Guides on Documentation

Catch-all VirtualHost with 301 redirect on Apache

Mon, 01 Jan 0001 00:00:00 +0000

Overview

If you want to make sure all traffic only uses your preferred domain name you can create a catch-all VirtualHost in Apache and redirect to the VirtualHost with the preferred domain name.

Configuration

On your apache node select config and edit the httpd.conf file. Replace the current <VirtualHost ...> section with the following and replace mydomain.com with your domain name.

Note: Before you make any changes, it is always recommended to create a backup copy of the old configuration file.

Change public IP without downtime

Mon, 01 Jan 0001 00:00:00 +0000

Overview

In Jelastic PaaS you can easily switch IP-addresses by yourself without any downtime.

Attach new IP-address

Expand your environment. If you hover over your Public IPv4-address, an icon for attaching or detaching IP-addresses will appear.

Attach a new IP by raising the number of IP-addresses to 2.

Verify that your node has been assigned two IP-addresses.

Update DNS-records

Update relevant DNS records at your DNS provider to point to the new IP address.

Please keep in mind that your DNS change can take up to 24 hours before it’s completely propagated worldwide. You can verify your DNS propagation here: DNS Checker

Copy a SQL database

Mon, 01 Jan 0001 00:00:00 +0000

Overview

This guide will walk you through the procedure of copying a SQL database between environments using the Jelastic GUI.

Export the database

Open up phpMyAdmin on the source environment by clicking the icon as shown below

Export the database by first choosing the database to the left, in our case example, and then click on Export on the top navigation bar. Make sure to check the box where it says “Save on server in the directory /var/lib/jelastic/phpMyAdmin/save” and then click “Go”.

Copy files between environments

Mon, 01 Jan 0001 00:00:00 +0000

Overview

This guide will help you getting started with moving files between environments using the Jelastic GUI.

Export directory

Find the configuration wrench on the Application Servers source node.

Go to folder /var/www/webroot (via favorites to the left). Click the cogwheel on the ROOT folder as shown on the image below and choose Export

Make sure to choose the correct target container where your target Application Server is at.

Enable IPv6

Mon, 01 Jan 0001 00:00:00 +0000

Overview

This guide will help you enable IPv6. Remember that you might need to configure your application to listen on IPv6.

Enabling IPv6

Expand your environment. If you hover over “Public IP”, an icon for attaching or detaching IP-addresses will appear.

Here we can choose to attach IPv4-addresses or enable Public IPv6 by switching the toggle to “ON”.

Verify that your environment have been assigned a new IPv6-address.

Enable X11-Forwarding on VPS

Mon, 01 Jan 0001 00:00:00 +0000

CentOS

Note: This was tested on CentOS 7.9 but should apply to all available versions. Some minor differences may be present.

Install Xauth with yum install xorg-x11-xauth
Make sure X11Forwarding is enabled by running grep X11Forwarding /etc/ssh/sshd_config, the output should look like: X11Forwarding yes If the output is X11Forwarding no, edit the value in the sshd config with vim /etc/ssh/sshd_config and restart sshd service sshds restart
Connect to the VPS ssh -X user@ip
Install an X application to verify that it works (for example: yum install xclock and then run it with xclock)

Ubuntu

Note: This was tested on Ubuntu 20.04 but should apply to all available versions. Some minor differences may be present.

FAQ

Mon, 01 Jan 0001 00:00:00 +0000

Q: We would like to explore migration options already now. How should we think?

A: Elastx provides a range of compute, database and other infrastructure products that can cover your needs. There is specific packaging in Virtuozzo PaaS which we - at this point in time - cannot substitute directly. However, we will present options later this year.

Q: We run one or a few VPS in Virtuozzo PaaS. Can we simply migrate to OpenStack IaaS?

A: Yes, however we strongly recommend that you migrate with the approach of rebuilding your workloads in OpenStack IaaS and migrate data there prior to shifting over your customer traffic. This way you may ensure that things are patched to the latest versions and tests are successful. Contact us at support@elastx.se and we will set up an OpenStack IaaS project for you.

Force HTTPS on Apache behind Nginx load balancer

Mon, 01 Jan 0001 00:00:00 +0000

Edit httd.conf

Add the following configuration in the Apache configuration file httd.conf.

<VirtualHost *:80>
...
RewriteEngine on
RewriteCond %{HTTP:X-Forwarded-Proto} !https
RewriteRule .* https://%{HTTP_HOST}%{REQUEST_URI} [R,L]
</VirtualHost>

Force HTTPS with Tomcat

Mon, 01 Jan 0001 00:00:00 +0000

Overview

This guide describes how to make Tomcat force all traffic over HTTPS.

Tomcat Configuration

On the Tomcat node, edit the web.xml file and add the following in the <web-app *> section.

    <security-constraint>
        <web-resource-collection>
            <web-resource-name>Protected Context</web-resource-name>
            <url-pattern>/*</url-pattern>
        </web-resource-collection>
        <!-- auth-constraint goes here if you require authentication -->
        <user-data-constraint>
            <transport-guarantee>CONFIDENTIAL</transport-guarantee>
        </user-data-constraint>
    </security-constraint>

With this, Tomcat will attempt to redirect any HTTP request to the specified context and instead use the HTTPS Connector, and as such never serve it under HTTP.

Log real client IP behind a proxy

Mon, 01 Jan 0001 00:00:00 +0000

Overview

This guide will demonstrate how to make your web server log your client’s real IP instead of the proxy’s. This is applicable both if your web server is behind your own proxy or our Jelastic resolver.

Nginx Configuration

Replace $remote_addr with $http_x_real_ip in your nginx.conf where the log format is defined.

This is what is should look like:

    log_format  main  '$http_x_real_ip:$http_x_remote_port - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for" '
                      '"$host" sn="$server_name" '
                      'rt=$request_time '
                      'ua="$upstream_addr" us="$upstream_status" '
                      'ut="$upstream_response_time" ul="$upstream_response_length" '
                      'cs=$upstream_cache_status' ;

And this is the default value, note that the only change is on the first row.

Nginx LB HTTP to HTTPS redirect

Mon, 01 Jan 0001 00:00:00 +0000

Overview

If you have an nginx load balancer in you environment and want to redirect all requests to https then you can add the following configuration.

nginx configuration

On the nginx load balancer node select config and create a new file under conf.d named redirect.conf. Add the following configuration to the file, save it and restart nginx.

server {
       listen *:80 default_server;
       access_log /var/log/nginx/redirect.access_log main;
       error_log /var/log/nginx/redirect.error_log info;
       location / {
         rewrite ^ https://$host$request_uri? permanent;
       }
}

Nginx redirect to HTTPS

Mon, 01 Jan 0001 00:00:00 +0000

Overview

If you have enabled https, have a public IP and want to redirect all traffic from http to https you can change the “/ location {}” section in nginx.conf to the following.

location / {
  rewrite ^ https://$host$request_uri? permanent;
}

If your webserver is located behind a proxy, loadbalancer or WAF (that sends x-forwarded headers) you can simply use the below snippet instead.

if ($http_x_forwarded_proto != "https") {
  rewrite ^ https://$host$request_uri? permanent;
}

Node.JS NPM Module Problems

Mon, 01 Jan 0001 00:00:00 +0000

Overview

If you have problems with installing node modules via npm and get “unmet dependency” errors then this guide might help.

Solution

Try to remove all installed modules, clear the npm cache and reinstall. Log in to the node with ssh and run the following commands:

cd /home/jelastic/ROOT

npm cache clean --force

rm -r node_modules

npm install

PHP max upload file size

Mon, 01 Jan 0001 00:00:00 +0000

Overview

This guide demonstrates how to increase (or decrease) the PHP max upload file size. We’ll need to both configure PHP and then the web server if you’re running nginx.

PHP Configuration

In php.ini, find the rows containing upload_max_filesize and post_max_size and change their values to the desired amount.

By default they will look something like this, depending on what type of node you’re running their values might differ:

upload_max_filesize = 100M
post_max_size = 100M          ; Maximum size of POST data that PHP will accept.

Continue with the web server configuration below.

Redirect nginx

Mon, 01 Jan 0001 00:00:00 +0000

Overview

If you want to make sure all traffic only uses your preferred domain name you can create a new server {} block that redirects to the preferred domain name.

Edit nginx.conf

On your nginx node select config and edit the nginx.conf file. In this example we’ll redirect my-site.jelastic.elastx.net to https://my-domain.tld

server {
    server_name my-site.jelastic.elastx.net;
    listen 80 default_server;
    return 301 https://my-domain.tld/$request_uri;
}

Restrict phpMyAdmin access

Mon, 01 Jan 0001 00:00:00 +0000

Overview

If you want to limit access to the database phpMyAdmin you can use a Apache access rule.

Configuration

In the Virtuozzo PaaS GUI, select “Config” on the database node.
Edit the file /conf.d/phpMyAdmin-jel.conf and make sure your <Directory /usr/share/phpMyAdmin/> looks like this. Edit the IP to the IP that should be granted access.

<Directory /usr/share/phpMyAdmin/>
     SetEnvIf X-Forwarded-For ^xxx\.xxx\.xxx\.xxx env_allow_1
     Require env env_allow_1
     Require ip xxx.xxx.xxx.xxx
     Require all denied
</Directory>

Note: Make sure to edit the IP in the example to your desired value

SMTP on port 25 not working

Mon, 01 Jan 0001 00:00:00 +0000

Overview

By default we block traffic to internet on tcp port 25. We do this to prevent abuse, mail abuse is very common and we do our best to prevent this from happening.

Alternatives

If you want to send e-mail from our platform we recommend using our Mail Relay service. All major SMTP services offer their service on other ports than port 25.

This way you can get an automated reliable SMTP service that is very cost effective.