The CentOS (Community Enterprise Operating System) Project is a community-driven free software effort focused on delivering a robust open source ecosystem. For users, CentOS offers a consistent manageable platform that suits a wide variety of deployments. For open source communities, CentOS offers a solid, predictable base to build upon, along with extensive resources to build, test, release, and maintain their code.
CentOS uses the Red Hat source code base to create a product similar to RHEL. So CentOS is very close to being RHEL without the branding and support. In particular, the library versions are the same, so binaries that work on one will work on the other. The administration tools are the same and configured in similar ways. However, there are a few differences, as the two distributions sometimes apply different minor patches.
Differences between Ubuntu and CentOS:
- The biggest difference between the two Linux distributions is that Ubuntu is based on the Debian architecture while CentOS is forked from Red Hat Enterprise Linux.
- In Ubuntu, you can download DEB packages using the apt-get package manager. Meanwhile, in CentOS, you have to use the yum command to download and install RPM packages from the central repository.
- CentOS is considered to be a more stable distribution compared to Ubuntu. Mainly because package updates are less frequent. This can also prove to be a disadvantage of CentOS. If you want the latest version of a certain application or software, you will have to install them manually.
CentOS vs Ubuntu – Comparison Table
| Ubuntu | CentOS |
| Based on Debian | Based on RHEL |
| Updated frequently | Updated scarcely |
| No cPanel support (has alternatives) | Supports cPanel/WHM |
| Larger user and developer community | Smaller user and developer community |
| Greater amount of help available in the form of tutorials and free guides | Lesser amount of help available |
| Easier to learn for beginners that have used Ubuntu desktop in the past | Harder to learn for beginners as there are not many famous desktop distros released by RHEL |
| .deb packages installed using the apt-getpackage manager | .rpm packages installed using the yum package manager |
1. Install CentOS in VMWare Workstation
This installation is using VMWare Workstation Easy Install method to complete the installation.
- Reboot CentOS: init 6 , reboot, shutdown -r now
- ShutdownCentOS: init 0, poweroff
- Sync time: ntpdate time.windows.com
- change to root: sudo -i
2. Network Interface Configuration
change to root: sudo -i
DHCP or Static:
Step 1 » Check the network interface name by typing below command
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[root@linux1 ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 9a:4a:27:66:a4:4c brd ff:ff:ff:ff:ff:ff inet 10.9.1.26/24 brd 10.91.128.255 scope global eth0 valid_lft forever preferred_lft forever inet6 fe80::984a:27ff:fe66:a44c/64 scope link valid_lft forever preferred_lft forever |
Here “lo” is the loopback interface and “eth0” is the network interface that you need to configure .
Step 2 » you can see the file named ifcfg-eth0 ( Interface name ) in the location “/etc/sysconfig/network-scripts/” , open the file and you can see the lines as below, which is static ip 10.9.1.26 assigned to interface eth0
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DEVICE=”eth0″
HWADDR=”00:22:19:09:4D:3C” NM_CONTROLLED=”yes” ONBOOT=”yes” # Interface enabled BOOTPROTO=”dhcp” #Assigning IP from DHCP |
Step 3 » Start the network service and you can see the status as below .
[root@linux1~]# service network start
Bringing up loopback interface: [ OK ]
Bringing up interface p4p1:
Determining IP information for p4p1... done. [ OK ]Some other similar commands:
- service network restart
- systemctl restart network.service
- hostnamectl set-hostname CentOS-test1
3. System Update and Package Mgmt Commands
- sudo -i
- yum check-update
- yum update
- yum list | less
- yum info firefox
- yum search vsftpd
- yum list openssh
- yum update mysql
- yum -y remove firefox
- yum clean all
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[john@linux1 /]$ rpm -qa |less
plymouth-0.8.9-0.24.20140113.el7.centos.x86_64
libsoup-2.48.1-3.el7.x86_64
libaio-0.3.109-13.el7.x86_64
dmidecode-2.12-9.el7.x86_64
passwd-0.79-4.el7.x86_64
bind-libs-lite-9.9.4-29.el7_2.2.x86_64
sed-4.2.2-5.el7.x86_64
grub2-2.02-0.34.el7.centos.x86_64
libcom_err-1.42.9-7.el7.x86_64
rsyslog-7.4.7-12.el7.x86_64
biosdevname-0.6.2-1.el7.x86_64
dracut-config-rescue-033-360.el7_2.x86_64
libacl-2.2.51-12.el7.x86_64
openssh-clients-6.6.1p1-23.el7_2.x86_64
xe-guest-utilities-6.5.0-1432.x86_64
libgcrypt-1.5.3-12.el7_1.1.x86_64
libpcap-1.5.3-8.el7.x86_64
cronie-1.4.11-14.el7.x86_64
iwl6050-firmware-41.28.5.1-43.el7.noarch
iwl4965-firmware-228.61.2.24-43.el7.noarch
iwl3160-firmware-22.0.7.0-43.el7.noarch
libunistring-0.9.3-9.el7.x86_64
iwl100-firmware-39.31.5.1-43.el7.noarch
perl-parent-0.225-244.el7.noarch
newt-0.52.15-4.el7.x86_64
perl-Pod-Escapes-1.04-286.el7.noarch
gdbm-1.10-8.el7.x86_64
perl-libs-5.16.3-286.el7.x86_64
…….
[john@linux1 /]$ rpm -qa |grep syslog
rsyslog-7.4.7-12.el7.x86_64
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4. System Performance and Monitoring Commands
- uptime
- top
- iostat
- vmstat
- ps and pstree
- sar
- crontab
- free
- pmap
- change to root: sudo -i
There are three different ways to do it.
vi /etc/sysctl.conf
net.ipv6.conf.all.disable_ipv6 =1
net.ipv6.conf.default.disable_ipv6 =1
net.ipv6.conf.enp0s3.disable_ipv6 =1
sysctl -p
echo 1>/proc/sys/net/ipv6/conf/all/disable_ipv6echo 1>/proc/sys/net/ipv6/conf/default/disable_ipv6
sysctl -w net.ipv6.conf.all.disable_ipv6=1sysctl -w net.ipv6.conf.default.disable_ipv6=1
- yum install policycoreutils iptables-services -y
- systemctl stop firewalld.service
- systemctl disable firewalld.service
- service iptables restart
- systemctl stop firewalld //Turn off the firewall
- systemctl start firewalld //Turn on the firewall
- systemctl status firewalld //Check firewall status
- systemctl stop firewalld.service #停止firewall
- systemctl disable firewalld.service #禁止firewall开机启动
- firewall-cmd –state #查看默认防火墙状态(关闭后显示notrunning，开启后显示running)
- Vim
- lrzsz
- bind-utils / net-tools
- Git
- Ansible
- Docker
- sudo -i
- sudo yum update
- sudo yum install docker
- sudo systemctl enable docker.service # Enable the service
- sudo systemctl start docker # Start the Docker daemon.
- sudo docker images # Show local images
- sudo docker pull tutum/wordpress # pull the image
- sudo docker run -d -p 80:80 tutum/wordpress # Run container
- sudo curl http://localhost/ # Test container
- sudo docker stop # Stop container
- sudo docker ps -a # Show container list
- sudo docker export 633748a43e01 > blog.tar # Export container
- cat blog.tar | sudo docker import – tutum/wordpress blog.tar # Import container
- docker pull ubuntu
- docker exec -it ubuntu /bin/bash
- docker cp /home/msg/name.tar 5ed1587b3923:/home/software #Copy file from host to container folder
- docker exec -ti 5ed1587b3923 /bin/bash # run command in the container
- docker run -dt -p 7000-8000:7000-8000 -v /usr/local/home:/usr/local/container/home centos/java8 /bin/bash #map port range and mount local folder to container
- vsftp
- yum install -y vsftpd
- vi /etc/vsftpd/vsftpd.conf
- anonymous_enable=YES #allow anonymous to visit
- anon_upload_enable=YES
- anon_mkdir_write_enable=YES
- systemctl enable vsftpd # enablevsftpd service when system started
- systemctl disable vsftpd
- systemctl start vsftpd
- systemctl status vsftpd
- Create user
- useradd ftpadmin //create user ftpadmin
- passwd ftpadmin //create password
- mkdir -p /home/app/ftpdir
- usermod -d /home/app/ftpdir ftpadmin // change user ftpadmin’s home folder to that new created folder
- Samba
- rpm -qa | grep ‘samba’ // Check Samba service if installed already
- yum -y install samba samba-common samba-client
- samba-3.6.9-151.el6.x86_64 //服务器端软件，主要提供samba服务器的守护程序，共享文档，日志的轮替
- samba-common-3.6.9-151.el6.x86_64 //主要提供samba服务器的设置文件与设置文件语法检验程序testparm
- samba-client-3.6.9-151.el6.x86_64 //客户端软件，主要提供linux主机作为客户端时，所需要的工具指令集
- service smb status //查看samba服务状态
- service smb start //启动samba服务
- service smb restart //重启samba服务
- vi /etc/samba/smb.conf //add following sharing information
[share]
path = /home/sambauser1/share
comment = sambauser1_share
public = yes
writable = yes
browseable = yes
guest ok = yes
valid users = sambauser1,root
available = yes
- smbpasswd -a sambauser1 //为sambauser1 用户增加共享用户，并设定samba密码
- pure-ftpd
- yum install -y pure-ftpd
- cd /etc/yum.repos.d
- yum install -y epel-release
- vim /etc/pure-ftpd/pure-ftpd.conf
- remove # sign at the head of line pureftpd.pdb
- systemctl start pure-ftpd // You will need to stop vsftpd to avoid port conflict
- mkdir /data/ftp
- useradd -u 1010 pure-ftp1
- chown -R pure-ftp1:pure-ftp1 /data/ftp // give permission to the folder
- pure-pw useradd ftp_usera -u pure-ftp1 -d /data/ftp
- 用pure-pw创建用户，用-u指定系统用户是谁。-d,指定虚拟用户的家目录，设置密码
- touch /data/ftp/1.txt
- pure-pw mkdb
- lftp [email protected]
- chown pure-ftp1:pure-ftp1 /data/ftp/1.txt
- getenforce //Check SELinux status, either enforcing, permissive or disabled
- setenforce [Enforcing | Permissive | 1 | 0]
# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
# enforcing – SELinux security policy is enforced.
# permissive – SELinux prints warnings instead of enforcing.
# disabled – No SELinux policy is loaded.
SELINUX=disabled
# SELINUXTYPE= can take one of three values:
# targeted – Targeted processes are protected,
# minimum – Modification of targeted policy. Only selected processes are protected.
# mls – Multi Level Security protection.12 SELINUXTYPE=targeted