使用Docker Compose，在一个命令中启动Sinatra和Redis容器
简而言之
通过使用Docker Compose，一个Docker的官方编排工具，试着运行一个包含Redis和Sinatra的应用程序。
Redis和Sinatra分别作为单独的容器运行。通常情况下需要运行两次docker run命令，或者在运行时添加-e和-p等选项，但是使用Compose可以通过一个命令简单地运行起来。
你好，世界。
范例应用
$ mkdir sample && cd sample
Sinatar 应用程序的代码大致如下。当被访问时，输出”你好，世界”并增加访问次数。
# app.rb
require "sinatra"
require "redis"
redis = Redis.new(
host: ENV["REDIS_HOST"],
port: ENV["REDIS_PORT"]
)
set :bind, '0.0.0.0'
get "/" do
"Hello World! I have been seen #{redis.incr('/')} times."
end
# Gemfile
source "https://rubygems.org"
ruby "2.2.0"
gem "sinatra"
gem "redis"
Dockerfile の作成
アプリケーションの依存関係を Dockerfile に書く
FROM ruby:2.2.0
ADD . /app
WORKDIR /app
RUN bundle install -j4
.dockerignore も用意しておきます。
# .dockerignore
## environment normalization
.env
.bundle
# ホストマシン側で bundle install --path vendor/bundle している場合
vendor/bundle
.ruby-version
## git
.git
.gitignore
## log
log
tmp
## docker
.dockerignore
## etc
# 他にも色々あるけど省略
服务的定义
在docker-compose.yml文件中编写服务的定义。
web:
build: .
command: bundle exec ruby app.rb
ports:
- 80:4567
volumes:
- .:/app
links:
- redis
environment:
- REDIS_HOST=redis
- REDIS_PORT=6379
redis:
image: redis:latest
在这里我们定义了两个服务，一个是 web，另一个是 redis。
使用Compose来构建图像并启动应用程序
docker-compose up コマンドで、Sinatar アプリケーションの Docker イメージのビルドをしてアプリケーションを起動する。
$ docker-compose up
Creating sample_redis_1...
Creating sample_web_1...
Building web...
Step 0 : FROM ruby:2.2.0
---> 51473a2975de
Step 1 : ADD . /app
---> 43ea79246bc4
Removing intermediate container 42a9412e6601
Step 2 : WORKDIR /app
---> Running in b8ccb1554b59
---> 4a5e4f5daae2
Removing intermediate container b8ccb1554b59
Step 3 : RUN bundle install --path vendor/bundle -j4
---> Running in 3bee7f6cdd9b
Don't run Bundler as root. Bundler can ask for sudo if it is needed, and
installing your bundle as root will break this application for all non-root
users on this machine.
Using tilt 1.4.1
Using redis 3.2.1
Using bundler 1.7.12
Using rack 1.6.0
Using rack-protection 1.5.3
Using sinatra 1.4.5
Your bundle is complete!
It was installed into ./vendor/bundle
---> cc2a6d3d33e4
Removing intermediate container 3bee7f6cdd9b
Successfully built cc2a6d3d33e4
Attaching to sample_redis_1, sample_web_1
redis_1 | [1] 01 Mar 11:24:35.546 # Warning: no config file specified, using the default config. In order to specify a config file use redis-server /path/to/redis.conf
redis_1 | _._
redis_1 | _.-``__ ''-._
redis_1 | _.-`` `. `_. ''-._ Redis 2.8.19 (00000000/0) 64 bit
redis_1 | .-`` .-```. ```\/ _.,_ ''-._
redis_1 | ( ' , .-` | `, ) Running in stand alone mode
redis_1 | |`-._`-...-` __...-.``-._|'` _.-'| Port: 6379
redis_1 | | `-._ `._ / _.-' | PID: 1
redis_1 | `-._ `-._ `-./ _.-' _.-'
redis_1 | |`-._`-._ `-.__.-' _.-'_.-'|
redis_1 | | `-._`-._ _.-'_.-' | http://redis.io
redis_1 | `-._ `-._`-.__.-'_.-' _.-'
redis_1 | |`-._`-._ `-.__.-' _.-'_.-'|
redis_1 | | `-._`-._ _.-'_.-' |
redis_1 | `-._ `-._`-.__.-'_.-' _.-'
redis_1 | `-._ `-.__.-' _.-'
redis_1 | `-._ _.-'
redis_1 | `-.__.-'
redis_1 |
redis_1 | [1] 01 Mar 11:24:35.547 # Server started, Redis version 2.8.19
redis_1 | [1] 01 Mar 11:24:35.547 # WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1' for this to take effect.
redis_1 | [1] 01 Mar 11:24:35.547 # WARNING you have Transparent Huge Pages (THP) support enabled in your kernel. This will create latency and memory usage issues with Redis. To fix this issue run the command 'echo never > /sys/kernel/mm/transparent_hugepage/enabled' as root, and add it to your /etc/rc.local in order to retain the setting after a reboot. Redis must be restarted after THP is disabled.
redis_1 | [1] 01 Mar 11:24:35.547 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.
redis_1 | [1] 01 Mar 11:24:35.547 * The server is now ready to accept connections on port 6379
web_1 | [2015-03-01 11:24:43] INFO WEBrick 1.3.1
web_1 | [2015-03-01 11:24:43] INFO ruby 2.2.0 (2014-12-25) [x86_64-linux]
web_1 | == Sinatra/1.4.5 has taken the stage on 4567 for development with backup from WEBrick
web_1 | [2015-03-01 11:24:43] INFO WEBrick::HTTPServer#start: pid=1 port=4567
当我访问时，显示出”Hello World”。
以守护模式运行
当在命令后添加“-d”并运行时，程序将以守护进程模式执行。
$ docker-compose up -d
Recreating sample_redis_1...
Recreating sample_web_1...
可以通过运行 docker-compose ps 命令来查看状态。
$ docker-compose ps
Name Command State Ports
---------------------------------------------------------------------------
sample_redis_1 /entrypoint.sh redis-server Up 6379/tcp
sample_web_1 bundle exec ruby app.rb Up 0.0.0.0:80->4567/tcp
REF (参考)
-
- 公式ドキュメント
- Docker Compose リファレンス
