CentOS 7 Minimal x86_64 Base Installation Guide - rharmonson/richtech GitHub Wiki
Updated article as of November 2017 at the URL below.
Revised: March 31, 2016. Added the "Note" below. No other changes.
Revised June 9, 2016. Provide link to newer document for CentOS 7.2.1511.
The purpose of this guide is provide the steps to build a standardized CentOS 7 build 1503 aka Red Hat Enterprise Linux (RHEL) 7.1 Minimal x86_64 base operating system.
Note
I am observing changes between minor versions that are significant. More specifically Red Hat's emphasis on systemd, firewalld, and NetworkManager (<-- ICK!). Future guides will provide specify the version in the title to distinguish them from each other.
CentOS-7 (1503) Release Notes can be found HERE: http://wiki.centos.org/Manuals/ReleaseNotes/CentOS7
CentOS FAQ can be found HERE: http://wiki.centos.org/FAQ/CentOS7
Base CentOS Installation Task Overview
- Obtain media
- Virtual Machine Creation
- CentOS Installation
- Network Interface configuration
- Name Resolution configuration
- Network Manager Text User Interface
- Verify operation
- Hostname settings
- Time zone
- Time
- EPEL
- Virtual Machine Drivers
- Update
If you are new to Linux or new to CentOS minimal installations, I would advise reviewing all the information at the URL below. Otherwise, scroll down and select the download URL under section 2. We will be using x86_64 version, also, known as 64 bit. The 32 bit version should work as well.
Download: http://wiki.centos.org/Download
Below describes how to create a virtual machine using VMware Workstation or ESXi, but may apply to other virtualization products.
After download of the installation ISO, create a new virtual machine specifying the following:
- CentOS 64 bit
- 1 CPU
- 1 GB RAM
- NAT (or Bridge) network adapter
- 20 GB, LSI Logic SAS, SCSI Disk
Note when creating a 'New Virtual Machine' in VMware Workstation 11 using 'Typical' will use the specifications above. If you have the resources available, increase CPU and RAM to 2 and 2048, respectively, but it is not a requirement. Do not enable the 'power-on' on completion.
In addition, customize hardware and remove the following:
- USB Controller
- Sound Card
- Printer
If you did not mount the CentOS 7 installation media during the creation of the virtual machine, do so before moving to the next step.
Next, use the "power-on to firmware" or BIOS feature to disable all unneeded devices. With VMware Workstation and ESXi, I disable Legacy Floppy A, then under 'Advanced' and 'I/O Device Configuration' disable all items:
- Serial ports
- Parallel port
- Floppy controller
Exit saving changes. After the power cycle, CentOS 7 installation should begin.
Note:
Selecting "Typical" installation method when creating a new virtual machine using VMware Workstation 11 (and ESXi 5.5?) will generate errors regarding missing packages. I suspect this is due to the wizard and either using the "Minimal" installation media or changes from the initial release of CentOS 7 and CentOS 7 build 1503. I prefer to use "Custom" not "Typical" which does not result in errors.
Boot from media and, generally, accept the defaults. You have an opportunity to provide time zone, a host name, configure network interfaces, provide DNS IP addresses, domain search, etc. If configured at this point, the installation script automatically configures the resulting installation using these settings. It is a time saver, however, I am going to assume these setting have not been set or changes will be needed.
Note:
During installation and under "Installation Source" you have an option or button "Verify" to run a "Media Verification." If this is your first use of the media, I advise using this feature. Nothing worse then losing hours or days to corrupted installation media. If you have previously verified the media at its current storage location, you can, generally, safely skip verification.
To review you current active interfaces, execute ip addr. For example:
[root@localhost ~]# ip addr
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: eno16777728: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:ad:96:16 brd ff:ff:ff:ff:ff:ff
[root@localhost ~]#
Note:
CentOS 7 no longer uses the naming convention previously used for network interfaces, e.g. eth0 or eth1. It now uses a designation as provided by the system BIOS. In the examples, eno16777728 is equivalent to interface eth0 found with CentOS 6 which results with the configuration file ifcfg-eno16777728 versus ifcfg-eth0.
Reference: http://wiki.centos.org/FAQ/CentOS7#head-62d45421abea0220e3038796e3dd5315906fa493
The default configuration for the network interface, eno16777728, is given below. You may have a different DEVICE and will have a different UUID.
[root@localhost ~]# cat /etc/sysconfig/network-scripts/ifcfg-eno16777728
TYPE=Ethernet
BOOTPROTO=dhcp
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
NAME=eno16777728
UUID=05d5a7d5-f16e-4492-9ea1-fa46b7134a8a
DEVICE=eno16777728
ONBOOT=no
IPV6_PEERDNS=yes
IPV6_PEERROUTES=yes
IPV6_PRIVACY=no
[root@localhost ~]#
If you desire to use DHCP, update ifcfg-* using ONBOOT value from no to yes, save, then restart network services.
[root@localhost ~]# vi /etc/sysconfig/network-scripts/ifcfg-eno16777728
Results
TYPE=Ethernet
BOOTPROTO=dhcp
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
NAME=eno16777728
UUID=05d5a7d5-f16e-4492-9ea1-fa46b7134a8a
DEVICE=eno16777728
ONBOOT=yes
IPV6_PEERDNS=yes
IPV6_PEERROUTES=yes
IPV6_PRIVACY=no
Restart network service:
[root@localhost ~]# service network restart
Restarting network (via systemctl): [ OK ]
Results with the following:
[root@localhost ~]# ip addr
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: eno16777728: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:ad:96:16 brd ff:ff:ff:ff:ff:ff
inet 172.16.1.136/24 brd 172.16.1.255 scope global dynamic eno16777728
valid_lft 1626sec preferred_lft 1626sec
inet6 fe80::20c:29ff:fead:9616/64 scope link
valid_lft forever preferred_lft forever
If you are going to use a static IP address, then you will need to update ifcfg-eno6777728 appropriately. Note you may use nmtui instead which I will provide basic instructions to follow.
[root@localhost ~]# vi /etc/sysconfig/network-scripts/ifcfg-eno16777728
TYPE=Ethernet
BOOTPROTO=none
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
NAME=eno16777728
UUID=05d5a7d5-f16e-4492-9ea1-fa46b7134a8a
DEVICE=eno16777728
ONBOOT=yes
DNS1=172.16.1.21
DOMAIN=2factor.net
IPADDR=172.16.1.25
PREFIX=24
GATEWAY=172.16.1.254
IPV6_PEERDNS=yes
IPV6_PEERROUTES=yes
IPV6_PRIVACY=no
Restart the network service
[root@localhost ~]# service network restart
Restarting network (via systemctl): [ OK ]
Results with
``
[root@localhost ~]# ip addr
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: eno16777728: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:ad:96:16 brd ff:ff:ff:ff:ff:ff
inet 172.16.1.25/24 brd 172.16.1.255 scope global eno16777728
valid_lft forever preferred_lft forever
inet6 fe80::20c:29ff:fead:9616/64 scope link
valid_lft forever preferred_lft forever
Additional references:
http://wiki.centos.org/FAQ/CentOS7#head-a21a9e454157700367c9b7e9ccb1ff9954bec881
Configure DNS resolution settings. Current settings shown below are a result of using DHCP, initially. Your resolv.conf may differ.
[root@localhost ~]# cat /etc/resolv.conf
; generated by /sbin/dhclient-script
search localdomain
nameserver 192.168.113.254
Update resolv.conf using vi and provide DNS IP addresses and domain suffix search order.
[root@localhost ~]# cat /etc/resolv.conf
search subdom.mydomain.com mydomain.com
nameserver 8.8.8.8
nameserver 8.8.4.4
For network interface and name resolution settings, nmtui is an alternative to editing configuration files by hand.
- Execute nmtui
[root@localhost ~]# nmtui
┌─┤ NetworkManager TUI ├──┐
│ │
│ Please select an option │
│ │
│ Edit a connection │
│ Activate a connection │
│ Set system hostname │
│ │
│ Quit │
│ │
│ <OK> │
│ │
└─────────────────────────┘
- Select "Edit a connection"
┌────────────────────────────────┐
│ │
│ ┌──────────────────┐ │
│ │ Ethernet ↑ │ <Add> │
│ │ eno16777728 ▒ │ │
│ │ ▒ │ <Edit...> │
│ │ ▒ │ │
│ │ ▒ │ <Delete> │
│ │ ▒ │ │
│ │ ▒ │ │
│ │ ▒ │ │
│ │ ▒ │ │
│ │ ▒ │ │
│ │ ▒ │ │
│ │ ▒ │ │
│ │ ▒ │ │
│ │ ▒ │ │
│ │ ▮ │ │
│ │ ↓ │ <Quit> │
│ └──────────────────┘ │
│ │
└────────────────────────────────┘
- Update the connection with the appropriate settings. Note the use of CIDR notation after the Addresses, e.g. "/24", which will need be specified if sub- or super-netting.
┌───────────────────────────┤ Edit Connection ├───────────────────────────┐
│ │
│ Profile name eno16777728_____________________________ │
│ Device eno16777728 (00:0C:29:AD:96:16)_________ │
│ │
│ ═ ETHERNET <Show> │
│ │
│ ╤ IPv4 CONFIGURATION <Manual> <Hide> │
│ │ Addresses 172.16.1.25/24___________ <Remove> │
│ │ <Add...> │
│ │ Gateway 172.16.1.254_____________ │
│ │ DNS servers 172.16.1.21______________ <Remove> │
│ │ <Add...> │
│ │ Search domains 2factor.net______________ <Remove> │
│ │ <Add...> │
│ │ │
│ │ Routing (No custom routes) <Edit...> │
│ │ [ ] Never use this network for default route │
│ │ │
│ │ [ ] Require IPv4 addressing for this connection │
│ └ │
│ │
│ ═ IPv6 CONFIGURATION <Automatic> <Show> │
│ │
│ [X] Automatically connect │
│ [X] Available to all users │
│ │
│ <Cancel> <OK> │
│ │
│ │
└─────────────────────────────────────────────────────────────────────────┘
- Select
<OK>then restart the network service to apply the changes
[root@localhost ~]# service network restart
Restarting network (via systemctl): [ OK ]
Results with:
[root@localhost ~]# ip addr
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: eno16777728: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:ad:96:16 brd ff:ff:ff:ff:ff:ff
inet 172.16.1.25/24 brd 172.16.1.255 scope global eno16777728
valid_lft forever preferred_lft forever
inet6 fe80::20c:29ff:fead:9616/64 scope link
valid_lft forever preferred_lft forever
Use ping to verify basic interface, routing, and name resolution operation.
[root@localhost ~]# ping www.google.com -c 5
PING www.google.com (74.125.239.48) 56(84) bytes of data.
64 bytes from nuq04s19-in-f16.1e100.net (74.125.239.48): icmp_seq=1 ttl=128 time=9.83 ms
64 bytes from nuq04s19-in-f16.1e100.net (74.125.239.48): icmp_seq=2 ttl=128 time=9.05 ms
64 bytes from nuq04s19-in-f16.1e100.net (74.125.239.48): icmp_seq=3 ttl=128 time=13.4 ms
64 bytes from nuq04s19-in-f16.1e100.net (74.125.239.48): icmp_seq=4 ttl=128 time=8.40 ms
64 bytes from nuq04s19-in-f16.1e100.net (74.125.239.48): icmp_seq=5 ttl=128 time=8.25 ms
--- www.google.com ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4070ms
rtt min/avg/max/mdev = 8.256/9.808/13.490/1.924 ms
I kept this section in this article for I suspect others may look to make host name changes utilizing /etc/sysconfig/network as was previously versions of CentOS 6. Don't! Use nmtui instead and select "Set system hostname."
Default settings after installation are as follows:
[root@localhost /]# cat /etc/sysconfig/network
# Created by anaconda
In addition, executing hostname results with:
[root@localhost ~]# hostname
localhost.localdomain
Using nmtui and setting the host name to "2fcosrad7.2factor.net" results with:
[root@2fcosrad7 /]# hostname
2fcosrad7.2factor.net
###Hosts settings Editing this file is not strictly required for DNS can be utilized to resolve the host. It is my personal preference to utilize /etc/hosts for hosts to resolve themselves.
Note the current settings.
[root@2fcosrad7 ~]# cat /etc/hosts
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
Update the host name:
[root@2fcosrad7 ~]# vi /etc/hosts
172.16.1.25 2fcosrad7 2fcosrad7.2factor.net
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
Testing with ping prior to the change and without a DNS record will fail, but testing after editing /etc/hosts will now result with success.
[root@2fcosrad7 ~]# ping -c 3 2fcosrad7
PING 2fcosrad7 (172.16.1.25) 56(84) bytes of data.
64 bytes from 2fcosrad7 (172.16.1.25): icmp_seq=1 ttl=64 time=0.050 ms
64 bytes from 2fcosrad7 (172.16.1.25): icmp_seq=2 ttl=64 time=0.041 ms
64 bytes from 2fcosrad7 (172.16.1.25): icmp_seq=3 ttl=64 time=0.037 ms
--- 2fcosrad7 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2022ms
rtt min/avg/max/mdev = 0.037/0.042/0.050/0.009 ms
[root@2fcosrad7 ~]# ping -c 3 2fcosrad7.2factor.net
PING 2fcosrad7 (172.16.1.25) 56(84) bytes of data.
64 bytes from 2fcosrad7 (172.16.1.25): icmp_seq=1 ttl=64 time=0.022 ms
64 bytes from 2fcosrad7 (172.16.1.25): icmp_seq=2 ttl=64 time=0.039 ms
64 bytes from 2fcosrad7 (172.16.1.25): icmp_seq=3 ttl=64 time=0.057 ms
--- 2fcosrad7 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2002ms
rtt min/avg/max/mdev = 0.022/0.039/0.057/0.015 ms
##Time zone Reminder to the author: NEED TO UPDATE TO SHOW A CHANGE IN TIME ZONE, e.g. New_York to Los_Angeles
After installation, the default time zone is America/New_York. CentOS 7 uses timedatectl to manage time and date related settings.
Check current settings using timedatectl
[root@2fcosrad7 ~]# timedatectl
Local time: Mon 2015-05-04 19:38:33 EDT
Universal time: Mon 2015-05-04 23:38:33 UTC
RTC time: Mon 2015-05-04 23:38:33
Timezone: America/New_York (EDT, -0400)
NTP enabled: n/a
NTP synchronized: no
RTC in local TZ: no
DST active: yes
Last DST change: DST began at
Sun 2015-03-08 01:59:59 EST
Sun 2015-03-08 03:00:00 EDT
Next DST change: DST ends (the clock jumps one hour backwards) at
Sun 2015-11-01 01:59:59 EDT
Sun 2015-11-01 01:00:00 EST
Find your time zone
[root@2fcosrad7 ~]# timedatectl list-timezones | grep New
America/New_York
America/North_Dakota/New_Salem
Set your time zone
[root@2fcosrad7 ~]# timedatectl set-timezone America/New_York
Results
[root@2fcosrad7 ~]# timedatectl
Local time: Mon 2015-05-04 19:44:19 EDT
Universal time: Mon 2015-05-04 23:44:19 UTC
RTC time: Mon 2015-05-04 23:44:19
Timezone: America/New_York (EDT, -0400)
NTP enabled: n/a
NTP synchronized: no
RTC in local TZ: no
DST active: yes
Last DST change: DST began at
Sun 2015-03-08 01:59:59 EST
Sun 2015-03-08 03:00:00 EDT
Next DST change: DST ends (the clock jumps one hour backwards) at
Sun 2015-11-01 01:59:59 EDT
Sun 2015-11-01 01:00:00 EST
References:
http://www.server-world.info/en/note?os=CentOS_7&p=timezone
##Time Time synchronization can play a big role in kerberos authentication and other services.
Install NTP package:
[root@2fcosrad7 ~]# yum install ntp
Results with
================================================================================
Package Arch Version Repository
Size
================================================================================
Installing:
ntp x86_64 4.2.6p5-19.el7.centos base 540 k
Installing for dependencies:
autogen-libopts x86_64 5.18-5.el7 base 66 k
ntpdate x86_64 4.2.6p5-19.el7.centos base 82 k
Transaction Summary
================================================================================
Install 1 Package (+2 Dependent packages)
Total download size: 689 k
Installed size: 1.6 M
Is this ok [y/d/N]:
Configure NTP:
[root@2fcosrad7 ~]# vi /etc/ntp.conf
Comment out the existing lines with "server" then add one line for time source. If integration with Microsoft Windows Active Directory, it is advisable to use the IP address or host name for each domain controller or use the time sources used by the domain controller with the FSMO PDC Emulator role.
...
server 0.us.pool.ntp.org
server 1.us.pool.ntp.org
server 2.us.pool.ntp.org
server 3.us.pool.ntp.org
...
Start NTP
[root@2fcosrad7 ~]# systemctl start ntpd
Enable NTP
[root@2fcosrad7 ~]# systemctl enable ntpd
Test NTP
[root@2fcosrad7 ~]# ntpq -p
remote refid st t when poll reach delay offset jitter
==============================================================================
kahuna.ruselabs 216.218.254.202 2 u 1 64 0 0.000 0.000 0.000
grom.polpo.org .STEP. 16 u 846 64 0 0.000 0.000 0.000
216.152.240.220 209.81.9.7 3 u 1 64 0 0.000 0.000 0.000
blue.1e400.net 91.189.94.4 3 u 1 64 0 0.000 0.000 0.000
##Virtual Machine Drivers
Assuming you are using CentOS on a virtual machine, it is advisable to install virtual machine drivers. Not a requirement, but you will, otherwise, lose functionality with most virtual machine technology solutions. I use open-vm-tools, but it is my personal preference. See this article explaining my reasons why: https://github.com/rharmonson/richtech/wiki/CentOS-6-and-7-&-Virtualization-with-VMware-=-open-vm--tools.
Execute the following where -y responds with yes to all queries and ;reboot execute a second command at the completion of yum to reboot the CentOS host:
[root@2fcosrad7 ~]# yum install open-vm-tools -y;reboot
Results with the following:
================================================================================
Package Arch Version Repository
Size
================================================================================
Installing:
open-vm-tools x86_64 9.4.0-6.el7 base 430 k
Installing for dependencies:
libdnet x86_64 1.12-13.1.el7 base 31 k
libicu x86_64 50.1.2-11.el7 base 6.9 M
net-tools x86_64 2.0-0.17.20131004git.el7 base 304 k
Transaction Summary
================================================================================
Install 1 Package (+3 Dependent packages)
Total download size: 7.6 M
Installed size: 26 M
Is this ok [y/N]:
##EPEL EPEL repository installation steps are as follows:
- Install the repository's key, so the package can be verified and trusted.
- Install the repository package for your distribution.
- Configure, if desired, the repository configuration files found
/etc/yum.repos.d.
For CentOS 7 64 bit
# rpm --import https://dl.fedoraproject.org/pub/epel/RPM-GPG-KEY-EPEL-7
# rpm -ivh http://mirror.sfo12.us.leaseweb.net/epel/7/x86_64/e/epel-release-7-5.noarch.rpm
Results with
[root@2fcosrad7 ~]# rpm --import https://dl.fedoraproject.org/pub/epel/RPM-GPG-KEY-EPEL-7
[root@2fcosrad7 ~]# rpm -ivh http://mirror.sfo12.us.leaseweb.net/epel/7/x86_64/e/epel-release-7-5.noarch.rpm
Retrieving http://mirror.sfo12.us.leaseweb.net/epel/7/x86_64/e/epel-release-7-5.noarch.rpm
Preparing... ################################# [100%]
Updating / installing...
1:epel-release-7-5 ################################# [100%]
Once installed, you can use the default settings; EPEL base is enabled.
##Update Update CentOS using base and EPEL repositories, then reboot.
# yum update -y; reboot
Results with:
================================================================================
Package Arch Version Repository Size
================================================================================
Installing:
kernel x86_64 3.10.0-229.1.2.el7 updates 31 M
Updating:
bind-libs-lite x86_64 32:9.9.4-18.el7_1.1 updates 712 k
bind-license noarch 32:9.9.4-18.el7_1.1 updates 80 k
binutils x86_64 2.23.52.0.1-30.el7_1.1 updates 5.0 M
centos-logos noarch 70.0.6-2.el7.centos updates 21 M
dnsmasq x86_64 2.66-13.el7_1 updates 228 k
dracut x86_64 033-241.el7_1.1 updates 300 k
dracut-config-rescue x86_64 033-241.el7_1.1 updates 44 k
dracut-network x86_64 033-241.el7_1.1 updates 82 k
freetype x86_64 2.4.11-10.el7_1.1 updates 391 k
kernel-tools x86_64 3.10.0-229.1.2.el7 updates 1.5 M
kernel-tools-libs x86_64 3.10.0-229.1.2.el7 updates 1.4 M
libgudev1 x86_64 208-20.el7_1.2 updates 56 k
libxml2 x86_64 2.9.1-5.el7_1.2 updates 664 k
openssl x86_64 1:1.0.1e-42.el7.4 updates 710 k
openssl-libs x86_64 1:1.0.1e-42.el7.4 updates 948 k
systemd x86_64 208-20.el7_1.2 updates 2.6 M
systemd-libs x86_64 208-20.el7_1.2 updates 161 k
systemd-sysv x86_64 208-20.el7_1.2 updates 43 k
tzdata noarch 2015d-1.el7 updates 431 k
Transaction Summary
================================================================================
Install 1 Package
Upgrade 19 Packages
Total download size: 68 M
Is this ok [y/d/N]:
Restart to utilize the new packages and drivers.
# reboot