CentOS -> Rocky?

[karai17]

With CentOS 8 EOL, is there any consideration to migrate the CentOS 8 docker images over to Rocky Linux? Rocky is meant to be a drop-in replacement for CentOS and they also have official Docker images.

https://hub.docker.com/r/rockylinux/rockylinux

I bring this up because I am suddenly getting errors when trying to create a new docker image using openresty/openresty:centos as a base.

Error: Failed to download metadata for repo 'appstream': Cannot prepare internal mirrorlist: No URLs in mirrorlist

[zhuizhuhaomeng]

@neomantra do you have any plan to upgrade CentOS to Rocky?

[neomantra]

Hi @zhuizhuhaomeng @karai17 I was wondering what the future of RH/CentOS/Fedora would be and it was clear that Centos8 is dead. I am not in that community so have no idea...

So is Rocky Linux what seems to be replacing CentOS going forward? I'm not opposed to Rocky Linux, I just don't know myself and don't want to have to support many CentOS variants here.

[karai17]

Yes, Rocky is the de facto replacement for CentOS. It was even started by the same person who started CentOS back in the day~

RHEL and Fedora themselves are unchanged, but CentOS is sadly dead and Rocky was created and funded explicitly to take its place.

[neomantra]

Thanks for that information. I'll get this going.

Does it make sense to archive the centos flavor? (which is CentOS 8, not centos7)

[karai17]

For postarity, I'd probaby archive centos and transition from centos 8.4 to rocky 8.5 and use the rocky tag going forward, though I am not exactly sure which version of centos 8 this docker image uses. RHEL, CentOS, and Rocky all use the same versioning scheme from RHEL so those versions match up.

[neomantra]

Actually, not that my memory is refreshed, the different CentOS variants (like Amazon Linux) are handled with build flags on the centos Dockerfile, so the new flavor is not a new Dockerfile. However, it looks like Rocky prefers dnf so the fedora Dockerfile works better.

This is what it looks like to DIY (change RESTY_RPM_ARCH to amd64 if needed):

git clone https://github.com/openresty/docker-openresty.git

cd docker-openresty

docker build -f fedora/Dockerfile \
  -t openresty:rocky-8.5 \
  --build-arg RESTY_IMAGE_BASE=rockylinux \
  --build-arg RESTY_IMAGE_TAG=8.5 \
  --build-arg RESTY_YUM_REPO="https://openresty.org/package/rocky/openresty.repo" \
  --build-arg RESTY_RPM_DIST="el8" \
  --build-arg RESTY_RPM_ARCH="aarch64" \
  .

I will add this flavor and push to CI/CD today.

[karai17]

Cool, thanks! Yeah it looks like dnf is meant to finally replace yum with RHEL 8, though I'm sure it'll take until RHEL 9 before yum is deprecated and who knows when it will be removed.

One of the big differences between the variants is that they host their own software repos. openresty:centos correctly updated at some point to use the centos vault, but rocky et al host repos with continued support a la RHEL. I was getting the error in my OP because i had not rebuilt my base image before extending it and so I was trying to pull from the centos repos that no longer existed. rebuilding my image fixed that, but being stuck on software from 2021-12-31 is certainly not ideal.

[neomantra]

@karai17 I am doing the rocky flavor, but I think your original problem is something different. Something with the undecorated centos tag I'm trying to understand.... As you saw, we patch the Centos Repos so I think you might be using an old version (because the centos tag is stale on Docker Hub).

Can you try building your derived image from openresty/openresty:1.21.4.1-0-centos or openresty/openresty:1.19.9.1-12-centos?

[karai17]

Aye, rebuilding fixed my original issue. My stale image was trying to pull from the non-vaulted repo which no longer exists.

[karai17]

RE: using fedora instead of centos as the base

Why not use the actual rockylinux dockerfile as the base instead of fedora?

[neomantra]

There doesn't need to be a specific "rockylinux" Dockerfile because the differences between fedora and rocky are just a few build parameters, so it is easier to maintain. Right now it's basically centos/Dockerfile for YUM-based installs and fedora/Dockerfile for DNF-based installs.

[neomantra]

Available now as image: openresty/openresty:rocky. Will do a tag over the weekend.

[neomantra]

This is released now: openresty/openresty:1.21.4.1-1-rocky.