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最後更新: 2017-05-31
Installation:
* Installer: Kickstart (a single file is created, containing the answers to all the questions)
* Boot Loader: GRUB2 (GPT, NTFS)
Storage:
* iSCSI: LIO kernel Target Subsystem
* /tmp directory can now be used as a temporary file storage system (tmpfs)
* LVM Cache
* Default file system: XFS
(XFS file system can also be defragmented and expanded while mounted and active. )
* pNFS (NFS v4.1)(layouts: files, objects, and blocks. )
Kernel:
* kernel version 3.10
* Dynamic kernel Patching (kpatch), AMD64 and Intel 64 architectures only
* swap memory compression
* includes the Open vSwitch kernel module
https://access.redhat.com/knowledge/articles/270223
KVM:
* virtio-blk-data-plane (dedicated thread that is optimized for I/O performance. )
* virtio_net
* virtio_scsi
(each virtual CPU can have a separate transmit or receive queue and separate interrupts)
* live migration: Page Delta Compression
* Live Migration Thread
* virtio-rng
* Bridge Zero Copy Transmit (disabled by default. )
* QCOW2 version 3 Image Format
VPS:
- Docker Format
- lxc
= net_cls — tags network packets with a class identifier (classid)
= hugetlb — allows to use virtual memory pages of large sizes
Network:
* bond2team (Network Teaming has been introduced as an alternative to bonding for link aggregation.)
* firewalld (Dynamic Firewall Daemon)
* DNSSEC
* SYNPROXY (filters out false SYN-ACK and ACK packets before the socket enters the "listen" state lock)
* Network Hardware Offload (Mellanox ConnectX3-pro Ethernet NIC card)
Services:
* Init: systemd
- On-demand starting of daemons
- Managing of control groups
Introducing:
- Apache 2.4 ( "Event" processing module )
- MariaDB 5.5
- Samba 4.1
= SMB3 transport enables encrypted transport
= server-side copy operations
Clustering:
- Pacemaker (pcs)
- HAProxy (TCP/HTTP reverse proxy)
= add, modify, and delete HTTP headers
= persistence through the use of HTTP cookies
= block requests matching particular patterns
- Keepalived (Layer-4 load balancing.)[Virtual Router Redundancy Protocol (VRRPv2)]
DOC:
https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/System_Administrators_Guide/index.html
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7...
https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Li...
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7...
Centos7
安裝 net-tools
# 找不到 ifconfig 及 netstat
yum install net-tools
/bin/netstat
/sbin/arp
/sbin/ether-wake
/sbin/ifconfig
/sbin/ipmaddr
/sbin/iptunnel
/sbin/mii-diag
/sbin/mii-tool
/sbin/nameif
/sbin/plipconfig
/sbin/route
/sbin/slattach
iptables
# 不想用 firewalld
yum install iptables-services
systemctl
systemctl stop avahi-daemon
systemctl disable avahi-daemon
service --status-all
nic name
CentOS7 has a default nic name as "en????"
修改 /etc/default/grub
GRUB_CMDLINE_LINUX="... net.ifnames=0 biosdevname=0 ..."grub2-mkconfig -o /boot/grub2/grub.cfg
# Disable the NetworkManager service
ifcfg-eth0
NM_CONTROLLED='no'
systemctl stop NetworkManager
systemctl disable NetworkManager
Timezone
timedatectl list-timezones
timedatectl set-timezone region/timezone
i.e.
timedatectl set-timezone Asia/Hong_Kong
Swap
fallocate -l 4G /swapfile
chmod 600 /swapfile
mkswap /swapfile
swapon /swapfile
sh -c 'echo "/swapfile none swap sw 0 0" >> /etc/fstab'
set hostname
新的 Centos 一共有以下 hostname 類型
(1) static,
(2) transient, and
(3) pretty.
The "static" hostname is also known as kernel hostname, which is initialized from /etc/hostname automatically at boot time.
The "transient" hostname is a temporary hostname assigned at run time, for example, by a DHCP or mDNS server.
"pretty" hostname is allowed to have a free-form
# 查看
hostnamectl status
Static hostname: localhost.localdomain
Transient hostname: x.y.z
Icon name: computer-vm
Chassis: vm
Machine ID: 80a476a9db4d449b8928ea7cf47ced6d
Boot ID: a4742856ccb94c3ba247f2af1f0a239d
Virtualization: vmware
Operating System: CentOS Linux 7 (Core)
CPE OS Name: cpe:/o:centos:centos:7
Kernel: Linux 3.10.0-123.13.2.el7.x86_64
Architecture: x86_64# To change all three hostnames
hostnamectl set-hostname <host-name>
/etc/hostname
OR
/etc/sysconfig/network
HOSTNAME=x.y.z
systemctl restart systemd-hostnamed
# Other CMD:
hostname <-- transient
rc.local 沒有執行
In CentOS 7, the /etc/rc.local not enabled by default,
ls -l /etc/rc.local
lrwxrwxrwx 1 root root 13 Jul 21 22:57 /etc/rc.local -> rc.d/rc.local
ls -l /etc/rc.d/rc.local
-rw-r--r--. 1 root root 474 Jul 21 22:57 /etc/rc.d/rc.local
解決:
chmod +x /etc/rc.d/rc.local
Environment
It is executed as root.
lt run as separate processes, which means they have no way to modify their parent's environment.
It runs before the operating system is fully booted but has not yet started the login shell,
so the environment variables we configured in /etc/profiles or bashrc are not executed.
Service
systemctl start rc-local
systemctl enable rc-local
systemctl status rc-local
cat /usr/lib/systemd/system/rc-local.service
Service start on boot
systemctl status mariadb
Loaded: loaded (/usr/lib/systemd/system/mariadb.service; enabled; vendor preset: disabled)enabled => will start on boot
CentOS 7 NetInstall
Step0:
到 http://ftp.cuhk.edu.hk/pub/Linux/centos/7.0.1406/isos/x86_64/ 下載 ISO
# 362M
CentOS-7.0-1406-x86_64-NetInstall.iso
Step1: Setup Network and Hostname
NetInstall URL
http://ftp.cuhk.edu.hk/pub/Linux/centos/7/os/x86_64/
OR
http://mirror.centos.org/centos/7/os/x86_64/
website 的 root directory 有
CentOS_BuildTag Packages/ repodata/
Grub boot menu
* Do not attempt to manually edit the boot menu ("/boot/grub2/grub.cfg")
grub2-mkconfig -o /boot/grub2/grub.cfg
設定
/etc/default/grub
/etc/grub.d/40_custom
grub2-editenv list
saved_entry=CentOS Linux (3.10.0-514.16.1.el7.x86_64) 7 (Core) with debugging
# 由 1 開始
grub2-set-default 1
# To list all the menu entries that will be displayed at system boot
grep "^menuentry" /boot/grub2/grub.cfg | cut -d "'" -f2
