[libvirt] [PATCH v2] libxl: define a per-domain logger.
libxl doesn't provide a way to write one log for each domain. Thus we need to demux the messages. If our logger doesn't know to which domain to attribute a message, then it will write it to the default log file. Starting with Xen 4.9 (commit f9858025 and following), libxl will write the domain ID in an easy to grab manner. The logger introduced by this commit will use it to demux the libxl log messages. Thanks to the default log file, this logger will also work with older versions of Xen. --- * v2: addressed Jim's comments src/Makefile.am | 1 + src/libxl/libxl_conf.c | 38 +------- src/libxl/libxl_conf.h | 4 +- src/libxl/libxl_domain.c | 4 + src/libxl/libxl_driver.c | 2 + src/libxl/libxl_logger.c | 223 +++++++++++++++++++++++++++++++++++++++++++++++ src/libxl/libxl_logger.h | 39 +++++++++ 7 files changed, 274 insertions(+), 37 deletions(-) create mode 100644 src/libxl/libxl_logger.c create mode 100644 src/libxl/libxl_logger.h diff --git a/src/Makefile.am b/src/Makefile.am index b71378728..e34d52345 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -851,6 +851,7 @@ LIBXL_DRIVER_SOURCES = \ libxl/libxl_capabilities.c libxl/libxl_capabilities.h \ libxl/libxl_domain.c libxl/libxl_domain.h \ libxl/libxl_driver.c libxl/libxl_driver.h \ + libxl/libxl_logger.c libxl/libxl_logger.h \ libxl/libxl_migration.c libxl/libxl_migration.h UML_DRIVER_SOURCES = \ diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c index b569ddad8..ac83b51c7 100644 --- a/src/libxl/libxl_conf.c +++ b/src/libxl/libxl_conf.c @@ -76,9 +76,7 @@ libxlDriverConfigDispose(void *obj) virObjectUnref(cfg->caps); libxl_ctx_free(cfg->ctx); - xtl_logger_destroy(cfg->logger); - if (cfg->logger_file) - VIR_FORCE_FCLOSE(cfg->logger_file); + libxlLoggerFree(cfg->logger); VIR_FREE(cfg->configDir); VIR_FREE(cfg->autostartDir); @@ -1356,8 +1354,6 @@ libxlDriverConfigPtr libxlDriverConfigNew(void) { libxlDriverConfigPtr cfg; - char *log_file = NULL; - xentoollog_level log_level = XTL_DEBUG; char ebuf[1024]; unsigned int free_mem; @@ -1386,9 +1382,6 @@ libxlDriverConfigNew(void) if (VIR_STRDUP(cfg->channelDir, LIBXL_CHANNEL_DIR) < 0) goto error; - if (virAsprintf(&log_file, "%s/libxl-driver.log", cfg->logDir) < 0) - goto error; - if (virFileMakePath(cfg->logDir) < 0) { virReportError(VIR_ERR_INTERNAL_ERROR, _("failed to create log dir '%s': %s"), @@ -1397,37 +1390,13 @@ libxlDriverConfigNew(void) goto error; } - if ((cfg->logger_file = fopen(log_file, "a")) == NULL) { - VIR_ERROR(_("Failed to create log file '%s': %s"), - log_file, virStrerror(errno, ebuf, sizeof(ebuf))); - goto error; - } - VIR_FREE(log_file); - - switch (virLogGetDefaultPriority()) { - case VIR_LOG_DEBUG: - log_level = XTL_DEBUG; - break; - case VIR_LOG_INFO: - log_level = XTL_INFO; - break; - case VIR_LOG_WARN: - log_level = XTL_WARN; - break; - case VIR_LOG_ERROR: - log_level = XTL_ERROR; - break; - } - - cfg->logger = - (xentoollog_logger *)xtl_createlogger_stdiostream(cfg->logger_file, - log_level, XTL_STDIOSTREAM_SHOW_DATE); + cfg->logger = libxlLoggerNew(cfg->logDir, virLogGetDefaultPriority()); if (!cfg->logger) { VIR_ERROR(_("cannot create logger for libxenlight, disabling driver")); goto error; } - if (libxl_ctx_alloc(&cfg->ctx, LIBXL_VERSION, 0, cfg->logger)) { + if (libxl_ctx_alloc(&cfg->ctx, LIBXL_VERSION, 0, (xentoollog_logger *)cfg->logger)) { VIR_ERROR(_("cannot initialize libxenlight context, probably not " "running in a Xen Dom0, disabling driver")); goto error; @@ -1478,7 +1447,6 @@ libxlDriverConfigNew(void) return cfg; error: - VIR_FREE(log_file); virObjectUnref(cfg); return NULL; } diff --git a/src/libxl/libxl_conf.h b/src/libxl/libxl_conf.h index 851f3afb4..69d78851a 100644 --- a/src/libxl/libxl_conf.h +++ b/src/libxl/libxl_conf.h @@ -41,6 +41,7 @@ # include "locking/lock_manager.h" # include "virfirmware.h" # include "libxl_capabilities.h" +# include "libxl_logger.h" # define LIBXL_DRIVER_NAME "xenlight" # define LIBXL_VNC_PORT_MIN 5900 @@ -74,8 +75,7 @@ struct _libxlDriverConfig { unsigned int version; /* log stream for driver-wide libxl ctx */ - FILE *logger_file; - xentoollog_logger *logger; + libxlLoggerPtr logger; /* libxl ctx for driver wide ops; getVersion, getNodeInfo, ... */ libxl_ctx *ctx; diff --git a/src/libxl/libxl_domain.c b/src/libxl/libxl_domain.c index 5cde576ef..3bc468f61 100644 --- a/src/libxl/libxl_domain.c +++ b/src/libxl/libxl_domain.c @@ -809,6 +809,8 @@ libxlDomainCleanup(libxlDriverPrivatePtr driver, VIR_FREE(xml); } + libxlLoggerCloseFile(cfg->logger, vm->def->id); + virDomainObjRemoveTransientDef(vm); virObjectUnref(cfg); } @@ -1291,6 +1293,8 @@ libxlDomainStart(libxlDriverPrivatePtr driver, */ vm->def->id = domid; + libxlLoggerOpenFile(cfg->logger, domid, vm->def->name); + /* Always enable domain death events */ if (libxl_evenable_domain_death(cfg->ctx, vm->def->id, 0, &priv->deathW)) goto destroy_dom; diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c index 7e5d9b69e..6a4ecddef 100644 --- a/src/libxl/libxl_driver.c +++ b/src/libxl/libxl_driver.c @@ -406,6 +406,8 @@ libxlReconnectDomain(virDomainObjPtr vm, /* Update domid in case it changed (e.g. reboot) while we were gone? */ vm->def->id = d_info.domid; + libxlLoggerOpenFile(cfg->logger, vm->def->id, vm->def->name); + /* Update hostdev state */ if (virHostdevUpdateActiveDomainDevices(hostdev_mgr, LIBXL_DRIVER_NAME, vm->def, hostdev_flags) < 0) diff --git a/src/libxl/libxl_logger.c b/src/libxl/libxl_logger.c new file mode 100644 index 000000000..d8ccdd852 --- /dev/null +++ b/src/libxl/libxl_logger.c @@ -0,0 +1,223 @@ +/* + * libxl_logger.c: libxl logger implementation + * + * Copyright (c) 2016 SUSE LINUX Products GmbH, Nuernberg, Germany. + * + * 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/>. + * + * Authors: + * Cédric Bosdonnat <cbosdonnat@suse.com> + */ +#include <config.h> + +#include <string.h> +#include <libxl.h> + +#include "internal.h" +#include "libxl_logger.h" +#include "util/viralloc.h" +#include "util/virerror.h" +#include "util/virfile.h" +#include "util/virhash.h" +#include "util/virstring.h" +#include "util/virtime.h" + +#define VIR_FROM_THIS VIR_FROM_LIBXL + +VIR_LOG_INIT("libxl.libxl_logger"); + +typedef struct xentoollog_logger_libvirt xentoollog_logger_libvirt; + +struct xentoollog_logger_libvirt { + xentoollog_logger vtable; + xentoollog_level minLevel; + const char *logDir; + + /* map storing the opened fds: "domid" -> FILE* */ + virHashTablePtr files; + FILE *defaultLogFile; +}; + +static void +libxlLoggerFileFree(void *payload, const void *key ATTRIBUTE_UNUSED) +{ + FILE *file = payload; + VIR_FORCE_FCLOSE(file); + file = NULL; +} + +ATTRIBUTE_FMT_PRINTF(5, 0) static void +libvirt_vmessage(xentoollog_logger *logger_in, + xentoollog_level level, + int errnoval, + const char *context, + const char *format, + va_list args) +{ + xentoollog_logger_libvirt *lg = (xentoollog_logger_libvirt *)logger_in; + FILE *logFile = lg->defaultLogFile; + char timestamp[VIR_TIME_STRING_BUFLEN]; + char *message = NULL; + char *start, *end; + char ebuf[1024]; + + VIR_DEBUG("libvirt_vmessage: context='%s' format='%s'", context, format); + + if (level < lg->minLevel) + return; + + if (virVasprintf(&message, format, args) < 0) + return; + + /* Should we print to a domain-specific log file? */ + if ((start = strstr(message, ": Domain ")) && + (end = strstr(start + 9, ":"))) { + FILE *domainLogFile; + + VIR_DEBUG("Found domain log message"); + + start = start + 9; + *end = '\0'; + + domainLogFile = virHashLookup(lg->files, start); + if (domainLogFile) + logFile = domainLogFile; + + *end = ':'; + } + + /* Do the actual print to the log file */ + if (virTimeStringNowRaw(timestamp) < 0) + timestamp[0] = '\0'; + + fprintf(logFile, "%s: ", timestamp); + if (context) + fprintf(logFile, "%s: ", context); + + fprintf(logFile, "%s", message); + + if (errnoval >= 0) + fprintf(logFile, ": %s", virStrerror(errnoval, ebuf, sizeof(ebuf))); + + fputc('\n', logFile); + fflush(logFile); + + VIR_FREE(message); +} + +static void +libvirt_progress(xentoollog_logger *logger_in ATTRIBUTE_UNUSED, + const char *context ATTRIBUTE_UNUSED, + const char *doingwhat ATTRIBUTE_UNUSED, + int percent ATTRIBUTE_UNUSED, + unsigned long done ATTRIBUTE_UNUSED, + unsigned long total ATTRIBUTE_UNUSED) +{ + /* This function purposedly does nothing: it's no logging info */ +} + +static void +libvirt_destroy(xentoollog_logger *logger_in) +{ + xentoollog_logger_libvirt *lg = (xentoollog_logger_libvirt*)logger_in; + VIR_FREE(lg); +} + + +libxlLoggerPtr libxlLoggerNew(const char *logDir, + virLogPriority minLevel) +{ + xentoollog_logger_libvirt logger; + libxlLoggerPtr logger_out = NULL; + char *path = NULL; + + switch (minLevel) { + case VIR_LOG_DEBUG: + logger.minLevel = XTL_DEBUG; + break; + case VIR_LOG_INFO: + logger.minLevel = XTL_INFO; + break; + case VIR_LOG_WARN: + logger.minLevel = XTL_WARN; + break; + case VIR_LOG_ERROR: + logger.minLevel = XTL_ERROR; + break; + } + logger.logDir = logDir; + + if ((logger.files = virHashCreate(3, libxlLoggerFileFree)) == NULL) + return NULL; + + if (virAsprintf(&path, "%s/libxl-driver.log", logDir) < 0) + goto error; + + if ((logger.defaultLogFile = fopen(path, "a")) == NULL) + goto error; + + logger_out = XTL_NEW_LOGGER(libvirt, logger); + + cleanup: + VIR_FREE(path); + return logger_out; + + error: + virHashFree(logger.files); + goto cleanup; +} + +void libxlLoggerFree(libxlLoggerPtr logger) +{ + xentoollog_logger *xtl_logger = (xentoollog_logger*)logger; + if (logger->defaultLogFile) + VIR_FORCE_FCLOSE(logger->defaultLogFile); + virHashFree(logger->files); + xtl_logger_destroy(xtl_logger); +} + +void libxlLoggerOpenFile(libxlLoggerPtr logger, int id, const char *name) +{ + char *path = NULL; + FILE *logFile = NULL; + char *domidstr = NULL; + char ebuf[1024]; + + if (virAsprintf(&path, "%s/%s.log", logger->logDir, name) < 0 || + virAsprintf(&domidstr, "%d", id) < 0) + goto cleanup; + + if (!(logFile = fopen(path, "a"))) { + VIR_WARN("Failed to open log file %s: %s", + path, virStrerror(errno, ebuf, sizeof(ebuf))); + goto cleanup; + } + ignore_value(virHashAddEntry(logger->files, domidstr, logFile)); + + cleanup: + VIR_FREE(path); + VIR_FREE(domidstr); +} + +void libxlLoggerCloseFile(libxlLoggerPtr logger, int id) +{ + char *domidstr = NULL; + if (virAsprintf(&domidstr, "%d", id) < 0) + return; + + ignore_value(virHashRemoveEntry(logger->files, domidstr)); + + VIR_FREE(domidstr); +} diff --git a/src/libxl/libxl_logger.h b/src/libxl/libxl_logger.h new file mode 100644 index 000000000..88c2868eb --- /dev/null +++ b/src/libxl/libxl_logger.h @@ -0,0 +1,39 @@ +/* + * libxl_logger.h: libxl logger implementation + * + * Copyright (c) 2016 SUSE LINUX Products GmbH, Nuernberg, Germany. + * + * 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/>. + * + * Authors: + * Cédric Bosdonnat <cbosdonnat@suse.com> + */ + +#ifndef __LIBXL_LOGGER_H +# define __LIBXL_LOGGER_H + +# include "util/virlog.h" + +typedef struct xentoollog_logger_libvirt libxlLogger; +typedef libxlLogger *libxlLoggerPtr; + +libxlLoggerPtr libxlLoggerNew(const char *logDir, + virLogPriority minLevel); +void libxlLoggerFree(libxlLoggerPtr logger); + +void libxlLoggerOpenFile(libxlLoggerPtr logger, int id, const char *name); +void libxlLoggerCloseFile(libxlLoggerPtr logger, int id); + +#endif /* __LIBXL_LOGGER_H */ -- 2.11.0
Cédric Bosdonnat wrote:
libxl doesn't provide a way to write one log for each domain. Thus we need to demux the messages. If our logger doesn't know to which domain to attribute a message, then it will write it to the default log file.
Starting with Xen 4.9 (commit f9858025 and following), libxl will write the domain ID in an easy to grab manner. The logger introduced by this commit will use it to demux the libxl log messages.
One thing I noticed when testing this on a Xen installation prior to that commit is log files are created that will never be written to. E.g. after starting libvirtd and one domain # ll /var/log/libvirt/libxl/ -rw-r--r-- 1 root root 0 Jan 5 15:48 Domain-0.log -rw-r--r-- 1 root root 17512 Jan 5 15:49 libxl-driver.log -rw-r--r-- 1 root root 0 Jan 5 15:49 sles12sp2-hvm.log IMO these empty, never-to-be-written-to log files might be a bit confusing to users. AFAIK there is no way to detect up front that the underlying Xen supports this capability right? Regards, Jim
Thanks to the default log file, this logger will also work with older versions of Xen. ---
* v2: addressed Jim's comments
src/Makefile.am | 1 + src/libxl/libxl_conf.c | 38 +------- src/libxl/libxl_conf.h | 4 +- src/libxl/libxl_domain.c | 4 + src/libxl/libxl_driver.c | 2 + src/libxl/libxl_logger.c | 223 +++++++++++++++++++++++++++++++++++++++++++++++ src/libxl/libxl_logger.h | 39 +++++++++ 7 files changed, 274 insertions(+), 37 deletions(-) create mode 100644 src/libxl/libxl_logger.c create mode 100644 src/libxl/libxl_logger.h
diff --git a/src/Makefile.am b/src/Makefile.am index b71378728..e34d52345 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -851,6 +851,7 @@ LIBXL_DRIVER_SOURCES = \ libxl/libxl_capabilities.c libxl/libxl_capabilities.h \ libxl/libxl_domain.c libxl/libxl_domain.h \ libxl/libxl_driver.c libxl/libxl_driver.h \ + libxl/libxl_logger.c libxl/libxl_logger.h \ libxl/libxl_migration.c libxl/libxl_migration.h
UML_DRIVER_SOURCES = \ diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c index b569ddad8..ac83b51c7 100644 --- a/src/libxl/libxl_conf.c +++ b/src/libxl/libxl_conf.c @@ -76,9 +76,7 @@ libxlDriverConfigDispose(void *obj)
virObjectUnref(cfg->caps); libxl_ctx_free(cfg->ctx); - xtl_logger_destroy(cfg->logger); - if (cfg->logger_file) - VIR_FORCE_FCLOSE(cfg->logger_file); + libxlLoggerFree(cfg->logger);
VIR_FREE(cfg->configDir); VIR_FREE(cfg->autostartDir); @@ -1356,8 +1354,6 @@ libxlDriverConfigPtr libxlDriverConfigNew(void) { libxlDriverConfigPtr cfg; - char *log_file = NULL; - xentoollog_level log_level = XTL_DEBUG; char ebuf[1024]; unsigned int free_mem;
@@ -1386,9 +1382,6 @@ libxlDriverConfigNew(void) if (VIR_STRDUP(cfg->channelDir, LIBXL_CHANNEL_DIR) < 0) goto error;
- if (virAsprintf(&log_file, "%s/libxl-driver.log", cfg->logDir) < 0) - goto error; - if (virFileMakePath(cfg->logDir) < 0) { virReportError(VIR_ERR_INTERNAL_ERROR, _("failed to create log dir '%s': %s"), @@ -1397,37 +1390,13 @@ libxlDriverConfigNew(void) goto error; }
- if ((cfg->logger_file = fopen(log_file, "a")) == NULL) { - VIR_ERROR(_("Failed to create log file '%s': %s"), - log_file, virStrerror(errno, ebuf, sizeof(ebuf))); - goto error; - } - VIR_FREE(log_file); - - switch (virLogGetDefaultPriority()) { - case VIR_LOG_DEBUG: - log_level = XTL_DEBUG; - break; - case VIR_LOG_INFO: - log_level = XTL_INFO; - break; - case VIR_LOG_WARN: - log_level = XTL_WARN; - break; - case VIR_LOG_ERROR: - log_level = XTL_ERROR; - break; - } - - cfg->logger = - (xentoollog_logger *)xtl_createlogger_stdiostream(cfg->logger_file, - log_level, XTL_STDIOSTREAM_SHOW_DATE); + cfg->logger = libxlLoggerNew(cfg->logDir, virLogGetDefaultPriority()); if (!cfg->logger) { VIR_ERROR(_("cannot create logger for libxenlight, disabling driver")); goto error; }
- if (libxl_ctx_alloc(&cfg->ctx, LIBXL_VERSION, 0, cfg->logger)) { + if (libxl_ctx_alloc(&cfg->ctx, LIBXL_VERSION, 0, (xentoollog_logger *)cfg->logger)) { VIR_ERROR(_("cannot initialize libxenlight context, probably not " "running in a Xen Dom0, disabling driver")); goto error; @@ -1478,7 +1447,6 @@ libxlDriverConfigNew(void) return cfg;
error: - VIR_FREE(log_file); virObjectUnref(cfg); return NULL; } diff --git a/src/libxl/libxl_conf.h b/src/libxl/libxl_conf.h index 851f3afb4..69d78851a 100644 --- a/src/libxl/libxl_conf.h +++ b/src/libxl/libxl_conf.h @@ -41,6 +41,7 @@ # include "locking/lock_manager.h" # include "virfirmware.h" # include "libxl_capabilities.h" +# include "libxl_logger.h"
# define LIBXL_DRIVER_NAME "xenlight" # define LIBXL_VNC_PORT_MIN 5900 @@ -74,8 +75,7 @@ struct _libxlDriverConfig { unsigned int version;
/* log stream for driver-wide libxl ctx */ - FILE *logger_file; - xentoollog_logger *logger; + libxlLoggerPtr logger; /* libxl ctx for driver wide ops; getVersion, getNodeInfo, ... */ libxl_ctx *ctx;
diff --git a/src/libxl/libxl_domain.c b/src/libxl/libxl_domain.c index 5cde576ef..3bc468f61 100644 --- a/src/libxl/libxl_domain.c +++ b/src/libxl/libxl_domain.c @@ -809,6 +809,8 @@ libxlDomainCleanup(libxlDriverPrivatePtr driver, VIR_FREE(xml); }
+ libxlLoggerCloseFile(cfg->logger, vm->def->id); + virDomainObjRemoveTransientDef(vm); virObjectUnref(cfg); } @@ -1291,6 +1293,8 @@ libxlDomainStart(libxlDriverPrivatePtr driver, */ vm->def->id = domid;
+ libxlLoggerOpenFile(cfg->logger, domid, vm->def->name); + /* Always enable domain death events */ if (libxl_evenable_domain_death(cfg->ctx, vm->def->id, 0, &priv->deathW)) goto destroy_dom; diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c index 7e5d9b69e..6a4ecddef 100644 --- a/src/libxl/libxl_driver.c +++ b/src/libxl/libxl_driver.c @@ -406,6 +406,8 @@ libxlReconnectDomain(virDomainObjPtr vm, /* Update domid in case it changed (e.g. reboot) while we were gone? */ vm->def->id = d_info.domid;
+ libxlLoggerOpenFile(cfg->logger, vm->def->id, vm->def->name); + /* Update hostdev state */ if (virHostdevUpdateActiveDomainDevices(hostdev_mgr, LIBXL_DRIVER_NAME, vm->def, hostdev_flags) < 0) diff --git a/src/libxl/libxl_logger.c b/src/libxl/libxl_logger.c new file mode 100644 index 000000000..d8ccdd852 --- /dev/null +++ b/src/libxl/libxl_logger.c @@ -0,0 +1,223 @@ +/* + * libxl_logger.c: libxl logger implementation + * + * Copyright (c) 2016 SUSE LINUX Products GmbH, Nuernberg, Germany. + * + * 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/>. + * + * Authors: + * Cédric Bosdonnat <cbosdonnat@suse.com> + */ +#include <config.h> + +#include <string.h> +#include <libxl.h> + +#include "internal.h" +#include "libxl_logger.h" +#include "util/viralloc.h" +#include "util/virerror.h" +#include "util/virfile.h" +#include "util/virhash.h" +#include "util/virstring.h" +#include "util/virtime.h" + +#define VIR_FROM_THIS VIR_FROM_LIBXL + +VIR_LOG_INIT("libxl.libxl_logger"); + +typedef struct xentoollog_logger_libvirt xentoollog_logger_libvirt; + +struct xentoollog_logger_libvirt { + xentoollog_logger vtable; + xentoollog_level minLevel; + const char *logDir; + + /* map storing the opened fds: "domid" -> FILE* */ + virHashTablePtr files; + FILE *defaultLogFile; +}; + +static void +libxlLoggerFileFree(void *payload, const void *key ATTRIBUTE_UNUSED) +{ + FILE *file = payload; + VIR_FORCE_FCLOSE(file); + file = NULL; +} + +ATTRIBUTE_FMT_PRINTF(5, 0) static void +libvirt_vmessage(xentoollog_logger *logger_in, + xentoollog_level level, + int errnoval, + const char *context, + const char *format, + va_list args) +{ + xentoollog_logger_libvirt *lg = (xentoollog_logger_libvirt *)logger_in; + FILE *logFile = lg->defaultLogFile; + char timestamp[VIR_TIME_STRING_BUFLEN]; + char *message = NULL; + char *start, *end; + char ebuf[1024]; + + VIR_DEBUG("libvirt_vmessage: context='%s' format='%s'", context, format); + + if (level < lg->minLevel) + return; + + if (virVasprintf(&message, format, args) < 0) + return; + + /* Should we print to a domain-specific log file? */ + if ((start = strstr(message, ": Domain ")) && + (end = strstr(start + 9, ":"))) { + FILE *domainLogFile; + + VIR_DEBUG("Found domain log message"); + + start = start + 9; + *end = '\0'; + + domainLogFile = virHashLookup(lg->files, start); + if (domainLogFile) + logFile = domainLogFile; + + *end = ':'; + } + + /* Do the actual print to the log file */ + if (virTimeStringNowRaw(timestamp) < 0) + timestamp[0] = '\0'; + + fprintf(logFile, "%s: ", timestamp); + if (context) + fprintf(logFile, "%s: ", context); + + fprintf(logFile, "%s", message); + + if (errnoval >= 0) + fprintf(logFile, ": %s", virStrerror(errnoval, ebuf, sizeof(ebuf))); + + fputc('\n', logFile); + fflush(logFile); + + VIR_FREE(message); +} + +static void +libvirt_progress(xentoollog_logger *logger_in ATTRIBUTE_UNUSED, + const char *context ATTRIBUTE_UNUSED, + const char *doingwhat ATTRIBUTE_UNUSED, + int percent ATTRIBUTE_UNUSED, + unsigned long done ATTRIBUTE_UNUSED, + unsigned long total ATTRIBUTE_UNUSED) +{ + /* This function purposedly does nothing: it's no logging info */ +} + +static void +libvirt_destroy(xentoollog_logger *logger_in) +{ + xentoollog_logger_libvirt *lg = (xentoollog_logger_libvirt*)logger_in; + VIR_FREE(lg); +} + + +libxlLoggerPtr libxlLoggerNew(const char *logDir, + virLogPriority minLevel) +{ + xentoollog_logger_libvirt logger; + libxlLoggerPtr logger_out = NULL; + char *path = NULL; + + switch (minLevel) { + case VIR_LOG_DEBUG: + logger.minLevel = XTL_DEBUG; + break; + case VIR_LOG_INFO: + logger.minLevel = XTL_INFO; + break; + case VIR_LOG_WARN: + logger.minLevel = XTL_WARN; + break; + case VIR_LOG_ERROR: + logger.minLevel = XTL_ERROR; + break; + } + logger.logDir = logDir; + + if ((logger.files = virHashCreate(3, libxlLoggerFileFree)) == NULL) + return NULL; + + if (virAsprintf(&path, "%s/libxl-driver.log", logDir) < 0) + goto error; + + if ((logger.defaultLogFile = fopen(path, "a")) == NULL) + goto error; + + logger_out = XTL_NEW_LOGGER(libvirt, logger); + + cleanup: + VIR_FREE(path); + return logger_out; + + error: + virHashFree(logger.files); + goto cleanup; +} + +void libxlLoggerFree(libxlLoggerPtr logger) +{ + xentoollog_logger *xtl_logger = (xentoollog_logger*)logger; + if (logger->defaultLogFile) + VIR_FORCE_FCLOSE(logger->defaultLogFile); + virHashFree(logger->files); + xtl_logger_destroy(xtl_logger); +} + +void libxlLoggerOpenFile(libxlLoggerPtr logger, int id, const char *name) +{ + char *path = NULL; + FILE *logFile = NULL; + char *domidstr = NULL; + char ebuf[1024]; + + if (virAsprintf(&path, "%s/%s.log", logger->logDir, name) < 0 || + virAsprintf(&domidstr, "%d", id) < 0) + goto cleanup; + + if (!(logFile = fopen(path, "a"))) { + VIR_WARN("Failed to open log file %s: %s", + path, virStrerror(errno, ebuf, sizeof(ebuf))); + goto cleanup; + } + ignore_value(virHashAddEntry(logger->files, domidstr, logFile)); + + cleanup: + VIR_FREE(path); + VIR_FREE(domidstr); +} + +void libxlLoggerCloseFile(libxlLoggerPtr logger, int id) +{ + char *domidstr = NULL; + if (virAsprintf(&domidstr, "%d", id) < 0) + return; + + ignore_value(virHashRemoveEntry(logger->files, domidstr)); + + VIR_FREE(domidstr); +} diff --git a/src/libxl/libxl_logger.h b/src/libxl/libxl_logger.h new file mode 100644 index 000000000..88c2868eb --- /dev/null +++ b/src/libxl/libxl_logger.h @@ -0,0 +1,39 @@ +/* + * libxl_logger.h: libxl logger implementation + * + * Copyright (c) 2016 SUSE LINUX Products GmbH, Nuernberg, Germany. + * + * 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/>. + * + * Authors: + * Cédric Bosdonnat <cbosdonnat@suse.com> + */ + +#ifndef __LIBXL_LOGGER_H +# define __LIBXL_LOGGER_H + +# include "util/virlog.h" + +typedef struct xentoollog_logger_libvirt libxlLogger; +typedef libxlLogger *libxlLoggerPtr; + +libxlLoggerPtr libxlLoggerNew(const char *logDir, + virLogPriority minLevel); +void libxlLoggerFree(libxlLoggerPtr logger); + +void libxlLoggerOpenFile(libxlLoggerPtr logger, int id, const char *name); +void libxlLoggerCloseFile(libxlLoggerPtr logger, int id); + +#endif /* __LIBXL_LOGGER_H */
On Thu, 2017-01-05 at 15:45 -0700, Jim Fehlig wrote:
Cédric Bosdonnat wrote:
libxl doesn't provide a way to write one log for each domain. Thus we need to demux the messages. If our logger doesn't know to which domain to attribute a message, then it will write it to the default log file.
Starting with Xen 4.9 (commit f9858025 and following), libxl will write the domain ID in an easy to grab manner. The logger introduced by this commit will use it to demux the libxl log messages.
One thing I noticed when testing this on a Xen installation prior to that commit is log files are created that will never be written to. E.g. after starting libvirtd and one domain
# ll /var/log/libvirt/libxl/ -rw-r--r-- 1 root root 0 Jan 5 15:48 Domain-0.log -rw-r--r-- 1 root root 17512 Jan 5 15:49 libxl-driver.log -rw-r--r-- 1 root root 0 Jan 5 15:49 sles12sp2-hvm.log
IMO these empty, never-to-be-written-to log files might be a bit confusing to users. AFAIK there is no way to detect up front that the underlying Xen supports this capability right?
No there is no way to know it since there is no public API change in libxl. The only thing we can do is delaying the creation of the file to the first message write. -- Cedric
Regards, Jim
Thanks to the default log file, this logger will also work with older versions of Xen. ---
* v2: addressed Jim's comments
src/Makefile.am | 1 + src/libxl/libxl_conf.c | 38 +------- src/libxl/libxl_conf.h | 4 +- src/libxl/libxl_domain.c | 4 + src/libxl/libxl_driver.c | 2 + src/libxl/libxl_logger.c | 223 +++++++++++++++++++++++++++++++++++++++++++++++ src/libxl/libxl_logger.h | 39 +++++++++ 7 files changed, 274 insertions(+), 37 deletions(-) create mode 100644 src/libxl/libxl_logger.c create mode 100644 src/libxl/libxl_logger.h
diff --git a/src/Makefile.am b/src/Makefile.am index b71378728..e34d52345 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -851,6 +851,7 @@ LIBXL_DRIVER_SOURCES = \ libxl/libxl_capabilities.c libxl/libxl_capabilities.h \ libxl/libxl_domain.c libxl/libxl_domain.h \ libxl/libxl_driver.c libxl/libxl_driver.h \ + libxl/libxl_logger.c libxl/libxl_logger.h \ libxl/libxl_migration.c libxl/libxl_migration.h UML_DRIVER_SOURCES = \ diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c index b569ddad8..ac83b51c7 100644 --- a/src/libxl/libxl_conf.c +++ b/src/libxl/libxl_conf.c @@ -76,9 +76,7 @@ libxlDriverConfigDispose(void *obj) virObjectUnref(cfg->caps); libxl_ctx_free(cfg->ctx); - xtl_logger_destroy(cfg->logger); - if (cfg->logger_file) - VIR_FORCE_FCLOSE(cfg->logger_file); + libxlLoggerFree(cfg->logger); VIR_FREE(cfg->configDir); VIR_FREE(cfg->autostartDir); @@ -1356,8 +1354,6 @@ libxlDriverConfigPtr libxlDriverConfigNew(void) { libxlDriverConfigPtr cfg; - char *log_file = NULL; - xentoollog_level log_level = XTL_DEBUG; char ebuf[1024]; unsigned int free_mem; @@ -1386,9 +1382,6 @@ libxlDriverConfigNew(void) if (VIR_STRDUP(cfg->channelDir, LIBXL_CHANNEL_DIR) < 0) goto error; - if (virAsprintf(&log_file, "%s/libxl-driver.log", cfg->logDir) < 0) - goto error; - if (virFileMakePath(cfg->logDir) < 0) { virReportError(VIR_ERR_INTERNAL_ERROR, _("failed to create log dir '%s': %s"), @@ -1397,37 +1390,13 @@ libxlDriverConfigNew(void) goto error; } - if ((cfg->logger_file = fopen(log_file, "a")) == NULL) { - VIR_ERROR(_("Failed to create log file '%s': %s"), - log_file, virStrerror(errno, ebuf, sizeof(ebuf))); - goto error; - } - VIR_FREE(log_file); - - switch (virLogGetDefaultPriority()) { - case VIR_LOG_DEBUG: - log_level = XTL_DEBUG; - break; - case VIR_LOG_INFO: - log_level = XTL_INFO; - break; - case VIR_LOG_WARN: - log_level = XTL_WARN; - break; - case VIR_LOG_ERROR: - log_level = XTL_ERROR; - break; - } - - cfg->logger = - (xentoollog_logger *)xtl_createlogger_stdiostream(cfg->logger_file, - log_level, XTL_STDIOSTREAM_SHOW_DATE); + cfg->logger = libxlLoggerNew(cfg->logDir, virLogGetDefaultPriority()); if (!cfg->logger) { VIR_ERROR(_("cannot create logger for libxenlight, disabling driver")); goto error; } - if (libxl_ctx_alloc(&cfg->ctx, LIBXL_VERSION, 0, cfg->logger)) { + if (libxl_ctx_alloc(&cfg->ctx, LIBXL_VERSION, 0, (xentoollog_logger *)cfg->logger)) { VIR_ERROR(_("cannot initialize libxenlight context, probably not " "running in a Xen Dom0, disabling driver")); goto error; @@ -1478,7 +1447,6 @@ libxlDriverConfigNew(void) return cfg; error: - VIR_FREE(log_file); virObjectUnref(cfg); return NULL; } diff --git a/src/libxl/libxl_conf.h b/src/libxl/libxl_conf.h index 851f3afb4..69d78851a 100644 --- a/src/libxl/libxl_conf.h +++ b/src/libxl/libxl_conf.h @@ -41,6 +41,7 @@ # include "locking/lock_manager.h" # include "virfirmware.h" # include "libxl_capabilities.h" +# include "libxl_logger.h" # define LIBXL_DRIVER_NAME "xenlight" # define LIBXL_VNC_PORT_MIN 5900 @@ -74,8 +75,7 @@ struct _libxlDriverConfig { unsigned int version; /* log stream for driver-wide libxl ctx */ - FILE *logger_file; - xentoollog_logger *logger; + libxlLoggerPtr logger; /* libxl ctx for driver wide ops; getVersion, getNodeInfo, ... */ libxl_ctx *ctx; diff --git a/src/libxl/libxl_domain.c b/src/libxl/libxl_domain.c index 5cde576ef..3bc468f61 100644 --- a/src/libxl/libxl_domain.c +++ b/src/libxl/libxl_domain.c @@ -809,6 +809,8 @@ libxlDomainCleanup(libxlDriverPrivatePtr driver, VIR_FREE(xml); } + libxlLoggerCloseFile(cfg->logger, vm->def->id); + virDomainObjRemoveTransientDef(vm); virObjectUnref(cfg); } @@ -1291,6 +1293,8 @@ libxlDomainStart(libxlDriverPrivatePtr driver, */ vm->def->id = domid; + libxlLoggerOpenFile(cfg->logger, domid, vm->def->name); + /* Always enable domain death events */ if (libxl_evenable_domain_death(cfg->ctx, vm->def->id, 0, &priv->deathW)) goto destroy_dom; diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c index 7e5d9b69e..6a4ecddef 100644 --- a/src/libxl/libxl_driver.c +++ b/src/libxl/libxl_driver.c @@ -406,6 +406,8 @@ libxlReconnectDomain(virDomainObjPtr vm, /* Update domid in case it changed (e.g. reboot) while we were gone? */ vm->def->id = d_info.domid; + libxlLoggerOpenFile(cfg->logger, vm->def->id, vm->def->name); + /* Update hostdev state */ if (virHostdevUpdateActiveDomainDevices(hostdev_mgr, LIBXL_DRIVER_NAME, vm->def, hostdev_flags) < 0) diff --git a/src/libxl/libxl_logger.c b/src/libxl/libxl_logger.c new file mode 100644 index 000000000..d8ccdd852 --- /dev/null +++ b/src/libxl/libxl_logger.c @@ -0,0 +1,223 @@ +/* + * libxl_logger.c: libxl logger implementation + * + * Copyright (c) 2016 SUSE LINUX Products GmbH, Nuernberg, Germany. + * + * 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/>. + * + * Authors: + * Cédric Bosdonnat <cbosdonnat@suse.com> + */ +#include <config.h> + +#include <string.h> +#include <libxl.h> + +#include "internal.h" +#include "libxl_logger.h" +#include "util/viralloc.h" +#include "util/virerror.h" +#include "util/virfile.h" +#include "util/virhash.h" +#include "util/virstring.h" +#include "util/virtime.h" + +#define VIR_FROM_THIS VIR_FROM_LIBXL + +VIR_LOG_INIT("libxl.libxl_logger"); + +typedef struct xentoollog_logger_libvirt xentoollog_logger_libvirt; + +struct xentoollog_logger_libvirt { + xentoollog_logger vtable; + xentoollog_level minLevel; + const char *logDir; + + /* map storing the opened fds: "domid" -> FILE* */ + virHashTablePtr files; + FILE *defaultLogFile; +}; + +static void +libxlLoggerFileFree(void *payload, const void *key ATTRIBUTE_UNUSED) +{ + FILE *file = payload; + VIR_FORCE_FCLOSE(file); + file = NULL; +} + +ATTRIBUTE_FMT_PRINTF(5, 0) static void +libvirt_vmessage(xentoollog_logger *logger_in, + xentoollog_level level, + int errnoval, + const char *context, + const char *format, + va_list args) +{ + xentoollog_logger_libvirt *lg = (xentoollog_logger_libvirt *)logger_in; + FILE *logFile = lg->defaultLogFile; + char timestamp[VIR_TIME_STRING_BUFLEN]; + char *message = NULL; + char *start, *end; + char ebuf[1024]; + + VIR_DEBUG("libvirt_vmessage: context='%s' format='%s'", context, format); + + if (level < lg->minLevel) + return; + + if (virVasprintf(&message, format, args) < 0) + return; + + /* Should we print to a domain-specific log file? */ + if ((start = strstr(message, ": Domain ")) && + (end = strstr(start + 9, ":"))) { + FILE *domainLogFile; + + VIR_DEBUG("Found domain log message"); + + start = start + 9; + *end = '\0'; + + domainLogFile = virHashLookup(lg->files, start); + if (domainLogFile) + logFile = domainLogFile; + + *end = ':'; + } + + /* Do the actual print to the log file */ + if (virTimeStringNowRaw(timestamp) < 0) + timestamp[0] = '\0'; + + fprintf(logFile, "%s: ", timestamp); + if (context) + fprintf(logFile, "%s: ", context); + + fprintf(logFile, "%s", message); + + if (errnoval >= 0) + fprintf(logFile, ": %s", virStrerror(errnoval, ebuf, sizeof(ebuf))); + + fputc('\n', logFile); + fflush(logFile); + + VIR_FREE(message); +} + +static void +libvirt_progress(xentoollog_logger *logger_in ATTRIBUTE_UNUSED, + const char *context ATTRIBUTE_UNUSED, + const char *doingwhat ATTRIBUTE_UNUSED, + int percent ATTRIBUTE_UNUSED, + unsigned long done ATTRIBUTE_UNUSED, + unsigned long total ATTRIBUTE_UNUSED) +{ + /* This function purposedly does nothing: it's no logging info */ +} + +static void +libvirt_destroy(xentoollog_logger *logger_in) +{ + xentoollog_logger_libvirt *lg = (xentoollog_logger_libvirt*)logger_in; + VIR_FREE(lg); +} + + +libxlLoggerPtr libxlLoggerNew(const char *logDir, + virLogPriority minLevel) +{ + xentoollog_logger_libvirt logger; + libxlLoggerPtr logger_out = NULL; + char *path = NULL; + + switch (minLevel) { + case VIR_LOG_DEBUG: + logger.minLevel = XTL_DEBUG; + break; + case VIR_LOG_INFO: + logger.minLevel = XTL_INFO; + break; + case VIR_LOG_WARN: + logger.minLevel = XTL_WARN; + break; + case VIR_LOG_ERROR: + logger.minLevel = XTL_ERROR; + break; + } + logger.logDir = logDir; + + if ((logger.files = virHashCreate(3, libxlLoggerFileFree)) == NULL) + return NULL; + + if (virAsprintf(&path, "%s/libxl-driver.log", logDir) < 0) + goto error; + + if ((logger.defaultLogFile = fopen(path, "a")) == NULL) + goto error; + + logger_out = XTL_NEW_LOGGER(libvirt, logger); + + cleanup: + VIR_FREE(path); + return logger_out; + + error: + virHashFree(logger.files); + goto cleanup; +} + +void libxlLoggerFree(libxlLoggerPtr logger) +{ + xentoollog_logger *xtl_logger = (xentoollog_logger*)logger; + if (logger->defaultLogFile) + VIR_FORCE_FCLOSE(logger->defaultLogFile); + virHashFree(logger->files); + xtl_logger_destroy(xtl_logger); +} + +void libxlLoggerOpenFile(libxlLoggerPtr logger, int id, const char *name) +{ + char *path = NULL; + FILE *logFile = NULL; + char *domidstr = NULL; + char ebuf[1024]; + + if (virAsprintf(&path, "%s/%s.log", logger->logDir, name) < 0 || + virAsprintf(&domidstr, "%d", id) < 0) + goto cleanup; + + if (!(logFile = fopen(path, "a"))) { + VIR_WARN("Failed to open log file %s: %s", + path, virStrerror(errno, ebuf, sizeof(ebuf))); + goto cleanup; + } + ignore_value(virHashAddEntry(logger->files, domidstr, logFile)); + + cleanup: + VIR_FREE(path); + VIR_FREE(domidstr); +} + +void libxlLoggerCloseFile(libxlLoggerPtr logger, int id) +{ + char *domidstr = NULL; + if (virAsprintf(&domidstr, "%d", id) < 0) + return; + + ignore_value(virHashRemoveEntry(logger->files, domidstr)); + + VIR_FREE(domidstr); +} diff --git a/src/libxl/libxl_logger.h b/src/libxl/libxl_logger.h new file mode 100644 index 000000000..88c2868eb --- /dev/null +++ b/src/libxl/libxl_logger.h @@ -0,0 +1,39 @@ +/* + * libxl_logger.h: libxl logger implementation + * + * Copyright (c) 2016 SUSE LINUX Products GmbH, Nuernberg, Germany. + * + * 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/>. + * + * Authors: + * Cédric Bosdonnat <cbosdonnat@suse.com> + */ + +#ifndef __LIBXL_LOGGER_H +# define __LIBXL_LOGGER_H + +# include "util/virlog.h" + +typedef struct xentoollog_logger_libvirt libxlLogger; +typedef libxlLogger *libxlLoggerPtr; + +libxlLoggerPtr libxlLoggerNew(const char *logDir, + virLogPriority minLevel); +void libxlLoggerFree(libxlLoggerPtr logger); + +void libxlLoggerOpenFile(libxlLoggerPtr logger, int id, const char *name); +void libxlLoggerCloseFile(libxlLoggerPtr logger, int id); + +#endif /* __LIBXL_LOGGER_H */
On 01/06/2017 01:04 AM, Cedric Bosdonnat wrote:
On Thu, 2017-01-05 at 15:45 -0700, Jim Fehlig wrote:
Cédric Bosdonnat wrote:
libxl doesn't provide a way to write one log for each domain. Thus we need to demux the messages. If our logger doesn't know to which domain to attribute a message, then it will write it to the default log file.
Starting with Xen 4.9 (commit f9858025 and following), libxl will write the domain ID in an easy to grab manner. The logger introduced by this commit will use it to demux the libxl log messages.
One thing I noticed when testing this on a Xen installation prior to that commit is log files are created that will never be written to. E.g. after starting libvirtd and one domain
# ll /var/log/libvirt/libxl/ -rw-r--r-- 1 root root 0 Jan 5 15:48 Domain-0.log -rw-r--r-- 1 root root 17512 Jan 5 15:49 libxl-driver.log -rw-r--r-- 1 root root 0 Jan 5 15:49 sles12sp2-hvm.log
IMO these empty, never-to-be-written-to log files might be a bit confusing to users. AFAIK there is no way to detect up front that the underlying Xen supports this capability right?
No there is no way to know it since there is no public API change in libxl. The only thing we can do is delaying the creation of the file to the first message write.
I think that is a wise thing to do, otherwise I envision bug reports such as "my domain log files are 0 bytes" :-). Regards, Jim
On Fri, Jan 06, 2017 at 08:15:58AM -0700, Jim Fehlig wrote:
On 01/06/2017 01:04 AM, Cedric Bosdonnat wrote:
On Thu, 2017-01-05 at 15:45 -0700, Jim Fehlig wrote:
Cédric Bosdonnat wrote:
libxl doesn't provide a way to write one log for each domain. Thus we need to demux the messages. If our logger doesn't know to which domain to attribute a message, then it will write it to the default log file.
Starting with Xen 4.9 (commit f9858025 and following), libxl will write the domain ID in an easy to grab manner. The logger introduced by this commit will use it to demux the libxl log messages.
One thing I noticed when testing this on a Xen installation prior to that commit is log files are created that will never be written to. E.g. after starting libvirtd and one domain
# ll /var/log/libvirt/libxl/ -rw-r--r-- 1 root root 0 Jan 5 15:48 Domain-0.log -rw-r--r-- 1 root root 17512 Jan 5 15:49 libxl-driver.log -rw-r--r-- 1 root root 0 Jan 5 15:49 sles12sp2-hvm.log
IMO these empty, never-to-be-written-to log files might be a bit confusing to users. AFAIK there is no way to detect up front that the underlying Xen supports this capability right?
No there is no way to know it since there is no public API change in libxl. The only thing we can do is delaying the creation of the file to the first message write.
I think that is a wise thing to do, otherwise I envision bug reports such as "my domain log files are 0 bytes" :-).
Or put some content in them :-) With the QEMU driver, every single /var/log/libvirt/qemu/$GUEST.log will at least have the QEMU command line arguments, followed by a timestamp showing when it started. The idea of the CLI args is that it gives an accurate record of the config of the guest from QEMU's POV, which is helpful to support people as you can't be sure the XML you see is the same as the XML when the guest first started. You don't have CLI args for libxl, but perhaps there's some confg you can easily serialize into there. The timestamp would at least be useful too, if nothing else. Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://entangle-photo.org -o- http://search.cpan.org/~danberr/ :|
On 01/06/2017 08:25 AM, Daniel P. Berrange wrote:
On Fri, Jan 06, 2017 at 08:15:58AM -0700, Jim Fehlig wrote:
On 01/06/2017 01:04 AM, Cedric Bosdonnat wrote:
On Thu, 2017-01-05 at 15:45 -0700, Jim Fehlig wrote:
Cédric Bosdonnat wrote:
libxl doesn't provide a way to write one log for each domain. Thus we need to demux the messages. If our logger doesn't know to which domain to attribute a message, then it will write it to the default log file.
Starting with Xen 4.9 (commit f9858025 and following), libxl will write the domain ID in an easy to grab manner. The logger introduced by this commit will use it to demux the libxl log messages.
One thing I noticed when testing this on a Xen installation prior to that commit is log files are created that will never be written to. E.g. after starting libvirtd and one domain
# ll /var/log/libvirt/libxl/ -rw-r--r-- 1 root root 0 Jan 5 15:48 Domain-0.log -rw-r--r-- 1 root root 17512 Jan 5 15:49 libxl-driver.log -rw-r--r-- 1 root root 0 Jan 5 15:49 sles12sp2-hvm.log
IMO these empty, never-to-be-written-to log files might be a bit confusing to users. AFAIK there is no way to detect up front that the underlying Xen supports this capability right?
No there is no way to know it since there is no public API change in libxl. The only thing we can do is delaying the creation of the file to the first message write.
I think that is a wise thing to do, otherwise I envision bug reports such as "my domain log files are 0 bytes" :-).
Or put some content in them :-)
With the QEMU driver, every single /var/log/libvirt/qemu/$GUEST.log will at least have the QEMU command line arguments, followed by a timestamp showing when it started.
The idea of the CLI args is that it gives an accurate record of the config of the guest from QEMU's POV, which is helpful to support people as you can't be sure the XML you see is the same as the XML when the guest first started. You don't have CLI args for libxl, but perhaps there's some confg you can easily serialize into there.
That's a good idea! libxl_domain_config_to_json() could be used to convert the libxl_domain_config object used at domain creation to json and write it to the domain log file. Regards, Jim
participants (4)
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Cedric Bosdonnat -
Cédric Bosdonnat
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Daniel P. Berrange -
Jim Fehlig