Debian – How to set the hostname for a Debian Jessie system

debianhostnamesystemd

Debian Jessie comes with systemd. The recommendation to set the hostname is using hostnamectl for systemd. However, this command does not work (even to display the current hostname) on the Debian Jessie image booted on EC2:

sudo hostnamectl
sudo: unable to resolve host ip-172-30-0-17
Failed to create bus connection: No such file or directory

So I tried to go ahead with Debian's recommendation here.

echo "myhostname" > /etc/hostname
echo "127.0.0.1 myhostname" >> /etc/hosts
/etc/init.d/hostname.sh start
/etc/init.d/networking force-reload

However, after logging out and logging in again, the hostname does not change. It does however change after a reboot, but that is not desirable to me.

This method used to work in Debian Wheezy.

Any help with getting this right is appreciated.

Best Answer

Found the problem. The base AMI on EC2 for Debian Jessie, does not have dbus installed. hostnamectl seems to need dbus. So the fix is to:

apt-get update && apt-get install -y dbus

And then:

hostname=myname
echo "127.0.0.1      $hostname" >> /etc/hosts
hostnamectl set-hostname "$hostname"
echo "$hostname" > /etc/hostname # uneeded

This worked.

Related Solutions

Linux – Setting the hostname: FQDN or short name

I would choose a consistent approach across the entire environment. Both solutions work fine and will remain compatible with most applications. There is a difference in manageability, though.

I go with the short name as the HOSTNAME setting, and set the FQDN as the first column in /etc/hosts for the server's IP, followed by the short name.

I have not encountered many software packages that enforce or display a preference between the two. I find the short name to be cleaner for some applications, specifically logging. Maybe I've been unlucky in seeing internal domains like server.northside.chicago.rizzomanufacturing.com. Who wants to see that in the logs or a shell prompt?

Sometimes, I'm involved in company acquisitions or restructuring where internal domains and/or subdomains change. I like using the short hostname in these cases because logging, kickstarts, printing, systems monitoring, etc. do not need full reconfiguration to account for the new domain names.

A typical RHEL/CentOS server setup for a server named "rizzo" with internal domain "ifp.com", would look like:

/etc/sysconfig/network:
HOSTNAME=rizzo
...

/etc/hosts:
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6

172.16.100.13   rizzo.ifp.com rizzo

[root@rizzo ~]# hostname 
rizzo

/var/log/messages snippet:
Dec 15 10:10:13 rizzo proftpd[19675]: 172.16.100.13 (::ffff:206.15.236.182[::ffff:206.15.236.182]) - Preparing to               
 chroot to directory '/app/upload/GREEK'
Dec 15 10:10:51 rizzo proftpd[20660]: 172.16.100.13 (::ffff:12.28.170.2[::ffff:12.28.170.2]) - FTP session opened.
Dec 15 10:10:51 rizzo proftpd[20660]: 172.16.100.13 (::ffff:12.28.170.2[::ffff:12.28.170.2]) - Preparing to chroot                
to directory '/app/upload/ftp/SRRID'

Linux – Why does the hostname appear with the address 127.0.1.1 rather than 127.0.0.1 in /etc/hosts

There isn't a great deal of difference between the two; 127/8 (eg: 127.0.0.0 => 127.255.255.255) are all bound to the loopback interface.

The reason why is documented in the Debian manual in Ch. 5 Network Setup - 5.1.1. The hostname resolution.

Ultimately, it is a bug workaround; the original report is 316099.

Best Answer

Related Solutions

Linux – Setting the hostname: FQDN or short name

Linux – Why does the hostname appear with the address 127.0.1.1 rather than 127.0.0.1 in /etc/hosts

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