Difference between revisions of "Virtual Private Server"

Latest revision as of 14:23, 30 April 2017

From Wikipedia:Virtual private server:

Virtual private server (VPS) is a term used by Internet hosting services to refer to a virtual machine. The term is used for emphasizing that the virtual machine, although running in software on the same physical computer as other customers' virtual machines, is in many respects functionally equivalent to a separate physical computer, is dedicated to the individual customer's needs, has the privacy of a separate physical computer, and can be configured to run server software.

This article discusses the use of Arch Linux on Virtual Private Servers, and includes some fixes and installation instructions specific to VPSes.

Providers that offer Arch Linux

Installation

KVM

See QEMU#Preparing an (Arch) Linux guest.

OpenVZ

Installing the latest Arch Linux on any OpenVZ provider

It is possible to directly copy an installation of Arch Linux over the top of a working OpenVZ VPS. This tutorial explains how to create a basic installation of Arch Linux with pacstrap (as used in a standard install) and then replace the contents of a target VPS with it using rsync.

This process (with minor modification) also works to migrate existing Arch installations between various environments and has been confirmed to work in migrating from OpenVZ to Xen and from Xen to OpenVZ. For an install to Xen, other hardware-virtualized platforms, or probably even to physical hardware (unconfirmed), extra steps (basically running mkinitcpio and installing a bootloader) are needed.

Prerequisites

• A working Arch Linux installation
  • To keep things simple, it should match the architecture you want to install on your VPS (x86_64 or i686).
  • To build from other distributions, arch-bootstrap.sh can be used in place of pacstrap.
• The arch-install-scripts, rsync, and openssh packages from the official repositories
  • SSH is not strictly required, but rsync over SSH is the method used here.
• A VPS running any distribution, with rsync and a working SSH server
  • Its architecture (x86_64 or i686) does not matter as long as the OpenVZ installation can support your target architecture.
• OpenVZ's serial console feature (usually accessible via your provider's control panel)
  • Without this, any network configuration for the target VPS will have to be done immediately after the "Build" step below.

Building a clean Arch Linux installation

As root, build the installation (optionally replacing build with your preferred target directory):

# mkdir build
# pacstrap -cd build

Other tweaks for the pacstrap command:

• -C custom-pacman-config.conf - Use a custom pacman configuration file. By default, pacstrap builds according to your local pacman.conf. This determines the architecture (i686 or x86_64) of the build, the mirror list, etc.
• -G - Prevent pacstrap from copying your system's pacman keyring to the new build. If you use this option, you will need to run pacman-key --init and pacman-key --populate archlinux in the Configuration step to set up the keyring.
• -M - Prevent pacstrap from copying your system's pacman mirror list to the new build.
• You can pass a list of packages to pacstrap to add them to your install, instead of the default base group. For example: pacstrap -cd build base openssh dnsutils gnu-netcat traceroute vim

Replacing everything on the VPS with the Arch build

Replace all files, directories, etc. on your target VPS with the contents of your build directory (replacing "YOUR.VPS.IP.ADDRESS" below):

# rsync -axH --delete-delay -e ssh --stats -P build/ YOUR.VPS.IP.ADDRESS:/

Explanation of options:

• -a - Required. Preserves timestamps, permissions, etc.
• --delete - Required. Deletes anything in the target that does not exist in the source
• -x - Important. Prevents the crossing of filesystem boundaries (other partitions, /dev, etc.) during the copy
• -H - Important. Preserves hardlinks
• --delete-delay - Recommended. Enables alternate deletion mode which waits to delete anything until the synchronization is otherwise complete, which may reduce the risk of a slow transfer causing the target VPS to lock-up
• -e ssh - Recommended. Uses rsync over SSH (recommended for simplicity compared to setting up an rsync server)
• -P - Recommended. Shows partial progress information during transfer
• --stats - Recommended. Shows transfer statistics at the end

Configuration

1. Reboot the VPS externally (using your provider's control panel, for example).
2. Using OpenVZ's serial console feature, configure the network and basic system settings (ignoring fstab generation and arch-chroot steps).
   • If you do not have access to the serial console feature, you will need to preconfigure your network settings before synchronizing Arch to the VPS.
   • On some VPS configuration you won't have a gateway to connect to, here is an example netctl configuration for this setup. It configures static IP addresses and default routes on venet0 and uses Google Public DNS.

/etc/netctl/venet

Description='VPS venet connection'
Interface=venet0
Connection=ethernet

IP=static
Address=('192.0.2.42/32')
Routes=('default')

IP6=static
Address6=('2001:db8::1234:5678/128')
Routes6=('default')

DNS=('2001:4860:4860::8888' '2001:4860:4860::8844' '8.8.8.8' '8.8.4.4')

Xen

See Xen.