Date: Sun, 24 Jan 2010 19:24:26 +0100 From: "Simon L. Nielsen" <simon@FreeBSD.org> To: Alexander Leidinger <Alexander@Leidinger.net> Cc: jail@FreeBSD.org, Remko Lodder <remko@FreeBSD.org> Subject: Re: starting jails in the background & dependencies Message-ID: <20100124182425.GC1314@frankie.nitro.dk> In-Reply-To: <20100114133516.21277ik0pthwdo0s@webmail.leidinger.net> References: <20091207080353.66241t4vpmnmrilc@webmail.leidinger.net> <20100105112447.00005e71@unknown> <0f8c4a9c3740e2185582ef1c922835b3.squirrel@www.jr-hosting.nl> <20100114133516.21277ik0pthwdo0s@webmail.leidinger.net>
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B0;251;0cOn 2010.01.14 13:35:16 +0100, Alexander Leidinger wrote:
> Quoting Remko Lodder <remko@FreeBSD.org> (from Tue, 5 Jan 2010
> 11:35:48 +0100):
>
> > On Tue, January 5, 2010 11:24 am, Alexander Leidinger wrote:
> >> On Mon, 07 Dec 2009 08:03:53 +0100 Alexander Leidinger
> >> <Alexander@Leidinger.net> wrote:
> >>
> >>> Hi,
> >>>
> >>> now that jails are started in the background (which is good, to
> >>
> >> I just realized yesterday that it also stops in parallel (in the
> >> background). This is bad. It may be the case that a jail is not fully
> >> stopped via the rc scripts when the OS decides to kill the remaining
> >> processes during a shutdown.
> >>
> >> My first reaction is to only allow to start in the background, but
> >> everything else needs to be serialized.
> >>
> >> Any objections or better ideas out there?
>
> > I think the best way at this moment is to revert the change ( I can do
> > that , or someone else, I dont mind ) and think of a better concept. Simon
> > also mentioned that he didn't like the current way of doing things, so I
> > kept it in, for possible suggestions. Reverting the change would mean that
> > the old behaviour at least works and is with what people are used to. We
> > can then further improve it where needed.
>
> What about the following? Just have a look at the principle, I haven't
> tested it yet. What it does is:
> - revert back to serial startup by default
> - allow to only start in the background (jail_parallel_start=YES)
In some thread there was talk about parallel stop as well, but I must
admit I never looked at it.
> - take input from /dev/null: in case a start script inside the
> jail wants to read from stdin (it shouldn't), it will not
> switch the process into STOP state (but should generate some
> message in the application log)
This seems like a fine change - especially since the output from the
actual jail is hidden.
> Copy&paste, so maybe messed up tabs:
The bottom part of rc.d/jail after the patch seems.... well, "messy"
in lack of a better word, but since I can't come up with a better
solution right now I think this patch should be committed, and then we
can always improve the implementation later.
Note that I haven't tsted it, but I don't see any errors in the patch.
> ---snip---
> Index: share/man/man5/rc.conf.5
> ===================================================================
> --- share/man/man5/rc.conf.5 (Revision 202277)
> +++ share/man/man5/rc.conf.5 (Arbeitskopie)
> @@ -24,7 +24,7 @@
> .\"
> .\" $FreeBSD$
> .\"
> -.Dd November 11, 2009
> +.Dd January 14, 2010
> .Dt RC.CONF 5
> .Os
> .Sh NAME
> @@ -3472,6 +3472,11 @@
> If set to
> .Dq Li NO ,
> any configured jails will not be started.
> +.It jail_parallel_start
> +.Pq Vt bool
> +If set to
> +.Dq Li YES
> +all configured jails will be started in the background (= in parallel).
> .It Va jail_list
> .Pq Vt str
> A space separated list of names for jails.
> Index: etc/rc.d/jail
> ===================================================================
> --- etc/rc.d/jail (Revision 202277)
> +++ etc/rc.d/jail (Arbeitskopie)
> @@ -636,7 +636,8 @@
> done
>
> eval ${_setfib} jail ${_flags} -i ${_rootdir} ${_hostname} \
> - \"${_addrl}\" ${_exec_start} > ${_tmp_jail} 2>&1
> + \"${_addrl}\" ${_exec_start} > ${_tmp_jail} 2>&1 \
> + </dev/null
>
> if [ "$?" -eq 0 ] ; then
> _jail_id=$(head -1 ${_tmp_jail})
> @@ -728,4 +729,19 @@
> if [ -n "$*" ]; then
> jail_list="$*"
> fi
> -run_rc_command "${cmd}" &
> +
> +# Only allow the parallel start of jails, other commands are not
> +# safe to execute in parallel.
> +case "${cmd}" in
> +*start)
> + ;;
> +*)
> + jail_parallel_start=NO
> +esac
> +
> +if checkyesno jail_parallel_start; then
> + run_rc_command "${cmd}" &
> +else
> + run_rc_command "${cmd}"
> +fi
> +
> Index: etc/defaults/rc.conf
> ===================================================================
> --- etc/defaults/rc.conf (Revision 202277)
> +++ etc/defaults/rc.conf (Arbeitskopie)
> @@ -630,6 +630,7 @@
> ### Jail Configuration #######################################
> ##############################################################
> jail_enable="NO" # Set to NO to disable starting of any jails
> +jail_parallel_start="NO" # Start jails in the background
> jail_list="" # Space separated list of names of jails
> jail_set_hostname_allow="YES" # Allow root user in a jail to change
> its hostname
> jail_socket_unixiproute_only="YES" # Route only TCP/IP within a jail
> ---snip---
--
Simon L. Nielsen
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