systemd version the issue has been seen with

$ systemctl --version
systemd 238
+PAM +AUDIT +SELINUX +IMA -APPARMOR +SMACK -SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT -GNUTLS -ACL +XZ +LZ4 +SECCOMP +BLKID -ELFUTILS +KMOD -IDN2 -IDN +PCRE2 default-hierarchy=legacy

Used distribution

$ cat /etc/os-release
NAME="Container Linux by CoreOS"
ID=coreos
VERSION=2023.4.0
# ...

Expected behaviour you didn't see
systemd-journald memory usage to be reasonable low.

Unexpected behaviour you saw
systemd-journald memory usage grows without bound until the unit is restarted. At the diagram you see that systemd-journald with CoreOS 2023.4.0 used 5.71GiB memory before restart of the unit.

On the other hand, the same config with CoreOS 1855.4.0 has reasonable memory usage - around ~10MiB.

Steps to reproduce the problem

1. Create a CoreOS 2023.4.0 node with docker, kubelet, ...
2. Ensure that systemd-journald has a very high memory usage that breaks another components such as kubelet.