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NAME | SYNOPSIS | DESCRIPTION | CONFIGURATION | USAGE | SEE ALSO | NOTES | COLOPHON |
SYSTEMD-COREDUMP(8) systemd-coredump SYSTEMD-COREDUMP(8)
systemd-coredump, systemd-coredump.socket, systemd-coredump@.service
- Acquire, save and process core dumps
/usr/lib/systemd/systemd-coredump
/usr/lib/systemd/systemd-coredump--backtrace
systemd-coredump@.service
systemd-coredump.socket
systemd-coredump@.service is a system service that can acquire core
dumps from the kernel and handle them in various ways. The
systemd-coredump executable does the actual work. It is invoked
twice: once as the handler by the kernel, and the second time in the
systemd-coredump@.service to actually write the data to the journal.
When the kernel invokes systemd-coredump to handle a core dump, it
runs in privileged mode, and will connect to the socket created by
the systemd-coredump.socket unit, which in turn will spawn an
unprivileged systemd-coredump@.service instance to process the core
dump. Hence systemd-coredump.socket and systemd-coredump@.service are
helper units which do the actual processing of core dumps and are
subject to normal service management.
Core dumps can be written to the journal or saved as a file. Once
saved they can be retrieved for further processing, for example in
gdb(1).
By default, systemd-coredump will log the core dump including a
backtrace if possible to the journal and store the core dump itself
in an external file in /var/lib/systemd/coredump.
The behavior of a specific program upon reception of a signal is
governed by a few factors which are described in detail in core(5).
In particular, the core dump will only be processed when the related
resource limits are sufficient.
It is also possible to invoke systemd-coredump with --backtrace
option. In this case, systemd-coredump expects a journal entry in the
journal Journal Export Format[1] on standard input. The entry should
contain a MESSAGE= field and any additional metadata fields the
caller deems reasonable. systemd-coredump will append additional
metadata fields in the same way it does for core dumps received from
the kernel. In this mode, no core dump is stored in the journal.
For programs started by systemd process resource limits can be set by
directive LimitCore=, see systemd.exec(5).
In order to be used by the kernel to handle core dumps,
systemd-coredump must be configured in sysctl(8) parameter
kernel.core_pattern. The syntax of this parameter is explained in
core(5). Systemd installs the file /usr/lib/sysctl.d/50-coredump.conf
which configures kernel.core_pattern accordingly. This file may be
masked or overridden to use a different setting following normal
sysctl.d(5) rules. If the sysctl configuration is modified, it must
be updated in the kernel before it takes effect, see sysctl(8) and
systemd-sysctl(8).
In order to by used in the --backtrace mode, an appropriate backtrace
handler must be installed on the sender side. For example, in case of
python(1), this means a sys.excepthook must installed, see
systemd-coredump-python[2].
The behavior of systemd-coredump itself is configured through the
configuration file /etc/systemd/coredump.conf and corresponding
snippets /etc/systemd/coredump.conf.d/*.conf, see coredump.conf(5). A
new instance of systemd-coredump is invoked upon receiving every core
dump. Therefore, changes in these files will take effect the next
time a core dump is received.
Resources used by core dump files are restricted in two ways.
Parameters like maximum size of acquired core dumps and files can be
set in files /etc/systemd/coredump.conf and snippets mentioned above.
In addition the storage time of core dump files is restricted by
systemd-tmpfiles, corresponding settings are by default in
/usr/lib/tmpfiles.d/systemd.conf.
Data stored in the journal can be viewed with journalctl(1) as usual.
coredumpctl(1) can be used to retrieve saved core dumps independent
of their location, to display information and to process them e.g. by
passing to the GNU debugger (gdb).
coredump.conf(5), coredumpctl(1), systemd-journald.service(8),
systemd-tmpfiles(8), core(5), sysctl.d(5), systemd-sysctl.service(8).
1. Journal Export Format
https://www.freedesktop.org/wiki/Software/systemd/export
2. systemd-coredump-python
https://github.com/keszybz/systemd-coredump-python
This page is part of the systemd (systemd system and service manager)
project. Information about the project can be found at
⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have a bug
report for this manual page, see
⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩. This
page was obtained from the project's upstream Git repository
⟨https://github.com/systemd/systemd.git⟩ on 2017-07-05. If you dis‐
cover any rendering problems in this HTML version of the page, or you
believe there is a better or more up-to-date source for the page, or
you have corrections or improvements to the information in this
COLOPHON (which is not part of the original manual page), send a mail
to man-pages@man7.org
systemd 234 SYSTEMD-COREDUMP(8)
Pages that refer to this page: coredumpctl(1), coredump.conf(5), systemd.directives(7), systemd.index(7), systemd-journald.service(8)