With a friend, we installed lxc on his server.
We spend 1 hour on the kernel config because we didn't knew :
- that lxc-checkconfig is a bash script and it can check a config before
running it
- which kernel config item whas not good
- that CONFIG_SECURITY_FILE_CAPABILITIES is obsolete since 2.6.33

So, here is a patch for lxc-checkconfig that could save time for lxc newbies
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Modified-by: Daniel Lezcano <daniel.lezcano@free.fr>
Signed-off-by: Guillaume Zitta <lxc@zitta.fr>

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

"lxc configure does not exist. You need to run ./autogen.sh to create it.
I think it needs to either be documented in INSTALL or you provide ./configure"
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Reported-by: Jamal Hadi Salim <hadi@cyberus.ca>

Clean up and factor a bit the pivot_root code.
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

First of all, when trying to start a container in a read-only root
lxc-start complains:
  lxc-start: Read-only file system - can't make temporary mountpoint

This is in conf.c:setup_rootfs_pivot_root() function.  That function
uses optional parameter "lxc.pivotdir", or creates (and later removes)
a temporary directory for pivot_root.  Obviously there's no way to
create a directory in a read-only filesystem.

But lxc.pivotdir does not work either. In the function mentioned above
it is used with leading dot (eg. if I specify "lxc.pivotdir=pivot" in
the config file the pivot_root() syscall will be made to ".pivot" with
leading dot, not to "pivot"), but later on it is used without that dot,
and fails:

  lxc-start: No such file or directory - failed to open /pivot/proc/mounts
  lxc-start: No such file or directory - failed to read or parse mount list '/pivot/proc/mounts'
  lxc-start: failed to pivot_root to '/stage/t'

(that's with "lxc.pivotdir = pivot" in the config file).  After symlinking
pivot to .pivot it still fails:

  lxc-start: Device or resource busy - could not unmount old rootfs
  lxc-start: failed to pivot_root to '/stage/t'
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Reported-by: Michael Tokarev <mjt@tls.msk.ru>

When the client console exits, the mainloop goes in an infinite loop
as the handler is not removed and we are notified from the disconnection
indefinitely.
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

If the SIGCHLD is sent from a process different from the container's init
process we ignore it, otherwise we finish to wait it.
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

When the init container is stopped, we don't check this condition
and we assume the child exited and we wait indefinitely for the child
to exit while this one is stopped.
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

Signed-off-by: Michel Normand <normand@fr.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

to be able to have lxc_fini symetric with lxc_init
Signed-off-by: Michel Normand <normand@fr.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

do the same checking as already done in lxc/restart.c
Signed-off-by: Michel Normand <normand@fr.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

Signed-off-by: Michel Normand <normand@fr.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

There is only one such perror call, so remove it in nl.c

In this same patch, verify that all functions of nl.c and network.c
are reporting a -errno value in case of error;
value that is reported in lxc log by the callers in conf.c
Signed-off-by: Michel Normand <normand@fr.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

lxc-kill send a signal to the process 1 of the container.

If this command is used on an application container ran by
lxc-execute, the lxc-init will receive the signal and will forward it to
the process 2 which is the command specified in the command line.
Signed-off-by: Greg Kurz <gkurz@fr.ibm.com>
Signed-off-by: Michel Normand <normand@fr.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

reformating given examples
and add reference to examples directory.
Signed-off-by: Michel Normand <normand@fr.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

Signed-off-by: Michel Normand <normand@fr.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

Signed-off-by: Michel Normand <normand@fr.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

update lxc man page to better explain:
* the notions of persistent and volatil container.
* the difference between lxc-execute and lxc-start commands
Signed-off-by: Michel Normand <normand@fr.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

Signed-off-by: Michel Normand <normand@fr.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

this is required to avoid to fill /cgroup
with pid number each time lxc-unshare is called.
Signed-off-by: Michel Normand <normand@fr.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

it's usage was removed by patch
28a4b0e5
"open the console later"
Signed-off-by: Michel Normand <normand@fr.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

as will be used later on in other patches.
Signed-off-by: Michel Normand <normand@fr.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

Signed-off-by: Michel Normand <normand@fr.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

This new option is to have user to pass a fd
in place of statefile name.

Simple usage with file open in bash:
===
$rm -f *.log; lxc-execute -n foo -- pi1  44444
$rm -rf /tmp/sf; lxc-checkpoint -n foo -k --statefd 3 3>/tmp/sf && lxc-restart -n bar --statefd 4 4</tmp/sf
===
Signed-off-by: Michel Normand <normand@fr.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

the fd 0,1 and 2 are still inherited
and we only need the fd 2 (stderr) after
the start/restart of the application.
Signed-off-by: Michel Normand <normand@fr.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

Signed-off-by: Michel Normand <normand@fr.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

Fail when we try to attach to an non existing container
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

This patch will try to change the default "/" directory to the
directory we were before attaching. In order to work correctly,
the path has to exist in the container, that makes sense with a
shared file system without rootfs.
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

The command to attach has to be fork/exec.
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>

This patch allows to shutdown the container when the system
is powered off in the container.
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

Store the container in the handler, so it is accessible
everywhere.
Signed-off-by: Daniel Lezcano <dlezcan@fr.ibm.com>

This patch adds a function to count the number of tasks in the
container. The result is not reliable as it may change with a fork
or an exit, but in some cases, for example, there is only one task, or
the container is frozen, the result is accurate.
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

When no console is specified, do not try to setup the console.
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

based on patch from: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>

but also:
* remove the deprecated --directory one.
* change liblxc api of checkpoint/restart to use fd and not string.
* explicitely report error messages for the checkpoint/restart stub functions.
Signed-off-by: Michel Normand <normand@fr.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

Fix type and missing capability.
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

The log file in lxc-init is quite useless as the code is trivial.
Signed-off-by: Michel Normand <normand@fr.ibm.com>
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

Wrong variable.
Signed-off-by: Michel Normand <normand@fr.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

When we try to attach to a container belonging to another user than us,
the command fails as expected but the return code is wrong, so we have
an "unknown error" instead of "permission denied".

The culprit is:

-                     strerror(command.answer.ret));
+                     strerror(-command.answer.ret));

The rest of the code is indentation without code impact.
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: Michel Normand <normand@fr.ibm.com>

This patch allows to execute a command or enter inside the container:
  * lxc-attach -n <name> [command]

If the <command is not specified>, the lxc-attach will retrieve your uid
and get your shell name and exec it in the container.
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>