SetupCentOS7.5

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1.Let’s setup CentOS7.5 server. Contains : ssh login,Promp, Partition, General user account

1.Setup Auto SnapShot of disk

2.Set SSH key login

2.1.Add id_rsa.pub SSH Key on cloud Control

2.2.Add correct host key in user/.ssh/known_hosts

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ssh-keygen -R xxx.xxx.xxx.xxx
#/.ssh/known_hosts updated.
#Are you sure you want to continue connecting (yes/no)? yes
ssh root@xxx.xxx.xxx.xxx

2.3. Disable passwd login

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vi /etc/ssh/sshd_config
PasswordAuthentication no
service sshd restart

3.4.Changed ip for domain may cause error

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#The ECDSA host key for www.heavenyu.com has changed,
#and the key for the corresponding IP address 106.12.110.178
#is unchanged. 
vi ~/.ssh/known_hosts
#change the key for domain manualy

3.Terminal

3.1.Set Promp

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vi .bashrc

add 

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export PS1='[\t \W]\$'
alias vi='vim'

to the end of the ~/.bashrc

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source .bashrc

we got this prompt:

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[22:40:00 ~]#

3.2.Vim

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vi /etc/vimrc
#add
:set number
set tabstop=4
set expandtab
set shiftwidth=4

4.Partition

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fdisk -l
fdisk /dev/vdb

Command (m for help): n
Partition type:
   p   primary (0 primary, 0 extended, 4 free)
   e   extended
Select (default p): p
Partition number (1-4, default 1):  
First sector (2048-104857599, default 2048): 
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-104857599, default 104857599): 50000000
Partition 1 of type Linux and of size 23.9 GiB is set

Command (m for help): n
Partition type:
   p   primary (1 primary, 0 extended, 3 free)
   e   extended
Select (default p): p
Partition number (2-4, default 2): 2
First sector (50000001-104857599, default 50001920): 
Using default value 50001920
Last sector, +sectors or +size{K,M,G} (50001920-104857599, default 104857599): 
Using default value 104857599
Partition 2 of type Linux and of size 26.2 GiB is set
Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.

fdisk -l

Disk /dev/vda: 53.7 GB, 53687091200 bytes, 104857600 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x000d64b4

   Device Boot      Start         End      Blocks   Id  System
/dev/vda1   *        2048   104857599    52427776   83  Linux

Disk /dev/vdb: 53.7 GB, 53687091200 bytes, 104857600 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0xd99cb4bf

   Device Boot      Start         End      Blocks   Id  System
/dev/vdb1            2048    50000000    24998976+  83  Linux
/dev/vdb2        50001920   104857599    27427840   83  Linux
mkfs.ext4 /dev/vdb1
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
1564672 inodes, 6249744 blocks
312487 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=2153775104
191 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks: 
	32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
	4096000

Allocating group tables: done                            
Writing inode tables: done                            
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done   

mkfs.ext4 /dev/vdb2
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
1716960 inodes, 6856960 blocks
342848 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=2155872256
210 block groups
32768 blocks per group, 32768 fragments per group
8176 inodes per group
Superblock backups stored on blocks: 
	32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
	4096000

Allocating group tables: done                            
Writing inode tables: done                            
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done   
mkdir /mnt/vdb1
mkdir /mnt/vdb2
mount /dev/vdb1 /data
mount /dev/vdb2 /home
vi /etc/fstab
#add
/dev/vdb1               /data   ext4    noatime,nodiratime      0 2
/dev/vdb2               /home   ext4    noatime,nodiratime      0 2

5.Create general user account

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#add general user
adduser user
#passwd
passwd user
#check permission
ls -l /etc/sudoers
#if read-only 
chmod -v u+w /etc/sudoers
#edit
vim /etc/sudoers
### Allow root to run any commands anywhere 
#root    ALL=(ALL)       ALL
### ADDED
#user  ALL=(ALL)       NOPASSWD: ALL
#change back to read-only
chmod -v u-w /etc/sudoers
#log as user
su user