Install LAMP + phpMyAdmin on 7 CentOS 7 / RHEL

The main attention is now replaced by the MySQL database MariaDB, and therefore representative of the LAMP Linux + Apache + MariaDB + PHP up.

System: The new CentOS 7 using systemd, thus some instruction vary ; now use alternative MariaDB MySQL as the database software, there will also be installed directly MariaDB.

Set HOSTNAME

echo “HOSTNAME=clusterserver3.rmohan.com” >> /etc/sysconfig/network
hostname “clusterserver3.rmohan.com”

INSTALL VIM

yum -y install vim

To make a color display code, and also supports line numbers and mouse positioning mark, you need to edit vim configuration file:

vim /etc/vimrc

set nu
set mouse=a

update configuration file /etc/hosts

192.168.1.22 clusterserver3.rmohan.com clusterserver3

remove the dhcp

systemctl list-unit-files –type=service dhcp

add timezone

ln -sf /usr/share/zoneinfo/Singapore /etc/localtime
timedatectl set-timezone Asia/Singapore ; timedatectl

yum update

install http

yum install httpd

http://192.168.1.22

[root@clusterserver3 ~]# systemctl enable httpd
Created symlink from /etc/systemd/system/multi-user.target.wants/httpd.service to /usr/lib/systemd/system/httpd.service.
[root@clusterserver3 ~]#

firewall-cmd –add-service=http –permanent
firewall-cmd –add-service=https –permanent
firewall-cmd –zone=public –add-port=22/tcp –permanent

systemctl restart firewalld

firewall-cmd –list-all

# firewall-cmd –state
# firewall-cmd –list-all
# firewall-cmd –list-interfaces
# firewall-cmd –get-service
# firewall-cmd –query-service service_name
# firewall-cmd –add-port=8080/tcp

install Mariadb

yum install mariadb-server mariadb

systemctl enable mariadb

[root@clusterserver3 ~]# systemctl enable mariadb
Created symlink from /etc/systemd/system/multi-user.target.wants/mariadb.service to /usr/lib/systemd/system/mariadb.service.
[root@clusterserver3 ~]#

top -u mysql

systemctl start mariadb
systemctl stop mariadb
systemctl restart mariadb
systemctl disable mariadb
systemctl is-active mariadb

Test MariaDB server in the local virtual machine CentOS 7 system, every time execution mysql command will always encounter “ERROR 2006 (HY000): MySQL server has gone away” error. Calibration of the time within a virtual machine, the aforementioned problems hours. Is there a necessary connection between the two is not to say, temporarily be recorded.

Execute an instruction casually in MariaDB, whether create database or just flush privileges or, before the implementation of the results will show a similar instruction such output,

MariaDB [(none)]> select now ();
ERROR 1305 (42000): FUNCTION now does not exist
MariaDB [(none)]>

mysql_secure_installation

[root@clusterserver3 ~]# mysql_secure_installation
/usr/bin/mysql_secure_installation: line 379: find_mysql_client: command not found

NOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MariaDB
SERVERS IN PRODUCTION USE!  PLEASE READ EACH STEP CAREFULLY!

In order to log into MariaDB to secure it, we’ll need the current
password for the root user.  If you’ve just installed MariaDB, and
you haven’t set the root password yet, the password will be blank,
so you should just press enter here.

Enter current password for root (enter for none):
ERROR 1045 (28000): Access denied for user ‘root’@’localhost’ (using password: YES)
Enter current password for root (enter for none):
OK, successfully used password, moving on…

Setting the root password ensures that nobody can log into the MariaDB
root user without the proper authorisation.

Set root password? [Y/n] Y
New password:
Re-enter new password:
Sorry, passwords do not match.

New password:
Re-enter new password:
Password updated successfully!
Reloading privilege tables..
… Success!

By default, a MariaDB installation has an anonymous user, allowing anyone
to log into MariaDB without having to have a user account created for
them.  This is intended only for testing, and to make the installation
go a bit smoother.  You should remove them before moving into a
production environment.

Remove anonymous users? [Y/n] y
… Success!

Normally, root should only be allowed to connect from ‘localhost’.  This
ensures that someone cannot guess at the root password from the network.

Disallow root login remotely? [Y/n] y
… Success!

By default, MariaDB comes with a database named ‘test’ that anyone can
access.  This is also intended only for testing, and should be removed
before moving into a production environment.

Remove test database and access to it? [Y/n] y
– Dropping test database…
… Success!
– Removing privileges on test database…
… Success!

Reloading the privilege tables will ensure that all changes made so far
will take effect immediately.

Reload privilege tables now? [Y/n] y
… Success!

Cleaning up…

All done!  If you’ve completed all of the above steps, your MariaDB
installation should now be secure.

Thanks for using MariaDB!
[root@clusterserver3 ~]#

MariaDB [(none)]> show global variables like ‘max_allowed_packet’;
+——————–+———+
| Variable_name      | Value   |
+——————–+———+
| max_allowed_packet | 1048576 |
+——————–+———+
1 row in set (0.00 sec)

MariaDB [(none)]>

MariaDB [(none)]> set global max_allowed_packet=1024*1024*16;
Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> show global variables like ‘max_allowed_packet’;
+——————–+———-+
| Variable_name      | Value    |
+——————–+———-+
| max_allowed_packet | 16777216 |
+——————–+———-+
1 row in set (0.00 sec)

MariaDB [(none)]>
time in centos 7
yum -y -q install ntp
ntpdate -s ntp.org
date

MariaDB [(none)]> select now();
+———————+
| now()               |
+———————+
| 2016-01-03 16:18:47 |
+———————+
1 row in set (0.00 sec)

MariaDB [(none)]>
Type ‘help;’ or ‘\h’ for help. Type ‘\c’ to clear the current input statement.

MariaDB [(none)]> select now();
+———————+
| now()               |
+———————+
| 2016-01-03 07:15:34 |
+———————+
1 row in set (0.00 sec)

MariaDB [(none)]>

yum install php

cp /etc/php.ini ~/confbak/php.ini.bak
cp /etc/httpd/conf.d/php.conf ~/confbak/httpd/conf.d/php.conf.bak
cp /etc/httpd/conf.modules.d/10-php.conf ~/confbak/httpd/conf.modules.

vi /etc/php.ini

error_reporting = E_COMPILE_ERROR|E_RECOVERABLE_ERROR|E_ERROR|E_CORE_ERROR
display_errors = Off
log_errors = On
max_execution_time = 300
memory_limit = 32M

yum install php-mysql

yum install http://dl.fedoraproject.org/pub/epel/7/x86_64/e/epel-release-7

yum install phpmyadmin

cp /etc/httpd/conf.d/phpMyAdmin.conf ~/confbak/httpd/conf.d/phpMyAdmin.conf.bak

#Alias /phpMyAdmin /usr/share/phpMyAdmin
#Alias /phpmyadmin /usr/share/phpMyAdmin

<Directory /usr/share/phpMyAdmin/>
………
</Directory>

Require ip 127.0.0.1
Require ip ::1

cp /etc/phpMyAdmin/config.inc.php ~/confbak/config.inc.php.bak
vi /etc/phpMyAdmin/config.inc.php

$cfg[‘blowfish_secret’] = ‘password’

systemctl restart httpd

we begin, we should take a look at our server’s storage to see if we already have some swap space available. While we can have multiple swap files or swap partitions, one should generally be enough.
We can see if the system has any configured swap by using swapon, a general-purpose swap utility. With the -s flag, swapon will display a summary of swap usage and availability on our storage device:

swapon -s

If nothing is returned by the command, then the summary was empty and no swap file exists.
Another way of checking for swap space is with the free utility, which shows us the system’s overall memory usage. We can see our current memory and swap usage (in megabytes) by typing:

[root@clusterserver3 ~]# free  -m
              total        used        free      shared  buff/cache   available
Mem:           3704         104        3464           8         135        3433
Swap:          3967           0        3967
[root@clusterserver3 ~]#

create a Swap File

Now that we know our available storage space, we can go about creating a swap file within our filesystem. We will create a file called swapfile in our root (/) directory, though you can name the file something else if you prefer. The file must allocate the amount of space that we want for our swap file.
 The fastest and easiest way to create a swap file is by using fallocate. This command creates a file of a preallocated size instantly. We can create a 4 gigabyte file by typing:

 fallocate -l 4G /swapfile


[root@clusterserver3 /]# ls -ltr /swapfile
-rw-r--r-- 1 root root 4294967296 Jan  2 00:34 /swapfile
[root@clusterserver3 /]#

Enable a Swap File

Right now, our file is created, but our system does not know that this is supposed to be used for swap. We need to tell our system to format this file as swap and then enable it.
 Before we do that, we should adjust the permissions on our swap file so that it isn't readable by anyone besides the root account. Allowing other users to read or write to this file would be a huge security risk. We can lock down the permissions with chmod:

 chmod 600 /swapfile

[root@clusterserver3 /]# mkswap /swapfile
Setting up swapspace version 1, size = 4194300 KiB
no label, UUID=75cdf9e6-f034-4aed-845e-59035534eeaf
[root@clusterserver3 /]#

Make the Swap File Permanent

Our swap file is enabled at the moment, but when we reboot, the server will not automatically enable the file for use. We can change that by modifying the fstab file, which is a table that manages filesystems and partitions.
 Edit the file with sudo privileges in your text editor:

vi /etc/fstab

At the bottom of the file, you need to add a line that will tell the operating system to automatically use the swap file that you created:

/swapfile   swap    swap    sw  0   0

weak Your Swap Settings (Optional)

There are a few options that you can configure that will have an impact on your system's performance when dealing with swap. These configurations are optional in most cases, and the changes that you make will depend on your application needs and your personal preference.

Swappiness

The swappiness parameter determines how often your system swaps data out of memory to the swap space. This is a value between 0 and 100 that represents the percentage of memory usage that will trigger the use of swap.
 With values close to zero, the system will not swap data to the drive unless absolutely necessary. Remember, interactions with the swap file are "expensive" in that they are a lot slower than interactions with memory, and this difference in read and write speed can cause a significant reduction in an application's performance. Telling the system not to rely on the swap as much will generally make your system faster.
 Values that are closer to 100 will try to put more data into swap in an effort to keep more memory free. Depending on your applications' memory profile, or what you are using your server for, this might be the better choice in some cases.
 We can see the current swappiness value by reading the swappiness configuration file:

cat /proc/sys/vm/swappiness

30

CentOS 7 defaults to a swappiness setting of 30, which is a fair middle ground for most desktops and local servers. For a VPS system, we'd probably want to move it closer to 0.
 We can set the swappiness to a different value by using the sysctl command. For instance, to set the swappiness to 10, we could type:

sudo sysctl vm.swappiness=10

vm.swappiness = 10

This setting will persist until the next reboot. To make the setting persist between reboots, we can add the outputted line to our sysctl configuration file:

sudo nano /etc/sysctl.conf

Add your swappiness setting to the bottom of the file:

vm.swappiness = 10

When you are finished adding the line, you can save and close the file. The server will now automatically set the swappiness to the value you declared on each bootup.

Cache Pressure

Another related value that you might want to modify is the vfs_cache_pressure. This setting affects the storage of special filesystem metadata entries. Constantly reading and refreshing this information is generally very costly, so storing it on the cache for longer is excellent for your system's performance.
 You can see the current value of this cache pressure by querying the proc filesystem again:

cat /proc/sys/vm/vfs_cache_pressure

100

As it is currently configured, our system removes inode information from the cache far too quickly. We can set this to a more conservative setting, like 50, by using sysctl:

sudo sysctl vm.vfs_cache_pressure=50

vm.vfs_cache_pressure = 50

Again, this is only valid for our current session. We can change that by adding it to our configuration file, like we did with our swappiness setting:

sudo nano /etc/sysctl.conf

At the bottom, add the line that specifies your new value:

vm.vfs_cache_pressure = 50

Reset Your Forgotten Root Password On CentOS 7

To get started, turn on the machine that you’ve forgotten the root password on. For CentOS 7 devices, you’ll be given 5 seconds at the boot menu to select the operating system kernel to boot into.

That 5 seconds is important, because allows for  admins to select different kernels or edit existing kernel parameters before booting.

At the boot menu, press e to edit the existing kernel (Core) as shown below.

Next, scroll down to the list until you see the line underlined below ( ro ) . What we need to do is change that ro to rw and start into a bash shell. It should look like this rw init=/sysroot/bin/sh.

Change the ro line to rw and add init=/sysroot/bin/sh

rw init=/sysroot/bin/sh

You’ll be prompted to create and confirm a new password.  After creating the password, run the commands below to update SELinux parameters

touch /.autorelabel