f721bf60fb-2531612879","container_name":"nginx","ecs_cluster":"nginx-cluster","ecs_task_arn":"arn:aws:ecs:ap-northeast-1:[AWSアカウントID]:task/nginx-cluster/d90128b0816e4a38b34888f721bf60fb","ecs_task_definition":"nginx-task-definition:8","log":"10.0.10.190 - - [22/Feb/2021:13:01:19 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"curl/7.68.0\" \"aaa.bbb.ccc.ddd\"","source":"stdout"}
2021-02-22T13:01:20.292000+00:00 nginx-log-stream-nginx-firelens-d90128b0816e4a38b34888f721bf60fb {"container_id":"d90128b0816e4a38b34888f721bf60fb-2531612879","container_name":"nginx","ecs_cluster":"nginx-cluster","ecs_task_arn":"arn:aws:ecs:ap-northeast-1:[AWSアカウントID]:task/nginx-cluster/d90128b0816e4a38b34888f721bf60fb","ecs_task_definition":"nginx-task-definition:8","log":"10.0.10.190 - - [22/Feb/2021:13:01:20 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"ELB-HealthChecker/2.0\" \"-\"","source":"stdout"}
2021-02-22T13:01:21.790000+00:00 nginx-log-stream-nginx-firelens-e07924a4952c4e36844603a88819b4ce {"container_id":"e07924a4952c4e36844603a88819b4ce-2531612879","container_name":"nginx","ecs_cluster":"nginx-cluster","ecs_task_arn":"arn:aws:ecs:ap-northeast-1:[AWSアカウントID]:task/nginx-cluster/e07924a4952c4e36844603a88819b4ce","ecs_task_definition":"nginx-task-definition:8","log":"10.0.10.190 - - [22/Feb/2021:13:01:21 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"curl/7.68.0\" \"aaa.bbb.ccc.ddd\"","source":"stdout"}
2021-02-22T13:01:23.825000+00:00 nginx-log-stream-nginx-firelens-d90128b0816e4a38b34888f721bf60fb {"container_id":"d90128b0816e4a38b34888f721bf60fb-2531612879","container_name":"nginx","ecs_cluster":"nginx-cluster","ecs_task_arn":"arn:aws:ecs:ap-northeast-1:[AWSアカウントID]:task/nginx-cluster/d90128b0816e4a38b34888f721bf60fb","ecs_task_definition":"nginx-task-definition:8","log":"10.0.10.190 - - [22/Feb/2021:13:01:23 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"curl/7.68.0\" \"aaa.bbb.ccc.ddd\"","source":"stdout"}
2021-02-22T13:01:25.862000+00:00 nginx-log-stream-nginx-firelens-d90128b0816e4a38b34888f721bf60fb {"container_id":"d90128b0816e4a38b34888f721bf60fb-2531612879","container_name":"nginx","ecs_cluster":"nginx-cluster","ecs_task_arn":"arn:aws:ecs:ap-northeast-1:[AWSアカウントID]:task/nginx-cluster/d90128b0816e4a38b34888f721bf60fb","ecs_task_definition":"nginx-task-definition:8","log":"10.0.10.190 - - [22/Feb/2021:13:01:25 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"curl/7.68.0\" \"aaa.bbb.ccc.ddd\"","source":"stdout"}
2021-02-22T13:01:27.899000+00:00 nginx-log-stream-nginx-firelens-d90128b0816e4a38b34888f721bf60fb {"container_id":"d90128b0816e4a38b34888f721bf60fb-2531612879","container_name":"nginx","ecs_cluster":"nginx-cluster","ecs_task_arn":"arn:aws:ecs:ap-northeast-1:[AWSアカウントID]:task/nginx-cluster/d90128b0816e4a38b34888f721bf60fb","ecs_task_definition":"nginx-task-definition:8","log":"10.0.10.190 - - [22/Feb/2021:13:01:27 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"curl/7.68.0\" \"aaa.bbb.ccc.ddd\"","source":"stdout"}
2021-02-22T13:01:29.937000+00:00 nginx-log-stream-nginx-firelens-e07924a4952c4e36844603a88819b4ce {"container_id":"e07924a4952c4e36844603a88819b4ce-2531612879","container_name":"nginx","ecs_cluster":"nginx-cluster","ecs_task_arn":"arn:aws:ecs:ap-northeast-1:[AWSアカウントID]:task/nginx-cluster/e07924a4952c4e36844603a88819b4ce","ecs_task_definition":"nginx-task-definition:8","log":"10.0.10.190 - - [22/Feb/2021:13:01:29 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"curl/7.68.0\" \"aaa.bbb.ccc.ddd\"","source":"stdout"}
2021-02-22T13:01:31.975000+00:00 nginx-log-stream-nginx-firelens-e07924a4952c4e36844603a88819b4ce {"container_id":"e07924a4952c4e36844603a88819b4ce-2531612879","container_name":"nginx","ecs_cluster":"nginx-cluster","ecs_task_arn":"arn:aws:ecs:ap-northeast-1:[AWSアカウントID]:task/nginx-cluster/e07924a4952c4e36844603a88819b4ce","ecs_task_definition":"nginx-task-definition:8","log":"10.0.10.190 - - [22/Feb/2021:13:01:31 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"curl/7.68.0\" \"aaa.bbb.ccc.ddd\"","source":"stdout"}
2021-02-22T13:01:34.013000+00:00 nginx-log-stream-nginx-firelens-d6bcefeb9a014f17bc444b18f2f0d487 {"container_id":"d6bcefeb9a014f17bc444b18f2f0d487-2531612879","container_name":"nginx","ecs_cluster":"nginx-cluster","ecs_task_arn":"arn:aws:ecs:ap-northeast-1:[AWSアカウントID]:task/nginx-cluster/d6bcefeb9a014f17bc444b18f2f0d487","ecs_task_definition":"nginx-task-definition:8","log":"10.0.10.190 - - [22/Feb/2021:13:01:34 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"curl/7.68.0\" \"aaa.bbb.ccc.ddd\"","source":"stdout"}
2021-02-22T13:01:36.049000+00:00 nginx-log-stream-nginx-firelens-e07924a4952c4e36844603a88819b4ce {"container_id":"e07924a4952c4e36844603a88819b4ce-2531612879","container_name":"nginx","ecs_cluster":"nginx-cluster","ecs_task_arn":"arn:aws:ecs:ap-northeast-1:[AWSアカウントID]:task/nginx-cluster/e07924a4952c4e36844603a88819b4ce","ecs_task_definition":"nginx-task-definition:8","log":"10.0.10.190 - - [22/Feb/2021:13:01:36 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"curl/7.68.0\" \"aaa.bbb.ccc.ddd\"","source":"stdout"}
2021-02-22T13:01:38.093000+00:00 nginx-log-stream-nginx-firelens-d6bcefeb9a014f17bc444b18f2f0d487 {"container_id":"d6bcefeb9a014f17bc444b18f2f0d487-2531612879","container_name":"nginx","ecs_cluster":"nginx-cluster","ecs_task_arn":"arn:aws:ecs:ap-northeast-1:[AWSアカウントID]:task/nginx-cluster/d6bcefeb9a014f17bc444b18f2f0d487","ecs_task_definition":"nginx-task-definition:8","log":"10.0.10.190 - - [22/Feb/2021:13:01:38 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"curl/7.68.0\" \"aaa.bbb.ccc.ddd\"","source":"stdout"}
2021-02-22T13:01:40.308000+00:00 nginx-log-stream-nginx-firelens-d6bcefeb9a014f17bc444b18f2f0d487 {"container_id":"d6bcefeb9a014f17bc444b18f2f0d487-2531612879","container_name":"nginx","ecs_cluster":"nginx-cluster","ecs_task_arn":"arn:aws:ecs:ap-northeast-1:[AWSアカウントID]:task/nginx-cluster/d6bcefeb9a014f17bc444b18f2f0d487","ecs_task_definition":"nginx-task-definition:8","log":"10.0.10.190 - - [22/Feb/2021:13:01:40 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"ELB-HealthChecker/2.0\" \"-\"","source":"stdout"}
2021-02-22T13:01:40.313000+00:00 nginx-log-stream-nginx-firelens-d90128b0816e4a38b34888f721bf60fb {"container_id":"d90128b0816e4a38b34888f721bf60fb-2531612879","container_name":"nginx","ecs_cluster":"nginx-cluster","ecs_task_arn":"arn:aws:ecs:ap-northeast-1:[AWSアカウントID]:task/nginx-cluster/d90128b0816e4a38b34888f721bf60fb","ecs_task_definition":"nginx-task-definition:8","log":"10.0.10.190 - - [22/Feb/2021:13:01:40 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"ELB-HealthChecker/2.0\" \"-\"","source":"stdout"}
2021-02-22T13:01:42.168000+00:00 nginx-log-stream-nginx-firelens-d6bcefeb9a014f17bc444b18f2f0d487 {"container_id":"d6bcefeb9a014f17bc444b18f2f0d487-2531612879","container_name":"nginx","ecs_cluster":"nginx-cluster","ecs_task_arn":"arn:aws:ecs:ap-northeast-1:[AWSアカウントID]:task/nginx-cluster/d6bcefeb9a014f17bc444b18f2f0d487","ecs_task_definition":"nginx-task-definition:8","log":"10.0.10.190 - - [22/Feb/2021:13:01:42 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"curl/7.68.0\" \"aaa.bbb.ccc.ddd\"","source":"stdout"}
先ほどとは、ログの形式が変わりましたね。
1行抜き出して、整形してみましょう。
$ echo '{"container_id":"d90128b0816e4a38b34888f721bf60fb-2531612879","container_name":"nginx","ecs_cluster":"nginx-cluster","ecs_task_arn":"arn:aws:ecs:ap-northeast-1:[AWSアカウントID]:task/nginx-cluster/d90128b0816e4a38b34888f721bf60fb","ecs_task_definition":"nginx-task-definition:8","log":"10.0.10.190 - - [22/Feb/2021:13:01:17 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"curl/7.68.0\" \"aaa.bbb.ccc.ddd\"","source":"stdout"}' | jq
{
"container_id": "d90128b0816e4a38b34888f721bf60fb-2531612879",
"container_name": "nginx",
"ecs_cluster": "nginx-cluster",
"ecs_task_arn": "arn:aws:ecs:ap-northeast-1:[AWSアカウントID]:task/nginx-cluster/d90128b0816e4a38b34888f721bf60fb",
"ecs_task_definition": "nginx-task-definition:8",
"log": "10.0.10.190 - - [22/Feb/2021:13:01:17 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"curl/7.68.0\" \"aaa.bbb.ccc.ddd\"",
"source": "stdout"
}
ログがJSON形式になり、container_id
、container_name
、ecs_cluster
、ecs_task_arn
、ecs_task_definition
、source
の6つのフィールドが増えました。
本来のログは、log
フィールドに格納されています。
おや?source
はいいとしても、付与されるフィールドは3つだったのでは?Amazon ECSメタデータの付与もオフにして確認してみましょう。
※ちなみにAWS for Fluent Bit自身のログは、単にawslogs
でAmazon CloudWatch Logsに出力しているだけなのでAWS FireLensと使わない場合と同じになります(よって割愛)
リソースを破棄します。
$ terraform destroy
Amazon ECSメタデータ付与なし
先ほどのコンテナ定義から、Amazon ECSのメタデータを付与しないように変更してみます。
nginx_with_fluentbit_container_definitions = <<JSON
[
{
"name": "log_router",
"image": "906394416424.dkr.ecr.ap-northeast-1.amazonaws.com/aws-for-fluent-bit:2.10.1",
"essential": true,
"firelensConfiguration": {
"type": "fluentbit",
"options":{
"enable-ecs-log-metadata": "false"
}
},
"logConfiguration": {
"logDriver": "awslogs",
"options": {
"awslogs-group": "${aws_cloudwatch_log_group.fluentbit.name}",
"awslogs-region": "ap-northeast-1",
"awslogs-stream-prefix": "fluentbit-log-stream"
}
}
},
{
"name": "nginx",
"image": "nginx:1.19.7",
"essential": true,
"portMappings": [
{
"protocol": "tcp",
"containerPort": 80
}
],
"logConfiguration": {
"logDriver": "awsfirelens",
"options": {
"Name": "cloudwatch",
"region": "ap-northeast-1",
"log_group_name": "${aws_cloudwatch_log_group.nginx.name}",
"log_stream_prefix": "nginx-log-stream-",
"auto_create_group": "false"
}
}
}
]
JSON
変更したのは、
"firelensConfiguration": {
"type": "fluentbit",
"options":{
"enable-ecs-log-metadata": "false"
}
},
この状態でapply
して
$ terraform apply
先ほどと同様、ロググループをtail
しつつリソースの構築後にcurl
でアクセスしてみます。
$ aws logs tail --follow /fargate/containers/nginx
得られたログはこちらです。
2021-02-22T13:39:14.048000+00:00 nginx-log-stream-nginx-firelens-37d9cebd8fbb4d57bd7fa646323e501a {"container_id":"37d9cebd8fbb4d57bd7fa646323e501a-2531612879","container_name":"nginx","log":"10.0.10.227 - - [22/Feb/2021:13:39:14 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"curl/7.68.0\" \"aaa.bbb.ccc.ddd\"","source":"stdout"}
2021-02-22T13:39:16.090000+00:00 nginx-log-stream-nginx-firelens-37d9cebd8fbb4d57bd7fa646323e501a {"container_id":"37d9cebd8fbb4d57bd7fa646323e501a-2531612879","container_name":"nginx","log":"10.0.10.227 - - [22/Feb/2021:13:39:16 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"curl/7.68.0\" \"aaa.bbb.ccc.ddd\"","source":"stdout"}
2021-02-22T13:39:18.137000+00:00 nginx-log-stream-nginx-firelens-37d9cebd8fbb4d57bd7fa646323e501a {"container_id":"37d9cebd8fbb4d57bd7fa646323e501a-2531612879","container_name":"nginx","log":"10.0.10.227 - - [22/Feb/2021:13:39:18 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"curl/7.68.0\" \"aaa.bbb.ccc.ddd\"","source":"stdout"}
2021-02-22T13:39:20.287000+00:00 nginx-log-stream-nginx-firelens-37d9cebd8fbb4d57bd7fa646323e501a {"container_id":"37d9cebd8fbb4d57bd7fa646323e501a-2531612879","container_name":"nginx","log":"10.0.10.227 - - [22/Feb/2021:13:39:20 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"curl/7.68.0\" \"aaa.bbb.ccc.ddd\"","source":"stdout"}
2021-02-22T13:39:22.330000+00:00 nginx-log-stream-nginx-firelens-37d9cebd8fbb4d57bd7fa646323e501a {"container_id":"37d9cebd8fbb4d57bd7fa646323e501a-2531612879","container_name":"nginx","log":"10.0.10.227 - - [22/Feb/2021:13:39:22 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"curl/7.68.0\" \"aaa.bbb.ccc.ddd\"","source":"stdout"}
2021-02-22T13:39:24.369000+00:00 nginx-log-stream-nginx-firelens-9e9a09f1b8924ce3926c7c6653bd3ec1 {"container_id":"9e9a09f1b8924ce3926c7c6653bd3ec1-2531612879","container_name":"nginx","log":"10.0.10.227 - - [22/Feb/2021:13:39:24 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"curl/7.68.0\" \"aaa.bbb.ccc.ddd\"","source":"stdout"}
2021-02-22T13:39:26.408000+00:00 nginx-log-stream-nginx-firelens-37d9cebd8fbb4d57bd7fa646323e501a {"container_id":"37d9cebd8fbb4d57bd7fa646323e501a-2531612879","container_name":"nginx","log":"10.0.10.227 - - [22/Feb/2021:13:39:26 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"curl/7.68.0\" \"aaa.bbb.ccc.ddd\"","source":"stdout"}
2021-02-22T13:39:28.447000+00:00 nginx-log-stream-nginx-firelens-37d9cebd8fbb4d57bd7fa646323e501a {"container_id":"37d9cebd8fbb4d57bd7fa646323e501a-2531612879","container_name":"nginx","log":"10.0.10.227 - - [22/Feb/2021:13:39:28 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"curl/7.68.0\" \"aaa.bbb.ccc.ddd\"","source":"stdout"}
2021-02-22T13:39:28.483000+00:00 nginx-log-stream-nginx-firelens-9e9a09f1b8924ce3926c7c6653bd3ec1 {"container_id":"9e9a09f1b8924ce3926c7c6653bd3ec1-2531612879","container_name":"nginx","log":"10.0.10.227 - - [22/Feb/2021:13:39:28 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"ELB-HealthChecker/2.0\" \"-\"","source":"stdout"}
2021-02-22T13:39:28.485000+00:00 nginx-log-stream-nginx-firelens-37d9cebd8fbb4d57bd7fa646323e501a {"container_id":"37d9cebd8fbb4d57bd7fa646323e501a-2531612879","container_name":"nginx","log":"10.0.10.227 - - [22/Feb/2021:13:39:28 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"ELB-HealthChecker/2.0\" \"-\"","source":"stdout"}
2021-02-22T13:39:28.485000+00:00 nginx-log-stream-nginx-firelens-e0f54e9a04cd4d59be03b4ae47c6c690 {"container_id":"e0f54e9a04cd4d59be03b4ae47c6c690-2531612879","container_name":"nginx","log":"10.0.10.227 - - [22/Feb/2021:13:39:28 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"ELB-HealthChecker/2.0\" \"-\"","source":"stdout"}
2021-02-22T13:39:30.488000+00:00 nginx-log-stream-nginx-firelens-9e9a09f1b8924ce3926c7c6653bd3ec1 {"container_id":"9e9a09f1b8924ce3926c7c6653bd3ec1-2531612879","container_name":"nginx","log":"10.0.10.227 - - [22/Feb/2021:13:39:30 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"curl/7.68.0\" \"aaa.bbb.ccc.ddd\"","source":"stdout"}
2021-02-22T13:39:32.530000+00:00 nginx-log-stream-nginx-firelens-37d9cebd8fbb4d57bd7fa646323e501a {"container_id":"37d9cebd8fbb4d57bd7fa646323e501a-2531612879","container_name":"nginx","log":"10.0.10.227 - - [22/Feb/2021:13:39:32 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"curl/7.68.0\" \"aaa.bbb.ccc.ddd\"","source":"stdout"}
2021-02-22T13:39:34.569000+00:00 nginx-log-stream-nginx-firelens-9e9a09f1b8924ce3926c7c6653bd3ec1 {"container_id":"9e9a09f1b8924ce3926c7c6653bd3ec1-2531612879","container_name":"nginx","log":"10.0.10.227 - - [22/Feb/2021:13:39:34 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"curl/7.68.0\" \"aaa.bbb.ccc.ddd\"","source":"stdout"}
1行抜き出して、先ほどと同じように整形してみます。
$ echo '{"container_id":"37d9cebd8fbb4d57bd7fa646323e501a-2531612879","container_name":"nginx","log":"10.0.10.227 - - [22/Feb/2021:13:39:14 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"curl/7.68.0\" \"aaa.bbb.ccc.ddd\"","source":"stdout"}' | jq
{
"container_id": "37d9cebd8fbb4d57bd7fa646323e501a-2531612879",
"container_name": "nginx",
"log": "10.0.10.227 - - [22/Feb/2021:13:39:14 +0000] \"GET / HTTP/1.1\" 200 612 \"-\" \"curl/7.68.0\" \"aaa.bbb.ccc.ddd\"",
"source": "stdout"
}
Amazon ECSのメタデータの付与をオフにしても、AWS FireLensを通すとcontainer_id
とcontainer_name
は追加されるんですね。
まとめ
ここまでの結果をまとめると
- AWS FireLensを通してログ出力すると、JSON形式になり、少なくとも
container_id
、container_name
およびログの出力元(source
が追加される) -
enable-ecs-log-metadata
をtrue
にすると、ecs_cluster
、ecs_task_arn
、ecs_task_definition
の3つが追加される(これはデフォルトの動作)
ということですね。
単にAmazon ECSのログをAmazon CloudWatch Logsに保存しておくだけの場合は、どのタスクがどのロググループにログを保存しているかはリソース定義を見ればわかるのでそれほど意味がないかもしれません。
このログを、さらに他の場所に集約したりする場合には、これらのメタデータが有効になってくるのでしょうね。
オマケ
ここまで省略していたVPCやALB等を含む、全体のリソース定義を載せておきます。
terraform {
required_version = "0.14.7"
required_providers {
aws = {
source = "hashicorp/aws"
version = "3.29.0"
}
}
}
provider "aws" {
}
module "vpc" {
source = "terraform-aws-modules/vpc/aws"
version = "2.71.0"
name = "my-vpc"
cidr = "10.0.0.0/16"
enable_dns_hostnames = true
enable_dns_support = true
azs = ["ap-northeast-1a", "ap-northeast-1c"]
public_subnets = ["10.0.10.0/24", "10.0.20.0/24"]
private_subnets = ["10.0.30.0/24", "10.0.40.0/24"]
map_public_ip_on_launch = false
enable_nat_gateway = true
single_nat_gateway = false
one_nat_gateway_per_az = false
}
module "load_balancer_sg" {
source = "terraform-aws-modules/security-group/aws//modules/http-80"
version = "3.18.0"
name = "load-balancer-sg"
vpc_id = module.vpc.vpc_id
ingress_cidr_blocks = ["0.0.0.0/0"]
}
module "nginx_service_sg" {
source = "terraform-aws-modules/security-group/aws"
version = "3.18.0"
name = "nginx-service-sg"
vpc_id = module.vpc.vpc_id
ingress_with_cidr_blocks = [
{
from_port = 80
to_port = 80
protocol = "tcp"
description = "nginx-service inbound ports"
cidr_blocks = "10.0.10.0/24"
},
{
from_port = 80
to_port = 80
protocol = "tcp"
description = "nginx-service inbound ports"
cidr_blocks = "10.0.20.0/24"
}
]
egress_with_cidr_blocks = [
{
from_port = 0
to_port = 0
protocol = "-1"
description = "nginx-service outbound ports"
cidr_blocks = "0.0.0.0/0"
}
]
}
module "load_balancer" {
source = "terraform-aws-modules/alb/aws"
version = "5.11.0"
name = "nginx-alb"
vpc_id = module.vpc.vpc_id
load_balancer_type = "application"
internal = false
subnets = module.vpc.public_subnets
security_groups = [module.load_balancer_sg.this_security_group_id]
target_groups = [
{
backend_protocol = "HTTP"
backend_port = 80
target_type = "ip"
health_check = {
interval = 20
}
}
]
http_tcp_listeners = [
{
port = 80
protocol = "HTTP"
}
]
}
locals {
vpc_id = module.vpc.vpc_id
private_subnets = module.vpc.private_subnets
nginx_service_security_groups = [module.nginx_service_sg.this_security_group_id]
load_balancer_target_group_arn = module.load_balancer.target_group_arns[0]
nginx_simple_container_definition = <<JSON
[
{
"name": "nginx",
"image": "nginx:1.19.7",
"essential": true,
"portMappings": [
{
"protocol": "tcp",
"containerPort": 80
}
],
"logConfiguration": {
"logDriver": "awslogs",
"options": {
"awslogs-group": "${aws_cloudwatch_log_group.nginx.name}",
"awslogs-region": "ap-northeast-1",
"awslogs-stream-prefix": "nginx-log-stream"
}
}
}
]
JSON
nginx_with_fluentbit_container_definitions = <<JSON
[
{
"name": "log_router",
"image": "906394416424.dkr.ecr.ap-northeast-1.amazonaws.com/aws-for-fluent-bit:2.10.1",
"essential": true,
"firelensConfiguration": {
"type": "fluentbit",
"options":{
"enable-ecs-log-metadata": "true"
}
},
"logConfiguration": {
"logDriver": "awslogs",
"options": {
"awslogs-group": "${aws_cloudwatch_log_group.fluentbit.name}",
"awslogs-region": "ap-northeast-1",
"awslogs-stream-prefix": "fluentbit-log-stream"
}
}
},
{
"name": "nginx",
"image": "nginx:1.19.7",
"essential": true,
"portMappings": [
{
"protocol": "tcp",
"containerPort": 80
}
],
"logConfiguration": {
"logDriver": "awsfirelens",
"options": {
"Name": "cloudwatch",
"region": "ap-northeast-1",
"log_group_name": "${aws_cloudwatch_log_group.nginx.name}",
"log_stream_prefix": "nginx-log-stream-",
"auto_create_group": "false"
}
}
}
]
JSON
}
data "aws_iam_policy_document" "ecs_assume_role" {
statement {
actions = ["sts:AssumeRole"]
principals {
type = "Service"
identifiers = ["ecs-tasks.amazonaws.com"]
}
}
}
data "aws_iam_policy" "ecs_task_execution_role_policy" {
arn = "arn:aws:iam::aws:policy/service-role/AmazonECSTaskExecutionRolePolicy"
}
resource "aws_iam_role" "ecs_task_execution_role" {
name = "MyEcsTaskExecutionRole"
assume_role_policy = data.aws_iam_policy_document.ecs_assume_role.json
}
resource "aws_iam_role_policy_attachment" "ecs_task_execution_role_policy_attachment" {
role = aws_iam_role.ecs_task_execution_role.name
policy_arn = data.aws_iam_policy.ecs_task_execution_role_policy.arn
}
data "aws_iam_policy_document" "ecs_task_role_policy_document" {
statement {
effect = "Allow"
actions = [
"logs:DescribeLogStreams",
"logs:CreateLogGroup",
"logs:CreateLogStream",
"logs:PutLogEvents"
]
resources = ["*"]
}
}
resource "aws_iam_policy" "ecs_task_role_policy" {
name = "MyEcsTaskPolicy"
policy = data.aws_iam_policy_document.ecs_task_role_policy_document.json
}
resource "aws_iam_role" "ecs_task_role" {
name = "MyEcsTaskRole"
assume_role_policy = data.aws_iam_policy_document.ecs_assume_role.json
}
resource "aws_iam_role_policy_attachment" "ecs_task_role_policy_attachment" {
role = aws_iam_role.ecs_task_role.name
policy_arn = aws_iam_policy.ecs_task_role_policy.arn
}
resource "aws_cloudwatch_log_group" "nginx" {
name = "/fargate/containers/nginx"
}
resource "aws_cloudwatch_log_group" "fluentbit" {
name = "/fargate/containers/fluentbit"
}
resource "aws_ecs_cluster" "nginx" {
name = "nginx-cluster"
}
resource "aws_ecs_task_definition" "nginx" {
family = "nginx-task-definition"
cpu = "512"
memory = "1024"
network_mode = "awsvpc"
requires_compatibilities = [
"FARGATE"]
execution_role_arn = aws_iam_role.ecs_task_execution_role.arn
task_role_arn = aws_iam_role.ecs_task_role.arn
# container_definitions = local.nginx_simple_container_definition
container_definitions = local.nginx_with_fluentbit_container_definitions
}
resource "aws_ecs_service" "nginx" {
name = "nginx-service"
cluster = aws_ecs_cluster.nginx.arn
task_definition = aws_ecs_task_definition.nginx.arn
desired_count = 3
launch_type = "FARGATE"
platform_version = "1.4.0"
deployment_minimum_healthy_percent = 50
network_configuration {
assign_public_ip = false
security_groups = local.nginx_service_security_groups
subnets = local.private_subnets
}
load_balancer {
target_group_arn = local.load_balancer_target_group_arn
container_name = "nginx"
container_port = 80
}
}
output "alb_arn" {
value = module.load_balancer.this_lb_arn
}
output "alb_dns_name" {
value = module.load_balancer.this_lb_dns_name
}