Re: [libvirt] [PATCH RFC 3/5] lxc: adds checkpoint and restore helper functions

This patch adds some helper functions for checkpointing/restoring linux containers. We use CRIU binary. Signed-off-by: Katerina Koukiou <k.koukiou(a)gmail.com&gt; --- 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(a)gmail.com&gt; + */ + +#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) {