CentOS installation Configuration

Source: Internet
Author: User
Tags virtual environment

Learning précis-writersInstallation of virtual machines
    • Choice of virtual machines: VMware (Premium software) or VirtualBox (open source free).

    • Number of CPU cores for virtual machines: The purpose is to increase the speed of the CPU and utilize the CPU's limited resources.

    • Choice of Virtual Machine network type:

  1. Bridging network: If you have a router in your network environment, you can support the automatic acquisition of IP addresses (VMnet0: Virtual Switches for virtual bridging networks)
    Characteristics: In this way, the IP of the virtual system can be set to the same network segment as the native system, the virtual system is equivalent to a separate machine within the network, and the local machine is plugged into a switch, the other machines in the network can access the virtual system, the virtual system can also access other machines in the network, Of course, two-way access to the native system is not a problem.

  2. NAT: Network environment is more complex, there is no router, can be set up, virtual machine through the real-world network card to the Internet (VMnet8: for virtual NAT network)
    Features: This approach also enables two-way access to both the native system and the virtual system. But other machines within the network cannot access the virtual system, but the virtual system can access other machines in the network through the NAT protocol of the native system, and can be connected to the Internet as a physical machine.

  3. Host only (Only-host): can only communicate with the host, with the real host in the same domain, can not connect to the Internet (VMnet8: Virtual Switch for Virtual NAT network)
    Characteristics: As the name implies, this method can only be used for network communication between the virtual machine and the host, while the other machines in the network cannot access the virtual system, nor can the virtual system access other machines.

    • The interface of the hard disk:
      IDE interface, SCSI interface, SATA interface

Installation of CentOS
  • Settings for partitions
    /boot: The file boot file used to put the boot, it is best to partition independently, to avoid other partition damage, but the system can not boot, but also to avoid the old BIOS can not recognize the new hard disk cannot find the boot kernel problem.
    swap: the equivalent of WIN's virtual memory, is in the case of insufficient memory, and then put in-memory data into the (swap) hard disk, generally set to twice times the size of memory.
    Recommended independent Zoning information
    /boot: System boot (important)
    /usr,/home,/VAR,/: Frequent reading of directories
    Swap: Memory Expansion standby

Learning Doubts
  1. Network knowledge and computer hardware knowledge lack.

  2. NAT mode virtual machine networking, after the Dhclient network card obtains the IP address, after the service netwoork restart, ifconfig cannot obtain the IP address of the network card
    /etc/sysconfig/network-scripts/ifcfg-eth0   Config file edit writing error.

    [[email protected] ~]# vim /etc/sysconfig/network-scripts/ifcfg-eth0 device= eth0hwaddr=00:0c:29:a3:53:4btype=ethernetuuid=9ee056e4-f8f4-4c17-af2a-8ea65c1a76f9onboot=yesnm_controlled=yes# bootproto=dhcpbootproto=staticnetmask=255.255.255.0#gateway=192.168.89.2#dns1=192.168.89.2 
after-school real Exercise Expand Learning
    • Hyper-Threading Technology

    • Virtual Machine Network type extension:
      VMware offers three modes of operation, which are bridged (bridging mode), NAT (network address translation mode), and host-only (host mode).

      If you want to use VMware to create a separate virtual server in your LAN, provide network services for LAN users, or you want to build a virtual system that is isolated from other machines in the network for special debugging. At this point, the choice of the operating mode of the virtual system is very important. If you choose to work in an incorrect mode, you won't be able to achieve this, and you won't be able to take full advantage of VMware's role in network management and maintenance. Now, let's get closer to VMware's three modes of operation.

Understand three modes of operation:

VMware offers three modes of operation, which are bridged (bridging mode), NAT (network address translation mode), and host-only (host mode). To properly apply them in network management and maintenance, you should first look at these three modes of work.

1.bridged (bridging mode)

The relationship between a virtual system using bridging mode and a host machine is like two computers connected to the same hub. To make them communicate with each other, you need to configure the IP address and subnet mask for the virtual system, or you will not be able to communicate.

If you want to use VMware to create a new virtual server within the LAN, to provide network services for LAN users, you should choose bridging mode.

2.host-only (host mode)

In some special network debugging environments, it is required to isolate the real environment from the virtual environment, then you can use the host-only mode. In host-only mode, all virtual systems can communicate with each other, but virtual systems and real networks are isolated.

Note: In host-only mode, the virtual system and the host machine system can communicate with each other, which is equivalent to the two machines connected by twisted pair.

===========================

If you want to use VMware to create a virtual system that is isolated from other machines in the network, you can choose Host-only mode for some special network debugging work.

3.NAT (network address translation mode)

If you want to use VMware to install a new virtual system, you can directly access the Internet without any manual configuration in the virtual system, we recommend that you use NAT mode.

> Note: The VMNET8 virtual Network in NAT mode mentioned above, the VMNET1 virtual network in host-only mode, and the VMnet0 virtual network in bridged mode are all generated by the automatic configuration of VMware virtual machines and do not need to be set by the user. VMnet8 and VMNET1 provide DHCP services, and VMNET0 virtual networks are not available.

    • HDD Interface Extension

  1. IDE Interface: The IDE's English is all called "Integrated drive Electronics", or "Electronic integrated Driver", which is intended to refer to the hard drive that integrates the "hard disk controller" with the "Disk body". The combination of the disk body and the controller reduces the number and length of the cable on the hard drive interface, the reliability of the data transfer is enhanced, and the hard drive is made easier because the hard drive manufacturer does not need to worry about the compatibility of the controllers produced by other manufacturers. Users are also more convenient to install.
    650) this.width=650; "src=" Http://img.pc841.com/allimg/140903/1_140903180754_1.jpg "alt=" IDE Interface "title=" IDE Interface hard disk " Style= "Padding:0px;margin:0px;border:0px;vertical-align:middle;"/>

  2. SCSI: SCSI's English is all called "Small computer system Interface" (Small computer system interface), this interface on the interface controller of the hard disk has a processor, is a completely different interface with the IDE (ATA), the IDE interface is the standard interface of the ordinary PC, SCSI is not specifically designed for the hard disk interface, is a widely used in small-scale computer-based high-speed data transmission technology. The SCSI interface has a wide range of applications, multitasking, high bandwidth, low CPU usage, and hot plug, and so on, but the high price makes it difficult to use as IDE hard disk, so the SCSI hard disk is mainly used in medium and high-end servers and high-end workstations.

  3. SATA: The use of SATA (Serial ATA) port of the hard disk is called Serial drive, is the future trend of PC hard disk. The Serial ATA uses a serial connection, the Serial ATA bus uses an embedded clock signal, has a stronger error correction capability, the biggest difference compared with the past is that the transmission instruction (not just the data) can be checked, if the error is automatically corrected, which greatly improves the reliability of data transmission. The serial interface also has the advantages of simple structure and hot-swappable support.
    650) this.width=650; "src=" http://img.pc841.com/allimg/140903/1_140903180821_1.jpg "alt=" SATA Interface "title=" SATA interface Hard Drive " Style= "Padding:0px;margin:0px;border:0px;vertical-align:middle;"/>


CentOS installation Configuration

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