[lxc-devel] [PATCH] lxc-checkpoint: add pre-checkpoint

Ruslan Kuprieiev kupruser at gmail.com
Fri Jun 26 08:24:32 UTC 2015


Drop this one, please.

Thanks.

On 05/19/2015 05:09 AM, Ruslan Kuprieiev wrote:
> Pre-checkpoint does a snapshot of a memory changes since previous pre-checkpoint,
> allowing to significantly decrease time of an actual checkpoint.
>
> We need it to be able to live-migrate containers faster.
>
> Signed-off-by: Ruslan Kuprieiev <kupruser at gmail.com>
> ---
>   src/lxc/criu.c           | 20 ++++++++++++++
>   src/lxc/criu.h           |  1 +
>   src/lxc/lxc_checkpoint.c | 41 +++++++++++++++++++++++++++-
>   src/lxc/lxccontainer.c   | 70 ++++++++++++++++++++++++++++++++++++++++++++++--
>   src/lxc/lxccontainer.h   | 15 ++++++++++-
>   5 files changed, 143 insertions(+), 4 deletions(-)
>
> diff --git a/src/lxc/criu.c b/src/lxc/criu.c
> index e939b37..a8fcc5f 100644
> --- a/src/lxc/criu.c
> +++ b/src/lxc/criu.c
> @@ -70,6 +70,13 @@ void exec_criu(struct criu_opts *opts)
>   		/* --leave-running */
>   		if (!opts->stop)
>   			static_args++;
> +	} else if (strcmp(opts->action, "pre-dump") == 0) {
> +		/* -t pid */
> +		static_args += 2;
> +
> +		/* --prev-images-dir */
> +		if (opts->prev_dir)
> +			static_args++;

>   	} else if (strcmp(opts->action, "restore") == 0) {
>   		/* --root $(lxc_mount_point) --restore-detached
>   		 * --restore-sibling --pidfile $foo --cgroup-root $foo */
> @@ -127,6 +134,11 @@ void exec_criu(struct criu_opts *opts)
>   	DECLARE_ARG("-o");
>   	DECLARE_ARG(log);
>   
> +	if (opts->prev_dir) {
> +		DECLARE_ARG("--prev-images-dir");
> +		DECLARE_ARG(opts->prev_dir);
> +	}
> +
>   	if (opts->verbose)
>   		DECLARE_ARG("-vvvvvv");
>   
> @@ -140,6 +152,14 @@ void exec_criu(struct criu_opts *opts)
>   		DECLARE_ARG(pid);
>   		if (!opts->stop)
>   			DECLARE_ARG("--leave-running");
> +	} else if (strcmp(opts->action, "pre-dump") == 0) {
> +		char pid[32];
> +
> +		if (sprintf(pid, "%d", opts->c->init_pid(opts->c)) < 0)
> +			goto err;
> +
> +		DECLARE_ARG("-t");
> +		DECLARE_ARG(pid);
>   	} else if (strcmp(opts->action, "restore") == 0) {
>   		void *m;
>   		int additional;
> diff --git a/src/lxc/criu.h b/src/lxc/criu.h
> index 1f65e47..e8ef24b 100644
> --- a/src/lxc/criu.h
> +++ b/src/lxc/criu.h
> @@ -53,6 +53,7 @@ struct criu_opts {
>   	/* restore: the file to write the init process' pid into */
>   	char *pidfile;
>   	const char *cgroup_path;
> +	char *prev_dir;
>   };
>   
>   void exec_criu(struct criu_opts *opts);
> diff --git a/src/lxc/lxc_checkpoint.c b/src/lxc/lxc_checkpoint.c
> index 2e76c2e..d4ff786 100644
> --- a/src/lxc/lxc_checkpoint.c
> +++ b/src/lxc/lxc_checkpoint.c
> @@ -36,6 +36,10 @@ static bool stop = false;
>   static bool verbose = false;
>   static bool do_restore = false;
>   static bool daemonize_set = false;
> +static char *prev_checkpoint_dir = NULL;
> +static bool do_pre_checkpoint = false;
> +
> +#define OPT_PREV_DIR OPT_VERSION - 1
>   
>   static const struct option my_longopts[] = {
>   	{"checkpoint-dir", required_argument, 0, 'D'},
> @@ -44,6 +48,8 @@ static const struct option my_longopts[] = {
>   	{"restore", no_argument, 0, 'r'},
>   	{"daemon", no_argument, 0, 'd'},
>   	{"foreground", no_argument, 0, 'F'},
> +	{"pre-checkpoint", no_argument, 0, 'p'},
> +	{"prev-checkpoint-dir", required_argument, 0, OPT_PREV_DIR},
>   	LXC_COMMON_OPTIONS
>   };
>   
> @@ -91,6 +97,14 @@ static int my_parser(struct lxc_arguments *args, int c, char *arg)
>   		args->daemonize = 0;
>   		daemonize_set = true;
>   		break;
> +	case 'p':
> +		do_pre_checkpoint = true;
> +		break;
> +	case OPT_PREV_DIR:
> +		prev_checkpoint_dir = strdup(arg);
> +		if (!prev_checkpoint_dir)
> +			return -1;
> +		break;
>   	}
>   	return 0;
>   }
> @@ -107,7 +121,9 @@ lxc-checkpoint checkpoints and restores a container\n\
>   Options :\n\
>     -n, --name=NAME           NAME for name of the container\n\
>     -r, --restore             Restore container\n\
> +  -p, --pre-checkpoint      Pre-checkpoint container\n\
>     -D, --checkpoint-dir=DIR  directory to save the checkpoint in\n\
> +  --prev-checkpoint-dir=DIR directory with previous checkpoint(relative to -D)\n\
>     -v, --verbose             Enable verbose criu logs\n\
>     Checkpoint options:\n\
>     -s, --stop                Stop the container after checkpointing.\n\
> @@ -131,7 +147,7 @@ bool checkpoint(struct lxc_container *c)
>   		return false;
>   	}
>   
> -	ret = c->checkpoint(c, checkpoint_dir, stop, verbose);
> +	ret = c->checkpoint(c, checkpoint_dir, prev_checkpoint_dir, stop, verbose);
>   	lxc_container_put(c);
>   
>   	if (!ret) {
> @@ -142,6 +158,27 @@ bool checkpoint(struct lxc_container *c)
>   	return true;
>   }
>   
> +bool pre_checkpoint(struct lxc_container *c)
> +{
> +	bool ret;
> +
> +	if (!c->is_running(c)) {
> +		fprintf(stderr, "%s not running, not pre-checkpointing.\n", my_args.name);
> +		lxc_container_put(c);
> +		return false;
> +	}
> +
> +	ret = c->pre_checkpoint(c, checkpoint_dir, prev_checkpoint_dir, verbose);
> +	lxc_container_put(c);
> +
> +	if (!ret) {
> +		fprintf(stderr, "Pre-checkpointing %s failed.\n", my_args.name);
> +		return false;
> +	}
> +
> +	return true;
> +}
> +
>   bool restore_finalize(struct lxc_container *c)
>   {
>   	bool ret = c->restore(c, checkpoint_dir, verbose);
> @@ -229,6 +266,8 @@ int main(int argc, char *argv[])
>   
>   	if (do_restore)
>   		ret = restore(c);
> +	else if (do_pre_checkpoint)
> +		ret = pre_checkpoint(c);
>   	else
>   		ret = checkpoint(c);
>   
> diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
> index 1c103e8..5e15a1b 100644
> --- a/src/lxc/lxccontainer.c
> +++ b/src/lxc/lxccontainer.c
> @@ -380,6 +380,16 @@ static rettype fnname(struct lxc_container *c, t1 a1, t2 a2, t3 a3)	\
>   	return ret;							\
>   }
>   
> +#define WRAP_API_4(rettype, fnname, t1, t2, t3, t4)			\
> +static rettype fnname(struct lxc_container *c, t1 a1, t2 a2, t3 a3, t4 a4)\
> +{									\
> +	rettype ret;							\
> +	current_config = c ? c->lxc_conf : NULL;			\
> +	ret = do_##fnname(c, a1, a2, a3, a4);				\
> +	current_config = NULL;						\
> +	return ret;							\
> +}
> +
>   WRAP_API(bool, lxcapi_is_defined)
>   
>   static const char *do_lxcapi_state(struct lxc_container *c)
> @@ -3712,7 +3722,7 @@ static bool do_lxcapi_detach_interface(struct lxc_container *c, const char *ifna
>   
>   WRAP_API_2(bool, lxcapi_detach_interface, const char *, const char *)
>   
> -static bool do_lxcapi_checkpoint(struct lxc_container *c, char *directory, bool stop, bool verbose)
> +static bool do_lxcapi_checkpoint(struct lxc_container *c, char *directory, char *prev_dir, bool stop, bool verbose)
>   {
>   	pid_t pid;
>   	int status;
> @@ -3745,6 +3755,7 @@ static bool do_lxcapi_checkpoint(struct lxc_container *c, char *directory, bool
>   
>   		os.action = "dump";
>   		os.directory = directory;
> +		os.prev_dir = prev_dir;
>   		os.c = c;
>   		os.stop = stop;
>   		os.verbose = verbose;
> @@ -3767,7 +3778,61 @@ static bool do_lxcapi_checkpoint(struct lxc_container *c, char *directory, bool
>   	}
>   }
>   
> -WRAP_API_3(bool, lxcapi_checkpoint, char *, bool, bool)
> +WRAP_API_4(bool, lxcapi_checkpoint, char *, char *, bool, bool)
> +
> +static bool do_lxcapi_pre_checkpoint(struct lxc_container *c, char *directory, char *prev_dir, bool verbose)
> +{
> +	pid_t pid;
> +	int status;
> +	char path[PATH_MAX];
> +
> +	if (!criu_ok(c))
> +		return false;
> +
> +	if (mkdir(directory, 0700) < 0 && errno != EEXIST)
> +		return false;
> +
> +	status = snprintf(path, sizeof(path), "%s/inventory.img", directory);
> +	if (status < 0 || status >= sizeof(path))
> +		return false;
> +
> +	if (access(path, F_OK) == 0) {
> +		ERROR("please use a fresh directory for the dump directory\n");
> +		return false;
> +	}
> +
> +	pid = fork();
> +	if (pid < 0)
> +		return false;
> +
> +	if (pid == 0) {
> +		struct criu_opts os;
> +
> +		os.action = "pre-dump";
> +		os.directory = directory;
> +		os.prev_dir = prev_dir;
> +		os.c = c;
> +		os.verbose = verbose;
> +
> +		/* exec_criu() returning is an error */
> +		exec_criu(&os);
> +		exit(1);
> +	} else {
> +		pid_t w = waitpid(pid, &status, 0);
> +		if (w == -1) {
> +			SYSERROR("waitpid");
> +			return false;
> +		}
> +
> +		if (WIFEXITED(status)) {
> +			return !WEXITSTATUS(status);
> +		}
> +
> +		return false;
> +	}
> +}
> +
> +WRAP_API_3(bool, lxcapi_pre_checkpoint, char *, char *, bool)
>   
>   static bool do_lxcapi_restore(struct lxc_container *c, char *directory, bool verbose)
>   {
> @@ -3966,6 +4031,7 @@ struct lxc_container *lxc_container_new(const char *name, const char *configpath
>   	c->detach_interface = lxcapi_detach_interface;
>   	c->checkpoint = lxcapi_checkpoint;
>   	c->restore = lxcapi_restore;
> +	c->pre_checkpoint = lxcapi_pre_checkpoint;
>   
>   	return c;
>   
> diff --git a/src/lxc/lxccontainer.h b/src/lxc/lxccontainer.h
> index d60e19a..1faded2 100644
> --- a/src/lxc/lxccontainer.h
> +++ b/src/lxc/lxccontainer.h
> @@ -773,7 +773,7 @@ struct lxc_container {
>   	 * \return \c true on success, else \c false.
>   	 * present at compile time).
>   	 */
> -	bool (*checkpoint)(struct lxc_container *c, char *directory, bool stop, bool verbose);
> +	bool (*checkpoint)(struct lxc_container *c, char *directory, char *prev_dir, bool stop, bool verbose);
>   
>   	/*!
>   	 * \brief Restore a container from a checkpoint.
> @@ -808,6 +808,19 @@ struct lxc_container {
>   	bool (*snapshot_destroy_all)(struct lxc_container *c);
>   
>   	/* Post LXC-1.1 additions */
> +
> +	/*!
> +	 * \brief Pre-checkpoint a container.
> +	 *
> +	 * \param c Container.
> +	 * \param directory The directory to dump the container to.
> +	 * \param prev_dir The directory with previous dump.
> +	 * \param verbose Enable criu's verbose logs.
> +	 *
> +	 * \return \c true on success, else \c false.
> +	 * present at compile time).
> +	 */
> +	bool (*pre_checkpoint)(struct lxc_container *c, char *directory, char *prev_dir, bool verbose);
>   };
>   
>   /*!



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