Description of problem:

On RHEL8, the coredump naming in /var/lib/systemd/coredump is hardcoded to "core.<COMM>.<UID>.<bootid>.<PID>.<TS>000000"

This needs to be enhanced to let the admin name the coredumps as he needs to, typically adding the <HOSTNAME> (hostname or container name), which is initially available when systemd-coredump executes through kernel.core_pattern.

This would help a lot analyzing OCP issues for examples.

Version-Release number of selected component (if applicable):

systemd-239 but also Upstream (looks like at least, from reading the code)

How reproducible:

ALWAYS

Steps to Reproduce:
1. Create a miniroot to execute "bash"

-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------

1. yum -y install --installroot=/tmp/test --releasever=/ bash
   • • • • • • • 8< ---------------- 8< ---------------- 8< ---------------- 8< --------

2. Spawn a container and crash bash in the container

-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------

1. systemd-nspawn -D /tmp/test bash
   Spawning container test on /tmp/test.
   Press ^] three times within 1s to kill container.

bash-4.4# ulimit -c unlimited
bash-4.4# function foo {
foo
}
bash-4.4# foo
Container test terminated by signal SEGV.
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------

3. Check the core filename (it doesn't show the container name, which would be useful)

Actual results:

------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------

1. ls /var/lib/systemd/coredump
   core.bash.0.33efdaea7a3c4cce86184cbbb6c28368.2343.1605715274000000
   • • • • • • • 8< ---------------- 8< ---------------- 8< ---------------- 8< --------

Expected results:

Some custom naming based on available properties