On Sat, Apr 13, 2019 at 01:32:11AM -0700, Kenneth Porter wrote:
I reboot when I yum update to a new kernel or systemd, which seems to come out about once a month. Should I do it for this week's glibc? Is that "core" enough to justify a reboot or should I wait for the next kernel update? I know the glibc update was mainly to handle the new Japanese calendar, so that shouldn't affect my usage. So my question is more about how shared libraries work and whether anything bad would happen with different forks of running services (mainly the mail suite with dovecot and the various content scanners launched by sendmail) running different versions of the library based on when they were started.
As a general rule we recommend that you reboot after updates for the kernel, glibc, ssh/openssl and systemd due to a lingering bug that breaks connectivity to dbus.
Rebooting activates the new kernel and as almost all of our kernel updates are security updates it's quite highly recommended to do so.
systemd has a lingering bug where it loses connectivity to dbus during a daemon restart and it doesn't get it back. Rebooting is the only method (at least that I am aware of) that addresses this.
ssh/openssl are always security updates, you really want to reboot to ensure everything is running off the new libraries.
We have seen odd issues with glibc updates without reboots that have cleared up after reboot; from memory I think they were locale issues but don't quote me on that. Considering how integral glibc is to the entire system you are strongly urged to reboot after said updates.
John