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0 pointslima6y ago0 comments

Most things on RHEL 7 aren't ancient - there's plenty of backports, even major ones.

Some examples:

- OpenSSL rebase to 1.0.2k (for HTTP/2 support).

- overlayfs2 kernel support.

- Kernel eBPF instrumentation.

- Introduction of podman and friends.

- Ansible is kept up-to-date.

- GCC 7 and Python 3.6 via Software Collections.

This includes extensive testing. I have non-production systems on Fedora which run mainline kernels and have seen my fair share of performance regressions and crashes.

I'm assuming there was no notable customer demand for colorful dmesg output.

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X-Istence6y ago

Some of the backports aren't nearly as fast or performant as using a newer kernel though.

For example eBPF was back ported (and also in CentOS), but running a syscall heavy work-load in a docker container on the older kernel about 50% of the CPU time was spent in the kernel filter.

I ended up moving our entire CI/CD platform to Ubuntu 18.04 and the performance issues went away and my workloads now run at full speed without slowdowns.

RHEL 8 comes with the 4.18 series of the Linux kernel that is already EOL. That's a shame and once again it will fall behind quickly :/

CameronNemo6y ago

Seriously why did they not up it to 4.19? Do they hate bicycles? Do they make money based on the fact that upstream LTS kernels have short shelf lives compared to RHEL's own LTS kernels?

rwmj6y ago

The kernel version was finalized some time before this release when 4.18 was current. Red Hat expends a ton of effort on long term maintenance and huge backports of new features to the kernel, so while I don't want to speak for the kernel team, I don't think the upstream stable kernels bring very much to the table.

Plus (my personal view) what goes into the upstream stable kernel is fairly random based on just mailing list NACKs, whereas what goes into the RH kernel has to pass a massive range of automated tests on a wide variety of real hardware.

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paulcarroty6y ago

> That's a shame and once again it will fall behind quickly

RH use kernel with TONS of patches, so, version isn't critical here.

pas6y ago

Their frankenkernel is very hit and miss, backports or not. Docker had to disable a few features, because at first they seemed to work, but then they were buggy on RHEL.

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VintageCool6y ago

Colorful dmesg output was already available on Cent7, just not the default.

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