CRIU supports dirty memory tracking to take incremental checkpoints.
Incremental checkpoints are one way of reducing downtime during
migration. The first checkpoint dumps all the memory pages and the
second (and third, and fourth, ...) only dumps pages which have changed.

Most of the necessary code has already been implemented. This just adds
the existing functionality to lxc-checkpoint:

  -p, --pre-dump            Only pre-dump the memory of the container.
                            Container keeps on running and following
                            checkpoints will only dump the changes.
  --predump-dir=DIR         path to images from previous dump (relative to -D)

The following is an example from a container running CentOS 7 with psql
and tomcat:

 # lxc-checkpoint -n c7 -D /tmp/cp -p
Container keeps on running
 # du -h /tmp/cp
 229M	/tmp/cp
Sync initial checkpoint to destination
 # rsync -a /tmp/cp host2:/tmp/
Sync file-system
 # rsync -a /var/lib/lxc/c7 host2:/var/lib/lxc/
Final dump; container is stopped
 # lxc-checkpoint -n c7 -D /tmp/cp --predump-dir=../cp -s
 # du -h /tmp/cp2
 90M	/tmp/cp2

After transferring the second (incremental checkpoint) and the changes
to the container's file system the container can be restored on the
second host by pointing lxc-checkpoint to the second checkpoint
directory:

 # lxc-checkpoint -n c7 -D /tmp/cp2 -r
Signed-off-by: Adrian Reber <areber@redhat.com>

conf: do not use %m format specifier

This is a GNU extension and some libcs might be missing it.
Signed-off-by: Christian Brauner <christian.brauner@canonical.com>

also stop lxc-net in runlevels 0 and 6

add lxc.egg-info to gitignore

install bash completion where pkg-config tells us to

Signed-off-by: Evgeni Golov <evgeni@debian.org>

Signed-off-by: Evgeni Golov <evgeni@debian.org>

there is no reason to not do this :)
Signed-off-by: Evgeni Golov <evgeni@debian.org>

cgroups: skip v2 hierarchy entry

Signed-off-by: Christian Brauner <christian.brauner@canonical.com>

templates: add squashfs support to lxc-ubuntu-cloud.in

Add squashfs format file support for lxc-ubuntu-cloud.in
Signed-off-by: Po-Hsu Lin <po-hsu.lin@canonical.com>

Update Ubuntu release name: add zesty

Add zesty to KNOWN_RELEASES
Remove EOL wily from KNOWN_RELEASES
Signed-off-by: Po-Hsu Lin <po-hsu.lin@canonical.com>

create symlink for /var/run

this patch create /var/run link to point to /run.

This will fix various issue present when /var/run is persistent.
Signed-off-by: Marc Gariepy <gariepy.marc@gmail.com>

cgfs: various fixes

start: CLONE_NEWCGROUP after we have setup cgroups

If we do it earlier we end up with a wrong view of /proc/self/cgroup. For
example, assume we unshare(CLONE_NEWCGROUP) first, and then create the cgroup
for the container, say /sys/fs/cgroup/cpuset/lxc/c, then /proc/self/cgroup
would show us:

     8:cpuset:/lxc/c

whereas it should actually show

     8:cpuset:/
Signed-off-by: Christian Brauner <christian.brauner@canonical.com>

c/r: check state before doing a checkpoint/restore

This would already fail, but with a not-as-good error message. Let's make
the error better.
Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>

cleanup: /usr/bin/bash vs /bin/bash consistency

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>

container start: clone newcgroup immediately

conf: merge network namespace move & rename on shutdown

c/r: save dump stdout too

When we read sizeof(buf) bytes here, we'd write off the end of the array,
which is bad :)
Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>

The macros put a \n in for us, so let's not put another one in.
Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>

This also allows us to commonize some bits of the dup2 code.
Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>

On shutdown we move physical network interfaces back to the
host namespace and rename them afterwards as well as in the
later lxc_network_delete() step. However, if the device had
a name which already exists in the host namespace then the
moving fails and so do the subsequent rename attempts. When
the namespace ceases to exist the devices finally end up
in the host namespace named 'dev<ID>' by the kernel.

In order to avoid this, we do the moving and renaming in a
single step (lxc_netdev_move_by_*()'s move & rename happen
in a single netlink transaction).
Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>

Do mount rewriting

We need to log longer lines due to CRIU arguments.
Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>

We switched to --ext-mount-map auto because of "system" (liblxc) added
mounts like the cgmanager socket that weren't in the config file. This had
the added advantage that we could drop all the mount processing code,
because we no longer needed an --ext-mount-map argument.

The problem here is that mounts can move between hosts. While
--ext-mount-map auto does its best to detect this situation, it explicitly
disallows moves that change the path name. In LXD, we bind mount
/var/lib/lxd/shmounts/$container to /dev/.lxd-mounts for each container,
and so when a container is renamed in a migration, the name changes.
--ext-mount-map auto won't detect this, and so the migration fails.

We *could* implement mount rewriting in CRIU, but my experience with cgroup
and apparmor rewriting is that this is painful and error prone. Instead, it
is much easier to go back to explicitly listing --ext-mount-map arguments
from the config file, and allow the source of the bind to change. We leave
--ext-mount-map auto to catch any stragling (or future) system added
mounts.

I believe this should fix Launchpad Bug 1580765
Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>

tools: use correct exit code for lxc-stop

When the container is already running our manpage promises to exit with 2.
Let's make it so.
Signed-off-by: Christian Brauner <christian.brauner@canonical.com>

Somehow this implementation of a cgroupfs backend decided to use the hierarchy
numbers it detects in /proc/cgroups and /proc/self/cgroups as indices for
the hierarchy struct. Controller numbering usually starts at 1 but may start at
0 if:

    a) the controller is not mounted on a cgroups v1 hierarchy;
    b) the controller is bound to the cgroups v2 single unified hierarchy; or
    c) the controller is disabled

To avoid having to rework our fallback backend significantly, we should
explicitly check for each controller if hierarchy[i] != NULL.
Signed-off-by: Christian Brauner <christian.brauner@canonical.com>

If cgroupv2 is enabled either alone or together with legacy hierarchies
/proc/self/cgroup can contain entries of the form:

        0::/

These entries need to be skipped.
Signed-off-by: Christian Brauner <christian.brauner@canonical.com>

Signed-off-by: Christian Brauner <christian.brauner@canonical.com>

lxc-ls help fixes