Article Directory
YUM overview
YUM (Yellow dog Updater Modified)
- Software update mechanism based on RPM package
- Can resolve dependencies automatically
- All software packages are provided by the centralized YUM software warehouse
Prepare the installation source
How to provide software warehouse
- Network source
FTP service: ftp://…
HTTP service: http://… - Local source
Local directory: file://...
The source of the RPM package
- A collection of RPM packages released by CentOS
- A collection of RPM packages released by third-party organizations
- User-defined RPM package collection
Build CentOS 7 software warehouse
- The RPM package comes from the CentOS 7 DVD disc
- Provide to the client via FTP (install and enable the vsftpd service)
mkdir -p /var/ftp/CentOS7
cp -rf /dev/cdrom/* /var/ftp/CentOS7
rpm -ivh /dev/cdrom/Packages/vsftp-3.0.2-21.el7.x86_64.rpm
systemctl start vsftpd
systemctl enabled vsftpd
Join the unofficial RPM package group in the software warehouse
-
Generally obtained through the Internet
-
Include all other RPM packages that have dependencies
-
Need to use createrepo tool to build repodata data file warehouse
-
The installation package file is stored in the /var/ftp/other directory
mkdir -p /var/ftp/other cd /var/ftp/other createrepo -g /dev/cdrom/repodata/repomd.xml ./
Visit YUM warehouse
Specify the location of the YUM warehouse for the client
Configuration file location: /etc/yum.repos.d/centos7.repo
vim /etc/yum.repos.d/centos7.repo
[base] #仓库类别，注意：方括号里面不能有空格。
name=CentOS 7 #仓库名称
baseurl=ftp:///192.168.249.254/CentOS7 #URL访问路径
enabled=1 #启用此软件仓库，默认该选项可以不写。如果值为0，则表示禁用这个软件源。
gpgcheck=1(或0：表示不验证公钥) #验证软件包的签名
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7 (软件校验公钥) #GPG公钥文件的位置
[other]
name=Other RPM Packages
baseurl=ftp:///192.168.249.254/other
enabled=1
gpgcheck=0
NFS shared storage service
Related concepts
- NFS is a network file system protocol based on TCP/IP transmission. By using the NFS protocol, the client can access the shared resources in the remote server as if it were accessing a local directory.
- For most load balancing clusters, it is a common practice to use the NFS protocol to share data storage. NFS is also a protocol that NAS storage devices must support. However, because NFS does not have a user authentication mechanism, and the data is transmitted in plain text on the network, the security is very poor, and it can only be used in a local area network.
- The implementation of the NFS service relies on the RPC (Remote Process Call) mechanism to complete the remote-to-local mapping process, so it is necessary to install the nfs-utils and rpcbind software packages to provide NFS sharing services.
nfs-utils is used for NFS share publishing and access
rpcbind for RPC support
NFS service configuration file
- The NFS configuration file is /etc/exports (the content inside is empty by default)
- The format is: shared directory location client address (permission option)
NFS service configuration details
Use NFS to publish shared resources in the file server
Install nfs-utils, rpcbind packages
rpm -q rpcbind nfs-utils
yum -y install nfs-utils rpcbind
Set up a shared directory
mkdir -p /opt/share
chmod 777 /opt/share/
vim /etc/exports
/opt/share 192.168.249.0/24(rw,sync,no_root_squash)
客户机地址可以是主机名、IP 地址、网段地址，允许使用“*”、“?”通配符。
Common options
“rw” 表示允许读写，“ro” 表示为只读；
sync ：表示同步写入到内存与硬盘中。
async ：将数据先保存在内存缓冲区中，必要时才写入磁盘。
no_root_squash ： 表示当客户机以root身份访问时赋予本地root权限（默认是root_squash）。
root_squash ：表示客户机用root用户访问该共享目录时，将root用户映射成匿名用户。
all_squash ：所有访问用户都映射为匿名用户或用户组。
subtree_check（默认）：若输出目录是一个子目录，则nfs服务器将检查其父目录的权限。
no_subtree_check ：即使输出目录是一个子目录，nfs服务器也不检查其父目录的权限，这样可以提高效率。
其他例子：
/var/ftp/pub 192.168.249.11(ro) 192.168.249.110(rw)
/share *(rw,sync)
Start the NFS service program
When manually loading the NFS sharing service, you should start rpcbind first, and then start nfs
systemctl start rpcbind
systemctl start nfs
systemctl enable rpcbind
systemctl enable nfs
netstat -anpt | grep 111 #查看rpcbind端口111是否开启， rpcbind默认使用tcp端口111
View the NFS shared directory published by this machine
exportfs -rv #发布共享
showmount -e #查看共享
Access NFS shared resources in the client
Install nfs-utils, rpcbind packages
rpm -q rpcbind nfs-utils
yum -y install nfs-utils rpcbind
systemctl start rpcbind
systemctl enable rpcbind
systemctl stop firewalld.service
setenforce 0
#查看 NFS 服务器端共享了哪些目录
showmount -e 192.168.249.10
Mount NFS shared directory
方法一：手动挂载
mkdir /myshare
mount 192.168.249.10:/opt/share /myshare
方法二：自动挂载
vim /etc/fstab
192.168.249.10:/opt/share /myshare nfs defaults,_netdev 0 0
_netdev ：表示挂载设备需要网络
mount -a #挂载 fstab 中的所有文件系统
df -Th #确认挂载结果
Manual mounting:
automatic mounting:
Forcibly uninstall NFS
If the server-side NFS service suddenly stops while the client is being mounted and used, the client will be stuck when executing the df -h command. At this time, you cannot uninstall directly by using the umount command directly, and you need to add the -lf option to uninstall.
umount -lf /myshare
