[libvirt] [PATCH RFC 3/5] lxc: adds checkpoint and restore helper functions
Katerina Koukiou
k.koukiou at googlemail.com
Thu Jul 21 15:37:25 UTC 2016
This patch adds some helper functions for checkpointing/restoring
linux containers. We use CRIU binary.
Signed-off-by: Katerina Koukiou <k.koukiou at gmail.com>
---
po/POTFILES.in | 1 +
src/Makefile.am | 3 +-
src/lxc/lxc_criu.c | 273 +++++++++++++++++++++++++++++++++++++++++++++++++++++
src/lxc/lxc_criu.h | 34 +++++++
4 files changed, 310 insertions(+), 1 deletion(-)
create mode 100644 src/lxc/lxc_criu.c
create mode 100644 src/lxc/lxc_criu.h
diff --git a/po/POTFILES.in b/po/POTFILES.in
index a6b6c9c..718b11d 100644
--- a/po/POTFILES.in
+++ b/po/POTFILES.in
@@ -95,6 +95,7 @@ src/lxc/lxc_cgroup.c
src/lxc/lxc_conf.c
src/lxc/lxc_container.c
src/lxc/lxc_controller.c
+src/lxc/lxc_criu.c
src/lxc/lxc_domain.c
src/lxc/lxc_driver.c
src/lxc/lxc_fuse.c
diff --git a/src/Makefile.am b/src/Makefile.am
index 78c493c..64a7680 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -750,7 +750,8 @@ LXC_DRIVER_SOURCES = \
lxc/lxc_process.c lxc/lxc_process.h \
lxc/lxc_fuse.c lxc/lxc_fuse.h \
lxc/lxc_native.c lxc/lxc_native.h \
- lxc/lxc_driver.c lxc/lxc_driver.h
+ lxc/lxc_driver.c lxc/lxc_driver.h \
+ lxc/lxc_criu.c lxc/lxc_criu.h
LXC_CONTROLLER_SOURCES = \
$(LXC_MONITOR_PROTOCOL_GENERATED) \
diff --git a/src/lxc/lxc_criu.c b/src/lxc/lxc_criu.c
new file mode 100644
index 0000000..6944223
--- /dev/null
+++ b/src/lxc/lxc_criu.c
@@ -0,0 +1,273 @@
+/*
+ * lxc_criu.c: wrapper functions for CRIU C API to be used for lxc migration
+ *
+ * Copyright (C) 2016 Katerina Koukiou
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * Author: Katerina Koukiou <k.koukiou at gmail.com>
+ */
+
+#include <config.h>
+
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/mount.h>
+
+#include "virobject.h"
+#include "virerror.h"
+#include "virlog.h"
+#include "virfile.h"
+#include "vircommand.h"
+#include "virstring.h"
+#include "viralloc.h"
+
+#include "lxc_domain.h"
+#include "lxc_driver.h"
+#include "lxc_criu.h"
+
+#define VIR_FROM_THIS VIR_FROM_LXC
+
+VIR_LOG_INIT("lxc.lxc_criu");
+
+#ifdef CRIU
+int lxcCriuDump(virLXCDriverPtr driver ATTRIBUTE_UNUSED,
+ virDomainObjPtr vm,
+ const char *checkpointdir)
+{
+ int fd;
+ int ret = -1;
+ virLXCDomainObjPrivatePtr priv;
+ virCommandPtr cmd;
+ struct stat sb;
+ char *path = NULL;
+ char *tty_info_path = NULL;
+ char *ttyinfo = NULL;
+ int status;
+
+ if (virFileMakePath(checkpointdir) < 0) {
+ virReportSystemError(errno,
+ _("Failed to mkdir %s"), checkpointdir);
+ return -1;
+ }
+
+ fd = open(checkpointdir, O_DIRECTORY);
+ if (fd < 0) {
+ virReportSystemError(errno,
+ _("Failed to open directory %s"), checkpointdir);
+ return -1;
+ }
+
+ cmd = virCommandNew(CRIU);
+ virCommandAddArg(cmd, "dump");
+
+ virCommandAddArgList(cmd, "--images-dir", checkpointdir, NULL);
+
+ virCommandAddArgList(cmd, "--log-file", "dump.log", NULL);
+
+ virCommandAddArgList(cmd, "-vvvv", NULL);
+
+ priv = vm->privateData;
+ virCommandAddArg(cmd, "--tree");
+ virCommandAddArgFormat(cmd, "%d", priv->initpid);
+
+ virCommandAddArgList(cmd, "--tcp-established", "--file-locks",
+ "--link-remap", "--force-irmap", NULL);
+
+ virCommandAddArgList(cmd, "--manage-cgroup", NULL);
+
+ virCommandAddArgList(cmd, "--enable-external-sharing",
+ "--enable-external-masters", NULL);
+
+ virCommandAddArgList(cmd, "--enable-fs", "hugetlbfs",
+ "--enable-fs", "tracefs", NULL);
+
+ /* Add support for FUSE */
+ virCommandAddArgList(cmd, "--ext-mount-map", "/proc/meminfo:fuse", NULL);
+ virCommandAddArgList(cmd, "--ghost-limit", "10000000", NULL);
+
+ virCommandAddArgList(cmd, "--ext-mount-map", "/dev/console:console", NULL);
+ virCommandAddArgList(cmd, "--ext-mount-map", "/dev/tty1:tty1", NULL);
+ virCommandAddArgList(cmd, "--ext-mount-map", "auto", NULL);
+
+ /* The master pair of the /dev/pts device lives outside from what is dumped
+ * inside the libvirt-lxc process. Add the slave pair as an external tty
+ * otherwise criu will fail.
+ */
+ if (virAsprintf(&path, "/proc/%d/root/dev/pts/0", priv->initpid) < 0)
+ goto cleanup;
+
+ if (stat(path, &sb) < 0) {
+ virReportSystemError(errno,
+ _("Unable to stat %s"), path);
+ goto cleanup;
+ }
+
+ if (virAsprintf(&tty_info_path, "%s/tty.info", checkpointdir) < 0)
+ goto cleanup;
+
+ if (virAsprintf(&ttyinfo, "tty[%x:%x]",
+ (unsigned int)sb.st_rdev, (unsigned int)sb.st_dev) < 0)
+ goto cleanup;
+
+ if (virFileWriteStr(tty_info_path, ttyinfo, 0666) < 0) {
+ virReportError(VIR_ERR_INTERNAL_ERROR,
+ _("Failed to write tty info to %s"), tty_info_path);
+ goto cleanup;
+ }
+
+ VIR_DEBUG("tty.info: tty[%x:%x]",
+ (unsigned int)sb.st_dev, (unsigned int)sb.st_rdev);
+ virCommandAddArg(cmd, "--external");
+ virCommandAddArgFormat(cmd, "tty[%x:%x]",
+ (unsigned int)sb.st_rdev, (unsigned int)sb.st_dev);
+
+ VIR_DEBUG("About to checkpoint domain %s (pid = %d)",
+ vm->def->name, priv->initpid);
+ virCommandRawStatus(cmd);
+ if (virCommandRun(cmd, &status) < 0)
+ goto cleanup;
+
+ ret = 0;
+
+ cleanup:
+ VIR_FORCE_CLOSE(fd);
+ VIR_FREE(path);
+ VIR_FREE(tty_info_path);
+ VIR_FREE(ttyinfo);
+
+ if (ret < 0)
+ return ret;
+ return status;
+}
+
+int lxcCriuRestore(virDomainDefPtr def, int restorefd,
+ int ttyfd)
+{
+ int ret = -1;
+ virCommandPtr cmd;
+ char *ttyinfo = NULL;
+ char *inheritfd = NULL;
+ char *tty_info_path = NULL;
+ char *checkpointfd = NULL;
+ char *checkpointdir = NULL;
+ char *rootfs_mount = NULL;
+
+ cmd = virCommandNew(CRIU);
+ virCommandAddArg(cmd, "restore");
+
+ if (virAsprintf(&checkpointfd, "/proc/self/fd/%d", restorefd) < 0) {
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("Failed to write checkpoint dir path"));
+ goto cleanup;
+ }
+
+ if (virFileResolveLink(checkpointfd, &checkpointdir) < 0) {
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("Failed to readlink checkpoint dir path"));
+ goto cleanup;
+ }
+
+ /* CRIU needs the container's root bind mounted so that it is the root of
+ * some mount.
+ */
+ if (virAsprintf(&rootfs_mount, "/tmp/%s", def->name) < 0) {
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("Failed to write rootfs dir mount path"));
+ goto cleanup;
+ }
+
+ virCommandAddArgList(cmd, "--images-dir", checkpointdir, NULL);
+
+ virCommandAddArgList(cmd, "--log-file", "restore.log", NULL);
+
+ virCommandAddArgList(cmd, "--pidfile", "pidfile", NULL);
+
+ virCommandAddArgList(cmd, "-vvvv", NULL);
+ virCommandAddArgList(cmd, "--tcp-established", "--file-locks",
+ "--link-remap", "--force-irmap", NULL);
+
+ virCommandAddArgList(cmd, "--enable-external-sharing",
+ "--enable-external-masters", NULL);
+
+ virCommandAddArgList(cmd, "--ext-mount-map", "auto", NULL);
+
+ virCommandAddArgList(cmd, "--enable-fs", "hugetlbfs",
+ "--enable-fs", "tracefs", NULL);
+
+ virCommandAddArgList(cmd, "--ext-mount-map", "fuse:/proc/meminfo", NULL);
+
+ virCommandAddArgList(cmd, "--ext-mount-map", "console:/dev/console", NULL);
+ virCommandAddArgList(cmd, "--ext-mount-map", "tty1:/dev/tty1", NULL);
+
+ /* Restore cgroup properties if only cgroup has been created by criu,
+ * otherwise do not restore properies
+ */
+ virCommandAddArgList(cmd, "--manage-cgroup", "soft", NULL);
+
+ virCommandAddArgList(cmd, "--restore-detached", "--restore-sibling", NULL);
+
+ /* Restore external tty that was saved in tty.info file
+ */
+ if (virAsprintf(&tty_info_path, "%s/tty.info", checkpointdir) < 0)
+ goto cleanup;
+
+ if (virFileReadAll(tty_info_path, 1024, &ttyinfo) < 0) {
+ virReportError(VIR_ERR_INTERNAL_ERROR,
+ _("Failed to read tty info from %s"), tty_info_path);
+ goto cleanup;
+ }
+ if (virAsprintf(&inheritfd, "fd[%d]:%s", ttyfd, ttyinfo) < 0)
+ goto cleanup;
+
+ virCommandAddArgList(cmd, "--inherit-fd", inheritfd, NULL);
+
+ /* Change the root filesystem because we run in mount namespace.
+ */
+ virCommandAddArgList(cmd, "--root", rootfs_mount, NULL);
+
+ /* If virCommandExec returns here we have an error */
+ ignore_value(virCommandExec(cmd));
+
+ ret = -1;
+
+ cleanup:
+ VIR_FREE(tty_info_path);
+ VIR_FREE(ttyinfo);
+ VIR_FREE(inheritfd);
+ VIR_FREE(checkpointdir);
+ VIR_FREE(checkpointfd);
+ VIR_FREE(rootfs_mount);
+ VIR_FREE(cmd);
+
+ return ret;
+}
+#else
+int lxcCriuDump(virLXCDriverPtr driver ATTRIBUTE_UNUSED,
+ virDomainObjPtr vm ATTRIBUTE_UNUSED,
+ const char *checkpointdir ATTRIBUTE_UNUSED)
+{
+ virReportUnsupportedError();
+ return -1;
+}
+
+int lxcCriuRestore(virDomainDefPtr def ATTRIBUTE_UNUSED,
+ int fd ATTRIBUTE_UNUSED,
+ int ttyfd ATTRIBUTE_UNUSED)
+{
+ virReportUnsupportedError();
+ return -1;
+}
+#endif
diff --git a/src/lxc/lxc_criu.h b/src/lxc/lxc_criu.h
new file mode 100644
index 0000000..757580c
--- /dev/null
+++ b/src/lxc/lxc_criu.h
@@ -0,0 +1,34 @@
+/*
+ * lxc_criu.h: CRIU C API methods wrapper
+ *
+ * Copyright (C) 2016 Katerina Koukiou
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * Author: Katerina Koukiou <k.koukiou at gmail.com>
+ */
+
+#ifndef LXC_CRIU_H
+# define LXC_CRIU_H
+
+# include "virobject.h"
+
+int lxcCriuDump(virLXCDriverPtr driver,
+ virDomainObjPtr vm,
+ const char *checkpointdir);
+
+int lxcCriuRestore(virDomainDefPtr def, int fd,
+ int ttyfd);
+#endif /* LXC_CRIU_H */
--
2.7.3
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