Docker 创建centos容器集群并实现远程登录

Docker 创建centos容器集群并实现远程登录功能

0.拉取Docker镜像(Centos7官方版)

拉取官方镜像(这个镜像里面几乎什么都没有,很多依赖库需要自己配置,实实在在的“纯净版”。关注我,下期教你用ISO镜像文件使用dockerfile制作究极完整版docker镜像)

docker pull centos:centos7

1.搭建网桥加入网络

创建docker bridge网桥

搭建网桥可以方便管理结点,并且让结点同时位于同一个网段下

sudo docker network create NodeNetWork

创建三个不同端口的结点容器

zwb@test-algo:~$ sudo docker run -itd --restart=always --hostname node01 --name Node01 -p 50001:22 -v /data/sda/sharedata:/share --network NodeNetWork --privileged=true centos:centos7 /sbin/init

zwb@test-algo:~$ sudo docker run -itd --restart=always --hostname node02 --name Node02 -p 50002:22 -v /data/sda/sharedata:/share --network NodeNetWork --privileged=true centos:centos7 /sbin/init

zwb@test-algo:~$ sudo docker run -itd --restart=always --hostname node03 --name Node03 -p 50003:22 -v /data/sda/sharedata:/share --network NodeNetWork --privileged=true centos:centos7 /sbin/init

# 参数解释:
# -itd
# 选项		选项简写		说明
# –detach		-d		在后台运行容器,并且打印容器id。
# –interactive	-i		即使没有连接,也要保持标准输入保持打开状态,一般与 -t 连用。
# –tty			-t		分配一个伪tty,一般与 -i 连用。
# --restart=always	机器启动时自启动
# --hostname 初始化的hostname
# -p 50001:22	端口映射 宿主机端口:容器端口这里为22表示容器内ssh端口
# --privileged=true		通过特权模式进入docker,不仅可以使用systemctl命令(centos 7系统),还可以开启ssh服务
# --network NodeNetWork 将容器结点加入网桥中

# 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 ,所以导致缺少相关文件无法运行。(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

2.配置机器网络环境并加入ssh

以Node01为例子,进入结点容器并配置网络环境并加入ssh

(base) zwb@test-algo:~$ sudo docker exec -it Node01 /bin/bash
[root@aa92cb71e3ab /]# yum -y install net-tools.x86_64
Failed to set locale, defaulting to C.UTF-8
CentOS Linux 8 - AppStream                                                               26  B/s |  38  B     00:01    
Error: Failed to download metadata for repo 'appstream': Cannot prepare internal mirrorlist: No URLs in mirrorlist

可以看到我们在安装网络工具包的时候出错了,上面的报错信息意思是,从仓库 ‘appstream’ 下载元数据失败:由于镜像列表中没有 URL,不能准备内部镜像列表。

🥎问题分析:

✨第一种可能的情况便是网络连接问题。检查是否可以连接外部网络,可以使用 ping baidu.com 查看是否有丢包情况。如果丢包,则进一步检查网络连接是否正常;如果没有丢包,继续阅读下文
✨那么第二种情况,便是 CentOS 已经停止维护的问题。2020 年 12 月 8 号,CentOS 官方宣布了停止维护 CentOS Linux 的计划,并推出了 CentOS Stream 项目,CentOS Linux 8 作为 RHEL 8 的复刻版本,生命周期缩短,于 2021 年 12 月 31 日停止更新并停止维护(EOL),更多的信息可以查看 CentOS 官方公告。如果需要更新 CentOS,需要将镜像从 mirror.centos.org 更改为 vault.centos.org
🥎那么针对上面提到的第二种情况,给出的解决方法如下:

🔔 首先,进入到 yum 的 repos 目录

cd /etc/yum.repos.d/

🔔其次,修改 centos 文件内容

sed -i 's/mirrorlist/#mirrorlist/g' /etc/yum.repos.d/CentOS-*
sed -i 's|#baseurl=http://mirror.centos.org|baseurl=http://vault.centos.org|g' /etc/yum.repos.d/CentOS-*

🔔 然后,生成缓存更新(第一次更新,速度稍微有点慢,耐心等待两分钟左右)

yum makecache

🔔 最后,运行 yum update 并重新安装工具包、ssh网络环境和vim

yum update -y
yum -y install net-tools.x86_64
yum -y install openssh-server
yum install vim

安装passwd并修改root密码

yum install passwd

[root@aa92cb71e3ab yum.repos.d]# passwd
Changing password for user root.
New password: 
Retype new password: 
passwd: all authentication tokens updated successfully.

重启docker

 systemctl stop docker
 systemctl start docker

查看容器

(base) zwb@test-algo:~$ sudo  docker ps -a
CONTAINER ID   IMAGE     COMMAND        CREATED          STATUS                        PORTS                                     NAMES
2b8fa155e71f   centos    "/sbin/init"   17 minutes ago   Up 9 seconds                  0.0.0.0:50003->22/tcp, :::50003->22/tcp   Node03
97041252bf37   centos    "/sbin/init"   17 minutes ago   Up 9 seconds                  0.0.0.0:50002->22/tcp, :::50002->22/tcp   Node02
aa92cb71e3ab   centos    "/sbin/init"   17 minutes ago   Up 9 seconds                  0.0.0.0:50001->22/tcp, :::50001->22/tcp   Node01

开放宿主机防火墙

(base) zwb@test-algo:~$ firewall-cmd --add-port=50022/tcp --permanent
You're performing an operation over default zone ('public'),
but your connections/interfaces are in zone 'docker' (see --get-active-zones)
You most likely need to use --zone=docker option.

Authorization failed.
    Make sure polkit agent is running or run the application as superuser.
(base) zwb@test-algo:~$ sudo firewall-cmd --add-port=50022/tcp --permanent
You're performing an operation over default zone ('public'),
but your connections/interfaces are in zone 'docker' (see --get-active-zones)
You most likely need to use --zone=docker option.

Warning: ALREADY_ENABLED: 50022:tcp
success
(base) zwb@test-algo:~$ sudo firewall-cmd --reload
success
(base) zwb@test-algo:~$ sudo firewall-cmd --list-port
You're performing an operation over default zone ('public'),
but your connections/interfaces are in zone 'docker' (see --get-active-zones)
You most likely need to use --zone=docker option.

50022/tcp

手动启动sshd

(base) zwb@test-algo:~$ sudo /usr/sbin/sshd
(base) zwb@test-algo:~$ sudo netstat -antp | grep sshd
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      929/sshd: /usr/sbin 
tcp        0     76 172.21.198.185:22       10.3.16.31:53836        ESTABLISHED 127529/sshd: zwb [p 
tcp        0      0 127.0.0.1:50522         127.0.0.1:38979         ESTABLISHED 127629/sshd: zwb@no 
tcp        0      0 127.0.0.1:50510         127.0.0.1:38979         ESTABLISHED 127629/sshd: zwb@no 
tcp        0      0 172.21.198.185:22       10.3.16.31:52932        ESTABLISHED 127260/sshd: zwb [p 
tcp6       0      0 :::22                   :::*                    LISTEN      929/sshd: /usr/sbin 

若发生以下问题

问题

[root@79a70e3d26cd /]# /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@79a70e3d26cd /]# 

解决方案

执行:

# 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 ""

通过宿主机ip和端口远程连接容器

# 这是在windows上的shell远程连接,可以看到已经通过ssh连接上了node01,aa92cb71e3ab表示的是Node01的docker容器id
PS C:\Users\99140> ssh root@172.21.198.185 -p 50001
The authenticity of host '[172.21.198.185]:50001 ([172.21.198.185]:50001)' can't be established.
ED25519 key fingerprint is SHA256:zqNzugPY6dYmLFlaDGFOfkxOF8qtY/a5mP0DXH7Vxbk.
This key is not known by any other names
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added '[172.21.198.185]:50001' (ED25519) to the list of known hosts.
root@172.21.198.185's password:
[root@aa92cb71e3ab ~]#

3. 查看容器中自启项内容

[root@79a70e3d26cd ~]# systemctl list-unit-files|grep enabled
autovt@.service                        enabled 
getty@.service                         enabled 
kdump.service                          enabled 
nis-domainname.service                 enabled 
sshd.service                           enabled 
remote-fs.target                       enabled 
dnf-makecache.timer                    enabled 
[root@62435d2d7fd2 ~]# 

容器在创建时通过----restart=always实现自启动 但还可以在使用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  xxx

最后重启测试一下自启动是否成功

reboot

最后在远程主机上ssh连接三台centos结点并查看其网络ip情况

# Node01
PS C:\Users\99140> ssh root@172.21.198.185 -p 50001
root@172.21.198.185's password:
Last login: Tue Mar 21 11:37:04 2023 from 10.3.16.31
[root@aa92cb71e3ab ~]# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 172.18.0.4  netmask 255.255.0.0  broadcast 172.18.255.255
        ether 02:42:ac:12:00:04  txqueuelen 0  (Ethernet)
        RX packets 46  bytes 5625 (5.4 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 30  bytes 4929 (4.8 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

eth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 172.17.0.4  netmask 255.255.0.0  broadcast 172.17.255.255
        ether 02:42:ac:11:00:04  txqueuelen 0  (Ethernet)
        RX packets 11  bytes 946 (946.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        
# Node02
PS C:\Users\99140> ssh root@172.21.198.185 -p 50002
root@172.21.198.185's password:
Last login: Tue Mar 21 11:37:16 2023 from 10.3.16.31
[root@97041252bf37 ~]# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 172.18.0.3  netmask 255.255.0.0  broadcast 172.18.255.255
        ether 02:42:ac:12:00:03  txqueuelen 0  (Ethernet)
        RX packets 46  bytes 5625 (5.4 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 29  bytes 4819 (4.7 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

eth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 172.17.0.3  netmask 255.255.0.0  broadcast 172.17.255.255
        ether 02:42:ac:11:00:03  txqueuelen 0  (Ethernet)
        RX packets 11  bytes 946 (946.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

# Node03
PS C:\Users\99140> ssh root@172.21.198.185 -p 50003
The authenticity of host '[172.21.198.185]:50003 ([172.21.198.185]:50003)' can't be established.
ED25519 key fingerprint is SHA256:JdfhD5YG8cVOheu8diTuPlByz+KKdjYtQW8c6/XL28I.
This key is not known by any other names
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added '[172.21.198.185]:50003' (ED25519) to the list of known hosts.
root@172.21.198.185's password:
[root@2b8fa155e71f ~]# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 172.18.0.2  netmask 255.255.0.0  broadcast 172.18.255.255
        ether 02:42:ac:12:00:02  txqueuelen 0  (Ethernet)
        RX packets 47  bytes 6271 (6.1 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 27  bytes 5135 (5.0 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

eth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 172.17.0.2  netmask 255.255.0.0  broadcast 172.17.255.255
        ether 02:42:ac:11:00:02  txqueuelen 0  (Ethernet)
        RX packets 11  bytes 946 (946.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

三台结点都能远程连接并且ip在同一网段下,完美,可以躺在寝室完美运行学校服务器上的结点集群了!

4. 参考文章:

https://www.cnblogs.com/code-red-memory/p/14371893.html#:~:text=docker%E6%8B%89%E5%8F%96centos%E9%95%9C%E5%83%8F%E5%B9%B6%E9%85%8D%E7%BD%AE%E8%BF%9C%E7%A8%8B%E8%AE%BF%E9%97%AE%201%20%E4%B8%80%E3%80%81docker%E9%95%9C%E5%83%8F%E5%AE%89%E8%A3%85%E5%8F%8A%E5%AE%B9%E5%99%A8%E5%90%AF%E5%8A%A8%201.%20docker%E6%8B%89%E5%8F%96centos%E9%95%9C%E5%83%8F%20…%202%20%E4%BA%8C%E3%80%81%E5%AE%89%E8%A3%85centos%E5%9F%BA%E7%A1%80%E7%8E%AF%E5%A2%83,3%20%E4%B8%89%E3%80%81%E5%BC%80%E6%94%BE%E5%AE%B9%E5%99%A8%E6%98%A0%E5%B0%84%E7%AB%AF%E5%8F%A3%EF%BC%88%E6%89%8B%E5%8A%A8%E8%B0%83%E6%95%B4%E9%85%8D%E7%BD%AE%E6%96%87%E4%BB%B6%EF%BC%89%201.%20…%204%20%E5%9B%9B%E3%80%81%E5%90%AF%E5%8A%A8%E5%AE%B9%E5%99%A8sshd%E6%9C%8D%E5%8A%A1%201.%20

https://blog.csdn.net/qq_41899586/article/details/108981036?ops_request_misc=%257B%2522request%255Fid%2522%253A%2522167935990016800211531628%2522%252C%2522scm%2522%253A%252220140713.130102334…%2522%257D&request_id=167935990016800211531628&biz_id=0&utm_medium=distribute.pc_search_result.none-task-blog-2allbaidu_landing_v2~default-3-108981036-null-null.142v74pc_new_rank,201v4add_ask,239v2insert_chatgpt&utm_term=%E4%BD%BF%E7%94%A8ssh%E8%BF%9C%E7%A8%8B%E8%AE%BF%E9%97%AEdocekr&spm=1018.2226.3001.4187

https://zhuanlan.zhihu.com/p/212772001

https://blog.csdn.net/chj_1224365967/article/details/109286763

https://www.cnblogs.com/davis12/p/14392125.html

https://blog.csdn.net/rjszz1314/article/details/112948993

其他常用工具命令

# 安装ifconfig
yum install net-tools
# 修改hostname
hostnamectl set-hostname 想要的名字
#会报错误:Could not set property: Failed to set static hostname: Device or resource busy,
#exit退出重新进入容器即可
原文地址:https://blog.csdn.net/qq_40282331/article/details/129761378

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