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docker DevOps

容器技术和docker简介

docker环境的各种搭建方法

通过Vagrant非常方便的安装一台linux虚拟机

# mkdir centos7
# cd cnetos7
# vagrant init centos/7
# vagrant up
# vagrant ssh
# sudo yum update
# vagrant status

# vagrant halt
# vagrant destroy

在centos上面安装docker

[cnetos安装docker](https://docs.docker.com/install/linux/docker-ce/centos/)

# centos7 启动docker

sudo systemctl start docker

cnetos安装docker

docker machine的本地使用 : vagrant 的另一种选择

什么是docker machine ? 是一个自动在虚拟机上安装docker engine的工具

docker-machine create demo # 通过一行命令创建一个使用docker的虚拟机    Boot2Docker ISO

docker-machine ls  # 列出创建好的docker-machine

连接docker server的方法:

# 使用方法一:
docker-machine ssh demo  # 进到demo机器里面

# 使用方法二:

~ devops> docker-machine env demo # 导出demo的环境变量

# Run this command to configure your shell:
# eval $(docker-machine env demo)

这样也能连接上


在ECS/AWS上面使用docker

  1. 安装阿里云driver driver 下载

  2. 拷贝bin文件到 /usr/local/bin/

  3. 验证安装成功


# 使用docker-machine是为了方便创建,直接在ecs上下载安装也是可以的
docker-machine create -d aliyunecs --help


# 下面的方法记得选择‘按量付费’
docker-machine create -d aliyunecs --aliyunecs-io-optimized=optimized --aliyunecs-description=aliyunecs-machine-driver --aliyunecs-instance-type=ecs.sn2.medium --aliyunecs-access-key-id=xx --aliyunecs-access-key-secret=yy  --aliyunecs-region=cn-hangzhou --aliyunecs-ssh-password=10086 docker-devops



Status Code: 403 Code: Forbidden.RAM Message: User not authorized to operate on the specified resource, or this API doesn't support RAM.

解决办法:在控制台的RAM授权

Failed to create instance: Aliyun API Error: RequestId: FB1F011A-C63A-4447-9D65-58687CBF3864 Status Code: 403 Code: InvalidResourceType.NotSupported Message: This resource type is not supported; please try other resource types.


docker playgorund

docker的镜像和容器

docker的架构和底层技术

docker engine:基础设施之上,应用程序之下

核心概念,具体包含

  • 后台进程(dockerd)
  • REST API Server
  • CLI接口(docker)

docker image 镜像

什么是image ?

  • 文件和meta data的集合 (root filesystem)
  • 分层的,并且每一层都可以添加改变删除文件,成为一个新的image
  • 不同的image可以共享相同的layer
  • image本身是只读的
# 列举本地已有的image
docker image ls

docker image 怎么获取

方法有二:

  1. docfile生成
  2. 从registry拉取,官方维护的hub,类似github
docker pull ubuntu:14.04

创建一个自己的 base image(直接基于Linux kernel)

为当前用户添加使用docker的权限

<!--每次docker version都需要sudo权限,通过如下方式解决-->
sudo groupadd docker
sudo gpasswd -a vagrnat docker

退出重入

执行image 就是去创建一个容器container

通过docfile创建自己的base image

mkdir -p base-image/hello-world
cd base-image/hello-world
vi hello.c

sudo yum install -y gcc glibc glibc-static
gcc -static hello.c  -o hello


vi Dockerfile  # 注意D大写

FROM scratch  # 不基于任何base image
ADD hello /   # 添加hello
CMD ["/hello"] # 执行命令

docker build -t xiaoxiang/hello-world .
docker image ls
docker history xiaoxiang/hello-world:latest
docker run xiaoxiang/hello-world  # docker run + Image = Container

初识container

  • 通过Image创建(copy)
  • 在Image layer之上建立一个container layer(可读写)
  • 类比面向对象:类和实例
  • Image负责app的存储和分发,Container负责运行app
docker container ls -a  # 查看全部的container

[vagrant@localhost hello-world]$ docker container ls -a
CONTAINER ID        IMAGE                   COMMAND             CREATED             STATUS                         PORTS               NAMES
74be44284dde        xiaoxiang/hello-world   "/hello"            11 minutes ago      Exited (13) 11 minutes ago                         determined_sinoussi
5dde243d053c        hello-world             "/hello"            42 minutes ago      Exited (0) 42 minutes ago                          dreamy_brahmagupta
40447e6eeb7f        hello-world             "/hello"            About an hour ago   Exited (0) About an hour ago                       condescending_yonath
docker run -it centos # 交互式运行,并无退出

docker -h # 查看帮助

alias:

docker rm <container id> # 移除一个container
docker ps -a  # 列出所有container
docker images # 列出所有image
docker rmi <image id>
docker rm $(docker container ls -aq) # 删除全部容器
docker rm $(docker container ls -f "status=exited" -q) # 删除已退出的容器

构建自己的docker image (镜像),方式有二:

# 1. 方法一:依据container生成image
docker container commit  # 简写为 docker commit,作用是:先依据某个Image创建一个container,做了一些变化,比如安装了一些软件等,然后依据这个container的修改生成一个image

# 2. 方法二:依据dockerfile生成image
docker image build  # 依据一个Docfile生成一个image ,简写 docker build

example

vagrant ssh
docker run -it centos
yum install -y vim


exit

[vagrant@localhost ~]$ docker ps -a
CONTAINER ID        IMAGE                   COMMAND             CREATED             STATUS                     PORTS               NAMES
f7260ede0e30        centos                  "/bin/bash"         3 minutes ago       Exited (0) 7 seconds ago                       reverent_ardinghelli
2cc06dd1fcb8        centos                  "/bin/bash"         4 minutes ago       Exited (0) 4 minutes ago                       vigilant_wing
4e1a841aba2b        centos                  "/bin/bash"         5 minutes ago       Exited (0) 5 minutes ago                       cocky_hypatia
74be44284dde        xiaoxiang/hello-world   "/hello"            47 hours ago        Exited (13) 47 hours ago                       determined_sinoussi
5dde243d053c        hello-world             "/hello"            47 hours ago        Exited (0) 47 hours ago                        dreamy_brahmagupta
40447e6eeb7f        hello-world             "/hello"            2 days ago          Exited (0) 2 days ago                          condescending_yonath
[vagrant@localhost ~]$ docker commit reverent_ardinghelli xiaoxiang/centos-vim
sha256:f5d1fa30bb6452358cdbe2f0542e946e0db43f460cca3278e03cad9b4f9b189c
[vagrant@localhost ~]$ docker images
REPOSITORY              TAG                 IMAGE ID            CREATED             SIZE
xiaoxiang/centos-vim    latest              f5d1fa30bb64        10 seconds ago      354MB
xiaoxiang/hello-world   latest              5cd6164ce49d        47 hours ago        844kB
centos                  latest              2d194b392dd1        2 weeks ago         195MB
hello-world             latest              f2a91732366c        4 months ago        1.85kB

[vagrant@localhost ~]$ docker run -it xiaoxiang/centos-vim
[root@15c4682a0f03 /]# vim # 正常使用


[vagrant@localhost ~]$ docker history 2d194b392dd1
IMAGE               CREATED             CREATED BY                                      SIZE                COMMENT
2d194b392dd1        2 weeks ago         /bin/sh -c #(nop)  CMD ["/bin/bash"]            0B
<missing>           2 weeks ago         /bin/sh -c #(nop)  LABEL name=CentOS Base Im…   0B
<missing>           2 weeks ago         /bin/sh -c #(nop) ADD file:8d83f3e2c14f39e7f…   195MB
[vagrant@localhost ~]$ docker history f5d1fa30bb64
IMAGE               CREATED             CREATED BY                                      SIZE                COMMENT
f5d1fa30bb64        18 minutes ago      /bin/bash                                       158MB
2d194b392dd1        2 weeks ago         /bin/sh -c #(nop)  CMD ["/bin/bash"]            0B
<missing>           2 weeks ago         /bin/sh -c #(nop)  LABEL name=CentOS Base Im…   0B
<missing>           2 weeks ago         /bin/sh -c #(nop) ADD file:8d83f3e2c14f39e7f…   195MB

对比上述发现,多了一层,这一层,主要是安装vim。

上述创建image的方式并不提倡,我们一般提倡通过Dockerfile创建Image

要删除Image,需要实现删除使用它的container

docker image rm image-id

使用Dockerfile创建image

vi Dockerfile
docker build -t xiaoxiang/centos-vim-docfile .

Dockerfile语法梳理和最佳实践: 最佳代码案例:https://github.com/docker-library

  1. FROM
  • !尽量使用官方的image作为base image
  1. LABEL
  • 定义了image的meta data,比如作者,版本,描述 等
  • MetaData不可少
  1. RUN
  • 每次运行RUN都会生成一层,所以为了避免无用分层,合并多条命令成一行
  • 为了美观,复杂的RUN请用反斜线换行
  1. WORKDIR
  • 设定当前工作目录,如果没有会去自动创建目录
  • 使用WORKDIR,不要使用RUN cd
  • 尽量使用绝对目录
  1. ADD COPY
  • 把本地的文件添加到image当中去
  • 大部分情况,COPY优于ADD,ADD除了COPY还有额外功能(解压)
  • 添加远程文件/目录请使用curl或者wget
  1. ENV : 尽量使用ENV增加可维护性
  • 设置常量
ENV MYSQL_VERSION 5.6 # 设置常量
RUN apt-get install -y mysql-server= "${MYSQL_VERSION}" \
	&& rm -rf /var/lib/apt/list/*
  1. VOLUME & EXPOSE : 存储和网络

  2. CMD & ENTRYPOINT

example

FROM debian:stretch-slim

# add our user and group first to make sure their IDs get assigned consistently, regardless of whatever dependencies get added
RUN groupadd -r mysql && useradd -r -g mysql mysql

RUN apt-get update && apt-get install -y --no-install-recommends gnupg dirmngr && rm -rf /var/lib/apt/lists/*

# add gosu for easy step-down from root
ENV GOSU_VERSION 1.7
RUN set -x \
	&& apt-get update && apt-get install -y --no-install-recommends ca-certificates wget && rm -rf /var/lib/apt/lists/* \
	&& wget -O /usr/local/bin/gosu "https://github.com/tianon/gosu/releases/download/$GOSU_VERSION/gosu-$(dpkg --print-architecture)" \
	&& wget -O /usr/local/bin/gosu.asc "https://github.com/tianon/gosu/releases/download/$GOSU_VERSION/gosu-$(dpkg --print-architecture).asc" \
	&& export GNUPGHOME="$(mktemp -d)" \
	&& gpg --keyserver ha.pool.sks-keyservers.net --recv-keys B42F6819007F00F88E364FD4036A9C25BF357DD4 \
	&& gpg --batch --verify /usr/local/bin/gosu.asc /usr/local/bin/gosu \
	&& rm -rf "$GNUPGHOME" /usr/local/bin/gosu.asc \
	&& chmod +x /usr/local/bin/gosu \
	&& gosu nobody true \
	&& apt-get purge -y --auto-remove ca-certificates wget

RUN mkdir /docker-entrypoint-initdb.d

RUN apt-get update && apt-get install -y --no-install-recommends \
# for MYSQL_RANDOM_ROOT_PASSWORD
		pwgen \
# for mysql_ssl_rsa_setup
		openssl \
# FATAL ERROR: please install the following Perl modules before executing /usr/local/mysql/scripts/mysql_install_db:
# File::Basename
# File::Copy
# Sys::Hostname
# Data::Dumper
		perl \
	&& rm -rf /var/lib/apt/lists/*

RUN set -ex; \
# gpg: key 5072E1F5: public key "MySQL Release Engineering <mysql-build@oss.oracle.com>" imported
	key='A4A9406876FCBD3C456770C88C718D3B5072E1F5'; \
	export GNUPGHOME="$(mktemp -d)"; \
	gpg --keyserver ha.pool.sks-keyservers.net --recv-keys "$key"; \
	gpg --export "$key" > /etc/apt/trusted.gpg.d/mysql.gpg; \
	rm -rf "$GNUPGHOME"; \
	apt-key list > /dev/null

ENV MYSQL_MAJOR 5.7
ENV MYSQL_VERSION 5.7.21-1debian9

RUN echo "deb http://repo.mysql.com/apt/debian/ stretch mysql-${MYSQL_MAJOR}" > /etc/apt/sources.list.d/mysql.list

# the "/var/lib/mysql" stuff here is because the mysql-server postinst doesn't have an explicit way to disable the mysql_install_db codepath besides having a database already "configured" (ie, stuff in /var/lib/mysql/mysql)
# also, we set debconf keys to make APT a little quieter
RUN { \
		echo mysql-community-server mysql-community-server/data-dir select ''; \
		echo mysql-community-server mysql-community-server/root-pass password ''; \
		echo mysql-community-server mysql-community-server/re-root-pass password ''; \
		echo mysql-community-server mysql-community-server/remove-test-db select false; \
	} | debconf-set-selections \
	&& apt-get update && apt-get install -y mysql-server="${MYSQL_VERSION}" && rm -rf /var/lib/apt/lists/* \
	&& rm -rf /var/lib/mysql && mkdir -p /var/lib/mysql /var/run/mysqld \
	&& chown -R mysql:mysql /var/lib/mysql /var/run/mysqld \
# ensure that /var/run/mysqld (used for socket and lock files) is writable regardless of the UID our mysqld instance ends up having at runtime
	&& chmod 777 /var/run/mysqld \
# comment out a few problematic configuration values
	&& find /etc/mysql/ -name '*.cnf' -print0 \
		| xargs -0 grep -lZE '^(bind-address|log)' \
		| xargs -rt -0 sed -Ei 's/^(bind-address|log)/#&/' \
# don't reverse lookup hostnames, they are usually another container
	&& echo '[mysqld]\nskip-host-cache\nskip-name-resolve' > /etc/mysql/conf.d/docker.cnf

VOLUME /var/lib/mysql

COPY docker-entrypoint.sh /usr/local/bin/
RUN ln -s usr/local/bin/docker-entrypoint.sh /entrypoint.sh # backwards compat
ENTRYPOINT ["docker-entrypoint.sh"]

EXPOSE 3306
CMD ["mysqld"]

RUN & CMD & ENTRYPOINT

RUN: 执行命令并创建新的Image Layer CMD: 设置容器启动后默认执行的命令和参数 ENTRYPOINT: 设置容器启动时运行的命令

Shell格式:

RUN apt-get install -y vim
CMD echo "hello,  docker"
ENTRYPOINT echo "hello docker"

Exec格式

RUN ["apt-get", "install", "-y", "vim"]
CMD ["/bin/echo", "hello, docker"]
ENTRYPOINT ["/bin/echo", "hello, docker"]

注意: shell格式的 ENTRYPOINT echo "hello docker" 等价于exec格式的 ENTRYPOINT ["/bin/bash","-c", "echo hello, docker"]

docker build -t xiaoxiang/hello-world .   # 依据Dockerfile构建的运行命令

CMD

  1. 容器启动时默认执行的命令
  2. 如果docker run指定了其他命令,CMD命令被忽略
  3. 如果定义了多个CMD,只有最后一个会执行

ENTRYPOINT

  1. 让容器以应用程序或者服务的形式运行,一般用来启动后台服务
  2. 不会被忽略,一定会执行
  3. 最佳实践:写一个shell脚本作为entrypoint
COPY docker-entrypoint.sh /usr/local/bin/
ENTRYPOINT ["docker-entrypoint.sh"]

EXPOSE 27017
CMD ["mongod"]

镜像的发布

想要推送到docker hub,必须以自己的docker id开头,类似 lazyreduceyourintelligence/hello-world


# 1. docker 登录
docker login

# 2. 推送repo到远程
docker push lazyreduceyourintelligence/hello-world:latest

# 3. 拉取远程repo
docker pull lazyreduceyourintelligence/hello-world

上面的方式并不推荐,最好的方式是:整合docker hub和github,自动化部署

1.自建 docker registry: 类似私有的docker hub


remote-server: docker run -d -p 5000:5000 --restart always --name registry registry:2


注意:
- {"insecure-registries":["139.129.44.2:5000"]}  sudo vi /etc/docker/daemon.json
- sudo vi /lib/systemd/system/docker.service  EnvironmentFile=-/etc/docker/daemon.json
- restart docker: sudo service docker restart

  1. Dockerfile 实战

EXPOSE 暴露端口

  1. 容器的操作
- docker exec

# 操作docker container

docker logs/inspect container-id
  1. 实战2
docker run -it ubuntu


bash# apt-get update && apt-get install -y stress  # linux压测工具

stress --vm 1 --verbose

top # 查看docker host的资源使用情况


> 如何向Dockerfile传参

FROM ubuntu
RUN apt-get update && apt-get install -y stress
ENTRYPOINT ["/usr/bin/stress"]
CMD []  # 典型方式

docker run c69 --vm 1 --verbose

  1. 容器的资源限制
设置内存:docker run --memory=200M c69 --vm 1 --verbose --vm-bytes 500M  #限制了内存,创建container失败

设置cpu: cpu-shares

docker的网络

网络的分层 docker network

网络基础

ping 检查连通性 ping ip telnet 检查服务的可用性 telnet ip port

有可能可以ping通,但是不能telnet,此种情况多是防火墙

wireshark 工具

linux网络命名空间


sudo docker run -d --name test1 busybox /bin/sh -c "while true; do sleep 3600;done"

不同的linux的网络命名空间 able to ping each other

docker容器之间可以相互ping通 查看ip :cat /etc/hosts

docker的持久化存储和数据共享

docker compose多容器部署

容器编排 docker swarm

devops初体验

容器编排 kubernetes

容器的运维和监控

Docker+DevOps实战——过程和工具