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Best Practices from Oracle Development's A‑Team

Installing Tomcat on Oracle Linux in Oracle Cloud

Emma Thomas
Principal Solutions Architect

Installing Tomcat on Oracle Linux in Oracle Cloud

In the article https://blogs.oracle.com/pshuff/installing-tomcat-on-oracle we saw how to install tomcat in the Oracle Cloud Gen 1, we will now look at the same process but in Oracle Cloud Gen 2.

We will talk you through the manual steps to installing Tomcat on Oracle Linux 7 compute instance in the Oracle Cloud.

*This example below uses only the compute instance to store all the data. For back up and recovery purpose it is recommended to use Oracle’s Block storage to contain your tomcat installation. This allows easy back up and the ability to attach/detach the block storage to a new compute instance. This will be covered in this accompanying article here.


Versions - Tomcat 9, Java 8 and Oracle Linux 7(OL7)
 

We will step through:

  1. Creating an Oracle Enterprise Linux instance on the Oracle Cloud Compute Service

  2. Install Java 8 and Tomcat 9

  3. Update iptables to open port 80 and 443


 

Step 1. Creating an Oracle Enterprise Linux instance on the Oracle Cloud Compute Service

First we need to create our Oracle Linux compute instance. Navigate to the Oracle Cloud Compute instances page with in the Oracle Cloud Infrastructure console.

How To Access Oracle Compute
 

Click the create instance button.

Enter a name for your instance. Oracle Linux 7.7 Image Build:2020.01.28-0 has been pre-selected. Select your Availability Domain, Instance Type, networking options.

If you wish your tomcat/system to be  accessible from the internet make sure “Assign a public IP address” is checked.

Before hitting make sure you add you public ssh key. Choose SSH key file (.pub) from your computer or paste into the textarea.

Wait for your new system to be provisioned.

One it is ready you will see it appear in the compute instances page. By clicking on the instance name you will be directed to the Instance Details page. Here you will see your Public IP address under the section “Primary VNIC Information”. Take note of your new IP address.

Take not of the IP address of your system. This can be found. You will need this for later steps.

 

Step 2. Install Java 8 and Tomcat 9

First I locally downloaded the software:

  • Java (I used jdk-8u241-linux-x64.rpm) click to “Accept the Licence Agreement” to download.

  • Apache Tomcat (I used apache-tomcat-9.0.30.tar.gz) You can use curl directly in the box if you prefer.

To install Java you need download the rpm file and in this case we take the version jdk-8u241-linux-x64.rpm.

You will need to use scp to copy the file over to the new box

$ scp version jdk-8u241-linux-x64.rpm opc@yourIPhere:/tmp

You can also use a gui tool like WINSCP to copy this file over. Also copy the tomcat apache-tomcat-9.0.30.tar.gz to this directory.

 

To install Java

Access the box with ssh. We need to login as opc so that we can execute sudo and install packages. You can use a gui tool like Putty. Making sure to add your authentication key to the Connection/SSH/Auth settings page.

$ sudo rpm -ivh jdk-8uversion-linux-x64.rpm

RPM installs the JDK into the /usr/java/ directory. Next set your system to use the Oracle JDK.

$ sudo alternatives --install /usr/bin/java java /usr/java/jdk1.8.0_version/bin/java 200000

Use the alternatives command to switch to the Oracle JDK.

$ sudo alternatives --config java

Verify it is now installed ok:

$ java -version
java version "1.8.0_241"
Java HotSpot(TM) 64-Bit Server VM (build 25.241-b07, mixed mode)

 

To install Tomcat:

First create a user tomcat:

$ sudo useradd tomcat
$ sudo mkdir -p /u01
$ sudo chown tomcat:tomcat /u01
$ sudo su - tomcat
$ mkdir -p /u01/tomcat
$ cd /u01/tomcat
$ tar xzf /tmp/apache-tomcat-9.0.30.tar.gz
$ ln -s apache-tomcat-9.0.30 latest$ cd /u01/tomcat/apache-tomcat-9.0.30/bin
$ ./startup.sh
Using CATALINA_BASE:   /u01/tomcat/apache-tomcat-9.0.30
Using CATALINA_HOME:   /u01/tomcat/apache-tomcat-9.0.30
Using CATALINA_TMPDIR: /u01/tomcat/apache-tomcat-9.0.30/temp
Using JRE_HOME:        /
Using CLASSPATH:       /u01/tomcat/apache-tomcat-9.0.30/bin/bootstrap.jar:/u01/tomcat/apache-tomcat-9.0.30/bin/tomcat-juli.jar
Tomcat started.

 

To verify things are ok run:

$ wget http://localhost:8080
--2020-02-06 11:10:58--  http://localhost:8080/
Resolving localhost (localhost)... 127.0.0.1, ::1
Connecting to localhost (localhost)|127.0.0.1|:8080... connected.
HTTP request sent, awaiting response... 200
Length: unspecified [text/html]
Saving to: ‘index.html’
    [ <=>                                   ] 11,196      --.-K/s   in 0s
2020-02-06 11:10:59 (27.4 MB/s) - ‘index.html’ saved [11196]

 

Configuring Java

First lets check where the java refers to:

$ sudo update-alternatives --config java
There are 2 programs which provide 'java'.
  Selection    Command
-----------------------------------------------
   1           /usr/java/jdk1.8.0_241-amd64/jre/bin/java
*+ 2           /usr/java/jdk1.8.0_241-amd64/bin/java 
Enter to keep the current selection[+], or type selection number: 1

This command updates the links in /etc/alternatives to point to the program for this purpose. The links in /etc/alternatives are just symbolic links. 

Confirm you are happy with this selection.

Using vim edit the .bashrc file. Here set the JAVA_HOME and CATALINA_HOME variables

$ sudo su – tomcat
vi /home/tomcat/.bash_profile

Insert the following:

export JAVA_HOME=/u01/java/latest
export CATALINA_HOME=/u01/tomcat/latest

Your file should look like this:

$ more /home/tomcat/.bash_profile
# .bash_profile

# Get the aliases and functions
if [ -f ~/.bashrc ]; then
        . ~/.bashrc
fi

# User specific environment and startup programs
export JAVA_HOME=/u01/java/latest
export CATALINA_HOME=/u01/tomcat/latest
PATH=$PATH:$HOME/.local/bin:$HOME/bin

export PATH

You should log out and in to verify this is applied.

 

Troubleshooting:

When using tomcat user run the following and you see:

$CATALINA_HOME/bin/startup.sh
-bash: /bin/startup.sh: No such file or directory


If you see this verify that the link to the “latest” tomcat is correct. In my case it was pointing one directory up so I navigated to the correct directory and reset the link using:

[tomcat@instance-xxxxxxx-xxxx apache-tomcat-9.0.30]$ ln -s apache-tomcat-9.0.30 latest
[tomcat@instance-xxxxxxx-xxxx apache-tomcat-9.0.30]$ $CATALINA_HOME/bin/startup.sh
-bash: /bin/startup.sh: No such file or directory
[tomcat@instance-xxxxxxx-xxxx apache-tomcat-9.0.30]$ exit
logout
[opc@instance-xxxxxxx-xxxx etc]$ sudo su - tomcat
Last login: Thu Feb  6 11:43:58 GMT 2020 on pts/2
[tomcat@instance-xxxxxxx-xxxx ~]$ $CATALINA_HOME/bin/startup.sh
Using CATALINA_BASE:   /u01/tomcat/latest
Using CATALINA_HOME:   /u01/tomcat/latest
Using CATALINA_TMPDIR: /u01/tomcat/latest/temp
Using JRE_HOME:        /u01/java/latest
Using CLASSPATH:       /u01/tomcat/latest/bin/bootstrap.jar:/u01/tomcat/latest/bin/tomcat-juli.jar
Tomcat started.

 

Again, run wget to if you want to verify this returns your index.html:

wget http://localhost:8080

All great!


 

Step 3. To change iptables

Once Tomcat is running we need to update the iptables to add ports 80, 8080, and 443 as pass through ports. Perform the following.

Using firewalld

# add ssh port as permanent opened port

sudo firewall-cmd --zone=public --add-port=80/tcp --permanent
sudo firewall-cmd --zone=public --add-port=443/tcp --permanent
sudo firewall-cmd --zone=public --add-port=8080/tcp --permanent
sudo firewall-cmd –reload

 

 

Security List in Oracle Cloud

From within the compute instance details page you should be able to see the “Subnet: Public Subnet” Click the public subnet hyperlink. This will take you to the Virtual Cloud Network settings used by your compute instance.

Select the Security List option from the Resources menu listed on the left.

Click “Default Security List for VirtualCloudNetwork-XXX-XXX” from the table of security lists.

Here we will add the ports 80, 443, and 8080:

Wait a couple of seconds and navigate to your ip followed by port 8080. You should see this:
 

 

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