Difference between pages "Repository Configuration" and "Hostname"

(Difference between pages)
(New repository layout)
 
 
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{{Warning|This article is a work-in-progress referring to a future Portage version. It does not apply to the current Funtoo Portage version. Please do not update your configuration yet.}}
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==Introduction==
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A hostname is a unique name created to identify a machine on a network. In computer networking, a hostname  is a label that is assigned to a device connected to a computer network and that is used to identify the device in various forms of electronic communication such as the World Wide Web, e-mail or Usenet. Hostnames may be simple names consisting of a single word or phrase, or they may be structured.
 +
==Configuration==
 +
In Funtoo Linux <code>/etc/conf.d/hostname</code> is the only configuration file for setting a hostname. In OpenRC framework <code>/etc/conf.d/foo</code> is the configuration file for a corresponding Init script <code>/etc/init.d/foo</code>.  With the case of hostname, default value in <code>/etc/conf.d/hostname</code> is set to ''localhost'', means when system boots and OpenRC's <code>/etc/init.d/hostname</code> script started a hostname getting only ''localhost'' name.  How it looks?  In your shell promt this will look in following way, an example for root:
 +
<console>
 +
localhost ~ # ##i## Hello :)
 +
</console>
 +
Let's play a bit with a configuration. Open <code>/etc/conf.d/hostname</code> with your favorite editor and set a hostname of your choice.  Below, I will use a real examples  from one of my working test boxes.
 +
<console>
 +
localhost ~ # ##i## nano /etc/conf.d/hostname
 +
</console>
 +
Let's set it to hostname="oleg-stable.host.funtoo.org". Save the file and restart  a hostname service:
 +
<console>
 +
localhost ~ # ##i## service hostname restart
 +
</console>
 +
Now, let's examine our changes, after a restarting a hostname
 +
<console>
 +
oleg-stable ~ # ##i## Hello :)
 +
</console>
 +
== Diving deeper==
 +
Notice, that in above output we seeing a shortened hostname and not a FQDN (Fully Qualified Domain Name). Don't be frustrated. This is how  default bash promt <code>PS1</code> set. To get nice promts, please, follow http://www.funtoo.org/Prompt_Magic
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Another way to test our settings is using a '''hostname''' command. Here we will show only  some of it's features. Let's try to execute '''hostname''' command:
 +
<console>
 +
oleg-stable ~ # ##i## hostname
 +
oleg-stable.host.funtoo.org
 +
</console>
 +
Now we see our fully qualified domain name hostname just how we configured it in <code>/etc/conf.d/hostname</code> in above paragraph. To get a short hostname we need to set '''-s ''' (short) argument to hostname command.
 +
<console>
 +
oleg-stable ~ # ##i## hostname -s
 +
oleg-stable
 +
</console>
 +
Good! Hostname offers more then just displaying a system host name but can also set one. Let's try:
 +
<console>
 +
oleg-stable ~ # ##i## hostname foo.bar.baz
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oleg-stable ~ # ##i## hostname
 +
foo.bar.baz
 +
</console>
 +
As you can see, we changed a hostname on-the-fly. This is not recommended way.
 +
{{fancywarning|Please, notice that using '''hostname''' command to configure will work temporary for a current session and will be reverted back to a value set in <code>/etc/conf.d/hostname</code> file with next system restart.}}
  
Starting with Portage-2.3.8, a switch to a new repository configuration framework is complete and users may want to update their configuration files. This document aims to describe the goals for the new framework and how to use it.
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Now that we got a brief description of a hostname and basic configuration steps, its time to reflect another important case which is directly related to a Funtoo Linux hostname generation, a hosts.
  
== Multiple repository layout ==
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==Hosts case==
One of the most important changes is the switch from the old ''overlay'' layout to a new cleaner ''repository'' system. The new layout is more flexible and more predictable. For example, repositories can now use resources (eclasses, for example) provided by other repositories.
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As per man page <code>hosts</code> stands for static table lookup for hostnames and it's configuration file is <code>/etc/hosts</code>. Here is how it looks
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{{file|name=/etc/hosts|body=
 +
# Auto-generated hostname. Please do not remove this comment.
 +
127.0.0.1      oleg-stable.host.funtoo.org oleg-stable localhost localhost.localdomain
 +
::1            oleg-stable.host.funtoo.org oleg-stable localhost localhost.localdomain
 +
}}
 +
As you can see it has entries from our <code>/etc/conf.d/hostname</code>. As you may have guessed, in Funtoo Linux <code>/etc/hosts</code> file entries are auto-generated, when OpenRC hostname service starts. Previously, it is used to edit <code>/etc/hosts</code> manually. In Funtoo Linux there is no such need.
  
The old layout was based on the concept of one ''main tree'' and optionally a number of overlays. The main tree provided base system ebuilds, eclasses, profiles, while overlays mostly were able to provide their own ebuilds. The ebuild provided by overlays overrode the ebuilds in main tree to the extend of making it impossible to install the main tree version. Overlays could also provide eclasses for their own ebuilds and package.* entries that applied to all overlays and to the main tree. The Package Manager is responsible for updating the main tree, while overlays are managed externally.
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What about custom hosts entries? This can be easily configured with 'aliases'. For example you want to have a hosts for your remote router or a computer in home LAN. Let's try to modify <code>/etc/conf.d/hostname</code> with adding following - my remote computer oleg.distant.home has an IP 10.1.1.2:
 
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<console>
The new layout is based on the concept of one or more configurable repositories. Each repository can either be stand-alone or depend upon other repositories. The distribution provides a repository called ''funtoo'' (a drop-in replacement for Gentoo's ''gentoo'' repository). Users can install more repositories at they will, the repositories providing their own ebuilds, eclasses and profiles as necessary and/or using them from other repositories. Users can explicitly choose the repository they want to install packages from. The Package Manager can update all repositories.
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oleg-stable ~ # ##i## echo 'aliases="10.1.12 oleg.distant.home"' >> /etc/conf.d/hostname
 
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oleg-stable ~ # ##i## service hostname restart
== Portage configuration ==
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</console>
=== New repository layout ===
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Examine our changes:
The repository configuration should be stored in <code>/etc/portage/repos.conf</code>. It can be either a single file or a directory containing one or more ''.conf'' files.
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<console>
 
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oleg-stable ~ # ##i## cat /etc/hosts
The default configuration is installed as <code>/usr/share/portage/config/repos.conf</code>. This file is internal configuration file installed with portage ebuild and should '''not''' be modified. Instead, the configuration in <code>/etc/portage/repos.conf</code> can override the defaults specified there.
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</console>
 
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{{file|name=/etc/hosts|body=
The configuration uses format similar to Windows .ini files. Each section heading (repository name in square brackets) signifies a single repository, followed by one or more key-value option pairs. For example, the following file copies default configuration for Funtoo repository:
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# Auto-generated hostname. Please do not remove this comment.
 
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10.1.1.2        oleg.distant.home
{{file|name=/etc/portage/repos.conf/funtoo.conf|desc=Example configuration override for Funtoo repository|body=
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127.0.0.1      oleg-stable.host.funtoo.org oleg-stable localhost localhost.localdomain
[funtoo]
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::1            oleg-stable.host.funtoo.org oleg-stable localhost localhost.localdomain
# moved to non-default location!
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location = /var/db/repos/funtoo
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sync-type = git
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sync-uri = git://github.com/funtoo/ports-2015.git
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auto-sync = yes
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}}
 
}}
Location variable is now what used to be a PORTDIR, when using old-fashioned <code>/etc/portage/make.conf</code>.  <code>/var/db/repos/funtoo</code> is a dummy location example. Default location in Funtoo is  set to <code>/usr/portage</code>. Users are free to choose a location of their suits. sync-type is a CVS tree used for portage tree, git is a default in Funtoo. sync-uri is what used to be a SYNC variable, when using old-fashioned configuration through <code>/etc/portage/make.conf</code>
 
The most useful repository configuration options are listed below:
 
;location: ''Obligatory.'' Specifies the directory where repository is/will be stored. If Portage knows how to sync the repository and the location does not exist, it will be created on next ''emerge --sync''. Otherwise, the directory must exist.
 
;priority: Specifies the priority used for ordering ebuilds from different repositories. If two repositories provide an ebuild with matching versions, the repository with higher priority will be used.
 
;auto-sync: Specifies whether ''emerge --sync'' should update the repository. Defaults to ''yes'' if ''sync-type'' is specified, ''no'' otherwise.
 
;sync-depth: Specifies ''--depth'' for git clone. Used only on initial sync. Defaults to 1. Can be set to 0 to force full clone (not pass ''--depth'' at all).
 
;sync-type: Specifies syncing/update method. Can be one of: ''cvs'', ''git'', ''rsync'', ''svn''.
 
;sync-umask: Specifies the umask used when updating/syncing the repository.
 
;sync-uri: Specifies remote URI from which the repository will be cloned/synced. Can use any syntax valid for a particular syncing method.
 
;sync-user: Specifies the user[:group] used to update/sync the repository. If ''FEATURES=usersync'' is used, defaults to the credentials of directory owner.
 
 
[[Category:Portage]]
 

Revision as of 16:06, February 24, 2015

Introduction

A hostname is a unique name created to identify a machine on a network. In computer networking, a hostname is a label that is assigned to a device connected to a computer network and that is used to identify the device in various forms of electronic communication such as the World Wide Web, e-mail or Usenet. Hostnames may be simple names consisting of a single word or phrase, or they may be structured.

Configuration

In Funtoo Linux /etc/conf.d/hostname is the only configuration file for setting a hostname. In OpenRC framework /etc/conf.d/foo is the configuration file for a corresponding Init script /etc/init.d/foo. With the case of hostname, default value in /etc/conf.d/hostname is set to localhost, means when system boots and OpenRC's /etc/init.d/hostname script started a hostname getting only localhost name. How it looks? In your shell promt this will look in following way, an example for root:

localhost ~ #  Hello :)

Let's play a bit with a configuration. Open /etc/conf.d/hostname with your favorite editor and set a hostname of your choice. Below, I will use a real examples from one of my working test boxes.

localhost ~ #  nano /etc/conf.d/hostname

Let's set it to hostname="oleg-stable.host.funtoo.org". Save the file and restart a hostname service:

localhost ~ #  service hostname restart

Now, let's examine our changes, after a restarting a hostname

oleg-stable ~ #  Hello :)

Diving deeper

Notice, that in above output we seeing a shortened hostname and not a FQDN (Fully Qualified Domain Name). Don't be frustrated. This is how default bash promt PS1 set. To get nice promts, please, follow http://www.funtoo.org/Prompt_Magic Another way to test our settings is using a hostname command. Here we will show only some of it's features. Let's try to execute hostname command:

oleg-stable ~ #  hostname
oleg-stable.host.funtoo.org

Now we see our fully qualified domain name hostname just how we configured it in /etc/conf.d/hostname in above paragraph. To get a short hostname we need to set -s (short) argument to hostname command.

oleg-stable ~ #  hostname -s
oleg-stable

Good! Hostname offers more then just displaying a system host name but can also set one. Let's try:

oleg-stable ~ #  hostname foo.bar.baz
oleg-stable ~ #  hostname 
foo.bar.baz

As you can see, we changed a hostname on-the-fly. This is not recommended way.

Warning

Please, notice that using hostname command to configure will work temporary for a current session and will be reverted back to a value set in /etc/conf.d/hostname file with next system restart.

Now that we got a brief description of a hostname and basic configuration steps, its time to reflect another important case which is directly related to a Funtoo Linux hostname generation, a hosts.

Hosts case

As per man page hosts stands for static table lookup for hostnames and it's configuration file is /etc/hosts. Here is how it looks

/etc/hosts
# Auto-generated hostname. Please do not remove this comment.
127.0.0.1       oleg-stable.host.funtoo.org oleg-stable localhost localhost.localdomain
::1             oleg-stable.host.funtoo.org oleg-stable localhost localhost.localdomain

As you can see it has entries from our /etc/conf.d/hostname. As you may have guessed, in Funtoo Linux /etc/hosts file entries are auto-generated, when OpenRC hostname service starts. Previously, it is used to edit /etc/hosts manually. In Funtoo Linux there is no such need.

What about custom hosts entries? This can be easily configured with 'aliases'. For example you want to have a hosts for your remote router or a computer in home LAN. Let's try to modify /etc/conf.d/hostname with adding following - my remote computer oleg.distant.home has an IP 10.1.1.2:

oleg-stable ~ #  echo 'aliases="10.1.12 oleg.distant.home"' >> /etc/conf.d/hostname
oleg-stable ~ #  service hostname restart
Examine our changes:
oleg-stable ~ #  cat /etc/hosts
/etc/hosts
# Auto-generated hostname. Please do not remove this comment.
10.1.1.2        oleg.distant.home
127.0.0.1       oleg-stable.host.funtoo.org oleg-stable localhost localhost.localdomain
::1             oleg-stable.host.funtoo.org oleg-stable localhost localhost.localdomain