Tag Archives: centos

How to install redis server on CentOS

In this tutorial we will learn, how to install redis server on CentOS 7 / RHEL 7 . The abbreviation of redis is REmote DIctionary Server. It is one the of the most popular open source,advanced key-value cache and store.

Project URL : http://redis.io/

Follow the given below steps to install redis server on CentOS 7 and Red Hat Enterprise Linux 7.

Install wget utility

Install wget command

yum install wget

Install EPEL repo

First we will install the EPEL repo. For more detail on EPEL repo, we suggest you to read our this post.

Because our system has x86_64 Operating System architecture, we will use only epel repo package for x86_64 . Search epel repo package as per your Operating System architecture(EPEL URL)

wget -r --no-parent -A 'epel-release-*.rpm' http://dl.fedoraproject.org/pub/epel/7/x86_64/e/

rpm -Uvh dl.fedoraproject.org/pub/epel/7/x86_64/e/epel-release-*.rpm

It will create two epel’s repo file inside /etc/yum.repos.d
These are –
1. epel.repo

[root@localhost ~]# ls -l /etc/yum.repos.d/
total 28
-rw-r--r--. 1 root root 1612 Jul  4 07:00 CentOS-Base.repo
-rw-r--r--. 1 root root  640 Jul  4 07:00 CentOS-Debuginfo.repo
-rw-r--r--. 1 root root 1331 Jul  4 07:00 CentOS-Sources.repo
-rw-r--r--. 1 root root  156 Jul  4 07:00 CentOS-Vault.repo
-rw-r--r--. 1 root root  957 Sep  2 12:14 epel.repo
-rw-r--r--. 1 root root 1056 Sep  2 12:14 epel-testing.repo
[root@localhost ~]#

Install redis server

Now use yum command to install redis server

yum install redis

Two important redis server configuration file’s path
1. /etc/redis.conf
2. /etc/redis-sentinel.conf

Now start the redis server after this.

systemctl start redis.service

Check the running status of redis server

systemctl status redis.service

To test the installation of Redis, use below given command

redis-cli ping

If the response output is PONG, it means installation is completed successfully.

[root@localhost ~]# redis-cli ping
[root@localhost ~]#

Start/Stop/Restart/Status and Enable redis server

To start redis server

systemctl start redis.service

To stop redis server

systemctl stop redis.service

To restart redis server

systemctl restart redis.service

To get running status of redis server

systemctl status redis.service

To enable redis server at system’s booting time.

systemctl enable redis.service

To disable redis server at system’s booting time.

systemctl disable redis.service

Listening Port Of Redis Server

Redis Server listens by default at port number 6379. Use below given ss command. (To learn more about ss command)

[root@localhost ~]# ss -nlp|grep redis
tcp    LISTEN     0      128                    *:*      users:(("redis-server",19706,4))
[root@localhost ~]#

Note: On minimal installed CentOS 7/ RHEL 7,you wont get netstat command. Instead of netstat command, use ss command which is by default available on system.

Learn Redis : http://redis.io/documentation

Who is using redis: Who is using Redis



How to Install Apache Tomcat on CentOS

Apache Tomcat is an open source Java Servlet implementation developed by the Apache Software Foundation. Beside Java Servlets, Tomcat implements several other Java server technologies including  JavaServer Pages (JSP), Java Expression Language, and Java WebSocket. Tomcat provides an HTTP Web Server for Java applications with support for HTTP/2, OpenSSL for JSSE and TLS virtual hosting.

In this tutorial, I will show you how to install and configure Apache Tomcat 8.5 on a CentOS 7 server and how to install and configure Java on a CentOS server which is one of the prerequisites for Tomcat.


  • Server with CentOS 7 – 64bit
  • 2 GB or more RAM (Recommended)
  • Root Privileges on the server

Step 1 – Install Java (JRE and JDK)

In this step, we will install the Java JRE and JDK from the CentOS repository. We will install Java 1.8.11 on the server with the yum command.

Run this command to install Java JRE and JDK from CentOS repository with yum:

yum -y install java-1.8.0-openjdk.x86_64 java-1.8.0-openjdk-devel.x86_64

It will take some time, wait until the installation finished.

Then you should check the Java version with the command below:

java -version

You should see results similar to the ones below:

openjdk version “1.8.0_111”
OpenJDK Runtime Environment (build 1.8.0_111-b15)
OpenJDK 64-Bit Server VM (build 25.111-b15, mixed mode)

Check the Java version

Step 2 – Configure the Java Home Environment

In the first step, we’ve installed Java. Now we need to configure the JAVA_HOME environment variable on the CentOS server so that Java applications can find the right Java version and Tomcat requires the JAVA_HOME environment to be setup properly, so we need to configure it.

Before we configure the JAVA_HOME environment, we need to know where the Java directory is. Check the Java directory with the command below:

sudo update-alternatives –config java

Java directory = “/usr/lib/jvm/java-1.8.0-openjdk-

Then edit the environment file with vim:

vim /etc/environment

Add the JAVA_HOME environment variable by adding the configuration below:


Save the /etc/environment file and exit vim.

Next, edit the .bash_profile file and add the JAVA_HOME variable as well:

vim ~/.bash_profile

At the end of the file, paste the configuration below:

export JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-
export PATH=$JAVA_HOME/bin:$PATH

Save the file, then reload the bash_profile file.

source ~/.bash_profile

Make sure there is no error, Finally check the JAVA_HOME environment variable:


You will see Java path directory.

Setup the Java home environment variable

Step 3 – Install Apache Tomcat 8.5

In this step, we will install Apache Tomcat under the user tomcat (which we have to create first).

Create a user and group named tomcat:

groupadd tomcat
useradd -s /bin/false -g tomcat -d /opt/tomcat tomcat

-s /bin/false = disable shell access
-g tomcat = assign new user to the group tomcat
-d /opt/tomcat = define the home directory for the user

Next, go to the /opt directory and download tomcat with the wget command:

cd /opt/
wget http://mirror.wanxp.id/apache/tomcat/tomcat-8/v8.5.6/bin/apache-tomcat-8.5.6.tar.gz

Extract Tomcat and move all the files and directories that are in the ‘apache-tomcat-8.5.6’ directory to the ‘tomcat’ directory.

tar -xzvf apache-tomcat-8.5.6.tar.gz
mv apache-tomcat-8.5.6/* tomcat/

Now change the owner of the tomcat directory to the tomcat user and group.

chown -hR tomcat:tomcat tomcat

Step 4 – Test Apache Tomcat

In step 3, we installed and configure tomcat. In this step, we just want to run a short test to make sure there are no errors.

Go to the tomcat/bin directory and run the command ‘startup.sh’ to test Apache Tomcat:

cd /opt/tomcat/bin/

Make sure the result is ‘Tomcat started’.

Tomcat is using port 8080 now, check the open port on the server with the netstat command.

netstat -plntu

Check that Tomcat has been started with netstat

Or visit the server IP address with port 8080 – in my case – with a web browser. You will see the Apache Tomcat default page.

Test Apache Tomcat with a Browser

Next, stop Apache Tomcat and because we will run it Tomcat with a systemd service file in the final configuration. Make sure the tomcat directory is owned by the tomcat user and group.

cd /opt/tomcat/bin/
chown -hR tomcat:tomcat /opt/tomcat/

Shutdown Apache Tomcat server test.

Step 5 – Setup Apache Tomcat Service

In this tutorial, we will run Apache Tomcat as tomcat user with a systemd service file for easy starting and stopping of the service. So the next step is to create a ‘tomcat.service’ file.

Go to the systemd system directory and create a new file ‘tomcat.service’.

cd /etc/systemd/system/
vim tomcat.service

Paste the configuration below:

Description=Apache Tomcat 8 Servlet Container
After=syslog.target network.target

Save the file and exit vim.

Reload the systemd daemon, then start and add the Apache Tomcat service at boot time.

systemctl daemon-reload
systemctl start tomcat
systemctl enable tomcat

Now check that tomcat is running by checking the open port 8080.

netstat -plntu

And check the tomcat status, make sure the service is active.

systemctl status tomcat

Check Tomcat service started with Systemd

Step 6 – Configure Apache Tomcat Users

In this step, we will configure the users for Apache Tomcat. Tomcat is installed, and it’s running by default on port 8080, we can access it with a web browser, but we can not access the site-manager dashboard yet. To enable and configure Tomcat users, edit the file ‘tomcat-users.xml’.

Go to the tomcat configuration directory and edit the tomcat-users.xml file with vim.

cd /opt/tomcat/conf/
vim tomcat-users.xml

Create a new line under line 43 and paste configuration below:

<role rolename="manager-gui"/>
<user username="admin" password="password" roles="manager-gui,admin-gui"/>

Save the file and exit vim.

Next, go to the manager directory and edit the context.xml file.

cd /opt/tomcat/webapps/manager/META-INF/
vim context.xml

Comment out line 19 and 20.

<Context antiResourceLocking=”false” privileged=”true” >
<!–  <Valve className=”org.apache.catalina.valves.RemoteAddrValve”
allow=”127\.\d+\.\d+\.\d+|::1|0:0:0:0:0:0:0:1″ /> –>

Save the file and exit vim.

Go to the host-manager directory and edit the context.xml file again.

cd /opt/tomcat/webapps/host-manager/META-INF/
vim context.xml

Comment out again line 19 and 20.

<Context antiResourceLocking=”false” privileged=”true” >
<!–  <Valve className=”org.apache.catalina.valves.RemoteAddrValve”
allow=”127\.\d+\.\d+\.\d+|::1|0:0:0:0:0:0:0:1″ /> –>

Save the file and exit, then restart tomcat.

systemctl restart tomcat

Step 7 – Configure Firewalld

In CentOS 7, we have a default firewall tool named firewalld. It replaces the iptables interface and connects to the Netfilter kernel code.

In this step, we will start the firewalld service and open port 8080 so we can access the Apache Tomcat server from the outside of the network.

Start the firewalld service and add it to start at boot time with the systemctl command.

systemctl start firewalld
systemctl enable firewalld

Next, add the apache tomcat port 8080 to the firewall with the firewall-cmd command, and reload the firewalld service.

firewall-cmd –zone=public –permanent –add-port=8080/tcp
firewall-cmd –reload

Check that all the services are available in the firewall and check that the Apache Tomcat port 8080 is open.

firewall-cmd –list-ports
firewall-cmd –list-services

Apache Tomcat port 8080 is accessible from outside of the network, and the ssh port is open by default as well.

Start Apache Tomcat Service with Systemd

Step 8 – Testing

Open your web browser and type in your server IP with port 8080. You will see the Apache Tomcat default page.

Apache Tomcat Home page

Go to the manager dashboard with URL below:

Type in the admin username ‘admin‘ with password ‘mypassword‘, the configuration that we made on step 5.

Apache Tomcat Manager Dashboard

Now go to the host-manager dashboard with URL below:

Enter the admin user and password that you set in step 5, you will see the Tomcat Virtual host Manager.

Apache Tomcat Virtual Host Manager Dashboard

Apache Tomcat 8.5 has been installed on a CentOS 7 Server.


How to install Tomcat on CentOS

How to Install Tomcat 8 on CentOS 7.0 (Multiple Instances)


Install Oracle Java JDK 8 On CentOS 7

yum install java-1.8.0-openjdk.x86_64

# java -version

# cd /usr/share
# wget http://archive.apache.org/dist/tomcat/tomcat-8/v8.0.9/bin/apache-tomcat-8.0.9.tar.gz
# tar zxvf apache-tomcat-8.0.9.tar.gz

# groupadd tomcat
# useradd -g tomcat -s /bin/bash -d /usr/share/apache-tomcat-8.0.9 tomcat
# chown -Rf tomcat.tomcat /usr/share/apache-tomcat-8.0.9/

# su – tomcat

$ cd bin
$ ./startup.sh

start the service: sh startup.sh or ./startup.sh

stop the service sh :shutdown.sh or ./shutdown.sh

netstat -an | grep 8080

ps -ef  | grep tomcat



<connector port=”80“protocol=”HTTP/1.1″connectionTimeout=”20000”      redirectPort=”8443″/>


<Host name=”www.mydomain.com”  appBase=”webapps”     unpackWARs=”true”/>


腾讯云 SSL证书管理

tomcat 配置SSl:


port=”443″ maxThreads=”200″
scheme=”https” secure=”true” SSLEnabled=”true”
keystoreFile=”conf/xxx.jks” keystorePass=”password”
clientAuth=”false” sslProtocol=”TLS”/>