В Thu, 05 Jun 2014 12:13:46 +0200
"Carlos E. R."
On 2014-06-05 06:39, Andrey Borzenkov wrote:
On Thu, Jun 5, 2014 at 4:47 AM, Carlos E. R. <> wrote:
On 2014-06-05 02:21, Felix Miata wrote:
2 & 3 are not identical. It used to be that 2 was multiuser without any networking.
Yes, I miss level 2. It was useful for some maintenance jobs.
What can be done in this level that can not be done in level 1? Why network must be disabled to do it?
I'm really interested.
Remote network, not the 'lo' interface, by the way.
Well, in level 1 most services are stopped, even syslog. Traditionally you got only terminal 1. I'm just testing level 1 in openSUSE 12.3 in a virtual machine, and the moment I start a second terminal, I'm restored automatically to level 3, I don't know if bug or intentional. IMO, bug.
In openSUSE getty@.service explicitly conflicts with rescue.service, so attempt to launch it kills rescue shell and proceeds with normal startup. This conflict does not exist upstream, I do not know for reasons behind it.
In another 13.1 machine, I can not start a second terminal, so no automatic return to level 3 either. No bug here.
Level 3 is more comfortable, you have several terminals available. You can work in one and look up man pages in another, for instance. Services are not stopped, syslog is working. Many maintenance jobs can be done here, comfortably. But it must be avoided that someone logs in via ssh, or that there is an nfs/samba share changing things.
Level 2 can be used, thus, for backing up databases, doing drastic changes to mail server, create partitions without the desktop interfering and automounting them... with several terminals to work with, and no external interference.
In level 2, remote network was stopped, and possibly other services using network. I would have to look it up to make sure which.
Ah, these:
Eleanor6:/etc/init.d/rc2.d # ls S* S01acpid S01dbus S01fbset S03syslog S07kbd S08irq_balancer S08splash S11cron S12stoppreload S01cpufreq S01earlysyslog S01random S04splash_early S08alsasound S08mcelog S10cups S11smartd
I honestly doubt that any of these services is required to do anything you listed before, which leaves is with ability to log in on multiple vt's. If screen for some reasons is taboo, the following systemd unit gives you multi-vt logins without starting any of "normal" services. Drop it into /etc/systemd/system and name runlevel2.target. It may need some tuning of course. --><-- [Unit] Description=Provide multi-vt login without any additional services. Wants=systemd-logind.service getty.target systemd-user-sessions.service After=basic.target --><--