Centos7 Upgrading Kernel to 3.19

Centos 7 is the latest release from the community.  Centos7 is shipped with 3.10 Kernel. Many times people may need the latest Kernel. This article telling about how to upgrade from 3.10 to latest upstream kernel.

# rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org

# rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-2.el7.elrepo.noarch.rpm

# yum --enablerepo=elrepo-kernel install kernel-ml

Once the installation is finished, make sure you have got new kernel.

# awk -F\' '$1=="menuentry " {print $2}' /etc/grub2.cfg

CentOS Linux, with Linux 3.19.0-1.el7.elrepo.x86_64

CentOS Linux, with Linux 3.10.0-123.el7.x86_64

CentOS Linux, with Linux 3.10.0-123.20.1.el7.x86_64

CentOS Linux, with Linux 0-rescue-b6ea1092b61e4ac7a546ba4454bd63d0

If the CentOS kernel version 3.19.x is listed first, then set grub to use 0 which will set the system to boot off the newer kernel. You might want to leave some of the older 3.10.x kernels on the system in case you decide to revert to the stock CentOS 7 kernel, but you can always modify the default kernel to use later on.

# grub2-set-default 0

Update the grub2 config so it's aware of the changes we just made.

# grub2-mkconfig -o /boot/grub2/grub.cfg

# reboot

Check the new kernal.

# uname -a

Linux compute1 3.19.0-1.el7.elrepo.x86_64 #1 SMP Mon Feb 9 09:57:29 EST 2015 x86_64 x86_64 x86_64 GNU/Linux

3 Node MySQL Cluster using Percona

Percona XtraDB Cluster is an active/active high availability and high scalability open source solution for MySQL clustering. It integrates Percona Server and Percona XtraBackup with the Galera library of MySQL high availability solutions in a single package which enables you to create a cost-effective MySQL high availability cluster. 

Here following a 3 node mysql cluster using Percona. The infrastructure is as follows.

All the Nodes are running on Centos 6.6. The IPAddress / Hostnames  of the Nodes are as follows. Turn off IPTABLES in all these nodes, OR allow traffic between these nodes.

192.168.1.1      cluster-node1

192.168.1.2      cluster-node2

192.168.1.3      cluster-node3

Add these entries in each and every nodes /etc/hosts files.

#vim /etc/hosts

192.168.1.1      cluster-node1

192.168.1.2      cluster-node2

192.168.1.3      cluster-node3

Disable SELINUX

Set Up SSH Keys and place into authorized_keys so all the id_rsa.pub values are in authorized_keys on all servers.

# ssh-keygen -t rsa

# cd /root/.ssh/

# cp id_rsa.pub authorized_keys 

# chmod 600  /root/.ssh/authorized_keys

# chmod 700  /root/.ssh/

Install the Needed Repositories for Percona & Socat.

# yum -y install http://www.percona.com/downloads/percona-release/percona-release-0.0-1.x86_64.rpm

# yum -y install http://mirror.pnl.gov/epel/6/x86_64/epel-release-6-8.noarch.rpm

# wget http://www.percona.com/downloads/RPM-GPG-KEY-percona /etc/pki/rpm-gpg/RPM-GPG-KEY-percona 

# wget http://www.percona.com/downloads/RPM-GPG-KEY-percona /etc/pki/rpm-gpg/RPM-GPG-KEY-percona 

# yum -y install socat

Remove the following applications to avoid the dependencies, Later we can bring them back.

# rpm -e mysql-libs postfix cronie redhat-lsb-core redhat-lsb-printing redhat-lsb-graphics libcgroup numad redhat-lsb sysstat crontabs cronie-anacron redhat-lsb-compat

Install the Percona Cluster Packages (Repeat the following Commands in all the Nodes)

#yum -y install Percona-XtraDB-Cluster-full-56

Start the Server.

[root@cluster-node1 ~]#  /etc/init.d/mysql start

Starting MySQL (Percona XtraDB Cluster)......... SUCCESS! 

[root@cluster-node2 ~]# /etc/init.d/mysql start

Starting MySQL (Percona XtraDB Cluster)......... SUCCESS!

[root@cluster-node3 ~]# /etc/init.d/mysql start

Starting MySQL (Percona XtraDB Cluster)......... SUCCESS! 

Run the following Commands

#mysql -e "CREATE FUNCTION fnv1a_64 RETURNS INTEGER SONAME 'libfnv1a_udf.so'" 

#mysql -e "CREATE FUNCTION fnv_64 RETURNS INTEGER SONAME 'libfnv_udf.so'"

#mysql -e "CREATE FUNCTION murmur_hash RETURNS INTEGER SONAME 'libmurmur_udf.so'"

Bring in Back the removed packages

#yum -y install postfix cronie redhat-lsb-core redhat-lsb-printing redhat-lsb-graphics libcgroup numad redhat-lsb sysstat crontabs cronie-anacron redhat-lsb-compat

Create the my.cnf file in first node and insert the following contents

#vim /etc/my.cnf

[mysqld]

datadir=/var/lib/mysql

user=mysql

# Path to Galera library

wsrep_provider=/usr/lib64/libgalera_smm.so

# Cluster connection URL contains the IPs of node#1, node#2 and node#3

# cluster-node 1 192.168.1.1

# cluster-nod3 2 192.168.1.2

# cluster-nod3 3 192.168.1.3

wsrep_cluster_address=gcomm://192.168.1.1,192.168.1.2,192.168.1.3

# In order for Galera to work correctly binlog format should be ROW

binlog_format=ROW

# MyISAM storage engine has only experimental support

default_storage_engine=InnoDB

# This changes how InnoDB auto increment locks are managed and is a requirement for Galera

innodb_autoinc_lock_mode=2

# Node #1 address

wsrep_node_address=192.168.1.1

# SST method

#wsrep_sst_method=xtrabackup

 wsrep_sst_method=rsync      #

# wsrep_sst_method=rsync_wan  #

# wsrep_sst_method=mysqldump  # SLOW

# Cluster name

wsrep_cluster_name=percona_cluster

# Authentication for SST method

wsrep_sst_auth="root:password" 

# server_id

server_id=3232235553  #SELECT INET_ATON('192.168.1.1')

#[client]

socket=/var/lib/mysql/mysql.sock

Start the First Clustering Node.

#/etc/init.d/mysql start --wsrep-cluster-address="gcomm://"

Starting MySQL (Percona XtraDB Cluster)...................................... SUCCESS!

Read the grastate.dat file . (It will be in /var/lib/mysql)

[root@cluster-node1 mysql]# cat grastate.dat
# GALERA saved state
version: 2.1
uuid:    68aa64c3-a966-11e4-96dd-b6bab6cb5af6
seqno:   -1

cert_index:

Check the Cluster Status.

mysql>select @@hostname\G show global status like 'wsrep_cluster_size' \G

*************************** 1. row ***************************
@@hostname: controller-node1
1 row in set (0.00 sec)

*************************** 1. row ***************************
Variable_name: wsrep_cluster_size
        Value: 3
1 row in set (0.00 sec)

#Now copy the following Contents in /etc/my.cnf file of Second Node

#vim /etc/my.cnf
[mysqld]

datadir=/var/lib/mysql
user=mysql

# Path to Galera library
wsrep_provider=/usr/lib64/libgalera_smm.so

# Cluster connection URL contains the IPs of node#1, node#2 and node#3
# cluster-node 1 192.168.1.1
# cluster-nod3 2 192.168.1.2
# cluster-nod3 3 192.168.1.3
wsrep_cluster_address=gcomm://192.168.1.1,192.168.1.2,192.168.1.3

# In order for Galera to work correctly binlog format should be ROW
binlog_format=ROW

# MyISAM storage engine has only experimental support
default_storage_engine=InnoDB

# This changes how InnoDB auto increment locks are managed and is a requirement for Galera
innodb_autoinc_lock_mode=2

# Node #1 address
wsrep_node_address=192.168.1.2

# SST method
#wsrep_sst_method=xtrabackup
 wsrep_sst_method=rsync      #
# wsrep_sst_method=rsync_wan  #
# wsrep_sst_method=mysqldump  # SLOW

# Cluster name
wsrep_cluster_name=percona_cluster

# Authentication for SST method
wsrep_sst_auth="root:password" 

# server_id
server_id=3232235553  #SELECT INET_ATON('192.168.1.2')

#[client]

socket=/var/lib/mysql/mysql.sock

Start the Cluster in Second Node.

[root@cluster-node2]#/etc/init.d/mysql start

Starting MySQL (Percona XtraDB Cluster)........................... SUCCESS!

Now check the Status in Both Nodes.

First Node

mysql> select @@hostname\G show global status like 'wsrep_cluster_size' \G

*************************** 1. row ***************************

@@hostname: controller-node1

1 row in set (0.00 sec)

*************************** 1. row ***************************

Variable_name: wsrep_cluster_size

        Value: 2

1 row in set (0.00 sec)

Second Node

mysql> select @@hostname\G show global status like 'wsrep_cluster_size' \G

*************************** 1. row ***************************

@@hostname: controller-node2

1 row in set (0.00 sec)

*************************** 1. row ***************************

Variable_name: wsrep_cluster_size

        Value: 2

1 row in set (0.00 sec)

Now, We are adding 3 Node to the Cluster. 

#Now copy the following Contents in /etc/my.cnf file of Third  Node

#vim /etc/my.cnf

[mysqld]

datadir=/var/lib/mysql
user=mysql

# Path to Galera library
wsrep_provider=/usr/lib64/libgalera_smm.so

# Cluster connection URL contains the IPs of node#1, node#2 and node#3
# cluster-node 1 192.168.1.1
# cluster-nod3 2 192.168.1.2
# cluster-nod3 3 192.168.1.3
wsrep_cluster_address=gcomm://192.168.1.1,192.168.1.2,192.168.1.3

# In order for Galera to work correctly binlog format should be ROW
binlog_format=ROW

# MyISAM storage engine has only experimental support
default_storage_engine=InnoDB

# This changes how InnoDB auto increment locks are managed and is a requirement for Galera
innodb_autoinc_lock_mode=2

# Node #1 address
wsrep_node_address=192.168.1.3

# SST method
#wsrep_sst_method=xtrabackup
 wsrep_sst_method=rsync      #
# wsrep_sst_method=rsync_wan  #
# wsrep_sst_method=mysqldump  # SLOW

# Cluster name
wsrep_cluster_name=percona_cluster

# Authentication for SST method
wsrep_sst_auth="root:password" 

# server_id
server_id=3232235553  #SELECT INET_ATON('192.168.1.3')

#[client]

socket=/var/lib/mysql/mysql.sock

[root@cluster-node3]#/etc/init.d/mysql start

Starting MySQL (Percona XtraDB Cluster)........................... SUCCESS!

Now Check the Cluster status in Each nodes. 

First Node

mysql> select @@hostname\G show global status like 'wsrep_cluster_size' \G
*************************** 1. row ***************************
@@hostname: controller-node1
1 row in set (0.00 sec)

*************************** 1. row ***************************
Variable_name: wsrep_cluster_size
        Value: 3
1 row in set (0.00 sec)


Second Node
mysql> select @@hostname\G show global status like 'wsrep_cluster_size' \G
*************************** 1. row ***************************
@@hostname: controller-node2
1 row in set (0.00 sec)

*************************** 1. row ***************************
Variable_name: wsrep_cluster_size
        Value: 3

1 row in set (0.00 sec)

Third Node
mysql> select @@hostname\G show global status like 'wsrep_cluster_size' \G
*************************** 1. row ***************************
@@hostname: controller-node2
1 row in set (0.00 sec)

*************************** 1. row ***************************
Variable_name: wsrep_cluster_size
        Value: 3

1 row in set (0.00 sec)

You can see that, the Value has changed to 3. All are Good Now.

Testing.

Create a Test Database in First Node, You can see that it will be replicated in Another nodes.