Consider moving from Centos7 to RHEL8 for 18.x

[AshCripps]

Whilst looking at #2740 ive discovered that Centos7 goes EOL by the end of 18.x, so we should consider moving off of centos7 before 18.x is cut next year.

A suitable option would be to upgrade to RHEL8 - Red Hat is providing a scheme for open source communities to gain free access to RHEL subscriptions but wanted to pose the question to the wider group to see if anyone had any objections?

cc @nodejs/build

[richardlau]

@AshCripps I don’t think we have enough ppc Linux hosts for both CentOS7 (existing workloads) and the next (e.g. RHEL8).

[AshCripps]

we are nowhere near our capacity for ppc linux machines atm (provided we are allowed to use everything given to us)

[mhdawson]

Confirming @AshCripps assessment that we should have no problem adding more ppc machines. We should look at the same for other architectures as well.

Either way I think it's something we have to figure out as I don't think we want to be building on an EOL Operating system. One of the main concerns is that it will main an increase in the minimum glibc levels...

[richardlau]

One thing we'd need to check for the x64 platforms is what is offered on the various cloud providers and if RHEL 8 is an out of the box offering (i.e. existing selectable image).

[richardlau]

Provider	RHEL 8 image available
DigitalOcean	No
IBM Cloud	Yes ( * Redhat / EL / 8.0-64 Minimal for VSI)
RackSpace	No

DigitalOcean

IBM Cloud

RackSpace

[richardlau]

So it looks like currently only IBM offer an OOTB RHEL image (of any version). On DigitalOcean we can use custom images but that's going to be some work to set up. Or we run RHEL in a container via Docker under a different host OS.

[AshCripps]

I assume all the other OS are free version? RHEL probably doesnt show up as it requires a subscription

[richardlau]

I've started adding RHEL8 s390x (LinuxONE) in #2859.

I've also requested a no-cost RHEL subscription under the Red Hat for Open Source Infrastructure program. We've had a positive response and this is in progress -- I was asked to create a Red Hat account to attach the entitlements to and I have created the account (details in the secrets repo) and am waiting for the entitlements.