srcmini本文概述
在处理Docker项目时, 大多数情况下, 现有的Docker映像无法满足你的要求。
这就是Dockerfile出现的地方；它将帮助你创建自定义Docker映像。因此, 了解Dockerfile是必不可少的。
什么是Dockerfile？
它是带有一组命令或指令的简单文本文件。这些命令/指令将依次执行以对基本映像执行操作以创建新的docker映像。
注释和命令+参数是Dockerfile语法中的两种主线块
注释语法
#Line blocks used for commenting
command argument argument1 …..命令+参数示例
#Line blocks used for commenting
command argument argument1 …..以下是你的工作流程外观。
- 创建一个Dockerfile并提及创建你的Docker映像的说明
- 运行docker build命令将构建一个docker镜像
- 现在可以使用docker映像了, 使用docker run命令创建容器
基本命令
FROM –定义要使用的基本映像并开始构建过程。
RUN –使用命令及其参数从映像运行它。
CMD –与RUN命令类似的功能, 但仅在实例化容器后才执行。
ENTRYPOINT –创建容器时, 它将在图像中定位默认应用程序。
ADD –将文件从源复制到目标(在容器内部)。
ENV –设置环境变量。
如何使用Dockerfile创建Docker镜像？
首先, 让我们创建一个Dockerfile。
[email protected]:~$ gedit Dockerfile将以下命令/说明放入其中并保存。
# Set the base image to Ubuntu
FROM ubuntu
# Update the repository sources list and install gnupg2
RUN apt-get update && apt-get install -y gnupg2
# Add the package verification key
RUN apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 7F0CEB10
# Add MongoDB to the repository sources list
RUN echo 'deb http://downloads-distro.mongodb.org/repo/ubuntu-upstart dist 10gen' > tee /etc/apt/sources.list.d/mongodb.list
# Update the repository sources list
RUN apt-get update
# Install MongoDB package (.deb)
RUN apt-get install -y mongodb
# Create the default data directory
RUN mkdir -p /data/db
# Expose the default port
EXPOSE 27017
# Default port to execute the entrypoint (MongoDB)
CMD ["--port 27017"]
# Set default container command
ENTRYPOINT usr/bin/mongodb在此Dockerfile中, 将ubuntu设置为基本映像。然后提到安装MongoDB所需的命令和参数。端口27017通过默认容器命令usr / bin / mongodb暴露给MongoDB
接下来, 我将运行它来创建一个docker镜像。
运行一个Dockerfile
成功执行后, 以下命令将创建一个名为geekflare_mongodb的Docker映像。
[email protected]:~$ docker build -t geekflare_mongodb .
Sending build context to Docker daemon 667.2MB
Step 1/9 : FROM ubuntu
latest: Pulling from library/ubuntu
7413c47ba209: Pull complete
0fe7e7cbb2e8: Pull complete
1d425c982345: Pull complete
344da5c95cec: Pull complete
Digest: sha256:c303f19cfe9ee92badbbbd7567bc1ca47789f79303ddcef56f77687d4744cd7a
Status: Downloaded newer image for ubuntu:latest
---> 3556258649b2
Step 2/10 : RUN apt-get update && apt-get install -y gnupg2
---> Running in de3706328761
Get:1 http://security.ubuntu.com/ubuntu bionic-security InRelease [88.7 kB]
Get:2 http://archive.ubuntu.com/ubuntu bionic InRelease [242 kB]
Fetched 16.9 MB in 38s (445 kB/s)
Reading package lists...
Reading package lists...
Building dependency tree...
Reading state information...
Need to get 5187 kB of archives.
After this operation, 15.8 MB of additional disk space will be used.
Get:1 http://archive.ubuntu.com/ubuntu bionic/main amd64 readline-common all 7.0-3 [52.9 kB]
Get:2 http://archive.ubuntu.com/ubuntu bionic/main amd64 libreadline7 amd64 7.0-3 [124 kB]
Get:3 http://archive.ubuntu.com/ubuntu bionic-updates/main amd64 libsqlite3-0 amd64 3.22.0-1ubuntu0.1 [497 kB]
Get:4 http://archive.ubuntu.com/ubuntu bionic-updates/main amd64 libssl1.1 amd64 1.1.1-1ubuntu2.1~18.04.4 [1300 kB]
debconf: delaying package configuration, since apt-utils is not installed
Fetched 5187 kB in 12s (416 kB/s)
Selecting previously unselected package readline-common.
(Reading database ... 4040 files and directories currently installed.)
Preparing to unpack .../00-readline-common_7.0-3_all.deb ...
Unpacking readline-common (7.0-3) ...
Selecting previously unselected package libreadline7:amd64.
Preparing to unpack .../01-libreadline7_7.0-3_amd64.deb ...
Selecting previously unselected package dirmngr.
Setting up libnpth0:amd64 (1.5-3) ...
Setting up libksba8:amd64 (1.3.5-2) ...
Setting up gnupg-l10n (2.2.4-1ubuntu1.2) ...
Processing triggers for libc-bin (2.27-3ubuntu1) ...
Removing intermediate container de3706328761
---> a32533894ed1
Step 3/10 : RUN apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 7F0CEB10
---> Running in 69c4dba38983
Warning: apt-key output should not be parsed (stdout is not a terminal)
Executing: /tmp/apt-key-gpghome.MuT5BDWwKZ/gpg.1.sh --keyserver hkp://keyserver.ubuntu.com:80 --recv 7F0CEB10
gpg: key 5F8F93707F0CEB10: public key "Totally Legit Signing Key <[email protected]>" imported
gpg: key 9ECBEC467F0CEB10: 1 signature not checked due to a missing key
gpg: key 9ECBEC467F0CEB10: public key "Richard Kreuter <[email protected]>" imported
gpg: Total number processed: 2
gpg: imported: 2
Removing intermediate container 69c4dba38983
---> cffbe06c1b50
Step 4/10 : RUN echo 'deb http://downloads-distro.mongodb.org/repo/ubuntu-upstart dist 10gen' > tee /etc/apt/sources.list.d/mongodb.list
---> Running in 40630fd7b0a9
Removing intermediate container 40630fd7b0a9
---> a1bd9d8d7e51
Step 5/10 : RUN apt-get update
---> Running in 750717d9c0ea
Hit:1 http://archive.ubuntu.com/ubuntu bionic InRelease
Hit:2 http://archive.ubuntu.com/ubuntu bionic-updates InRelease
Hit:3 http://security.ubuntu.com/ubuntu bionic-security InRelease
Hit:4 http://archive.ubuntu.com/ubuntu bionic-backports InRelease
Reading package lists...
Removing intermediate container 750717d9c0ea
---> 397d6501db58
Step 6/10 : RUN apt-get install -y mongodb
---> Running in 88609c005e73
Reading package lists...
Building dependency tree...
Reading state information...
The following NEW packages will be installed:
libboost-filesystem1.65.1 libboost-iostreams1.65.1
libboost-program-options1.65.1 libboost-system1.65.1 libgoogle-perftools4
libpcap0.8 libpcrecpp0v5 libsnappy1v5 libstemmer0d libtcmalloc-minimal4
libunwind8 libyaml-cpp0.5v5 mongo-tools mongodb mongodb-clients
mongodb-server mongodb-server-core
0 upgraded, 17 newly installed, 0 to remove and 0 not upgraded.
Need to get 53.7 MB of archives.
After this operation, 218 MB of additional disk space will be used.
Get:1 http://archive.ubuntu.com/ubuntu bionic-updates/universe amd64 mongodb-clients amd64 1:3.6.3-0ubuntu1.1 [20.2 MB]
Get:2 http://archive.ubuntu.com/ubuntu bionic-updates/universe amd64 mongodb-server-core amd64 1:3.6.3-0ubuntu1.1 [20.3 MB]
Get:3 http://archive.ubuntu.com/ubuntu bionic-updates/universe amd64 mongodb-server all 1:3.6.3-0ubuntu1.1 [12.6 kB]
Get:4 http://archive.ubuntu.com/ubuntu bionic-updates/universe amd64 mongodb amd64 1:3.6.3-0ubuntu1.1 [9968 B]
Fetched 53.7 MB in 10s (5485 kB/s)
Selecting previously unselected package libpcap0.8:amd64.
(Reading database ... 4390 files and directories currently installed.)
Selecting previously unselected package mongodb-clients.
Preparing to unpack .../13-mongodb-clients_1%3a3.6.3-0ubuntu1.1_amd64.deb ...
Unpacking mongodb-clients (1:3.6.3-0ubuntu1.1) ...
Selecting previously unselected package mongodb-server-core.
Preparing to unpack .../14-mongodb-server-core_1%3a3.6.3-0ubuntu1.1_amd64.deb ...
Unpacking mongodb-server-core (1:3.6.3-0ubuntu1.1) ...
Selecting previously unselected package mongodb-server.
Preparing to unpack .../15-mongodb-server_1%3a3.6.3-0ubuntu1.1_all.deb ...
Unpacking mongodb-server (1:3.6.3-0ubuntu1.1) ...
Selecting previously unselected package mongodb.
Preparing to unpack .../16-mongodb_1%3a3.6.3-0ubuntu1.1_amd64.deb ...
Unpacking mongodb (1:3.6.3-0ubuntu1.1) ...
Setting up mongodb-server-core (1:3.6.3-0ubuntu1.1) ...
Setting up mongo-tools (3.6.3-0ubuntu1) ...
Setting up mongodb-clients (1:3.6.3-0ubuntu1.1) ...
Setting up mongodb-server (1:3.6.3-0ubuntu1.1) ...
invoke-rc.d: could not determine current runlevel
invoke-rc.d: policy-rc.d denied execution of start.
Setting up mongodb (1:3.6.3-0ubuntu1.1) ...
Processing triggers for libc-bin (2.27-3ubuntu1) ...
Removing intermediate container 88609c005e73
---> d9c072cb1f84
Step 7/10 : RUN mkdir -p /data/db
---> Running in f817778f69ab
Removing intermediate container f817778f69ab
---> a3fbdb3def5c
Step 8/10 : EXPOSE 27017
---> Running in 8d070e2a1e07
Removing intermediate container 8d070e2a1e07
---> f770776a538c
Step 9/10 : CMD ["--port 27017"]
---> Running in ab612410df77
Removing intermediate container ab612410df77
---> e5830b80934f
Step 10/10 : ENTRYPOINT usr/bin/mongod
---> Running in 95f574727aab
Removing intermediate container 95f574727aab
---> 095d17727ca0
Successfully built 095d17727ca0
Successfully tagged geekflare_mongodb:latest让我们检查是否使用名称geekflare_mongodb创建了docker映像。
[email protected]:~$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
geekflare_mongodb latest 095d17727ca0 3 minutes ago 325MB
ubuntu latest 3556258649b2 4 days ago 64.2MB
mean_express latest 35dcb3df9806 6 days ago 923MB
mean_angular latest 9f8d61db600c 6 days ago 1.29GB在容器mongo_container中运行docker映像geekflare_mongodb。
[email protected]:~$ docker run --name mongo_container -i -t geekflare_mongodb
2019-07-27T19:38:23.734+0000 I CONTROL [initandlisten] MongoDB starting : pid=6 port=27017 dbpath=/data/db 64-bit host=b0095c1e5536
2019-07-27T19:38:23.735+0000 I CONTROL [initandlisten] db version v3.6.3
2019-07-27T19:38:23.735+0000 I CONTROL [initandlisten] git version: 9586e557d54ef70f9ca4b43c26892cd55257e1a5
2019-07-27T19:38:23.736+0000 I CONTROL [initandlisten] OpenSSL version: OpenSSL 1.1.1 11 Sep 2018
2019-07-27T19:38:23.739+0000 I CONTROL [initandlisten] allocator: tcmalloc
2019-07-27T19:38:23.739+0000 I CONTROL [initandlisten] modules: none
2019-07-27T19:38:23.739+0000 I CONTROL [initandlisten] build environment:
2019-07-27T19:38:23.739+0000 I CONTROL [initandlisten] distarch: x86_64
2019-07-27T19:38:23.739+0000 I CONTROL [initandlisten] target_arch: x86_64
2019-07-27T19:38:23.739+0000 I CONTROL [initandlisten] options: {}
2019-07-27T19:38:23.745+0000 I STORAGE [initandlisten] wiredtiger_open config: create, cache_size=2038M, session_max=20000, eviction=(threads_min=4, threads_max=4), config_base=false, statistics=(fast), log=(enabled=true, archive=true, path=journal, compressor=snappy), file_manager=(close_idle_time=100000), statistics_log=(wait=0), verbose=(recovery_progress), 2019-07-27T19:38:24.733+0000 I CONTROL [initandlisten]
2019-07-27T19:38:24.734+0000 I CONTROL [initandlisten] ** WARNING: Access control is not enabled for the database.
2019-07-27T19:38:24.735+0000 I CONTROL [initandlisten] ** Read and write access to data and configuration is unrestricted.
2019-07-27T19:38:24.736+0000 I CONTROL [initandlisten] ** WARNING: You are running this process as the root user, which is not recommended.
2019-07-27T19:38:24.736+0000 I CONTROL [initandlisten]
2019-07-27T19:38:24.736+0000 I CONTROL [initandlisten] ** WARNING: This server is bound to localhost.
2019-07-27T19:38:24.737+0000 I CONTROL [initandlisten] ** Remote systems will be unable to connect to this server.
2019-07-27T19:38:24.737+0000 I CONTROL [initandlisten] ** Start the server with --bind_ip <address> to specify which IP
2019-07-27T19:38:24.737+0000 I CONTROL [initandlisten] ** addresses it should serve responses from, or with --bind_ip_all to
2019-07-27T19:38:24.737+0000 I CONTROL [initandlisten] ** bind to all interfaces. If this behavior is desired, start the
2019-07-27T19:38:24.738+0000 I CONTROL [initandlisten] ** server with --bind_ip 127.0.0.1 to disable this warning.
2019-07-27T19:38:24.738+0000 I CONTROL [initandlisten]
2019-07-27T19:38:24.739+0000 I STORAGE [initandlisten] createCollection: admin.system.version with provided UUID: 4b8b509d-633a-46c1-a302-cb8c82b0d5d3
2019-07-27T19:38:24.788+0000 I COMMAND [initandlisten] setting featureCompatibilityVersion to 3.6
2019-07-27T19:38:24.818+0000 I STORAGE [initandlisten] createCollection: local.startup_log with generated UUID: 6c1c0366-4b1b-4b92-9fcd-d18acc126072
2019-07-27T19:38:24.862+0000 I FTDC [initandlisten] Initializing full-time diagnostic data capture with directory '/data/db/diagnostic.data'
2019-07-27T19:38:24.866+0000 I NETWORK [initandlisten] waiting for connections on port 27017打开一个新终端, 然后检查mongo_container是否正在运行。
[email protected]:~$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
b0095c1e5536 geekflare_mongodb "/bin/sh -c usr/bin/…" 35 seconds ago Up 33 seconds 27017/tcp mongo_container如你所见, 从geekflare_mongodb映像创建的容器已启动并正在运行。
我希望这能使你对dockerfile及其好处有所了解。你还可以查看有关Dockerfile最佳实践的文档以了解更多信息。
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