Difference between pages "Generic 64" and "Hostname"

Revision as of 16:38, February 20, 2015

w.i.p

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, consult http://www.ibm.com/developerworks/library/l-tip-prompt/ <-- this one should be on Funtoo wiki :) 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.

@@ Line 1: / Line 1: @@
-{{Subarch
+w.i.p
-|CPU Family=64-Bit Processors (PC-Compatible, Generic)
+==Introduction==
-|subarch=generic_64
+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.
-|CHOST=x86_64-pc-linux-gnu
+==Configuration==
-|CFLAGS=-mtune=generic -O2 -pipe
+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:
-|USE=mmx sse sse2
+<console>
-|Description=The generic_64 subarch is designed to support 64-bit PC-compatible CPUs, such as the AMD K8-series processors, which were introduced in late 2003.
+localhost ~ # ##i## Hello :)
-}}
+</console>
-The '''generic_64''' subarch is designed to support 64-bit PC-compatible CPUs, such as the [[Wikipedia:AMD_K8|AMD K8-series processors]], which were introduced in late 2003. They were notable as the first processors that supported the [[Wikipedia:X86-64|AMD64 (also called X86-64) 64-bit instruction set]] for PC-compatible systems, which was introduced as a backwards-compatible 64-bit alternative to Intel's IA-64 architecture. Intel followed suit and also began supporting this 64-bit instruction set, which they called "[[Wikipedia:X86-64#Intel_64|Intel 64]]", by releasing X86-64 64-bit compatible CPUs from mid-2004 onwards (See [[Wikipedia:X86-64#Intel_64_implementations|Intel 64 implementations]].)
+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, consult http://www.ibm.com/developerworks/library/l-tip-prompt/ <-- this one should be on Funtoo wiki :)
+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
+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.}}
-AMD desktop 64-bit CPUs include the Athlon 64, Athlon 64 FX, Athlon 64 X2, Athlon X2, Turion 64, Turion 64 X2 and Sempron series processors. AMD server processors were released under the Opteron brand and have codenames SledgeHammer, Venus, Troy, Athens, Denmark, Italy, Egypt, Santa Ana and Santa Rosa. All Opterons released through late 2006 were based on the K8 microarchitecture with original X86-64 instructions.
+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 <code>hosts</code> stands for static table lookup for hostnames and it's configuration file is <code>/etc/hosts</code>.