RHCE6 Preperation (6) - httpd, lvm, grep, ssh, nfs

1, install the http server, make it automatically startup

yum install -y http*
/etc/init.d/httpdd start
chkconfig httpd on      

2, create logical volume, name as lv0, lv0 belong to logical group vg0, PE size as 8M, logical volume as 40 PE, formatted as ext4, mount to /data, and make it automatically mounted when start,

fdisk /dev/sda      

to create physical partition, label as 0x8e, make it usable by partx command,

partx -a /dev/sda      

create pv,

pvcreate /dev/sda4      

create vg, the PE size as 8M

vgcreate –s 8M vg0 /dev/sda4      

 create lv, name as lv0, size as 40 PE.

lvcreate –l 40 –n lv0 vg0      

formatted the system as ext4, better use the disk mapping system,

mkfs –t ext4 /dev/mapper/vg0-lv0      

mount to /data, if there is no data folder, create it,

mount /dev/mapper/vg0-lv0 /data      

add the auto mount to fstab,  /etc/fstab

/dev/mapper/vg0-lv0 /data ext4 defaults 0 0      

another way to create the logical volume, logical volume name as engineering, belong to group development, 20 extends, 32M size for each extend in the logic group development, use vfat format to format and auto mounted to /mnt/engineering

fdisk /dev/sda
p #check the status of the partition
n #create new partition
p #the primary partition
#size as +800M
w #save      

command "sytstem-config-lvm" to enter the UI, create the logical group as development, physical extend size as 32M, select eh logical view, and create the logical volume name as engineering, the UI interface doesn't have the vfat format, needs to use the command to format the logical volume.

mkfs.vfat /dev/development/engineering
mkdir /mnt/engineering
vim /etc/fstab      

add one line to auto mount,

/dev/development/engineering /mnt/engineering vfat defaults 0 0      

to mount all,

mount -a      

3, find the lines in the /etc/testfile contains "abcde", and dump into /tmp/testfile, and the sequence should be the same as /etc/testfile

to see the content of the /etc/testfile,

cat /etc/testfile      

grep command search /etc/testfile,

grep -n [abcde] /etc/testfile > /tmp/testfile      

4, configure the SSH as, has the remote access to your machine from with example.com, client with the remote.test cannot access to ssh to your system

modify the /etc/host.allow, to add one line,

sshd: .example.com      

modify the /etc/host.deny, to add one line,

sshd: .remote.test      

add auto on,

chkconfig sshd on      

5, Export your /common directory via NFS to the example.com domain only

modify the /etc/export, add one line,

/common *.example.com(ro,sync)      

restart the nfs and make it auto on,

/etc/init.d/nfs restart
chkconfig nfs on      

test the result at the instructor computer, make sure the firewall let the nfs service go through, otherwise the problem will be,

[root@instructor ~]# showmount -e server3.example.com
clnt_create: RPC: Port mapper failure - Unable to receive: errno 113 (No route to host)      

enable the firewall to allow the nfs go through, two ways to do this,

a, let the eth0 to allow all service go through,

iptables -I INPUT 4 -i eth0 -j ACCEPT      

service iptables save      

b, let the firewall to allow specific port to go through,

modify the nfs configuration file, to let the nfs to use the fixed port,

vim /etc/sysconfig/nfs      

uncomment this line

MOUNTD_PORT=892      

restart the nfs service

service nfs restart      

add three line in the iptables,

-A INPUT -p tcp -m state --state NEW -m tcp --dport 111 -j ACCEPT
-A INPUT -p udp -m state --state NEW -m udp --dport 111 -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 892 -j ACCEPT      

restart the iptables,

service iptables restart      

test on the instructor computer again,

[root@instructor ~]# showmount -e server4.example.com
Export list for server3.example.com:
/home   *
/common 192.168.0.0/24