【干活实战】Docker新建centos镜像并配置远程访问
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写在前面
我们可能遇到过这种情况 , 为我们用于练习 , 需要好几台服务器 , 但是我们又没有 , 但是也想用 , 怎么办呢?
Docker可以帮助我们解决 , 我们知道Docker镜像中有一个centos镜像 , 他就相当于一个小型的虚拟机 , 服务器 , 我们可以启动多次centos镜像容器来达到多个服务器的效果 。
下面我来带大家配置Docker创建centos镜像 , 并配置远程访问
- 查找官方centos镜像
[root@wangliuchuang ~]# docker search centos
NAME DESCRIPTION STARS OFFICIAL AUTOMATED
centos The official build of CentOS. 6823 [OK]
ansible/centos7-ansible Ansible on Centos7 135 [OK]
consol/centos-xfce-vnc Centos container with "headless" VNC session… 132 [OK]
jdeathe/centos-ssh OpenSSH / Supervisor / EPEL/IUS/SCL Repos - … 121 [OK]
centos/systemd systemd enabled base container. 104 [OK]
imagine10255/centos6-lnmp-php56 centos6-lnmp-php56 58 [OK]
tutum/centos Simple CentOS docker image with SSH access 48
centos/postgresql-96-centos7 PostgreSQL is an advanced Object-Relational … 45
centos/httpd-24-centos7 Platform for running Apache httpd 2.4 or bui… 40
.......
starlabio/centos-native-build Our CentOS image for native builds 0 [OK]
smartentry/centos centos with smartentry 0 [OK]
- 下载镜像(不选择版本 , 默认下载的是最新的版本)
[root@hrkj-video ~]# docker pull centos
Using default tag: latest
latest: Pulling from library/centos
a1d0c7532777: Pull complete
Digest: sha256:a27fd8080b517143cbbbab9dfb7c8571c40d67d534bbdee55bd6c473f432b177
Status: Downloaded newer image for centos:latest
[root@hrkj-video ~]#
- Docker启动镜像
[root@wangliuchuang ~]# docker run -it -d --name centos-latest --privileged=true centos /sbin/init
3f04ab1a71dc67a41dcf69bc81fcd9d16ead89457be09f7f1593c7518daa4ab6
[root@wangliuchuang ~]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
c3053259c69c centos "/sbin/init" 7 seconds ago Up 7 seconds centos-latest
[root@wangliuchuang ~]#
注意 : 在Linux Docker 中无法使用 systemd(systemctl) 相关命令的原因是1号进程不是init , 而是其他例如 /bin/bash ,
所以导致相关文件无法进行 (System has not been booted with systemd as init system (PID 1). Can’t operat)
解决方案 : /sbin/init并且--privilaged=true一定要加上的。
- Docker查看centos容器的启动情况
[root@wangliuchuang ~]# docker ps | grep centos
c3053259c69c centos "/sbin/init" 2 minutes ago Up 2 minutes centos-latest
[root@wangliuchuang ~]#
- Docker进入到centos容器
[root@wangliuchuang ~]# docker exec -it c3053259c69c /bin/bash
[root@c3053259c69c /]# ifconfig
bash: ifconfig: command not found
[root@c3053259c69c /]#
- 安装centos基础环境 (安装网络环境，完成后使用ifconfig查看ip等信息)
yum -y install net-tools.x86_64
yum -y install openssh-server
yum install vim
yum install passwd
命令演示 :
[root@c3053259c69c /]# yum -y install net-tools.x86_64
Failed to set locale, defaulting to C.UTF-8
CentOS Linux 8 - AppStream 9.7 MB/s | 9.5 MB 00:00
CentOS Linux 8 - BaseOS 592 kB/s | 7.5 MB 00:13
CentOS Linux 8 - Extras 13 kB/s | 10 kB 00:00
Dependencies resolved.
=====================================================================================================================================================================
Package Architecture Version Repository Size
=====================================================================================================================================================================
Installing:
net-tools x86_64 2.0-0.52.20160912git.el8 baseos 322 k
.......
Installed:
net-tools-2.0-0.52.20160912git.el8.x86_64
Complete!
[root@c3053259c69c /]#
# 安装 sshd
[root@c3053259c69c /]# yum -y install openssh-server
Failed to set locale, defaulting to C.UTF-8
Last metadata expiration check: 0:01:31 ago on Thu Oct 28 10:24:23 2021.
Dependencies resolved.
=====================================================================================================================================================================
Package Architecture Version Repository Size
=====================================================================================================================================================================
.....
Complete!
[root@c3053259c69c /]#
# 安装 vim
[root@c3053259c69c /]# yum install vim
Failed to set locale, defaulting to C.UTF-8
Last metadata expiration check: 0:02:01 ago on Wed Nov 3 03:03:33 2021.
Dependencies resolved.
===================================================================================================================================================================
Package Architecture Version Repository Size
===================================================================================================================================================================
....
Installed:
gpm-libs-1.20.7-17.el8.x86_64 vim-common-2:8.0.1763-15.el8.x86_64 vim-enhanced-2:8.0.1763-15.el8.x86_64 vim-filesystem-2:8.0.1763-15.el8.noarch
which-2.21-12.el8.x86_64
Complete!
[root@c3053259c69c /]#
# 安装 passwd
[root@c3053259c69c /]# yum install passwd
Failed to set locale, defaulting to C.UTF-8
Last metadata expiration check: 0:03:31 ago on Wed Nov 3 03:03:33 2021.
Dependencies resolved.
===================================================================================================================================================================
Package Architecture Version Repository Size
===================================================================================================================================================================
Installing:
....
libuser-0.62-23.el8.x86_64 passwd-0.80-3.el8.x86_64
Complete!
[root@c3053259c69c /]#
- 修改root密码 , 服务器的登录密码
[root@c3053259c69c /]# passwd
Changing password for user root.
New password: # 输入新密码
Retype new password: # 再次输入密码
passwd: all authentication tokens updated successfully.
[root@c3053259c69c /]#
- 启动容器sshd服务
[root@c3053259c69c /]# /usr/sbin/sshd (此命令可以会出现问题 , 下面有对应的解决方案)
[root@c3053259c69c /]# netstat -antp | grep sshd
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 233/sshd
tcp6 0 0 :::22 :::* LISTEN 233/sshd
[root@c3053259c69c /]#
问题 :
[root@c3053259c69c /]# /usr/sbin/sshd
Unable to load host key: /etc/ssh/ssh_host_rsa_key
Unable to load host key: /etc/ssh/ssh_host_ecdsa_key
Unable to load host key: /etc/ssh/ssh_host_ed25519_key
sshd: no hostkeys available -- exiting.
[root@c3053259c69c /]#
解决方案 : 执行以下命令
ssh-keygen -t rsa -f /etc/ssh/ssh_host_rsa_key -N ""
ssh-keygen -t ecdsa -f /etc/ssh/ssh_host_ecdsa_key -N ""
ssh-keygen -t ed25519 -f /etc/ssh/ssh_host_ed25519_key -N ""
- 提交镜像
[root@c3053259c69c /]#
[root@c3053259c69c /]# (使用 Ctrl + p + q) 来不停止退出容器
[root@wangliuchuang ~]#
[root@wangliuchuang ~]#
# 提交镜像
[root@wangliuchuang ~]# docker commit -a="lep" -m "this is a ssh_centos" c3053259c69c ssh_centos
sha256:0c6d3118787dc04f0da1851f6a2c24f8f5ec8cb9026ac799d86a11e875986399
[root@wangliuchuang ~]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
ssh_centos latest 0c6d3118787d 4 seconds ago 310MB
centos latest 5d0da3dc9764 6 weeks ago 231MB
[root@wangliuchuang ~]#
运行测试
- 指定端口来启动新的镜像
[root@wangliuchuang ~]# docker run -it -d --name k8s-master -p 7010:22 --privileged=true ssh_centos /sbin/init
b07adedf27ff22f1e37aff9943c79bfeb740cedc51c71538c48fa526d1b5bb1b
[root@wangliuchuang ~]#
[root@wangliuchuang ~]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
b07adedf27ff ssh_centos "/sbin/init" 34 seconds ago Up 33 seconds 0.0.0.0:7010->22/tcp k8s-master
- 测试访问(外网访问)
C:\Users\lep>ssh root@wangliuchuang.top -p 7010
The authenticity of host '[wangliuchuang.top]:7010 ([39.105.56.212]:7010)' can't be established.
ECDSA key fingerprint is SHA256:e2NfNXC+RLLrW9rwfwInjtRW2hGTMwbYwnlUOIF4iaQ.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added '[wangliuchuang.top]:7010,[39.105.56.212]:7010' (ECDSA) to the list of known hosts.
root@wangliuchuang.top's password:
Last login: Wed Nov 3 03:47:22 2021 from 103.208.12.5
[root@b07adedf27ff ~]#
配置容器自启动
当我们重启服务器时 , 容器也会跟着停止 , 这样是很危险的 , 所以下面配置了容器自启动
设置容器参数 docker update --restart=always 容器id
[root@wangliuchuang ~]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
c3053259c69c centos "/sbin/init" 18 minutes ago Up 18 minutes centos-latest
[root@wangliuchuang ~]# docker update --restart=always c3053259c69c
c3053259c69c
[root@wangliuchuang ~]#
还可以在使用on - failure策略时，指定Docker将尝试重新启动容器的最大次数
docker run --restart=on-failure:10 容器id
Docker启动时 , 指定容器的ip
Docker创建容器时默认采用bridge网络 , 自行分配ip , 不允许自己指定
在实际的部署中 , 我们需要指定容器的ip , 不允许其自行分配ip , 尤其是搭建集群时 , 固定的ip是必须的
我们可以创建自己的bridge网络 : mynet , 创建容器时指定网络mynet并指定ip即可
- 查看网络模式
[root@wangliuchuang /]# docker network ls
NETWORK ID NAME DRIVER SCOPE
11565a6f8478 bridge bridge local
43b7c730c59d host host local
d6f31afd8e07 none null local
[root@wangliuchuang /]#
- 创建一个新的bridge网络
[root@wangliuchuang ~]# docker network create --driver bridge --subnet 192.168.0.0/16 --gateway 192.168.0.1 k8s-mynet
7402804f99b8096b231b85066eb90d303061f2504c3d8ff9d6d425e8a5d00324
[root@wangliuchuang ~]# docker network ls
NETWORK ID NAME DRIVER SCOPE
11565a6f8478 bridge bridge local
43b7c730c59d host host local
7402804f99b8 k8s-mynet bridge local
d6f31afd8e07 none null local
[root@wangliuchuang ~]#
- 查看创建的网络的信息
[root@wangliuchuang ~]# docker network inspect 7402804f99b8
[
{
"Name": "k8s-mynet",
"Id": "7402804f99b8096b231b85066eb90d303061f2504c3d8ff9d6d425e8a5d00324",
"Created": "2021-11-03T15:11:20.019208537+08:00",
"Scope": "local",
"Driver": "bridge",
"EnableIPv6": false,
"IPAM": {
"Driver": "default",
"Options": {},
"Config": [
{
"Subnet": "192.168.0.0/16",
"Gateway": "192.168.0.1"
}
]
},
"Internal": false,
"Attachable": false,
"Ingress": false,
"ConfigFrom": {
"Network": ""
},
"ConfigOnly": false,
"Containers": {},
"Options": {},
"Labels": {}
}
]
[root@wangliuchuang ~]#
- 指定端口 , 指定网络 , 指定ip 来启动一个容器(注意 ; 分配内网ip时 , 设置大点 , 不至于被占用)
[root@wangliuchuang /]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
ssh_centos latest 0c6d3118787d 6 hours ago 310MB
centos latest 5d0da3dc9764 6 weeks ago 231MB
[root@wangliuchuang /]# docker run -e TZ="Asia/Shanghai" -p 7010:22 --privileged -itd -h k8s-master --name k8s-master --network=k8s-mynet --ip 192.168.2.1 ssh_centos /usr/sbin/init
fac0f09991af0ca4902b3e7fbbb9b8e26eca30c957caded77ff96be755fc1f17
[root@wangliuchuang /]#
[root@wangliuchuang /]# ssh root@192.168.2.1
The authenticity of host '192.168.2.1 (192.168.2.1)' can't be established.
ECDSA key fingerprint is SHA256:e2NfNXC+RLLrW9rwfwInjtRW2hGTMwbYwnlUOIF4iaQ.
ECDSA key fingerprint is MD5:8f:b9:57:8a:b2:5c:d9:d9:25:7f:ac:ce:57:c5:81:be.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.2.1' (ECDSA) to the list of known hosts.
root@192.168.2.1's password:
# 可惜只能内网访问 , 外网就不行了 , 想要需要外网访问 , 还需要修改一些其他的配置
Permission denied, please try again.
root@192.168.2.1's password:
Last failed login: Wed Nov 3 09:41:42 UTC 2021 from 192.168.0.1 on ssh:notty
There was 1 failed login attempt since the last successful login.
[root@k8s-master ~]#
[root@k8s-master ~]#
如果你想在容器中使用docker命令 , 有下面两种方式
- 在docker容器中下载 docker , 但是
- -v /var/run/:/var/run/ -v /usr/bin/docker:/usr/bin/docker
The end.
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