[lxc-devel] [PATCH] Add a non-null group for autobooting
Michael H. Warfield
mhw at WittsEnd.com
Sat May 3 22:17:39 UTC 2014
On Fri, 2014-05-02 at 17:41 -0400, Stéphane Graber wrote:
> On Fri, May 02, 2014 at 05:37:37PM -0400, Stéphane Graber wrote:
> > On Fri, May 02, 2014 at 05:20:11PM -0400, Michael H. Warfield wrote:
> > > On Fri, 2014-05-02 at 17:09 -0400, Michael H. Warfield wrote:
> > > > On Fri, 2014-05-02 at 21:03 +0000, Serge Hallyn wrote:
> > > > > Quoting Michael H. Warfield (mhw at WittsEnd.com):
> > > > > > On Thu, 2014-05-01 at 17:26 -0400, Michael H. Warfield wrote:
> > > > > > > Looks good to me with the provisio that I feel that autoboot on bootup
> > > > > > > should be for all groups and not just the null group. Dwight told me in
> > > > > > > another message that he did it that way because the Upstart script did
> > > > > > > it that way. Was it an oversight or was it a decision? That can be a
> > > > > > > separate patch to fix.
> > > > > >
> > > > > > I haven't seen Dwight's patch go in and I haven't seen any other
> > > > > > commentary about it or my suggested change. His patch fixes a reported
> > > > > > problem and my change supports allowing containers which are members of
> > > > > > designated groups to boot (which I require). Therefore, I'm submitting
> > > > > > this patch. Both "boot" and "autoboot" were suggested for names of the
> > > > > > autoboot group. I choose to use "onboot" just to make it a little
> > > > > > clearer and disambiguate it from some of the other options.
> > > > > >
> > > > > > This patch is dependent on Dwight's patch Subject:
> > > > > > [PATCH v2] have systemd service call lxc-autostart via script
> > > > > >
> > > > > > Regards,
> > > > > > Mike
> > > > > >
> > > > > > --
> > > > > > Add a non-null group for autobooting
> > > > > >
> > > > > > This adds a non-null group (onboot) to the sysvinit startup script
> > > > > > for autobooting containers. This allows for containers which are
> > > > > > in other groups to be included in the autoboot process.
> > > > > >
> > > > > > This script is used by both the sysvinit systems and the systemd
> > > > > > systems.
> > > > > >
> > > > > > Signed-off-by: Michael H. Warfield <mhw at WittsEnd.com>
> > >
> > > > > While this is the right place to do it, I don't think we should encourage
> > > > > differences among init systems... So we should either do it in upstart
> > > > > as well, or not do it at all imo. Otherwise admins will become very
> > > > > confused.
> > >
> > > > I absolutely agree but I haven't been involved in that one. I would
> > > > strongly recommend that someone update the Upstart stuff. Do you want
> > > > me to look at it or do you want someone more familiar with Upstart to
> > > > look at it? I'll take a look.
> > >
> > > I just had a look in that area and I have no idea what those files are
> > > doing. I gather they're doing an "lxc-autostart -L" and then picking
> > > off the first parameter as a container name to start in "lxc-instance"
> > > and I can see where "order" might be handled by "lxc-autostart -L" in
> > > the output but where is the "delay" parameter managed? The "simple"
> > > thing would be to prepend another loop. I'll submit a patch for that.
> > > Someone should look in more depth at what that's doing wrt the delay
> > > parameter.
> >
> > We use upstart instances for the containers so they show up in "initctl
> > list" as separate jobs which can be stopped or restarted.
> >
> > The upstart job calls lxc-autostart in list mode which will spit out the
> > order in which the containers would be started, for each of those there
> > are two columns, the first is the container name, the second is the
> > delay.
> >
> > The job then does "(start lxc-instance NAME=$1 && sleep $2) || true"
> > which will trigger the instance and wait for the delay before moving on.
> >
> >
> > I haven't looked at the rest of your change yet, but assuming you added
> > the "empty" value to lxc-autostart as we suggested earlier, it should
> > just be a matter of replacing "lxc-autostart -L" by "lxc-autostart -L -g
> > ,boot".
> Just went and looked at the submitted patch now (sorry), so yeah, two
> loops in the upstart job should do the trick.
> onboot seems reasonable as a name, it may be worth documenting it
> somewhere though, probably in lxc.container.conf in the lxc.group
> section.
Actually, I was thinking in maybe both lxc.container.conf and lxc-start.
Something along these lines...
--
Autostart and System Boot
LXC Autostart is used as part of the LXC system service when enabled to
run at host system bootup and shutdown. It's used to select which
containers to start in what order and how much to delay between each
startup.
Each container can be part of any number of groups or no group at all.
Two groups are special. One is the NULL group, i.e. the container does
not belong to any group. The other group is the "onboot" group.
When the system boots with the LXC service enabled, it will first
attempt to boot any containers with lxc.start.auto == 1 that is a member
of the "onboot" group. The startup will be in order of lxc.start.order.
If an lxc.start.delay has been specified, that delay will be honored
before attempting to start the next container to give the current
container time to begin initialization and reduce overloading the host
system. After starting the members of the "onboot" group, the LXC system
will proceed to boot containers with lxc.start.auto == 1 which are not
members of any group (the NULL group) and proceed as with the onboot
group.
--
Written for lxc-autostart. Rehash appropriately for lxc.container.conf.
> >
> > >
> > > Regards,
> > > Mike
> > >
> > > > > > ---
> > > > > > config/init/sysvinit/lxc.in | 3 +++
> > > > > > 1 file changed, 3 insertions(+)
> > > > > >
> > > > > > diff --git a/config/init/sysvinit/lxc.in b/config/init/sysvinit/lxc.in
> > > > > > index b1a725c..0b802af 100644
> > > > > > --- a/config/init/sysvinit/lxc.in
> > > > > > +++ b/config/init/sysvinit/lxc.in
> > > > > > @@ -64,6 +64,9 @@ case "$1" in
> > > > > >
> > > > > > # Start containers
> > > > > > wait_for_bridge
> > > > > > + # Start autoboot containers first.
> > > > > > + action $"Starting LXC onboot containers: " /usr/bin/lxc-autostart -g onboot
> > > > > > + # Start NULL group containers last.
> > > > > > action $"Starting LXC containers: " "$bindir"/lxc-autostart
> > > > > > touch "$localstatedir"/lock/subsys/lxc
> > > > > > ;;
> > > > > > --
> > > > > > 1.9.0
> > > > > >
> > > > > >
> > > > > >
> > > > > > --
> > > > > > Michael H. Warfield (AI4NB) | (770) 978-7061 | mhw at WittsEnd.com
> > > > > > /\/\|=mhw=|\/\/ | (678) 463-0932 | http://www.wittsend.com/mhw/
> > > > > > NIC whois: MHW9 | An optimist believes we live in the best of all
> > > > > > PGP Key: 0x674627FF | possible worlds. A pessimist is sure of it!
> > > > > >
> > > > >
> > > > >
> > > > >
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> > > > >
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> > > > >
> > > >
> > >
> > > --
> > > Michael H. Warfield (AI4NB) | (770) 978-7061 | mhw at WittsEnd.com
> > > /\/\|=mhw=|\/\/ | (678) 463-0932 | http://www.wittsend.com/mhw/
> > > NIC whois: MHW9 | An optimist believes we live in the best of all
> > > PGP Key: 0x674627FF | possible worlds. A pessimist is sure of it!
> > >
> >
> >
> >
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> >
> >
> > --
> > Stéphane Graber
> > Ubuntu developer
> > http://www.ubuntu.com
>
>
>
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>
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--
Michael H. Warfield (AI4NB) | (770) 978-7061 | mhw at WittsEnd.com
/\/\|=mhw=|\/\/ | (678) 463-0932 | http://www.wittsend.com/mhw/
NIC whois: MHW9 | An optimist believes we live in the best of all
PGP Key: 0x674627FF | possible worlds. A pessimist is sure of it!
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