Enabling systemd-coredump by default is from the perspective of ABRT the biggest change in Fedora 26.

How ABRT works?

There is a service abrt-ccpp.service which runs /usr/sbin/abrt-install-ccpp-hook install that causes ABRT’s kernel.core_pattern hook to be installed. What it basically does is that it saves current kernel.core_pattern to /var/run/abrt/saved_core_pattern and replaces it with string |/usr/libexec/abrt-hook-ccpp %s %c %p %u %g %t %P %I. This causes that all coredumps are processed by ABRT’s hook which by default dumps core into ABRT’s problem directories which are created in /var/spool/abrt. After processing is finished you can use abrt command line tool for further analysis (remote backtrace generating, run GDB against the problem, print information about the problem and so on). For more information about the tool see man abrt.

How will ABRT work in Fedora 26?

abrt-ccpp.service won’t be enabled so default kernel.core_pattern won’t be replaced by ABRT’s one. It means, coredumps will be processed by systemd-coredump and metadata about coredumps will be stored in the systemd journal. The abrt-ccpp.service service will be replaced by abrt-journal-core.service. This service extracts coredumps and other important information about problems from systemd journal.

How does it affect ABRT users?

ABRT users shouldn’t experience any changes. Problem directories will be still created in /var/spool/abrt and all will work like in older Fedoras. If users want to use ABRT’s hook instead of the systemd one they can easily disable abrt-journal-core.service and enable abrt-ccpp.service by running following commands:

# systemctl disable abrt-journal-core.service
# systemctl stop abrt-journal-core.service
# systemctl enable abrt-ccpp.service
# systemctl start abrt-ccpp.service