372 lines
12 KiB
Markdown
372 lines
12 KiB
Markdown
<h1><center>Docker应用</center></h1>
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**作者：行癫（盗版必究）**
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------
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## 一：端口转发
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容器：172.16.0.2 5000
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client----->eth0:10.18.45.197------->172.16.0.2:5000
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5000
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使用端口转发解决容器端口访问问题
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-p:
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创建应用容器的时候，一般会做端口映射，这样是为了让外部能够访问这些容器里的应用。可以用多个-p指定多个端口映射关系
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mysql应用端口转发：
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```shell
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查看本地地址：
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[root@xingdian ~]# ip a
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ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
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link/ether 00:0c:29:0a:5b:8b brd ff:ff:ff:ff:ff:ff
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inet 192.168.245.134/24 brd 192.168.245.255 scope global dynamic ens33
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valid_lft 1444sec preferred_lft 1444sec
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```
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运行容器：使用-p作端口转发，把本地3307转发到容器的3306，其他参数需要查看发布容器的页面提示
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```shell
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[root@xingdian ~]# docker run --name mysql1 -p 3307:3306 -e MYSQL_ROOT_PASSWORD=123 daocloud.io/library/mysql
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```
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通过本地IP：192.168.245.134的3307端口访问容器mysql1内的数据库，出现如下提示恭喜你
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```shell
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[root@xingdian /]# mysql -u root -p123 -h 192.168.245.134 -P3307
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Welcome to the MariaDB monitor. Commands end with ; or \g.
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Your MySQL connection id is 3
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Server version: 5.7.18 MySQL Community Server (GPL)
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Copyright (c) 2000, 2016, Oracle, MariaDB Corporation Ab and others.
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Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
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MySQL [(none)]>
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```
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## 二：部署私有仓库
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仓库镜像，Docker hub官方已提供容器镜像registry,用于搭建私有仓库
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拉取镜像：
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```shell
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[root@xingdian ~]# docker pull daocloud.io/library/registry:latest
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```
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运行容器：
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```shell
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[root@xingdian ~]# docker run --restart=always -d -p 5000:5000 daocloud.io/library/registry
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```
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注：如果创建容器不成功，报错防火墙，解决方案如下
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```shell
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[root@xingdian ~]# systemctl stop firewalld
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[root@xingdian ~]# systemctl restart docker
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```
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查看运行的容器：
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```shell
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[root@xingdian ~]# docker ps
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CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
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1f444285bed8 daocloud.io/library/registry "/entrypoint.sh /etc/" 23 seconds ago Up 21 seconds 0.0.0.0:5000->5000/tcp elegant_rosalind
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```
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连接容器查看端口状态：
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```shell
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[root@xingdian ~]# docker exec -it 1f444285bed8 /bin/sh //这里是sh 不是bash
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/ # netstat -antpl //查看5000端口是否开启(容器内查看)
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Active Internet connections (only servers)
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Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
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tcp 0 0 :::5000 :::* LISTEN 1/registry
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Active UNIX domain sockets (only servers)
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Proto RefCnt Flags Type State I-Node PID/Program name Path
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```
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在本机查看能否访问该私有仓库, 看看状态码是不是200：
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```shell
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[root@xingdian registry]# curl -I 127.0.0.1:5000
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HTTP/1.1 200 OK
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Cache-Control: no-cache
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Date: Thu, 08 Oct 2020 05:34:32 GMT
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```
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为了方便，下载1个比较小的镜像,buysbox：
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```shell
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[root@xingdian registry]# docker pull busybox
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```
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上传前必须给镜像打tag 注明ip和端口：
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```shell
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[root@xingdian ~]# docker tag busybox 本机IP：端口/busybox
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```
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这是直接从官方拉的镜像，很慢：
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```shell
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[root@xingdian ~]# docker tag busybox 192.168.245.136:5000/busybox
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```
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下面这个Mysql是我测试的第二个镜像，从daocloud拉取的：
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```shell
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[root@xingdian ~]# docker tag daocloud.io/library/mysql 192.168.245.136:5000/daocloud.io/library/mysql
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```
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注意：
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tag后面可以使用镜像名称也可以使用id,我这里使用的镜像名称，如果使用官方的镜像，不需要加前缀，但是daocloud.io的得加前缀
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修改请求方式为http:
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```shell
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默认为https，不改会报以下错误:
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Get https://master.up.com:5000/v1/_ping: http: server gave HTTP response to HTTPS client
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[root@xingdian ~]# vim /etc/docker/daemon.json
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{ "insecure-registries":["192.168.245.136:5000"] }
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重启docker:
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[root@xingdian ~]# systemctl restart docker
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```
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上传镜像到私有仓库：
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```shell
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[root@xingdian ~]# docker push 192.168.245.136:5000/busybox
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[root@xingdian ~]# docker push 192.168.245.136:5000/daocloud.io/library/mysql
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```
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查看私有仓库里的所有镜像：
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```shell
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[root@xingdian ~]# curl 192.168.245.130:5000/v2/_catalog
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{"repositories":["busybox"]}
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```
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查看私有仓库里的镜像版本：
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```shell
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[root@docker ~]# curl 10.11.67.110:5000/v2/busybox/tags/list
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{"name":"busybox","tags":["v1","v2"]}
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```
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```shell
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[root@docker ~]# curl -XGET http://10.11.67.110:3000/v2/busybox/tags/list
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{"name":"busybox","tags":["v1","v2"]}
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查询镜像digest_hash，删除命令里边要填写的 镜像digest_hash 就是 查询结果里边 Docker-Content-Digest: 后边的内容
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[root@docker ~]# curl --header "Accept:application/vnd.docker.distribution.manifest.v2+json" -I -XGET http://10.11.67.110:3000/v2/busybox/manifests/v1
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HTTP/1.1 200 OK
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Content-Length: 527
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Content-Type: application/vnd.docker.distribution.manifest.v2+json
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Docker-Content-Digest: sha256:c9249fdf56138f0d929e2080ae98ee9cb2946f71498fc1484288e6a935b5e5bc
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Docker-Distribution-Api-Version: registry/2.0
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Etag: "sha256:c9249fdf56138f0d929e2080ae98ee9cb2946f71498fc1484288e6a935b5e5bc"
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X-Content-Type-Options: nosniff
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Date: Thu, 12 Nov 2020 07:29:46 GMT
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删除私有库镜像
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进入/etc/docker/registry/config.yml添加,在stroage后面加
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delete
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enabled: true
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修改完后重新启动容器
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[root@docker ~]# curl -I -XDELETE http://10.11.67.110:3000/v2/busybox/manifests/sha256:c9249fdf56138f0d929e2080ae98ee9cb2946f71498fc1484288e6a935b5e5bc
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HTTP/1.1 202 Accepted
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Docker-Distribution-Api-Version: registry/2.0
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X-Content-Type-Options: nosniff
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Date: Thu, 12 Nov 2020 07:30:22 GMT
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Content-Length: 0
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查看镜像信息可以看到镜像的标签显示为空 null
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[root@docker ~]# curl -XGET http://10.11.67.110:3000/v2/busybox/tags/list
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{"name":"busybox","tags":null}
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```
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## 三：部署centos7容器应用
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systemd 整合:
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因为 systemd 要求 CAPSYSADMIN 权限，从而得到了读取到宿主机 cgroup 的能力，CentOS7 中已经用 fakesystemd 代替了 systemd 来解决依赖问题。 如果仍然希望使用 systemd，可用参考下面的 Dockerfile：
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```shell
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[root@xingdian ~]# vim Dockerfile
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FROM daocloud.io/library/centos:7
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MAINTAINER "xingdian" xingdian@qq.com
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ENV container docker
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RUN yum -y swap -- remove fakesystemd -- install systemd systemd-libs
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RUN yum -y update; yum clean all; \
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(cd /lib/systemd/system/sysinit.target.wants/; for i in *; do [ $i == systemd-tmpfiles-setup.service ] || rm -f $i; done); \
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rm -f /lib/systemd/system/multi-user.target.wants/*;\
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rm -f /etc/systemd/system/*.wants/*;\
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rm -f /lib/systemd/system/local-fs.target.wants/*; \
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rm -f /lib/systemd/system/sockets.target.wants/*udev*; \
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rm -f /lib/systemd/system/sockets.target.wants/*initctl*; \
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rm -f /lib/systemd/system/basic.target.wants/*;\
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rm -f /lib/systemd/system/anaconda.target.wants/*;
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VOLUME [ "/sys/fs/cgroup" ]
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CMD ["/usr/sbin/init"]
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```
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这个Dockerfile删除fakesystemd 并安装了 systemd
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然后再构建基础镜像:
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```shell
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[root@xingdian ~]# docker build --rm -t local/c7-systemd .
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```
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为了使用像上面那样包含 systemd 的容器，需要创建一个类似下面的Dockerfile：
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```shell
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[root@xingdian ~]# vim Dockerfile
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FROM local/c7-systemd
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RUN yum -y install httpd; yum clean all; systemctl enable httpd.service
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EXPOSE 80
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CMD ["/usr/sbin/init"]
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```
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构建镜像：
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```shell
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[root@xingdian ~]# docker build --rm -t local/c7-systemd-httpd .
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```
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运行包含 systemd 的应用容器：
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为了运行一个包含 systemd 的容器，需要使用--privileged选项， 并且挂载主机的 cgroups 文件夹。 下面是运行包含 systemd 的 httpd 容器的示例命令：
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```shell
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[root@xingdian ~]# docker run --privileged -ti -v /sys/fs/cgroup:/sys/fs/cgroup:ro -p 80:80 local/c7-systemd-httpd
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```
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注意：上条命令不能添加/bin/bash，添加了会导致服务不可用，而且有些服务可能会发现之前提到的权限不够的问题，但是如果不加会运行在前台(没有用-d)，可以用ctrl+p+q放到后台去
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测试可用：
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```shell
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# elinks --dump http://docker //下面为apache默认页面
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Testing 123..
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This page is used to test the proper operation of the [1]Apache HTTP
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server after it has been installed. If you can read this page it means
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that this site is working properly. This server is powered by [2]CentOS.
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```
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## 四：固定容器IP
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#### 1.容器网络
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docker安装后，默认会创建三种网络类型，bridge、host和none
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显示当前网络：
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```
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[root@xingdian ~]# docker network list
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NETWORK ID NAME DRIVER SCOPE
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90b22f633d2f bridge bridge local
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e0b365da7fd2 host host local
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da7b7a090837 none null local
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```
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bridge：网络桥接
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默认情况下启动、创建容器都是用该模式，所以每次docker容器重启时会按照顺序获取对应ip地址，这就导致容器每次重启，ip都发生变化
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none：无指定网络
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启动容器时，可以通过network=none,docker容器不会分配局域网ip
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host：主机网络
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docker容器的网络会附属在主机上，两者是互通的
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#### 2.创建固定ip容器
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创建自定义网络类型，并且指定网段：
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```shell
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[root@xingdian ~]# docker network create --subnet=192.168.0.0/16 staticnet
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```
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通过docker network ls可以查看到网络类型中多了一个staticnet
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使用新的网络类型创建并启动容器：
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```shell
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[root@xingdian ~]# docker run -it --name userserver --net staticnet --ip 192.168.0.2 centos:6 /bin/bash
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```
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通过docker inspect可以查看容器ip为192.168.0.2，关闭容器并重启，发现容器ip并未发生改变
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## 五：BUG整理
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#### 1.基于centos7的docker容器出现的一个bug
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centos7下部署的docker容器中启动服务，报错如下：
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```shell
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[root@a3c8baf6961e .ssh]# systemctl restart sshd.service
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Failed to get D-Bus connection: Operation not permitted
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```
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这是centos7容器里面出现的一个BUG
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即centos7镜像创建的容器里面安装服务后，不能用systemctl/service启动服务，centos6的容器里没有这个坑！可以通过使用其他的方式启动或者换用centos6的镜像来避免这个错误
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解决方案如下：
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原因是dbus-daemon没能启动。其实systemctl并不是不可以使用，可以将你的CMD设置为/usr/sbin/init即可
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这样就会自动将dbus等服务启动起来。即采用 /usr/sbin/init自动启动dbus daemon；即把之前的容器关闭并删除（docker stop container-id），然后重新启动容器，注意：启动时一定要加上参数--privileged和/usr/sbin/init，如下
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```shell
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[root@localhost ~]# docker run --privileged -it centos7:7.3.1611 /sbin/init
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```
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#### 2.解决容器内字符集乱码问题
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容器内操作：
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1. 查找 .vimrc文件
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通常有2个地方保存这个文件的：
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在/etc/文件夹下面，是所有用户的vim配置
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每个用户的开始登录的文件夹下面
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2. 修改.vimrc文件
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建议修改当前使用的用户下面，这样只会影响到当前用户
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然后添加下面几行，保存后，重新登录即可
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```shell
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set fileencodings=utf-8,gb2312,gb18030,gbk,ucs-bom,cp936,latin1
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set enc=utf8
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set fencs=utf8,gbk,gb2312,gb18030
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```
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修改后如下：
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