Dockerfile & Docker Swarm & Docker Stack & Docker Compose

Dockerfile

通俗地講，它是為了指導單個鏡像從無到有的構建過程。如果你鏡像是從Docker registry上面拉下來的，那就用不到這個文件；如果你是自己的應用，想打包成鏡像，那就需要這個文件。

Dockerfile資料：http://www.docker.org.cn/dockerppt/114.html

Docker Swarm

一句話，這個東西是用來搭建Docker集群的。

示例：（兩台已經安裝好Docker的機器：192.168.192.128 和 192.168.192.130）

128上：（初始化為Manager，然后開啟防火牆端口）

[root@localhost DockerComposeFolder]# docker swarm init
Swarm initialized: current node (pmio659q4pm90nlvtoe5ak293) is now a manager.

To add a worker to this swarm, run the following command:

    docker swarm join --token SWMTKN-1-17usxu5fddmp2laagvpatbgrq8tiigfj4ejgcmuof1oy942842-9r9jkrf33tico042cs684e886 192.168.192.128:2377

To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions.

[root@localhost DockerComposeFolder]# firewall-cmd --zone=public --add-port=2377/tcp --permanent
success
[root@localhost DockerComposeFolder]# systemctl restart firewalld

130上：（加入集群成為一個Worker）

[root@localhost admin]# firewall-cmd --zone=public --add-port=2377/tcp --permanent
success
[root@localhost admin]# systemctl restart firewalld
[root@localhost admin]# docker swarm join --token SWMTKN-1-17usxu5fddmp2laagvpatbgrq8tiigfj4ejgcmuof1oy942842-9r9jkrf33tico042cs684e886 192.168.192.128:2377
This node joined a swarm as a worker.

128上：（列出節點列表）

[root@localhost DockerComposeFolder]# docker node ls
ID                            HOSTNAME                STATUS              AVAILABILITY        MANAGER STATUS      ENGINE VERSION
ply3z1rbyxn967zqdqltc5j7w     localhost.localdomain   Ready               Active                                  19.03.2
pmio659q4pm90nlvtoe5ak293 *   localhost.localdomain   Ready               Active              Leader              19.03.1

當前節點退出集群

docker swarm leave --force

更新集群

docker swarm update

應用示例：（在Learder上【128節點】）

1. 編寫一個compose文件

[root@localhost DockerComposeFolder]# vim docker-compose-demo.yml

---

version: '3.7'

services:
  redis:
    image: redis
    ports:
      - "6379"
    deploy:
      replicas: 2
      update_config:
        parallelism: 2
        delay: 10s
      restart_policy:
        condition: on-failure
    networks:
      - swarmnet

  visualizer:
    image: dockersamples/visualizer:stable
    ports:
      - "8080:8080"
    stop_grace_period: 1m30s
    volumes:
      - "/var/run/docker.sock:/var/run/docker.sock"
    deploy:
      placement:
        constraints: [node.role == manager]
    networks:
      - swarmnet
networks: # 自定義網絡
  swarmnet:

2. 啟動

[root@localhost DockerComposeFolder]# docker stack deploy -c docker-compose-demo.yml my_first_app
Creating network my_first_app_swarmnet
Creating service my_first_app_visualizer
Creating service my_first_app_redis
[root@localhost DockerComposeFolder]# 

3. 查看

# stack列表
[root@localhost DockerComposeFolder]# docker stack ls
NAME                SERVICES            ORCHESTRATOR
my_first_app        2                   Swarm

# 服務列表
[root@localhost DockerComposeFolder]# docker service ls
ID                  NAME                      MODE                REPLICAS            IMAGE                             PORTS
w3a6mgfouljz        my_first_app_redis        replicated          2/2                 redis:latest                      *:30005->6379/tcp
pmakz6gwandv        my_first_app_visualizer   replicated          1/1                 dockersamples/visualizer:stable   *:8080->8080/tcp

4. 訪問Visualizer（Leader的IP:8080）記得開放防火牆端口

5. 停止stack

[root@localhost DockerComposeFolder]# docker stack rm my_first_app
Removing service my_first_app_redis
Removing service my_first_app_visualizer
Removing network my_first_app_swarmnet

6. 說明配置：deploy下的placement

配置這個可以規定服務的位置，如上面的結果，Visualizer只會在Manager上運行，而redis則會出現在Manager以及Worker上。

 

部署應用示例

打包鏡像參考：https://www.cnblogs.com/LUA123/p/11436805.html

注意，本示例中，web程序的開放端口是8081

1. 配置倉庫

因為我們的本地應用倉庫在128上，如果130節點也想運行我們的web項目，那么需要配置倉庫地址，不然找不到

vim /etc/docker/daemon.json
# 里面是倉庫地址，根據情況自行修改
{
  "insecure-registries":["192.168.192.128:443"]
}

2. 編寫yml文件

version: '3.7'

services:
  web:
    image: 192.168.192.128:443/hello-2
    deploy:
      replicas: 2
      restart_policy:
        condition: on-failure
      resources:
        limits:
          cpus: "0.1"
          memory: 50M
    ports:
      - "8081:8081"
    networks:
      - swarmnet

  redis:
    image: redis
    ports:
      - "6379"
    deploy:
      replicas: 2
      update_config:
        parallelism: 2
        delay: 10s
      restart_policy:
        condition: on-failure
    networks:
      - swarmnet

  visualizer:
    image: dockersamples/visualizer:stable
    ports:
      - "8080:8080"
    stop_grace_period: 1m30s
    volumes:
      - "/var/run/docker.sock:/var/run/docker.sock"
    deploy:
      placement:
        constraints: [node.role == manager]
    networks:
      - swarmnet
networks: # 自定義網絡
  swarmnet:

啟動

[root@localhost DockerComposeFolder]# docker stack deploy -c docker-compose-demo.yml my_first_app
Creating network my_first_app_swarmnet
Creating service my_first_app_redis
Creating service my_first_app_visualizer
Creating service my_first_app_web

128節點查看

 

130節點查看

 

訪問128節點的Visualizer ：http://192.168.192.128:8080/

打開8081防火牆端口后訪問

 

Docker Stack（Docker堆棧）

在上面的小例子已經有了體現。一句話，能夠一鍵部署一整套服務。

1. docker stack deploy 部署新的堆棧或者更新現有堆棧

docker stack deploy -c docker-compose-demo.yml my_first_app

-c：指定配置文件
my_first_app：指定stack名字

2. docker stack ls 顯示堆棧列表

[root@localhost DockerComposeFolder]# docker stack ls
NAME                SERVICES            ORCHESTRATOR
my_first_app        2                   Swarm

3. docker stack ps 列出堆棧中的任務

[root@localhost DockerComposeFolder]# docker stack ps my_first_app
ID                  NAME                        IMAGE                             NODE                    DESIRED STATE       CURRENT STATE           ERROR               PORTS
r41ww3p604z5        my_first_app_visualizer.1   dockersamples/visualizer:stable   localhost.localdomain   Running             Running 8 minutes ago                       
1jirtqlappdp        my_first_app_redis.1        redis:latest                      localhost.localdomain   Running             Running 8 minutes ago                       
yr4sz7k5uwpk        my_first_app_redis.2        redis:latest                      localhost.localdomain   Running             Running 8 minutes ago                       

4. docker stack services 列出堆棧中的服務

[root@localhost DockerComposeFolder]# docker stack services my_first_app
ID                  NAME                      MODE                REPLICAS            IMAGE                             PORTS
pmakz6gwandv        my_first_app_visualizer   replicated          1/1                 dockersamples/visualizer:stable   *:8080->8080/tcp
w3a6mgfouljz        my_first_app_redis        replicated          2/2                 redis:latest                      *:30005->6379/tcp

5. docker stack rm 刪除一個或多個堆棧

[root@localhost DockerComposeFolder]# docker stack rm my_first_app
Removing service my_first_app_redis
Removing service my_first_app_visualizer
Removing network my_first_app_swarmnet

 

Docker Compose

它是為了指導單個“服務”的構建過程，“服務”實際上包含一個或者多個運行狀態下的容器。在服務中運行的單個容器稱為任務，每個任務的ID是數字唯一遞增的。一般你的應用都需要依賴很多其它的環境，比如：數據庫啊、redis啊、zookeeper啊等等，你也可以一個一個配置參數啟動，但是有了docker-compose，你只需要把事先准備的好的配置寫在文件里，然后docker-compose up一鍵啟動即可，相比一個一個手動啟動，方便了很多也減少了出錯機會。你會發現，它和Docker Stack的作用差不多。區別如下：

stack部署到集群（配合swarm），compose只能部署到一個節點。

stack會跳過build過程，所以stack只能使用現成的鏡像；compose不會跳過build，所以compose對開發人員比較友好。

雖然compose也能進行生產環境的部署，但是在集群角度來看，stack更適合生產部署。

詳解docker-compose.yml文件

version

 

查看Docker信息執行：docker info 或者 docker --version

[root@localhost admin]# docker --version
Docker version 19.03.1, build 74b1e89

提醒：你可以結合docker 命令（比如：build、run、network等等）來理解docker-compose

Run命令：https://docs.docker.com/engine/reference/commandline/run/

Docker-Compose-File：https://docs.docker.com/compose/compose-file/

以下選項是 docker-compose up 支持，而docker stack deploy 不支持的

build
cgroup_parent
container_name
devices
tmpfs
external_links
links
network_mode
restart
security_opt
sysctls
userns_mode

compose文件（包含大部分選項）

version: "3.7"
services:
  webapp:
    # build，構建一個鏡像（利用docker-compose執行此文件）；如果在集群模式下部署，將忽略此項，docker stack僅僅接受預先構建好的鏡像。
    build:
      # 包含Dockerfile的路徑，當提供的是相對路徑，解釋為相對於compose文件的位置。
      context: ./dir
      # Compose使用指定的Dockerfile文件來構建
      dockerfile: Dockerfile-alternate
      # 構建參數，這些參數只能在構建過程中訪問
      args:
        - buildno=1
        - hash=cdc3b19
      # 緩存（v3.2開始）
      cache_from:
        - alpine:latest
      # 構建指定階段的Dockerfile（v3.4開始。參考：多階段構建文檔：https://docs.docker.com/develop/develop-images/multistage-build/）
      target: prod
      # 指定生成的容器中/dev/shm分區的大小（v3.5開始。可以為字符串'1gb'或者整數數字1000000）
      shm_size: '1gb'

    # build或者指定鏡像的話，此項為鏡像名稱
    image:app:tag
    # 容器標簽（也可以這樣寫 com.example.description: "Accounting webapp"）
    labels:
      - "com.example.description=Accounting webapp"
    # 添加容器功能（執行man 7 capabilities查看全部）
    cap_add:
      - ALL
    # 刪除容器功能
    cap_drop:
      - NET_ADMIN
      - SYS_ADMIN
    # 為容器指定可選的父cgroup
    cgroup_parent: m-executor-abcd
    #覆蓋默認命令（也可以是個列表，類似於Dockerfile：command: ["bundle", "exec", "thin", "-p", "3000"]）
    command: bundle exec thin -p 3000
    # 默認docker-compose up 會按照順序啟動服務，如果你有前后順序，可以指定這個參數，代表db和redis先於webapp啟動
    depends_on:
      - db
      - redis
    # 部署（僅限v3版本，並且只適合集群部署（docker stack），docker-compose up 將忽略這個選項）
    deploy:
      # 啟動容器副本數
      replicas: 6
      # 資源限制
      resources:
        # 不超過單核CPU的50%可用處理時間 & 不超過50M內存
        limits:
          cpus: '0.50'
          memory: 50M
        # 始終可用25%CPU時間 & 20M內存
        reservations:
          cpus: '0.25'
          memory: 20M
      # 重啟策略
      restart_policy:
        # 重啟時機（none、on-failure、any，默認any）
        condition: on-failure
        # 重啟嘗試的等待時間
        delay: 5s
        # 最大重試次數（默認永遠重試）
        max_attempts: 3
        # 在決定重新啟動是否成功之前等待多長時間（默認立即決定）
        window: 120s
      # 配置服務如何更新
      update_config:
        # 一次更新的容器數
        parallelism: 2
        # 更新一組容器之間的等待時間
        delay: 10s
      # 服務標簽
      labels:
        com.example.description: "This label will appear on the web service"
    # 覆蓋默認的entrypoint
    entrypoint: /code/entrypoint.sh
    # 從文件添加環境變量。可以是單個值（env_file: .env）或列表，文件內容每一行都是var=val格式化的，# 開頭的和空行都被忽略
    env_file:
      - ./common.env
      - ./apps/web.env
      - /opt/secrets.env
    # 添加環境變量，如果是布爾值要用引號括起來
    environment:
      - RACK_ENV=development
      - SHOW=true
      - SESSION_SECRET
    # 暴露端口但是不把它們發布到主機，它們只能被鏈接服務訪問。只能指定內部端口。
    expose:
      - "3000"
      - "8000"
    # 鏈接到外部的容器（格式為 容器名稱:別名）
    external_links:
      - redis_1
      - project_db_1:mysql
      - project_db_1:postgresql
    # 添加主機名映射
    extra_hosts:
      - "somehost:162.242.195.82"
      - "otherhost:50.31.209.229"
    # 日志
    logging:
      # 驅動（默認json-file，還可以為syslog和none）
      driver: "json-file"
      options:
        # 日志最大大小，以及文件數量
        max-size: "200k"
        max-file: "10"
    # 網絡（要引入頂級配置的network）
    networks:
     - some-network
     - other-network
    # 暴露端口，以HOST:CONTAINER格式映射端口
    ports:
      - "3000"
      - "3000-3005"
      - "8000:8000"
      - "9090-9091:8080-8081"
      - "49100:22"
      - "127.0.0.1:8001:8001"
    # 重啟（"no",always,on-failure,unless-stopped）
    restart: "no"
    # 設置內核參數
    sysctls:
      - net.core.somaxconn=1024
      - net.ipv4.tcp_syncookies=0
    # 將容器目錄映射到主機目錄（格式 HOST:CONTAINER）
    volumes:
      - "/var/run/postgres/postgres.sock:/var/run/postgres/postgres.sock"
      - "dbdata:/var/lib/postgresql/data"

  redis:
    image: redis
  db:
    image: postgres

# 配置網絡
networks:
  some-network:
  other-network:
    external:
      name: actual-name-of-network

命令

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 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

例：docker-compose-simple.yml

version: '3.7'
services:
  zookeeper:
    image: zookeeper
    ports:
      - "2181:2181"

1. docker-compose up 創建並啟動服務

# 指定yml文件，后台啟動服務
[root@localhost DockerComposeFolder]# docker-compose -f docker-compose-simple.yml up -d
Creating network "dockercomposefolder_default" with the default driver
Creating dockercomposefolder_zookeeper_1 ... done

2. docker-compose stop 停止服務

[root@localhost DockerComposeFolder]# docker-compose -f docker-compose-simple.yml stop
Stopping dockercomposefolder_zookeeper_1 ... done

3. docker-compose start 啟動已存在的服務

[root@localhost DockerComposeFolder]# docker-compose -f docker-compose-simple.yml start
Starting zookeeper ... done

4. docker-compose restart 重啟服務

[root@localhost DockerComposeFolder]# docker-compose -f docker-compose-simple.yml restart
Restarting dockercomposefolder_zookeeper_1 ... done

5. docker-compose images 列出鏡像

[root@localhost DockerComposeFolder]# docker-compose -f docker-compose-simple.yml images
           Container              Repository    Tag       Image Id      Size 
-----------------------------------------------------------------------------
dockercomposefolder_zookeeper_1   zookeeper    latest   e7c648f28c78   215 MB

6. docker-compose logs 查看日志

[root@localhost DockerComposeFolder]# docker-compose -f docker-compose-simple.yml logs
Attaching to dockercomposefolder_zookeeper_1
zookeeper_1  | ZooKeeper JMX enabled by default
zookeeper_1  | Using config: /conf/zoo.cfg
zookeeper_1  | 2019-10-09 06:46:29,917 [myid:] - INFO  [main:QuorumPeerConfig@133] - Reading configuration from: /conf/zoo.cfg
zookeeper_1  | 2019-10-09 06:46:29,920 [myid:] - INFO  [main:QuorumPeerConfig@375] - clientPort is not set
zookeeper_1  | 2019-10-09 06:46:29,920 [myid:] - INFO  [main:QuorumPeerConfig@389] - secureClientPort is not set
zookeeper_1  | 2019-10-09 06:46:29,929 [myid:] - ERROR [main:QuorumPeerConfig@645] - Invalid configuration, only one server specified (ignoring)
zookeeper_1  | 2019-10-09 06:46:29,932 [myid:1] - INFO  [main:DatadirCleanupManager@78] - autopurge.snapRetainCount set to 3
zookeeper_1  | 2019-10-09 06:46:29,933 [myid:1] - INFO  [main:DatadirCleanupManager@79] - autopurge.purgeInterval set to 0

7. docker-compose top 查看進程

8. docker-compose ps 查看容器

[root@localhost DockerComposeFolder]# docker-compose -f docker-compose-simple.yml ps
             Name                            Command               State                          Ports                        
-------------------------------------------------------------------------------------------------------------------------------
dockercomposefolder_zookeeper_1   /docker-entrypoint.sh zkSe ...   Up      0.0.0.0:2181->2181/tcp, 2888/tcp, 3888/tcp, 8080/tcp

9. docker-compose version 查看版本

[root@localhost DockerComposeFolder]# docker-compose -f docker-compose-simple.yml version
docker-compose version 1.24.1, build 4667896b
docker-py version: 3.7.3
CPython version: 3.6.8
OpenSSL version: OpenSSL 1.1.0j  20 Nov 2018

10. docker-compose pause 暫停服務

[root@localhost DockerComposeFolder]# docker-compose -f docker-compose-simple.yml pause
Pausing dockercomposefolder_zookeeper_1 ... done

11. docker-compose unpause 終止暫停服務

[root@localhost DockerComposeFolder]# docker-compose -f docker-compose-simple.yml unpause
Unpausing dockercomposefolder_zookeeper_1 ... done

12. docker-compose config 查看配置

[root@localhost DockerComposeFolder]# docker-compose -f docker-compose-simple.yml config
services:
  zookeeper:
    image: zookeeper
    ports:
    - published: 2181
      target: 2181
version: '3.7'

13. docker-compose port 查看服務暴露的端口

# 服務名稱為我們定義在yml文件中的名字，端口為容器內部端口
[root@localhost DockerComposeFolder]# docker-compose -f docker-compose-simple.yml port zookeeper 2181
0.0.0.0:2181

14. docker-compose down 停止並移除已啟動的容器

[root@localhost DockerComposeFolder]# docker-compose -f docker-compose-simple.yml down
Stopping dockercomposefolder_zookeeper_1 ... done
Removing dockercomposefolder_zookeeper_1 ... done
Removing network dockercomposefolder_default

15. docker-compose rm 移除已停止的容器

[root@localhost DockerComposeFolder]# docker-compose -f docker-compose-simple.yml rm
Going to remove dockercomposefolder_zookeeper_1
Are you sure? [yN] y
Removing dockercomposefolder_zookeeper_1 ... done

 

后記：若是去理解這幾個東西，很好理解，但是如何靈活運用，就需要積累了（說實話官方給的文檔比較節省筆墨，有很多地方看了N遍也不明所以，還是自己要多去實踐）