利用Docker Compose快速搭建本地測試環境
阿新 • • 發佈：2019-06-19
前言
Compose是一個定義和執行多個Docker應用的工具，用一個YAML（dockder-compose.yml）檔案就能配置我們的應用。然後用一個簡單命令就能啟動所有的服務。Compose編排Docker服務的優勢是在單機測試場景，因為Compose的安裝簡單，開箱即用，yaml的定義也複用了Dockerfile的語法。但是叢集中容器編排服務還是推薦K8S或者Mesos+Marathon這樣的編排排程系統。
演示環境
$ uname -a Darwin 18.6.0 Darwin Kernel Version 18.6.0: Thu Apr 25 23:16:27 PDT 2019; root:xnu-4903.261.4~2/RELEASE_X86_64 x86_64 $ docker version Client: Docker Engine - Community Version: 18.09.2 API version: 1.39 Go version: go1.10.8 Git commit: 6247962 Built: Sun Feb 10 04:12:39 2019 OS/Arch: darwin/amd64 Experimental: false
示例
老規矩，我會先用一個示例來引入接下來要講解的內容。下面我將演示用Docker Compose一鍵執行集中式日誌系統ELK。ELK是一套日誌收集方案，是三款軟體產品的名字縮寫，Elasticsearch，Logstash 和 Kibana。
ELK的docker-compose.yml 來自github倉庫docker-elk。docker-compose.yml的內容如下：
version: '2'
services:
elasticsearch:
build:
context: elasticsearch/
args:
ELK_VERSION: $ELK_VERSION
volumes:
- ./elasticsearch/config/elasticsearch.yml:/usr/share/elasticsearch/config/elasticsearch.yml:ro
ports:
- "9200:9200"
- "9300:9300"
environment:
ES_JAVA_OPTS: "-Xmx256m -Xms256m"
ELASTIC_PASSWORD: changeme
networks:
- elk
logstash:
build:
context: logstash/
args:
ELK_VERSION: $ELK_VERSION
volumes:
- ./logstash/config/logstash.yml:/usr/share/logstash/config/logstash.yml:ro
- ./logstash/pipeline:/usr/share/logstash/pipeline:ro
ports:
- "5000:5000"
- "9600:9600"
environment:
LS_JAVA_OPTS: "-Xmx256m -Xms256m"
networks:
- elk
depends_on:
- elasticsearch
kibana:
build:
context: kibana/
args:
ELK_VERSION: $ELK_VERSION
volumes:
- ./kibana/config/kibana.yml:/usr/share/kibana/config/kibana.yml:ro
ports:
- "5601:5601"
networks:
- elk
depends_on:
- elasticsearch
networks:
elk:
driver: bridge
進入到docker-compose.yml目錄，通過docker-compose up -d 這條命令就能啟動一個本地環境的ELK系統：
$ docker-compose up -d
Building kibana
Step 1/2 : ARG ELK_VERSION
Step 2/2 : FROM docker.elastic.co/kibana/kibana:${ELK_VERSION}
7.1.1: Pulling from kibana/kibana
8ba884070f61: Already exists
3dd92e31d54b: Downloading [====================> ] 18.31MB/44.81MB
47d37f21fc3a: Pull complete
97eef8537832: Pull complete
151d3d8996bb: Pull complete
003e03312113: Pull complete
0fbb6a4413a0: Pull complete
c455cf619e40: Pull complete
Digest: sha256:fbf558c6df18500f00ab9c1e1ce2d566ad2c1800d023106e4a4a85274b0d40cd
Status: Downloaded newer image for docker.elastic.co/kibana/kibana:7.1.1
---> 67f17df6ca3e
Successfully built 67f17df6ca3e
Successfully tagged docker-elk_kibana:latest
WARNING: Image for service kibana was built because it did not already exist. To rebuild this image you must use `docker-compose build` or `docker-compose up --build`.
Creating docker-elk_elasticsearch_1 ... done
Creating docker-elk_kibana_1 ... done
Creating docker-elk_logstash_1 ... done
Attaching to docker-elk_elasticsearch_1, docker-elk_kibana_1, docker-elk_logstash_1
$ docker-compose ps
Name Command State Ports
------------------------------------------------------------------------------------------------------------------------------
docker-elk_elasticsearch_1 /usr/local/bin/docker-entr ... Up 0.0.0.0:9200->9200/tcp, 0.0.0.0:9300->9300/tcp
docker-elk_kibana_1 /usr/local/bin/kibana-docker Up 0.0.0.0:5601->5601/tcp
docker-elk_logstash_1 /usr/local/bin/docker-entr ... Up 0.0.0.0:5000->5000/tcp, 5044/tcp, 0.0.0.0:9600->9600/tcp訪問kibana頁面：
如果傳統物理程序搭建ELK系統，首先要下載和安裝Java JDK，下載ELK的版本，然後安裝Elasticsearch，Logstash 和 Kibana。這整一套下來沒有半天根本搞不定，現在整合到docker-compose只需要一條命令docker-compose up就能執行起來。所以利用docker-compose可以快速搭建本地測試環境，大大提高開發效率。相對於使用docker run這樣的方式一個個起停容器，docker-compose提供了一個容器編排的服務，定義一組容器的起停依賴關係。也可以通過docker-compose stop logstash 來停止單一的logstash等服務。
詳細說明
通過上面的例子我們已經掌握了Docker Comopose的起停等簡單用法，那麼Docker Compose一共有多少種用法呢，我們可以通過--help得到答案：
$ docker-compose --help
Define and run multi-container applications with Docker.
Usage:
docker-compose [-f <arg>...] [options] [COMMAND] [ARGS...]
docker-compose -h|--help
Options:
-f, --file FILE Specify an alternate compose file
(default: docker-compose.yml)
-p, --project-name NAME Specify an alternate project name
(default: directory name)
--verbose Show more output
--log-level LEVEL Set log level (DEBUG, INFO, WARNING, ERROR, CRITICAL)
--no-ansi Do not print ANSI control characters
-v, --version Print version and exit
-H, --host HOST Daemon socket to connect to
--tls Use TLS; implied by --tlsverify
--tlscacert CA_PATH Trust certs signed only by this CA
--tlscert CLIENT_CERT_PATH Path to TLS certificate file
--tlskey TLS_KEY_PATH Path to TLS key file
--tlsverify Use TLS and verify the remote
--skip-hostname-check Don't check the daemon's hostname against the
name specified in the client certificate
--project-directory PATH Specify an alternate working directory
(default: the path of the Compose file)
--compatibility If set, Compose will attempt to convert deploy
keys in v3 files to their non-Swarm equivalent
Commands:
build Build or rebuild services
bundle Generate a Docker bundle from the Compose file
config Validate and view the Compose file
create Create services
down Stop and remove containers, networks, images, and volumes
events Receive real time events from containers
exec Execute a command in a running container
help Get help on a command
images List images
kill Kill containers
logs View output from containers
pause Pause services
port Print the public port for a port binding
ps List containers
pull Pull service images
push Push service images
restart Restart services
rm Remove stopped containers
run Run a one-off command
scale Set number of containers for a service
start Start services
stop Stop services
top Display the running processes
unpause Unpause services
up Create and start containers
version Show the Docker-Compose version information
-f 指定compose檔案，不是必須項，如果沒有指定就變數當前路徑或者父目錄的docker-compose.yml檔案。
-p 指定專案名稱, 預設是目錄名，例如例子中預設的docker-elk。
-v 顯示Docker Compose版本。
--tls* 是加密證書相關選項。本機環境一般用不上。
build 建立容器服務，例如用Dockerfile build映象。
ps 顯示所有容器。
pull 拉取服務映象。
push 推送服務映象。
start 啟動服務。
stop 停止服務。
up 建立和啟動容器服務。相當於build（or pull）和start。
version 顯示Docker Compose版本資訊。
$ docker-compose version
docker-compose version 1.23.2, build 1110ad01
docker-py version: 3.6.0
CPython version: 3.6.6
OpenSSL version: OpenSSL 1.1.0h 27 Mar 2018
$ docker-compose stop logstash
Stopping docker-elk_logstash_1 ... done
$ docker-compose ps
Name Command State Ports
---------------------------------------------------------------------------------------------------------------------
docker-elk_elasticsearch_1 /usr/local/bin/docker-entr ... Up 0.0.0.0:9200->9200/tcp, 0.0.0.0:9300->9300/tcp
docker-elk_kibana_1 /usr/local/bin/kibana-docker Up 0.0.0.0:5601->5601/tcp
docker-elk_logstash_1 /usr/local/bin/docker-entr ... Exit 0
$ docker-compose start logstash
Starting logstash ... done
$ docker-compose ps
Name Command State Ports
------------------------------------------------------------------------------------------------------------------------------
docker-elk_elasticsearch_1 /usr/local/bin/docker-entr ... Up 0.0.0.0:9200->9200/tcp, 0.0.0.0:9300->9300/tcp
docker-elk_kibana_1 /usr/local/bin/kibana-docker Up 0.0.0.0:5601->5601/tcp
docker-elk_logstash_1 /usr/local/bin/docker-entr ... Up 0.0.0.0:5000->5000/tcp, 5044/tcp, 0.0.0.0:9600->9600/tcp
總結
文章用一鍵執行ELK系統演示了Docker Compose搭建環境的高效性，然後詳細介紹了Docker Compose的大部分選型的含義和用法。
參考
https://docs.docker.com/compose/overview/
&nbs