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GLEP: 20
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Title: /srv - Services Home Directory Support
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Version: $Revision: 1.1 $
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Last-Modified: $Date: 2004/02/22 02:09:07 $
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Author: Stuart Herbert <stuart@gentoo.org>, Rob Holland <tigger@gentoo.org>
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Status: Approved
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Type: Standards Track
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Content-Type: text/x-rst
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Created: 09-Feb-2004
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Post-History: 21-Feb-2004, 11-Nov-2004
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Thanks To
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=========
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Thanks to Robin H. Johnson (robbat2@gentoo.org) for his assistance in writing
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this GLEP.
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Abstract
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========
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This GLEP proposes a new root-level directory - /srv - as an optional home
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for the data (and sometimes the software too) for software that provides
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services.
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/srv will be supported via a USE flag. This gives users the choice
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of using a dedicated service home hierarchy or not.
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/srv is defined in FHS 2.3, which is part of the upcoming LSB v2.0 release
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(http://bugs.freestandards.org/cgi-bin/bugzilla/show_bug.cgi?id=16)
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Motivation
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==========
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Gentoo currently does not provide sufficiently flexible support for
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sites which wish to consolidate the data for their service-orientated
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software under one simple, easy to administer, location.
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Adding optional support for the /srv directory structure will give
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sites increased flexibility on how to layout their machines.
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Specification
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=============
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A new global USE flag - srvdir - will be added to Portage.
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Ebuilds that choose to support the srvdir USE flag will configure the
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package to install and use their data under the /srv directory.
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Ebuilds that choose to support the srvdir USE flag - and which install
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packages that need write access to the same directories that the
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software is installed into - will configure the package to install
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the software under the /srv directory.
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All packages configured to support the srvdir USE flag will support
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this breakdown of /srv:
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/srv/<fqdn>/<service>/<service-specific tree>
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where
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<fqdn> is the fully-qualified domain name
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<service> is the name of the service
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<service-specific tree> is unique to the package
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Ebuilds that install anything into /srv will install into /srv/localhost.
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/srv/localhost - or any of the <service> directories underneath it - may be
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symlinks created by the local administrator.
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Examples
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========
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For example, backup packages which support the srvdir USE flag could
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save backup data under the /srv/<hostname>/backups directory for each
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host on the network that they perform backups for.
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For example, web-based applications which support the srvdir USE flag
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could install their software under the /srv/localhost/www/htdocs directory.
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Ebuilds for web-based applications which also support the vhost USE flag
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will allow the user to install software under other service domains
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through the webapp-config package. See GLEP #11 and the vhost-config tool for
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more information on how this works.
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There are many other packages that could support the srvdir USE flag -
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including Portage itself.
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For packages that do not support the srvdir USE flag, there is currently no
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recommended default location to use - although /var/localhost may prove a
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useful alternative.
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Rationale
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=========
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Introducing optional support for the /srv directory will benefit a number of
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groups of Gentoo users.
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* Users who wish to have /usr mounted read-only
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/srv provides an optional alternative for packages that install writable
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files into /usr.
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* Users who wish to isoloate services from /home utilisation
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Services stop working when real users fill /home. As many packages cannot
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detect or robustly cope with this situation, services that write files
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to disk normally end up corrupting those files.
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* Users who do not wish to export /var or its sub-directories
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Exporting /var - or its subdirectories - via NFS et al is something that
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some system administrators simply do not wish to do. Providing these users
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with the choice of installing into /srv fits with the published Gentoo
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philosophy of allowing users as much choice as possible.
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* Users who share resources via NFS, or who use Network-Attached Storage (NAS)
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Allowing system administrators to choose to configure service-providing
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software to use a single file hierarchy will greatly simply the management
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and maintenance of NFS exports - and imports - in clustered environments.
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* Service providers, who host more than one customer's services on a machine
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Grouping all the storage (web, ftp, databases, IMAP, etc etc) under one
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location greatly simplifies managing disk quotas on that host.
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It is common practice for shared hosted systems to place web sites,
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ftp sites and so on under a user's actual home directory. This practice
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requires the user's home directory to be world-readable, which does not
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promote strong security!
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* Users who wish to store service-orientated files onto a single logical
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volume to support future growth
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The Gentoo Philosophy clearly states that Gentoo Linux will be a
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highly-configurable meta-distribution. Adding optional support for /srv is
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very much in keeping with our Philosophy.
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Implementation
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==============
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A new USE flag - srvdir - will be added to Portage.
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Ebuilds and eclasses will choose to support the srvdir USE flag or not on
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an individual basis.
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(Author's note: If this GLEP is approved, all web-based applications will
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support the srvdir USE flag through the work being carried out under GLEP #11)
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There has been some debate about whether the /srv directory should be provided
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by the basesystem package or not. Because this support is optional, and
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because different sites will have different storage requirements, we believe
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that it should be left to the local Gentoo system administrator to manually
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create the /srv directory.
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If baselayout feels that it must install a /srv, then we propose that
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baselayout installs /srv as a symlink to /var/srv. This approach will support
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installations that mount the root filesystem read-only.
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Backwards Compatibility
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=======================
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Users who choose not to use the new srvdir USE flag will see little to no
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change. It is likely that some ebuilds will change their non-srvdir directory
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layout to reduce the amount of effort required to support both options.
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Copyright
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=========
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This document is licensed under the Creative Commons - Attribution / Share
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Alike license. (http://creativecommons.org/licenses/by-sa/1.0)
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