Info

All silkv1 sites have been migrated to silkv2 as of December 17, 2019.

You can find out which platform your account is located on by logging into your account with SSH and reading the messages displayed before your command prompt. If you miss the message, you can also look at the file /etc/motd, which will say something like:

This is a second generation UVM silk hosting server.

Migrating between silk platforms

Your account can be migrated from silkv1 to silkv2 by contacting SAA.

Most things about silkv1 and silkv2 work the same, though some older software will remain only on silkv1 and some newer software is only available on silkv2. Most differences, however, are simply that silkv2 makes available newer versions of the same software.

Considerations when migrating to silkv2

  • All sites under a silk account will be migrated at once. Plan for a short downtime while changes are provisioned and files are copied.
  • PHP: All silkv1 PHP sites use PHP 5.5. However, PHP 5.5 was retired December 17 and silkv2 sites began using PHP 7.2.
  • WebAuth: .htaccess files using WebAuth authentication and requiring WebAuthOptional support currently do not work on silkv2; this will be addressed mid-November.
  • Proxied sites: Silkv1 sites proxied through www.uvm.edu that depend on their Host: header specifying www.uvm.edu instead of the actual silk site name may require minor changes, as this behavior on silkv1 is nonstandard and unsupported on silkv2. (This does not appear to be common.) You can instead find the original Host: header in the X-Forwarded-Host: header.
  • .htaccess changes: Silkv2 uses a newer version of the Apache web server than silkv1. Although configuration compatibility is enabled, there exist edge cases where an .htaccess file might need tweaking. Common scenarios are not usually impacted.
  • File/directory paths: If you specified the full path to system files or directories outside your home directory in your applications, configuration files, or cron jobs, these locations could in certain cases be different on silkv2, usually because available software versions are more recent.

Platform differences

Item Silkv1 Silkv2
Operating System Red Hat Enterprise Linux 6
originally released in 2010
Red Hat Enterprise Linux 7
originally released in 2014
Sunset Date December 17, 2019 likely in 2021
Git 1.9.x 2.9.x
Go current release
Java 1.7 (IBM) 1.8 (IBM), 11 (OpenJDK)
Node.js 8.x, 10.x 8.x, 10.x, 12.x
Perl 5.10 5.16
PHP 5.5 7.2, 7.3, 7.4
Python 2.6, 2.7 2.7, 3.5, 3.6
R current release current release
Ruby 1.9 1.9, 2.4

The following are specific to silkv2:

  • Node.js and Ruby web applications.
  • Python WSGI applications are managed by the Phusion Passenger application server, allowing them to be more robust and easier to manage.

Further details can be found by running the silk-info command from a login shell.