Right now lxc-start always does one of two things: it creates
a new namespace or inherits it from the parent environment.
This patch adds a third option: share a namespace with another
container (actually: a process).
In some situations this is handy. For example by sharing a network
namespace it is possible to migrate services between containers
without (or with little) downtime.
This patch creates an infrastructure for inheriting any type
of namespace, but only the network namespace is supported for now.
The idea was simply misguided.
If you provide a custom configuration file, you still should be
putting the command sock into the real lxcpath, not an 'anon' one.
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
The API header was included in a variety of ways before, standardize
those to "include <lxc/lxccontainer.h>" as this will always work both in
tree and on a system with the headers installed.
Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Being able to set close_all_fds via API would be usefull for the
situations like running an application (let's say web server)
that controls the lifecycle of the container using the LXC API.
We don't want forked process to inherit parent's resource (file, socket, ...)
Signed-off-by: S.Çağlar Onur <caglar@10ur.org>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Normal lxc-start usage tends to be "lxc-start -n name [-P lxcpath]".
This causes $lxcpath/$name/config to be the configuration for the
container. However, lxc-start is more flexible than that. You can
specify a custom configuration file, in which case $lxcpath/$name/config
is not used. You can also (in addition or in place of either of these)
specify configuration entries one-by-one using "-s lxc.utsname=xxx".
To support this using the API, if we are not using
$lxcpath/$name/config then we put ourselves into a custom lxcpath
called (configurable using LXCPATH) /var/lib/lxc_anon. To stop a
container so created, then, you would use
lxc-stop -P /var/lib/lxc_anon -n name
TODO: we should walk over the list of &defines by hand and set them
using c->set_config_item. I haven't done that in this patch.
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
When doing reboot test, must add clone_newuser to clone flags, else
we can't clone(CLONE_NEWPID).
If we don't have caps at lxc-start, don't refuse to start. Drop the
lxc_caps_check() function altogether as it is unused now.
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
When running lxc-start command with valgrind, it reports a memory leak error.
When lxc-start command fails, the conf which is from malloc has not been released.
This patch fix the problem.
Signed-off-by: Weng Meiling <wengmeiling.weng@huawei.com>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
On Fri, 26 Apr 2013 10:18:12 -0500
Serge Hallyn <serge.hallyn@ubuntu.com> wrote:
> Quoting Dwight Engen (dwight.engen@oracle.com):
> > On Fri, 26 Apr 2013 09:37:49 -0500
> > Serge Hallyn <serge.hallyn@ubuntu.com> wrote:
> >
> > > Quoting Dwight Engen (dwight.engen@oracle.com):
> > > > Using lxc configured with --enable-configpath-log, and
> > > > specifying a path to the lxc commands with -P, the log file
> > > > path is generated with a basename of LOGPATH instead of the
> > > > lxcpath. This means for example if you do
> > > >
> > > > lxc-start -P /tmp/containers -n test01 -l INFO
> > > >
> > > > your log file will be
> > > >
> > > > /var/lib/lxc/test01/test01.log
> > > >
> > > > I was expecting the log to be /tmp/containers/test01/test01.log.
> > > > This is particularly confusing if you also have test01 on the
> > > > regular lxcpath. The patch below changes the log file path to be
> > > > based on lxcpath rather than LOGPATH when lxc is configured with
> > > > --enable-configpath-log.
> > > >
> > > > I think that even in the normal non --enable-configpath-log case
> > > > we should consider using lxcpath as the base and not having
> > > > LOGPATH at all, as attempting to create the log files
> > > > in /var/log is not going to work for regular users on their own
> > > > lxcpath. If we want that, I'll update the patch to do that as
> > > > well.
> > >
> > >
> > > Perhaps we should do:
> > >
> > > 1. If lxcpath == default_lxc_path(), then first choice is
> > > LOGPATH, second is lxcpath/container.log
> > > 2. when opening, if first choice fails, use second choice
> > > if there is any.
> > >
> > > That way 'system' containers will go to /var/log/lxc, as I think
> > > they should. Custom-lxcpath containers should never go
> > > to /var/log/lxc, since their names could be dups of containers in
> > > default_lxc_path(). And if the system is a weird one where
> > > default_lxc_path is set up so that an unprivileged user can use
> > > it, then we should log into $lxcpath.
> >
> > That sounds good to me. So these rules would apply in both the
> > regular and --enable-configpath-log cases.
I updated the patch to try to open the log file according to the
choices given above. Along the way I cleaned up log.c a bit, making
some things static, grouping external interfaces together, etc...
Hopefully that doesn't add too much noise.
> > > (Note this patch will trivially conflict with my new lxc_clone.c
> > > causing it to fail to build - unfortunate result of timing)
> >
> > Yeah unfortunately this touches every lxc_log_init() caller. I can
> > work on the above logic and re-submit after your new lxc_clone
> > stuff goes in.
>
> No no, I'll just need to remember to update mine. Don't hold up on
> mine, this is just the nature of such collaboration :)
>
> > Did you have any thoughts on the XXX what to pass in for lxcpath in
> > lxc_init? Right now it just falls back to LOGPATH.
>
> No - that's a weird one, since lxc_init runs in the container. If
> there were only system containers I'd say always use LOGPATH.
> However there are people (apparently :) who use container sharing the
> host's rootfs...
>
> lxc-execute does know the lxcpath. Perhaps we can simply have
> src/lxc/execute.c:execute_start() look at handler->conf to see if a
> rootfs is set. If rootfs is NOT set, then pass lxcpath along to
> lxc-init. Then lxc-init can mostly do the same as the others? (It
> doesn't use src/lxc/arguments.c, so you'd have to add lxcpath to
> options[] in lxc-init.c)
So I did this, only to realize that lxc-init is passing "none" for the
file anyway, so it currently doesn't intend to log. This makes me
think that passing NULL for lxcpath is the right thing to do in
this patch. If you want me to make it so lxc-init can log, I can do
that but I think it should be in a different change :)
--
Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
For the lxc-* C binaries, introduce a -P|--lxcpath command line option
to override the system default.
With this, I can
lxc-create -t ubuntu -n r1
lxc-create -t ubuntu -n r1 -P /home/ubuntu/lxcbase
lxc-start -n r1 -d
lxc-start -n r1 -d -P /home/ubuntu/lxcbase
lxc-console -n r1 -d -P /home/ubuntu/lxcbase
lxc-stop -n r1
all working with the right containers (module cgroup stuff).
To do:
* lxc monitor needs to be made to handle cgroups.
This is another very invasive one. I started doing this as
a part of this set, but that gets hairy, so I'm sending this
separately. Note that lxc-wait and lxc-monitor don't work
without this, and there may be niggles in what I said works
above - since start.c is doing lxc_monitor_send_state etc
to the shared abstract unix domain socket.
* Need to handle the cgroup conflicts.
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
The previous lxcpath patches added support for a custom LXCPATH set
through a system-wide configuration file.
This was also exposed through the C api, so that a custom lxcpath could
be set at the container object instanciation time, or set at runtime.
However the command sock filename was always located under the global
lxcpath, which could be confusing, and would be a problem for users
with insufficient perms to the system-wide lxc path (i.e. if setting
lxcpath to $HOME/lxcbase). This patch changes that by passing the
lxcpath to all callers of lxc_command().
It remains to add an lxcpath command line argument to most of the
command line tools (which are not using the C api) - lxc-start,
lxc-info, lxc-stop, etc.
At this point it becomes tempting to do something like
c = lxc.Container("r1", "/var/lib/lxc")
c2 = lxc.Container("r1", "$HOME/lxcbase")
However, that's problematic - those two will use the same directory
names for cgroup directories.
What would be the best way to handle this? One way (which I kind
of like) is to give up on naming the cgroups after the container.
use mkstemp for the cgroup name, let lxc keep track of the cgroup
name based on the command socket, and make users use lxc-cgroup to get
and change settings.
Other ideas?
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
Here is a patch to introduce a configurable system-wide
lxcpath. It seems to work with lxc-create, lxc-start,
and basic python3 lxc usage through the api.
For shell functions, a new /usr/share/lxc/lxc.functions is
introduced which sets some of the basic global variables,
including evaluating the right place for lxc_path.
I have not converted any of the other python code, as I was
not sure where we should keep the common functions (i.e.
for now just default_lxc_path()).
configure.ac: add an option for setting the global config file name.
utils: add a default_lxc_path() function
Use default_lxc_path in .c files
define get_lxc_path() and set_lxc_path() in C api
use get_lxc_path() in lua api
create sh helper for getting default path from config file
fix up scripts to use lxc.functions
Changelog:
feb6:
fix lxc_path in lxc.functions
utils.c: as Dwight pointed out, don't close a NULL fin.
utils.c: fix the parsing of lxcpath line
lxc-start: print which rcfile we are using
commands.c: As Dwight alluded to, the sockname handling was just
ridiculous. Clean that up.
use Dwight's recommendation for lxc.functions path: $datadir/lxc
make lxccontainer->get_config_path() return const char *
Per Dwight's suggestion, much nicer than returning strdup.
feb6 (v2):
lxccontainer: set c->config_path before using it.
convert legacy lxc-ls
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
Until now, if a lxc-* (i.e. lxc-start) command did not specify a logfile
(with -o logfile), the default was effectively 'none'. With this patch,
the default becomes a per-container log file.
If a container config file specifies 'lxc.logfile', that will override
the default. If a '-o logfile' argument is specifed at lxc-start,
then that will override both the default and the configuration file
entry. Finally, '-o none' can be used to avoid having a logfile at
all (in other words, the previous default), and that will override
a lxc.logfile entry in the container configuration file.
If the user does not have rights to open the default, then 'none' will
be used. However, in that case an error will show up on console. (We
can work on removing that if it annoys people, but I think it is
helpful, at least while we're still ironing this set out) If the user
or container configuration file specified a logfile, and the user does
not have rights to open the default, then the action will fail.
One slight "mis-behavior" which I have not fixed (and may not fix) is
that if a lxc.logfile is specified, the default logfile will still
get created before we read the configuration file to find out there
is a lxc.logfile entry.
changelog: Jan 24:
add --enable-configpath-log configure option
When we log to /var/lib/lxc/$container/$container.log, several things
need to be done differently than when we log into /var/log/lxc (for
instance). So give it a configure option so we know what to do
When the user specifies a logfile, we bail if we can't open it. But
when opening the default logfile, the user may not have rights to
open it, so in that case ignore it and continue as if using 'none'.
When using /var/lib/lxc/$c/$c.log, we use $LOGPATH/$name/$name.log.
Otherwise, we use $LOGPATH/$name.log.
When using /var/lib/lxc/$c/$c.log, don't try to create the log path
/var/lib/lxc/$c. It can only not exist if the container doesn't
exist. We don't want to create the directory in that case. When
using /var/log/lxc, then we do want to create the path if it does
not exist.
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
The logfile changes broke lxc-info and possibly more command line
tools. Revert for now until we get those issues addressed.
This reverts commit 74476cf144.
[ Thanks to Stéphane and Dwight for the feedback on the previous patch ]
Until now, if a lxc-* (i.e. lxc-start) command did not specify a logfile
(with -o logfile), the default was effectively 'none'. With this patch,
the default becomes $LOGPATH/<container>/<container>.log. LOGPATH is
specified at configure time with '--with-log-path='. If unspecified, it
is $LXCPATH, so that logs for container r2 will show up at
/var/lib/lxc/r2/r2/log. LOGPATH must exist, while lxc will make sure to
create $LOGPATH/<name>. As another example, Ubuntu will likely specify
--with-log-path=/var/log/lxc (and place /var/log/lxc into
debian/lxc.dirs), placing r2's logs in /var/log/lxc/r2/r2.log.
If a container config file specifies 'lxc.logfile', that will override
the default. If a '-o logfile' argument is specifed at lxc-start,
then that will override both the default and the configuration file
entry. Finally, '-o none' can be used to avoid having a logfile at
all (in other words, the previous default), and that will override
a lxc.logfile entry in the container configuration file.
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
Ok... Here's the patch again. Since Serge is removing the loglevel
structure member, this patch no longer references that element.
From the original description:
1) Removes run_makedev() and the call to it from conf.c per discussion.
2) Adds an lxc.hook.autodev hook.
Note: This hook is very close (one routine level abstracted) from where
the run_makedev was called. Anyone really rrreeeaaalllyyy needing
MAKEDEV can add it in with a small shim script to do whatever they want
under whatever distro they're using, so no functionality is lost there.
3) Added a number of environment variables for all the hook scripts to
reference to assist in execution. Things like LXC_ROOTFS_MOUNT could be
very useful but others were added as well. Room for more if anyone has
an itch. All in one spot in lxc_start.c.
4) clearenv and putenv( "container=lxc" ) calls were moved to just after
the "start" hook in the container just prior to actually firing up the
container so we could use environment variables prior to that and have
them flushed them before firing up init. Nice side effect is that you
can define environment variables and then call lxc-start and have them
show up in those hooks scripts.
5) I actually DID update the man page for lxc.conf! I guess I lied when
I said I wouldn't get that done.
[... and ...]
I added the rcfile to the lxc_conf structure as suggested and moved the
setenv bundle from lxc-start.c over to start.c just prior to calling
run_lxc_hooks for the pre-start hook.
Signed-off-by: Michael H. Warfield <mhw@WittsEnd.com>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
lxc-start -c makes the named file/device the container's console, but using
this with a regular file in order to get a log of the console output does
not work very well if you also want to login on the console. This change
implements an additional option (-L) to simply log the console's output to
a file.
Both options can be used separately or together. For example to get a usable
console and log: lxc-start -n name -c /dev/tty8 -L console.log
The console state is cleaned up more when lxc_delete_console is called, and
some of the clean up paths in lxc_create_console were fixed.
The lxc_priv and lxc_unpriv macros were modified to make use of gcc's local
label feature so they can be expanded more than once in the same function.
Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Clear env before starting a container. Do it right before setting
the container=lxc variable.
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
Add option to create a pidfile for lxc-start. This is helpful for
init scripts and process monitors when running as daemon.
Signed-off-by: Natanael Copa <ncopa@alpinelinux.org>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
Starting a container with insufficient privilege (correctly) fails
during lxc_init. However, if starting a daemonized container, we
daemonize before we get to that check. Therefore while the
container will fail to start, and the logfile will show this, the
'lxc-start -n x -d' command will return success. For ease of
scripting, do a check for the required privilege before we exit.
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
The option is implied by '-d', because the admin won't see the warning
message.
Signed-off-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Let's export the 'container' variable and let init receive it
as a kernel command line option.
In the upstart init scripts, we can distinguish if we are in a
container context or not.
===============================================================================
# /dev/console - getty
#
# This service maintains a getty on /dev/console from the point the
# system is started until it is shut down again.
# It only runs in lxc containers.
start on stopped rc RUNLEVEL=[2345]
stop on runlevel [!2345]
env container
pre-start script
[ "x$container" != "xlxc" ] && { stop; exit 0; }
exit 0;
end script
respawn
exec /sbin/getty -8 38400 /dev/console
===============================================================================
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
When the reboot is detected, reboot the container.
That needs to set all file descriptor opened by lxc-start
to be flagged with the close-on-exec flag, otherwise when
re-execing ourself, we inherit our own fd.
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
The actual behaviour of the console is messy as:
* it relies on a heuristic (tty or not, rootfs or not, etc ...)
* the container init stole the tty and we lose the control
The following patch:
* allocates a tty
* maps this tty to the container console
* proxy the io from the console to the file specified in the configuration
lxc.console=<file>
That allows to specify a file, a fifo, a $(tty), and can be extended with an
uri like file://mypath, net://1.2.3.4:1234, etc ...
That solves the problem with the heuristic and the container does no longer stole
our current tty.
Note by default, the console output will go to a blackhole if no configuration is
specified making the container showing nothing.
In order to access the console from the tty, use
lxc-start -n foo -s lxc.console=$(tty)
I propose the make the container to daemonize by default now.
I tried the following:
in a shell:
touch /var/lib/lxc/foo/console
tail --retry -f /var/lib/lxc/foo/console
in another shell:
lxc-start -n foo -s lxc.console=/var/lib/lxc/foo/console
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
lxc_<cmd>.c and <cmd>.c files use the same log category : lxc_<cmd>.
The symbol is multiply defined and linking statically lxc commands is
not possible.
The patch introduces new log categories with a '_ui' suffix to
differentiate the command line interface from the library routine.
Reported-by: Ciprian Dorin, Craciun <ciprian.craciun@gmail.com>
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
conf object is on stack and is used in forked process.
Signed-off-by: Michel Normand <normand@fr.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
If you're running (by mistake or typo) (via lxc-start) container that does not
exists it will run with lxc.rootfs=/, meaning that /sbin/init will
restart initialization procedure, efficiently messing host's system,
that may lead to unpredictable results or even destroy (make inaccessible) host
system (by reseting network configuration or something like that).
(Actually, it _did_ destroy system of everyone who tested this).
Actually, I finally lost any meaning of having such a feature for
full-system containers. You may not use hosts's FS - it's described at
above. You may not use some temporary directory - that's nonsense.
This patch forbinds starting container via lxc-start without rcfile and
custom start program, but probably it fixes only small part of problem.
I really don't see much sense in such a feature without ability of
overriding 'default' setting with command line switches. Anyway, default
behaviour should be as save as possible.
Signed-off-by: Andrian Nord <NightNord@gmail.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
The rcfile is parsed in the lxc_start function. This is not the place
to do that. Let's the caller to do that.
In the meantime, we have the lxc_conf structure filled right before
calling the lxc_start function so we can do some sanity check on the
configuration to not break the system when we launch the container.
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
The container will be a directory where the user can store everything,
so we create one directory and store a configuration file inside.
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
With the previous modifications, a temporary directory is created
to mount the rootfs in order to have the system container to remount
itself the '/' directory.
But in case of daemonize, we change the directory, so when the rootfs
is specified with a relative path, we can not access it.
Don't chdir, as that will be done automatically later in the chroot
setup.
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
The command specifies a configuration file => use it
The command does not specify a configuration but the container
was created before, use the configuration.
The command does not specify a configuration and the container
was not created before, use default.
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
<lxc/lxc.h> should only include what is needed. This patch removes
all useless headers from lxc.h and fixed other .c files.
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
