Install XWiki and all dependant programs on a 4 GB cloud server. This means:

1) Java
2) Tomcat
3) MySQL/MariaDB
4) XWiki
5) Nginx

Here we use Nginx as a reverse proxy to firstly redirect all HTTP to HTTPS and then forward all requests on port 80/443 to port 8080 (tomcat) on the localhost. Here I use LetsEncrytp for my SSL certificates.

Before we begin…

Setup DNS

wiki.dummydomains.org.uk ——> 134.213.27.60

Prepare the Server

Update

Update and reboot the server.

apt-get update
apt-get dist-upgrade
reboot

Enable the firewall

ufw status
ufw enable
ufw allow ssh
ufw reload
ufw status

Install Oracle Java

This is a requirement before installing Tomcat or XWiki. At the time of writing, Java 8.x is recommended as 9.x is too new and has a number of known bugs still.

apt-get install software-properties-common
add-apt-repository ppa:webupd8team/java
apt-get update
apt-get install oracle-java8-installer

You will need to accept the license agreement:

Because many programs check for $JAVA_HOME, it is a good idea to set it now. If you don’t know the path, check with:

root@wiki:~# update-alternatives --config java
There is 1 choice for the alternative java (providing /usr/bin/java).

  Selection    Path                                     Priority   Status
------------------------------------------------------------
  0            /usr/lib/jvm/java-8-oracle/jre/bin/java   1081      auto mode
* 1            /usr/lib/jvm/java-8-oracle/jre/bin/java   1081      manual mode

Press &amp;lt;enter&amp;gt; to keep the current choice[*], or type selection number:

Then edit your system $PATH variable so that the /usr/lib/jvm/java-8-oracle is the first path.

nano /etc/environment

Mine looks like this:

root@wiki:~# cat /etc/environment
PATH="/usr/lib/jvm/java-8-oracle:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games"

You will need to log out and back in first but you can test with the below command.

root@wiki:~# echo $JAVA_HOME
/usr/lib/jvm/java-8-oracle

Create Virtual Host and Generate SSL

Install Nginx and LetsEncrypt.

Nginx

Install and configure Nginx.

apt-get install apache2-utils nginx
systemctl enable nginx

Create a very basic virtual host by editing the nginx configuration file and inserting your server name in the server_name variable.

vim /etc/nginx/sites-enabled/default

Mine looks like this.

root@wiki:~# egrep -v "^$|^[[:space:]]*#" /etc/nginx/sites-available/default 
server {
	listen 80 default_server;
	listen [::]:80 default_server;
	root /var/www/html;
	index index.html index.htm index.nginx-debian.html;
	server_name wiki.dummydomains.org.uk;
	location / {
		try_files $uri $uri/ =404;
	}
}

Restart:

systemctl restart nginx

Check it works!

If it doesn’t, check the firewall…

Allow HTTP and HTTPS Traffic

If you use a local firewall like UFW or iptables, you will need to allow port 80 and 443.

ufw status
ufw allow http
ufw allow https
ufw status
ufw reload

LetsEncrypt

add-apt-repository ppa:certbot/certbot
apt-get update
apt-get install python-certbot-nginx
certbot --nginx -d wiki.dummydomains.org.uk -d dummydomains.org.uk

Your certificate will get saved to /etc/letsencrypt/live/wiki.dummydomains.org.uk.

LetsEncrypt will edit your virtual hosts file. The parts we are interested in are:

  listen 443 ssl; # managed by Certbot
  ssl_certificate /etc/letsencrypt/live/wiki.dummydomains.org.uk/fullchain.pem; # managed by Certbot
  ssl_certificate_key /etc/letsencrypt/live/wiki.dummydomains.org.uk/privkey.pem; # managed by Certbot
  include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
  ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot

  if ($scheme != "https") {
    return 301 https://$host$request_uri;
  } # managed by Certbot

Install XWiki

Install XWiki.

wget -q "https://maven.xwiki.org/public.gpg" -O- | apt-key add -
wget "https://maven.xwiki.org/stable/xwiki-stable.list" -P /etc/apt/sources.list.d/
apt-get update

Search for XWiki packages to install.

apt-cache search xwiki

According to the official documentation, the enterprise version is out-of-date and the non-enterprise version should be used.

apt-get install xwiki-tomcat8-mysql

Set the root MySQL password:

2@&EG7dMhPF^44ed

When asked if you should configure the database with dbconfig-common, say yes.

MySQL application password:

zB9j@xht4@

Check tomcat8 is listening on port 8080:

root@wiki:~# netstat -plnt | grep :8080
tcp6       0      0 :::8080                 :::*                    LISTEN      15840/java

Check your memory usage:

root@wiki:~# free -h
              total        used        free      shared  buff/cache   available
Mem:           3.9G        487M        1.9G         10M        1.5G        3.3G
Swap:            0B          0B          0B

You will need to increase the default about of memory allocated to Java. Here’s how:

vim /etc/default/tomcat8

Before:

root@wiki:~# grep ^JAVA_OPTS /etc/default/tomcat8
JAVA_OPTS="-Djava.awt.headless=true -Xmx128m -XX:+UseConcMarkSweepGC"

After:

root@wiki:~# grep ^JAVA_OPTS /etc/default/tomcat8
JAVA_OPTS="-Djava.awt.headless=true -Xmx1024m -XX:+UseConcMarkSweepGC"

Restart Tomcat

systemctl restart tomcat8

Test using using a browser:

http://dummydomains.org.uk:8080/xwiki

If you’ve enabled a firewall and you want to test:

ufw allow 8080/tcp
ufw reload

However I’m not going to do this – I’m going to setup Nginx as a proxy first.

Configure Nginx

Remove the default virtual host configuration.

rm -v /etc/nginx/sites-enabled/default.conf
vim /etc/nginx/sites-available/wiki.dummydomains.org.uk.conf

My site configuration look as follows:

upstream tomcat {
  server 127.0.0.1:8080 fail_timeout=0;
  keepalive 64;
}

server {
  
  listen 134.213.27.60:80;
  listen [::]:80;
  
  listen 134.213.27.60:443 ssl;
  listen [::]:443 ssl;
  
  server_name wiki.dummydomains.org.uk dummydomains.org.uk;
  
  ssl_certificate /etc/letsencrypt/live/wiki.dummydomains.org.uk/fullchain.pem;
  ssl_certificate_key /etc/letsencrypt/live/wiki.dummydomains.org.uk/privkey.pem;
  include /etc/letsencrypt/options-ssl-nginx.conf;
  ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem;
  
  # redirect http to https
  if ($scheme != "https") {
    return 301 https://$host$request_uri;
  }

  auth_basic "Authentication Required";
  auth_basic_user_file xwiki-access;

  location / {
    client_max_body_size 20M;
    proxy_set_header X-Forwarded-Host $host;
    proxy_set_header X-Forwarded-Server $host;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_pass_request_headers on;
    proxy_set_header Connection "keep-alive";
    proxy_store off;
    proxy_headers_hash_max_size 512;
    
    allow 81.143.223.118;
    allow 188.114.113.2;
    deny all;

    proxy_pass http://tomcat/;
  }
}

I also want to password protect my wiki:

htpasswd -c /etc/nginx/xwiki-access andy

Enable the site:

cd /etc/nginx/sites-enabled/
ln -s ../sites-available/xwiki.dummydomains.org.uk.conf .

….and check configuration file for errors.

root@wiki:~# nginx -t
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful

Check config and restart Nginx:

systemctl restart nginx

Now try entering the following into your browser and complete the on-screen installation instructions:

https://wiki.dummydomains.org.uk/xwiki

Complete Installation

Here are few things I normally do after an installation.

Make Root Application

I want to make this Wiki instance the root web application and remove the trailing /xwiki from the URL.

systemctl stop tomcat8.service
mv -v /etc/tomcat8/Catalina/localhost/xwiki.xml /etc/tomcat8/Catalina/localhost/ROOT.xml
vim /etc/xwiki/xwiki-tomcat8.xml

Change:

<Context path="/xwiki" docBase="/usr/lib/xwiki" privileged="true" crossContext="true">
  <!-- make symlinks work in Tomcat -->
  <Resources allowLinking="true" />
</Context>

To:

<Context path="/" docBase="/usr/lib/xwiki" privileged="true" crossContext="true">
  <!-- make symlinks work in Tomcat -->
  <Resources allowLinking="true" />
</Context>

Don’t forget to start Tomcat again:

systemctl start tomcat8.service

Now the URL is simply:

https://wiki.dummydomains.org.uk

Enable superadmin

This is needed if you plan to import XWiki pages from a previous installation.

vim /etc/xwiki/xwiki.cfg

Find the following section.

#-# Enable to allow superadmin. It is disabled by default as this could be a
#-# security breach if it were set and you forgot about it. Should only be enabled
#-# for recovering the Wiki when the rights are completely messed.
# xwiki.superadminpassword=system

….and change to:

#-# Enable to allow superadmin. It is disabled by default as this could be a
#-# security breach if it were set and you forgot about it. Should only be enabled
#-# for recovering the Wiki when the rights are completely messed.
xwiki.superadminpassword=siFwMXlUzKQ6

Don’t forget to restart Tomcat if necessary.

Update Cookie Encryption Keys

When a user logs in, three cookies are saved to their machine. These cookies are encrypted with the below details. First we need to get the two random strings of equal length.

root@wiki:~# date +%s | sha256sum | base64 | head -c 32 ; echo
MWJjNzE4ZTE2ODM0MTVlZDNjODVmNjJl
root@wiki:~# date +%s | sha256sum | base64 | head -c 32 ; echo
Y2M5M2M2ZGEyMGRkYzM3ZmJjZTYyNjYy

Then edit the xwiki.cfg file.

vim /etc/xwiki/xwiki.cfg

Find the relevant section and edit to look like the below.

xwiki.authentication.validationKey=MWJjNzE4ZTE2ODM0MTVlZDNjODVmNjJl
xwiki.authentication.encryptionKey=Y2M5M2M2ZGEyMGRkYzM3ZmJjZTYyNjYy

Don’t forget to restart Tomcat if necessary.

Complete the Installation

Click continue.

Continue.

Select 9.9 and continue.

Confirm installation again.

Continue.

Continue again.

Confirm the report by clicking continue.

Installation complete!

Import old XWiki Content

Lets see if the import feature works! Log in as the superadmin user and then navigate to the Administration section:

https://wiki.dummydomains.org.uk/bin/admin/XWiki/XWikiPreferences

Then select Content, followed by Import:

Select the backup.xar that you (hopefully) took earlier and import all the content.

Select the following options.

To test that your Java Development Kit (JDK) is installed correctly, you need to write a simple Java program, compile it, and run the compiled bytecode.

[andy@home-pc ~]$ mkdir ~/java-demos
[andy@home-pc ~]$ cd ~/java-demos
[andy@home-pc java-demos]$ vim HelloWorld.java

A simple Java HelloWorld example looks like this.

class HelloWorld {
    public static void main(String[] args) {
        System.out.println("\nThe Java Development Kit (JDK) is installed and working!!\n");
    }
}

You compile Java code with the javac command, and then run the resulting file with the java command.

$ ls
HelloWorld.java
$ javac HelloWorld.java
$ ls
HelloWorld.class
HelloWorld.java
$ java HelloWorld

The Java Development Kit (JDK) is installed and working!!

$

You should note that although the resulting Java bytecode is a file called HelloWorld.class, you run the program without any file extension.

You could take this a step further and write some code that returns some Java system properties about the current installation.

$ ls
HelloWorld.class
HelloWorld.java
$ cp -v HelloWorld.java JDKInstallationTest.java

The below code makes use of the getProperties() method, of the System</code class.

import java.util.Map;

class JDKInstallationTest {
    public static void main(String[] args) {
        System.out.println("\nThe " + System.getProperty("java.vendor") + " Java version " + System.getProperty("java.version") + " is installed on this system.\n");

        // Print a list of Java properties
        System.out.println("Java Properties:");
        for(Map.Entry e  : System.getProperties().entrySet()) {
            if (((String)e.getKey()).startsWith("java")) {
                    System.out.println(e);
            }
        }
        System.out.println();
    }
}

Again, run it like so.

$ ls
HelloWorld.class
HelloWorld.java
JDKInstallationTest.java
$ javac JDKInstallationTest.java
$ ls
HelloWorld.class
HelloWorld.java
JDKInstallationTest.class
JDKInstallationTest.java
$ java JDKInstallationTest

The output will look something like this.

The Oracle Corporation Java version 1.8.0_31 is installed on this system.

Java Properties:
java.runtime.name=Java(TM) SE Runtime Environment
java.vm.version=25.31-b07
java.vm.vendor=Oracle Corporation
java.vendor.url=http://java.oracle.com/
java.vm.name=Java HotSpot(TM) 64-Bit Server VM
java.vm.specification.name=Java Virtual Machine Specification
java.runtime.version=1.8.0_31-b13
java.awt.graphicsenv=sun.awt.X11GraphicsEnvironment
java.endorsed.dirs=/usr/lib/jvm/java-8-jdk/jre/lib/endorsed
java.io.tmpdir=/tmp
java.vm.specification.vendor=Oracle Corporation
java.library.path=/usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib
java.specification.name=Java Platform API Specification
java.class.version=52.0
java.awt.printerjob=sun.print.PSPrinterJob
java.specification.version=1.8
java.class.path=.
java.vm.specification.version=1.8
java.home=/usr/lib/jvm/java-8-jdk/jre
java.specification.vendor=Oracle Corporation
java.vm.info=mixed mode
java.version=1.8.0_31
java.ext.dirs=/usr/lib/jvm/java-8-jdk/jre/lib/ext:/usr/java/packages/lib/ext
java.vendor=Oracle Corporation
java.vendor.url.bug=http://bugreport.sun.com/bugreport/

$

You can then delete the .class files if you wish, leaving only the source (.java) files.

$ ls
HelloWorld.class
HelloWorld.java
JDKInstallationTest.class
JDKInstallationTest.java
$ rm -v ./*.class
removed ‘./HelloWorld.class’
removed ‘./JDKInstallationTest.class’
$ ls
HelloWorld.java
JDKInstallationTest.java
$

Category: Java

XWiki on Ubuntu 16.04 LTS with Nginx Reverse Proxy