Hardware Requirements: General Concepts

The simplified PaaS cluster (Virtuozzo Application Platform) structure from top to bottom can be shown in the following image:

Virtuozzo PaaS cluster

It consists of several levels:

User Experience Level - shows all the platform users' services with which the developers, platform administrators, and end-users interact.

Virtuozzo Application Platform Infrastructure Level - represents the set of the platform infrastructure hosts and hosts for users’ containers and virtual machines united into a single system.

  • Infrastructure hosts (infra nodes) - servers with PaaS services running
  • User hosts (user nodes) - servers with user applications

Compute Provisioning Level - means a service provider or cloud computing platform that can buy/create/install bare-metal hosts or virtual machines with specific virtualization technology and unite them into one whole via the external and internal network.

Hardware Level - represents the underlying low-level infrastructure with a set of bare metal servers and networking, which is used for resource provisioning.

Also, the cluster consists of:

  • external network, which usually should be accessible from the Internet, with one or more ranges of public IP addresses, routable in this network
  • isolated internal network, entirely devoted to the PaaS cluster, with private IP addresses
  • DNS zone, which will be controlled by the platform (i.e. {plarformDomain} and {regionDomain})
  • wildcard SSL certificate(s) for infrastructure and end-user domains (i.e. covering also *.{plarformDomain} and *.{regionDomain})
Note: When choosing the hardware provider, please, check the list of the supported hardware vendors and virtualization solutions available for the platform installations.

High-Level Requirements

According to the general concepts, to have the Virtuozzo Application Platform installed, you need to provide:

Note: All the specifics and requirements stated below are suitable for a comfortable launch and initial workload. Depending on the platform’s growth, additional hardware capacities may be required in the future.

1. Bare-metal servers or virtual machines - hosts. The hardware requirements depend on a particular installation scenario.

2. External or pseudo-external NAT network, which usually should be accessible for platform users (customers/visitors).

  • one or more public IP ranges, routable in this network

Note: The correct and fast functioning of the PaaS depends on the high-speed availability of the external repositories.

For example, during user environment creation, the platform downloads a large amount of data from the Docker Hub, Virtuozzo, and other resources.

Also, a high-speed internet connection is mandatory for the platform installation procedure. Please ensure that the chosen provider can supply at least 300 Mbit/s of bandwidth before initiating the process.

3. Internal network, isolated for platform use only.

  • one or more private IP ranges, routable in this network (a single network of /8 or /16 addresses is preferred)

4. DNS subdomains, which will be controlled by the platform (short ones are highly recommended, see the Note below for a detailed explanation):

  • *.{platformDomain} - the main domain of your platform (should differ from the company site/domain). For example, it is used for the end-users' dashboard (app.{platformDomain}, e.g. app.mypaas.com, app.mycloud.net) and admin panel (jca.{platformDomain}, e.g. jca.mypaas.com, jca.mycloud.net)
  • *.{regionDomain} - a domain name for each region used on the PaaS (should differ from the platform and other region domains). It is automatically used for all the environments created by end-users in the appropriate region ({envName}.{regionDomain}, e.g. awesomesite.euregion.com, supershop.usregion.net)

We highly recommend using different domains for the platform and each region. It is required to prevent the whole platform from being blocked (blocklisted) in case of abuse from the end-users (spamming, phishing, etc.). On the Virtuozzo Application Platform side, we aim to keep the shared domains to be compliant and isolated for the customers with the help of PSL. However, the process of adding new domains to the list is not real-time due to delays (verification) on a PSL maintainers' side.

The following setup can be used as an example:

  • platform domain - mypaas.com
    • dashboard - app.mypaas.com
    • cluster admin - jca.mypaas.com
  • first region - euregion.com
    • environment example - awesomesite.euregion.com
  • second region - usregion.com
    • environment example - supershop.usregion.com

Note: The length of the container hostname is limited to 64 characters due to the Linux specifics. As a result, short region names are preferable as they leave more space for the user-provided environment names. Let’s analyze the general example of the hostname for a container at Virtuozzo Application Platform:

platform hostname length


  • {nodeId} - ID of a container (e.g. node12345)
  • {envName} - user-provided name of the environment
  • {regionDomain} - domain name provided during the region configuration

The {nodeId} length depends on the number of containers on the platform, usually up to 10 symbols, which supports a million containers. The recommended size of the {regionDomain} is no more than 25 characters. Also, two separators are used in the hostname. The remaining length is used for the {envName}, which, in our case, can contain up to a maximum of 27 symbols (64 - 10 - 25 - 2 = 27).

5. Multi-domain Wildcard SSL certificate for this DNS subdomain, covering the following DNS names:

  • *.{plarformDomain} (added as SAN)
  • *.{regionDomain} (added as CN)

6. Storage for the user-uploaded content (Uploader Storage), can be shared with Docker templates cache storage.

  • external NFS mount (or SCSI LUN shared over infrastructure nodes) is recommended

7. Storage for Docker templates cache (Docker Storage), can be shared with uploader storage.

  • external SCSI LUN shared over infrastructure nodes is recommended

8. SMTP (Simple Mail Transfer Protocol) server for sending automatic notifications from the platform, can be configured using the SMTP Server Configuration guide.

  • SMTP Relay component is optional but recommended to enhance the process

9. Docker Hub billing account, which should be set as default via the Templates > Docker Registries tab in the admin panel.

  • an account with unlimited pulls is required to ensure that end-users won’t be restricted based on the number of containers created on the platform

10. According to the Virtuozzo Support Policy, the host’s kernel version should always be up-to-date:

Supported Versions: Virtuozzo will provide support only for the versions of the product specified in the product documentation or as specified at the time of purchase. Changes to supported versions will be announced in advance through notifications sent by email and as posted on the Virtuozzo website. Virtuozzo products shipped with a Linux kernel get support if running the latest released update in user space. In addition Virtuozzo will provide support for the last 2 released kernels.

The up-to-date kernels contain a number of important fixes that are necessary for stable and correct platform functionality.

You can find a list of supported VZ7 kernels on the official changelog web page.

Backup Server

Backup servers can be configured based on the shared storage connected to any existing host (via NFS, iSCSI, etc.) or a dedicated server with local disk space. The selected storage should provide a sufficient level of redundancy and reliability to store backups.

The storage server must meet the following requirements:

  • the minimum required disk space is calculated as the total capacity of the /vz(/private) directories on all of the hosts that will be backed up (2x is recommended)
  • the server must be located in the same network as the hosts that will be backed up
  • network bandwidth at least 1Gbit/sec, 10 Gbit/sec is recommended for a high-performance production platform
  • CPU x86_64 with 8+ cores / 16+ threads
  • 16GB+ RAM

Installation Scenarios

For the public beta and commercial launch, there are two possible scenarios for the Virtuozzo Application Platform installation:

Please refer to the appropriate linked page to see the specific scenario-depended requirements on hardware, network, and OS configurations.

Note: In the case of selecting the latter scenario, the following additional high-level requirements are added: internal network, dedicated to the Cloud Storage - 2 or more NICs per server (please see the sizing guidelines within the document linked above).

System Settings

The following OS settings are configured on the servers during the Virtuozzo PaaS Installation. They must not be changed or removed after the installation. Please, review the list below for possible contradictions with your operations and maintenance practices:

  • Changes to the system configuration files are prohibited.
  • PaaS cluster installation updates additional system configuration files; these changes must not be removed or overwritten after the installation.
  • Specific kernel modules are configured for pre-loading during the installation, and these settings must not be altered after the installation.
  • TCP stack settings are modified during the installation and must not be altered after the installation.
  • The PaaS cluster installation adds specific iptables rules, which must not be removed or overwritten after the installation.
  • The list of IP addresses used by the platform infrastructure should be allowed by the firewall.
  • For the Virtuozzo Operations team to have the ability to access the required host node in case of emergency, the appropriate SSH keys should be added to each of them.
  • The server timezone is set to UTC during the installation and must not be updated after the installation.
  • The SELinux module is switched OFF during the installation and must not be turned ON after the installation.

Contact Support or Operations if any of these points represent a potential conflict.

Tip: For more details on maintaining the Virtuozzo Application Platform, please, refer to the Operations Guide.

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