Speeding up Ruby on Rails in docker

1. Bundle package will create a cached copy, so bundler in docker will not fetch all dependencies all the time.

bundle package

1. Create separate bundler data volume to perisist bundle between builds. Set BUNDLE_PATH to data volume. You can include this option just for development docker-compose.yml file and not to include in production.

version: “2” services: memcached: image: memcached networks: — back-tier redis: image: redis ports: [“6379”] networks: — back-tier db: image: mysql:5 volumes: — ./sql:/docker-entrypoint-initdb.d — mysql:/var/lib/mysql networks: — back-tier sse: image: mprokopov/sse build: context: sse/. command: “bundle exec rackup — host 0.0.0.0 — port 9292” environment: — RACK_ENV=production ## docker database settings in config.yml ports: — “9292:9292” links: — redis — db depends_on: — db — redis networks: — back-tier — front-tier worker: image: mprokopov/itservice_web_dev command: “bundle exec rake environment resque:work” environment: — QUEUE=* links: — db — redis depends_on: — db — redis networks: — back-tier worker-schedule: image: mprokopov/itservice_web_dev command: “bundle exec rake environment resque:scheduler” links: — db — redis depends_on: — redis networks: — back-tier search: image: mprokopov/itservice_search build: ./search volumes: — search-data:/search depends_on: — db links: — db networks: — back-tier expose: — “9306” web: ports: — “3000:3000” environment: — LETTER_OPENER=letter_opener_web — RAILS_SERVE_STATIC_FILES=true — SLACK_NOTIFICATION=false — EMAIL_NOTIFICATION=false — SLACK_WEBHOOK_CHANNEL=#events_test — STREAM_API=http://localhost:9292 depends_on: — db — redis links: — db — redis — search networks: — back-tier — front-tier volumes: — search-data:/search volumes: search-data: mysql: networks: back-tier: front-tier:

Unlike docker-compose sometimes kubectl provides you better tooling for docker container access.

Let me share with you my useful findings.

With port-forward, you can easily connect to pods service and debug it.

kubectl port-forward podname port

For example

kubectl port-forward sharepass-78d566f866-4dvv5 3000

kubectl port-forward sharepass-78d566f866–4dvv5 3000
Forwarding from 127.0.0.1:3000 -> 3000
Forwarding from [::1]:3000 -> 3000
Handling connection for 3000
Handling connection for 3000

This will forward port 3000 to localhost, so you can open URL http://localhost:3000 and enjoy access to your service.

TLDR: because of the networking layer and how docker volumes implemented.