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© - BASE, Inc.
Container-based
Application Design
Real Practices
. . #dockertokyo - @hgsgtk
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Talk Summary
Keep each components is Decoupled
Keep Balance with development efficiency
Use Cloud-based Design Principles
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About me
Kazuki Higashiguchi
Twitter / GitHub : @hgsgtk
Server-side Engineer
BASE BANK, Inc.
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Agenda
.Configuration
.Logging
.Building Application
.Monitoring
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Configuration
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Features of Configuration
• “Runtime” Data (Necessary at startup)
• Different for each environment
• A lot of values
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Requests for configuration
• Manage hierarchically
• Make configurations easy to understand
• Externalize configuration
• Get rid of configurations from Application
• Minimal accessibility
• Configurations includes credentials
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Related Principles
• “ . CONFIGURATION, CREDENTIALS, AND
CODE” in “Beyond the Twelve-Factor App”
• “IMAGE IMMUTABILITY PRINCIPLE(IIP)” in
“Principles of container-based application
design (redhat)”
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. CONFIGURATION, CREDENTIALS, AND CODE (WIP)
• Get rid of configurations from Code
• Not include in Version Control System
• “Treat Your Apps Like Open Source”
• Environment variables are considered the best
practice for externalized configuration,
• Externalized configurations
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Extra: Beyond the Twelve-Factor App
• Best practices of cloud-native
application
• published by Pivotal
• https://content.pivotal.io/blog/
beyond-the-twelve-factor-app
• Original is “The Twelve-Factor
App”
• https:// factor.net/
• Original + New = factors
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Extra: Principles of container-based application
design (redhat)
• Design Principles of container-
based application
• published by red-hot
• https://www.redhat.com/en/
resources/cloud-native-
container-design-whitepaper
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Configuration: Practical example
• AWS ECS(Fargate)
• Configurations are stored in
Parameter Store
• Encryption using Key
Management Store
• See also:
• https://devblog.thebase.in/
entry/ / / /
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Configuration: Real Issues
• Depends on Features provided by Cloud vendor
• If well-integrated features, become “Simple”
• If Not, may become “Complicated”
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For example: Fargate & Parameter Store
• A example to use Parameter Store as
externalized configuration store
• Before Platform Version .
• Each container access Parameter Store via API
• Write entrypoint.sh by myself
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entrypoint.sh
#!/usr/bin/env bash
set -e
# request multiple times
export DB_HOST=$(aws ssm get-parameters --name /prd/
database/host --query "Parameters[0].Value" --region ap-
northeast-1 --output text)
export DB_PORT=$(aws ssm get-parameters --name /prd/
database/port --query "Parameters[0].Value" --region ap-
northeast-1 --output text)
exec "$@"
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For example: Fargate & Parameter Store
• After Released .
• “AWS Fargate Platform Version . Adds
Secrets Support”
• Just write task definition (and set IAM role)
• Become well-integrated features.
• It makes our application “Simpler”
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Logging
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Requests for Logging
• Realtime
• Know “What is happening now”
• Availability
• “No” Missing Log
• Searching
• Make identifying the cause of problem “Easy”
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Related Principles
• “ . LOGS” in “Beyond the Twelve-Factor App”
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“ . LOGS”
• Treat Log as Event Stream
• Not depends on File System
• Log on STDOUT/STDERR
• Use tools (ex. ElasticSearch, Logstash, Kibana)
to satisfied the requirements of aggregation,
processing, storage of logs
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LOGGING: Practical Examples
• Application writes logs to STDOUT/STDERR
• Fargate -> CloudWatchLogs(CWL) -> S ->
ElasticSearch & Kibana
• See also https://qiita.com/tomy rider/items/
aa dd
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Build Application
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Requests for Build Application
• Dependency Management
• Manage Application Dependency
• Work in Difference environments
• Work in Local, QA, Stating, Production
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Application Components
• Runtime Engine
• Code
• Dependencies
• Configuration
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Container Application
• Container includes
• Runtime Engine
• Code
• Dependencies
• Configuration is
injected at startup
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For environments, Same Container
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Related Principles
• “ . DEPENDENCY MANAGEMENT” in “Beyond
the Twelve-Factor App”
• “ . DESIGN, BUILD, RELEASE, RUN” in “Beyond
the Twelve-Factor App”
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Build Application: Practical example
• Use case
• API developed by Go
• One Dockerfile for
deploy
• Build image provide to
environments
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Build Application: Real Issues
• Best practices: same container
provides ALL environments
• However, in Local environments,
Development efficiency is also
important
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Build Application: Real Issues
• One Dockerfile for deploy
• Another Dockerfile for
developer
• Live reloading
• See also
• https://go-
talks.appspot.com/
github.com/hgsgtk/
gocon -lt/realize.slide#
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Find the suitable balance for you
• “Docker for local”
• -> weakens the merit
• -> strengthen developers
• Necessity to find suitable balance
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Monitoring
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Requests for Monitoring
• Check Health
• Monitor application is healthy
• Keep Watching Metrics
• Keep watching Metrics
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Related Principles
• “HIGH OBSERVABILITY PRINCIPLE (HOP)” in
“Principles of container-based application
design (redhat)”
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HIGH OBSERVABILITY PRINCIPLE (HOP)
• Treat Container like “Black box”
• Provide API for various status check
• Activity status
• Preparation status
• Log important events on STDOUT/STDERR
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Health endpoint pattern
• One of application monitoring patterns
• Provide HTTP endpoints in the application
• convey the health of the application
• See also: “Practical Monitoring—Effective
Strategies for the Real World”
• http://shop.oreilly.com/product/
.do
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Mackerel Container Agent
• Monitor “Inside Container”
• CPU, Memory, Network etc
• Run as a task / pod sidecar
• See also: https://mackerel.io/ja/docs/entry/
howto/container-agent
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Monitoring: Practical example
/.health_check endpoint return “OK”
See also: https://devblog.thebase.in/entry/ /
/ /
-> % curl -i http://localhost/.health_check
HTTP/1.1 200 OK
Content-Type: application/json; charset=utf-8
Date: Mon, 04 Mar 2019 13:24:23 GMT
Content-Length: 15
{"status":200}
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Monitoring: Practical example
/.health_check endpoint also return “NG”
See also: https://devblog.thebase.in/entry/ /
/ /
-> % curl -i http://localhost/.health_check
HTTP/1.1 503 Service Unavailable
Content-Type: application/json; charset=utf-8
Date: Mon, 04 Mar 2019 13:35:38 GMT
Content-Length: 106
{"status":503,"message":"failed to get connection
database","string":"sql: connection is already closed"}
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Talk Summary
Keep each components is Decoupled
Keep Balance with development efficiency
Use Cloud-based Design Principles
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Extra: Related Presentations
• “Container-based Application Design Reference and Practice”
at Docker Tokyo Meetup
• https://speakerdeck.com/hgsgtk/container-based-application-design-
reference-and-practice-number-dockertokyo
• “Docker Go development environment starting with realize”
at Go Conference Autumn
• https://go-talks.appspot.com/github.com/hgsgtk/gocon -lt/
realize.slide#
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Extra: Related Blogs
• “ECS(Fargate)でコンテナアプリケーションを動かすための設定情報の扱
い⽅”
• https://devblog.thebase.in/entry/ / / /
• “アプリケーション監視のパターン「Health エンドポイントパターン」
を実践する | 書籍『⼊⾨ 監視 ―モダンなモニタリングのためのデザイン
パターン』を読んで”
• https://devblog.thebase.in/entry/ / / /
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Extra: Related Books
• 『⼊⾨ 監視 モダンなモニタリングのためのデザインパターン』
https://www.oreilly.co.jp/books/ /
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Extra: Related Documents
• Beyond the Twelve-Factor App
• https://content.pivotal.io/blog/beyond-the-twelve-factor-app
• Principles of container-based application design (redhat)
• https://www.redhat.com/en/resources/cloud-native-container-design-
whitepaper (English Edition)
• https://www.redhat.com/ja/resources/cloud-native-container-design-
whitepaper (Japanese Edition)
• AWS Cloud Design Patterns
• http://en.clouddesignpattern.org/index.php/Main_Page
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Extra: Related Documents
• “AWS Fargate Platform Version . Adds Secrets Support”
• https://aws.amazon.com/about-aws/whats-new/ / /aws-
fargate-platform-version- - -adds-secrets-support/?nc =h_ls