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Date:      Sun, 13 May 2001 19:58:35 +0200
From:      Erik Trulsson <ertr1013@student.uu.se>
To:        freebsd-stable@FreeBSD.ORG
Subject:   Re: Running Stable on remote production server
Message-ID:  <20010513195835.A20679@student.uu.se>
In-Reply-To: <NEBBJFPJOMGCGNBMJMCHCEKGCCAA.nospam@hiltonbsd.com>; from nospam@hiltonbsd.com on Sun, May 13, 2001 at 12:15:03PM -0500
References:  <20010513181834.A19888@student.uu.se> <NEBBJFPJOMGCGNBMJMCHCEKGCCAA.nospam@hiltonbsd.com>

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On Sun, May 13, 2001 at 12:15:03PM -0500, Stephen Hilton wrote:
> Regarding a "quiet" system, would ipfilter, ipnat, ipmon, snort,
> named, qualify as O.K. processes to be running while the installworld
> is taking place via SSH in multi-user mode.

They are probably O.K. Personally I would probably kill named anyway
just in case (and it shouldn't be needed during the installworld.) The
other I have no experience with so I don't know.


Most of the time you could probably get away with doing an installworld
without preventing any logins or killing any processes. 
Note: *Most* of the time, not all the time. Better safe than sorry.

> 
> > Otherwise you will have to disable further logins (see shutdown(8) or
> > nologin(5) for info on how to do this) and then manually kill most
> > processes. (Just be careful not to kill your own shell or sshd :-) )

One problem I just noticed here. It appears as if sshd will allow
logins even when one of the files /etc/nologin or /var/run/nologin
exists which is contrary to the manpage for sshd(8).
This is probably a bug somewhere. 

A workaround is to kill the parent sshd process. This will prevent any
further logins via sshd. (in the listing below that would be pid 191)

> 
> I have already modified the source tree so ipfilter 3.4.17 is the
> installed version, not 3.14.16 which comes as default. And the named
> version would remain the same.
> 
> > and then manually kill most processes.
> 
> What are some guidelines for which process's to kill
> example ps -wwaux output follows:

Primarily processes which might start other processes on their own. So
inetd and cron should definitely be killed.
Starting a new process when you are installing the executable for that
program or installing shared libraries which it needs is probably not a
good idea.

Any programs which might read/write to files that are updated by
mergemaster is also probably a good idea to kill.
Most programs read from /etc only when they are started and few write
there so this is probably not a big problem.

> 
> USER   PID %CPU %MEM   VSZ  RSS  TT  STAT STARTED      TIME COMMAND
> root     1  0.0  0.0   532    0  ??  ILs  Sat10AM   0:00.09 /sbin/init --
> root     2  0.0  0.0     0    0  ??  DL   Sat10AM   0:00.76  (pagedaemon)
> root     3  0.0  0.0     0    0  ??  DL   Sat10AM   0:00.00  (vmdaemon)
> root     4  0.0  0.0     0    0  ??  DL   Sat10AM   0:00.30  (bufdaemon)
> root     5  0.0  0.0     0    0  ??  DL   Sat10AM   0:01.73  (syncer)
> root    30  0.0  0.0   208    0  ??  Is   Sat10AM   0:00.00 adjkerntz -i
> root   163  0.0  0.2   936  204  ??  Ss    3:36PM   0:00.25 syslogd -s -s
> bind   167  0.0  0.3  2404  416  ??  Is    3:36PM   0:00.30 /usr/sbin/named -u b
> ind -g bind
> root   186  0.0  0.0  1028    0  ??  Is    3:36PM   0:00.00 inetd -wW
> root   188  0.0  0.1   980  172  ??  Ss    3:36PM   0:00.26 /usr/sbin/cron
> root   191  0.0  0.0  2176   12  ??  Is    3:36PM   0:00.87 /usr/sbin/sshd
> root   218  0.0  0.0   900    0  ??  Is    3:36PM   0:00.00 moused -p /dev/psm0
> -t auto
> root   246  0.0  0.1   912   68  ??  Ss    3:36PM   0:01.29 /sbin/ipmon
> root   262  0.0  0.0   944    0  v2  Is+   3:36PM   0:00.00 /usr/libexec/getty P
> c ttyv2
> root   262  0.0  0.0   944    0  v2  Is+   3:36PM   0:00.00 /usr/libexec/getty P
> c ttyv2
> root   263  0.0  0.0   944    0  v3  Is+   3:36PM   0:00.02 /usr/libexec/getty P
> c ttyv3
> root   264  0.0  0.0   944    0  v4  Is+   3:36PM   0:00.01 /usr/libexec/getty P
> c ttyv4
> root   265  0.0  0.0   944    0  v5  Is+   3:36PM   0:00.01 /usr/libexec/getty P
> c ttyv5
> root   266  0.0  0.0   944    0  v6  Is+   3:36PM   0:00.00 /usr/libexec/getty P
> c ttyv6
> root   267  0.0  0.0   944    0  v7  Is+   3:36PM   0:00.00 /usr/libexec/getty P
> c ttyv7
> root   363  0.0  0.0   944    0  v1  Is+   3:59PM   0:00.01 /usr/libexec/getty P
> c ttyv1
> root   364  0.0  0.0   636   24  v0  Is+   3:59PM   0:00.03 -sh (sh)
> root 35092  0.0  0.2  2260  224  ??  S    11:32AM   0:00.22 sshd: root@ttyp2 (ss
> hd)
> root 35093  0.0  0.2   636  280  p2  Ss   11:33AM   0:00.05 -sh (sh)
> root 53642  0.0  1.7 13616 2136  ??  Ss   11:52AM   0:01.42 /usr/local/bin/snort
> root     0  0.0  0.0     0    0  ??  DLs  Sat10AM   0:00.02  (swapper)
> 
> 
> > Single-user mode is not really necessary to do an installworld/mergemaster.
> > What is required is that the machine is "quiet", meaning no other users are
> > logged in and no programs that might interfere with the installation should
> > be running.
> > For a machine to which one has access to the console the easiest way of
> > accomplishing this is going to single-user mode. 
> 
> > Otherwise you will have to disable further logins (see shutdown(8) or
> > nologin(5) for info on how to do this) and then manually kill most
> > processes. (Just be careful not to kill your own shell or sshd :-) )
> 
> > Then you should be able do an installworld/mergemaster.
> 
> Stephen Hilton
> 

-- 
<Insert your favourite quote here.>
Erik Trulsson
ertr1013@student.uu.se


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