控制服務

1.用什麼控制服務
	系統初始化程序可以對服務進行相應的控制
2.當前系統初始化程序是什麼
	systemd		---> 系統初始化程序
	pstree		---> 顯示系統中的程序樹
3.程序控制命令
	ssh 	    -------->   sshd
	client(客戶埠)	      server(服務埠)
4.systemctl -------->服務控制命令
	systemctl 	status	sshd	##檢視服務狀態，inactive(不可用)，active（可用）
	systemctl	start 	sshd	##開啟服務
	systemctl	stop 	sshd	##關閉服務
	systemctl 	restart	sshd	##重啟服務
	systemctl 	reload	sshd	##重新載入服務配置
	systemctl 	enable	sshd	##設定服務開機啟動
	systemctl	disable	sshd	##設定服務開機不啟動
	systemctl	list-units	##列出已經開啟服務當前狀態
	systemctl 	list-unit-files	##列出所有服務開機啟動的狀態 disable,enable,static
	systemctl 	list-dependencies	##列出服務的倚賴
	systemctl	set-default multi-user.target	##設定系統啟動級別為多使用者模式（無圖形）
	systemctl	set-default graphical.target	##設定系統啟動級別為圖形模式
 

遠端連線（需要密碼登陸）

ssh 遠端連結

ssh 對方使用者名稱@對方主機ip地址  ---> 遠端連結虛擬機器
1.nm-connection-editor ---> 圖形介面更改ip地址
2.ip 地址檢視 
	ip addr show  ----> 建議使用
	ifconfig 		---> 不建議使用
3.連線方式
	ssh	[email protected]	文字模式的連線
	ssh	-X [email protected]	可以在連線成功後開啟圖形
	cheese			 ---> 連線開啟對方電腦的攝像頭
注意：第一次連線陌生主機時要建立認證檔案；會詢問是否建立連線，需要輸入yes；下次不再需要
      再次連線此主機時，因為已經生成~/.ssh/know_hosts
4.遠端複製
	scp	file	
 
[email protected]:dir		#上傳（dir為絕對路徑）
	scp	[email protected]:file	dir	#下載(file為絕對路徑)
	scp	-rp	[email protected]:dir	dir	#下載(dir為絕對路徑)

遠端連線（不需要密碼登陸）

ssh的key認證

#client (客戶埠)
[[email protected] ~]# ssh-keygen  ---> 生成金鑰的命令
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa): #指定儲存加密字元的檔案
Enter passphrase (empty for no passphrase):   ---> 設定密碼
Enter same passphrase again:    ----> 在此確定設定的密碼
Your identification has been saved in /root/.ssh/id_rsa.    ---> 私鑰
Your public key has been saved in /root/.ssh/id_rsa.pub.    ---> 公鑰
The key fingerprint is:
e4:94:45:27:62:b9:94:66:42:87:09:6f:2d:67:2d:b4 
 
[email protected]
The key's randomart image is:
+--[ RSA 2048]----+
|    .o.o=++ .    |
|     .+=** o     |
|      +=E..      |
|     . B..       |
|        S        |
|                 |
|                 |
|                 |
|                 |
+-----------------+
[[email protected] ~]# cd /root/.ssh/
[[email protected] .ssh]# ls  	  ---> 檢視金鑰是否生成
id_rsa #（私鑰） id_rsa.pub #（公鑰） known_hosts 
[[email protected] .ssh]# ssh-copy-id -i id_rsa.pub [email protected]   --->  將公鑰給主機ip為113的root使用者，加密root使用者
The authenticity of host '172.25.254.113 (172.25.254.113)' can't be established.
ECDSA key fingerprint is 65:4d:ac:8a:c9:58:82:b5:0c:91:c4:ef:a5:e6:f6:65.
Are you sure you want to continue connecting (yes/no)? yes #
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
[email protected]'s password: 

Number of key(s) added: 1

Now try logging into the machine, with:   "ssh '[email protected]'"
and check to make sure that only the key(s) you wanted were added.


[[email protected] .ssh]# ls
authorized_keys #（這個檔案出現，表示加密成功） id_rsa  id_rsa.pub  known_hosts
[[email protected] .ssh]# scp id_rsa [email protected]:/root/.ssh/ #分發鑰匙，將主機ip為113的私鑰分發給ip為213的主機
[email protected]'s password: 
id_rsa                                        100% 1675     1.6KB/s   00:00    

#server(服務埠)
[[email protected] ~]# cd /root/.ssh/
[[email protected] .ssh]# \ls
id_rsa	known_hosts
[[email protected] .ssh]# ssh [email protected] #連線時發現直接登陸不需要輸入ip113 root密碼
Last login: Wed Oct  3 00:25:55 2018 from 172.25.254.13
[[email protected] ~]# logout
Connection to 172.25.254.113 closed.

#修改主機名稱更改
[[email protected] ~]$ hostnamectl set-hostname hao  #更改主機名稱為hao
[[email protected] ~]$ hostname		      #檢視主機名稱