Link lxc_checkpoint, lxc_restart with USERCR[2]
Following set of patches, when applied to LXC 0.6.5 and built with
USERCR, enable lxc_checkpoint and lxc_restart of some simple containers.
TODO:
- For simplicity, this patchset currently links *statically* with
USERCR. We should eventually build checkpoint.o and restart.o in
USERCR as shared objects and link lxc_checkpoint/lxc_restart with
these shared objects and liblxc.so. (This also required rebuilding
lxc-execute statically, so lxc_checkpoint can communicate with
lxc-execute to get the root-pid of container).
- Determine if lxc_checkpoint needs a --container option (see
TODOs in src/lxc/checkpoint.c)
- This patchset was tested using lxc-macvlan.conf. But for the VNC
server testing I ran into a problem with lxc-macvlan.conf. I
switched to 'lxc-no-netns.conf' and was able to C/R the VNC server.
I have not debugged the problem with VNC and lxc-macvlan.conf.
- 'global_send_sigint' is still a global variable in USERCR. We need
to define a better interface to expose its functionality to callers
of app_restart().
- Choose better names and API for USERCR :-)
Changelog[v2]:
(Based on feedback from Oren Laadan, Serge Hallyn, Daniel Lezcano
and Cedric Le Goater)
- Rather than drop --directory option to lxc_checkpoint/lxc_restart
add a new option (--image).
- Integrate lxc_checkpoint to work with USERCR
- USERCR renamed usercr.h to "app-checkpoint.h"
- USERCR does not create/install libcheckpoint.a and usercr.h for now.
So link directly with app-checkpoint.h, restart.o and checkpoint.o
- USERCR renames the interfaces to app_checkpoint() and app_restart()
'struct app_checkpoint_args' 'struct app_restart_args'.
USAGE:
1. Build USERCR
$ cd /root
$ git-clone git://git.ncl.cs.columbia.edu/pub/git/user-cr.git user-cr
$ git-checkout ckpt-v20
# Apply patches in the following set:
#
https://lists.linux-foundation.org/pipermail/containers/2010-March/023793.html
$ cd /root/user-cr
$ make
This should create restart.o and checkpoint.o
2. Build/install lxc_checkpoint and lxc_restart
# Do normal LXC build/install of 0.6.5.
# Then replace 'lxc-execute', 'lxc-checkpoint', 'lxc-restart' with
# new version. i.e Apply attached patches and:
$ cd src/lxc
$ USERCR=/root/user-cr \
make -f Makefile2 lxc_checkpoint lxc_restart lxc_execute
$ cp lxc_checkpoint lxc_restart lxc-execute /usr/local/bin
3. Checkpoint/restart a simple LXC container
$ lxc-execute --name foo --rcfile lxc-no-netns.conf -- /bin/sleep 1000
$ lxc-freeze --name foo
$ lxc-checkpoint --name foo --image /root/lxc-foo.ckpt
$ lxc-unfreeze --name foo
$ lxc-stop --name foo
$ lxc-restart --name foo --image /root/lxc-foo.ckpt
4. Checkpoint/restart other LXC containers such as:
- a file-io session (see run-fileio1 in cr-tests[1])
- process-tree (see run-ptree1 in cr-tests[1])
- A vi session inside a VNC Server using "twm". i.e
$ cat /root/.vnc/xstartup
#!/bin/sh
xsetroot -solid grey
vncconfig -iconic &
xterm -geometry 80x24+10+10 -ls -title "$VNCDESKTOP Desktop" &
twm &
$ lxc-execute --name foo --rcfile lxc-no-netns.conf -- \
/usr/bin/vncserver :1
$ vncviewer :1
# Open a vi session
$ lxc-freeze --name foo
etc
[1]: cr-tests: git://git.sr71.net/~hallyn/cr_tests.git
[2]: USERCR: git://git.ncl.cs.columbia.edu/pub/git/user-cr.git
Signed-off-by: Sukadev Bhattiprolu <[email protected]>
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