[lxc-devel] [PATCH] lxc-checkpoint: add pre-checkpoint
Ruslan Kuprieiev
kupruser at gmail.com
Thu Jun 25 16:44:21 UTC 2015
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);
};
/*!
--
2.1.0
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