Fix releasever to 7 for RHEL and CentOS in yum docker repository

[irozzo-1A]

What this PR does / why we need it:
Recently docker introduced docker-ce repository for CentOS 8 it only contains docker version 19.03.13-3. This caused a regression when using RHEL/CentOS 8, because previously we were using CentOS 7 repo indistinctly for CentOS/RHEL 7/8 but now the docker versions we were installing are no longer available in CentOS 8 repo.

As we do not have OS versioning yet the quick and dirty solution is to always use CentOS 7 repo for the docker versions that are not available on both repos.

https://download.docker.com/linux/centos/8/x86_64/stable/Packages/
https://download.docker.com/linux/centos/7/x86_64/stable/Packages/

Which issue(s) this PR fixes (optional, in fixes #<issue number> format, will close the issue(s) when PR gets merged):
Fixes #

Special notes for your reviewer:

Optional Release Note:

Fix docker installation for CentOS/RHEL 8 

[kron4eg]

It's impossible to deduct CentOS release from the kubelet version, this logic is flawed.

For now I propose to patch .repo unconditionally, once we have somehow figured out OS versioning we could return to this part.

[irozzo-1A]

It's impossible to deduct CentOS release from the kubelet version, this logic is flawed.

For now I propose to patch .repo unconditionally, once we have somehow figured out OS versioning we could return to this part.

@kron4eg I'm not deducing the CentOS release from the kubelet version, I'm unconditionally patching the repo for docker versions that are not present in both CentOS 7 and 8 repos, that is all but 19.03.13-3. The problem is that kubernetes versions previous to 1.17 do not work with this docker version.

[kron4eg]

versions that are not present in both CentOS 7 and 8 repos, that is all but 19.03.13-3.

[root@bc944ddd6770 ~]# yum install docker-ce-${DOCKER_VERSION} docker-ce-cli-${DOCKER_VERSION} Failed to set locale, defaulting to C.UTF-8 Last metadata expiration check: 0:01:02 ago on Thu Sep 24 20:00:30 2020. Dependencies resolved. ================================================================================ Package Arch Version Repository Size ================================================================================ Installing: docker-ce x86_64 3:19.03.13-3.el7 docker-ce-stable 24 M docker-ce-cli x86_64 1:19.03.13-3.el7 docker-ce-stable 38 M

This is with patched .repo file. Latest an greatest 19.03.13 in $releasever=7 repo.

[irozzo-1A]

This is with patched .repo file. Latest an greatest 19.03.13 in $releasever=7 repo.

I'm not sure to understand your point, let me try to explain my logic again.

At the moment 19.03.13 is the only version that is present on both centos 7 and 8 repos (it's also the only version present in centos 8 docker stable repo). It is preferable and safer to to use the appropriate repo instead of enforcing centos 7 when we can use such version, that is for k8s versions >= 1.17.

Unfortunately k8s versions < 1.17 do not support docker versions more recent than 18.06, in those cases we are obliged to use centos 7 repo.

[kron4eg]

My point is that we have everything what we need in centos/7 repo, we don't need any guessing and please always patch the .repo file. We will do the proper fix once we decided on OS versioning.

[xrstf]

When there are no downsides to always using the repo for 7, I would prefer the simpler solution. It doesn't introduce a preliminary OS versioning hack that we would have to revert later on.

[irozzo-1A]

@xrstf Well using the repository for another version and doing a hack for installing docker is something I consider a downside.

It's true that it is slightly more complex, but has the benefit of using the appropriate repository for all k8s versions >= 1.17 and it's already implemented.

What kind of risks you foresee with this approach?

[xmudrii]

I agree with @xrstf and @kron4eg. I'd prefer that we keep it simple and just use the CoreOS7 repo for both versions until we don't get the OS versioning.

[irozzo-1A]

@xrstf @kron4eg As the consensus is to always use the centos7 repo I will conform to it. I don't fully understand the logic behind this position, but this has to be fixed soon.

[xrstf]

/approve

[kubermatic-bot]

LGTM label has been added.

Git tree hash: e22dbed172348a3149c8f41af1373013cffae0e6

[kubermatic-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: irozzo-1A, xrstf

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [irozzo-1A,xrstf]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[irozzo-1A]

/cherry-pick release/v1.14

[kubermatic-bot]

@irozzo-1A: #826 failed to apply on top of branch "release/v1.14":

Applying: Fix releasever to 7 for RHEL and CentOS in yum docker repository Using index info to reconstruct a base tree... M	pkg/userdata/centos/provider.go M	pkg/userdata/centos/testdata/kubelet-v1.15-aws.yaml M	pkg/userdata/centos/testdata/kubelet-v1.16-aws.yaml M	pkg/userdata/centos/testdata/kubelet-v1.17-aws-external.yaml M	pkg/userdata/centos/testdata/kubelet-v1.17-aws.yaml M	pkg/userdata/centos/testdata/kubelet-v1.17-vsphere-mirrors.yaml M	pkg/userdata/centos/testdata/kubelet-v1.17-vsphere-proxy.yaml M	pkg/userdata/centos/testdata/kubelet-v1.17-vsphere.yaml M	pkg/userdata/rhel/provider.go M	pkg/userdata/rhel/testdata/kubelet-v1.15-aws.yaml M	pkg/userdata/rhel/testdata/kubelet-v1.16-aws.yaml M	pkg/userdata/rhel/testdata/kubelet-v1.17-aws-external.yaml M	pkg/userdata/rhel/testdata/kubelet-v1.17-aws.yaml M	pkg/userdata/rhel/testdata/kubelet-v1.17-vsphere-mirrors.yaml M	pkg/userdata/rhel/testdata/kubelet-v1.17-vsphere-proxy.yaml M	pkg/userdata/rhel/testdata/kubelet-v1.17-vsphere.yaml Falling back to patching base and 3-way merge... Auto-merging pkg/userdata/rhel/testdata/kubelet-v1.17-vsphere.yaml CONFLICT (content): Merge conflict in pkg/userdata/rhel/testdata/kubelet-v1.17-vsphere.yaml Auto-merging pkg/userdata/rhel/testdata/kubelet-v1.17-vsphere-proxy.yaml CONFLICT (content): Merge conflict in pkg/userdata/rhel/testdata/kubelet-v1.17-vsphere-proxy.yaml Auto-merging pkg/userdata/rhel/testdata/kubelet-v1.17-vsphere-mirrors.yaml CONFLICT (content): Merge conflict in pkg/userdata/rhel/testdata/kubelet-v1.17-vsphere-mirrors.yaml Auto-merging pkg/userdata/rhel/testdata/kubelet-v1.17-aws.yaml CONFLICT (content): Merge conflict in pkg/userdata/rhel/testdata/kubelet-v1.17-aws.yaml Auto-merging pkg/userdata/rhel/testdata/kubelet-v1.17-aws-external.yaml CONFLICT (content): Merge conflict in pkg/userdata/rhel/testdata/kubelet-v1.17-aws-external.yaml Auto-merging pkg/userdata/rhel/testdata/kubelet-v1.16-aws.yaml CONFLICT (content): Merge conflict in pkg/userdata/rhel/testdata/kubelet-v1.16-aws.yaml Auto-merging pkg/userdata/rhel/testdata/kubelet-v1.15-aws.yaml CONFLICT (content): Merge conflict in pkg/userdata/rhel/testdata/kubelet-v1.15-aws.yaml Auto-merging pkg/userdata/rhel/provider.go CONFLICT (content): Merge conflict in pkg/userdata/rhel/provider.go Auto-merging pkg/userdata/centos/testdata/kubelet-v1.17-vsphere.yaml CONFLICT (content): Merge conflict in pkg/userdata/centos/testdata/kubelet-v1.17-vsphere.yaml Auto-merging pkg/userdata/centos/testdata/kubelet-v1.17-vsphere-proxy.yaml CONFLICT (content): Merge conflict in pkg/userdata/centos/testdata/kubelet-v1.17-vsphere-proxy.yaml Auto-merging pkg/userdata/centos/testdata/kubelet-v1.17-vsphere-mirrors.yaml CONFLICT (content): Merge conflict in pkg/userdata/centos/testdata/kubelet-v1.17-vsphere-mirrors.yaml Auto-merging pkg/userdata/centos/testdata/kubelet-v1.17-aws.yaml CONFLICT (content): Merge conflict in pkg/userdata/centos/testdata/kubelet-v1.17-aws.yaml Auto-merging pkg/userdata/centos/testdata/kubelet-v1.17-aws-external.yaml CONFLICT (content): Merge conflict in pkg/userdata/centos/testdata/kubelet-v1.17-aws-external.yaml Auto-merging pkg/userdata/centos/testdata/kubelet-v1.16-aws.yaml CONFLICT (content): Merge conflict in pkg/userdata/centos/testdata/kubelet-v1.16-aws.yaml Auto-merging pkg/userdata/centos/testdata/kubelet-v1.15-aws.yaml CONFLICT (content): Merge conflict in pkg/userdata/centos/testdata/kubelet-v1.15-aws.yaml Auto-merging pkg/userdata/centos/provider.go CONFLICT (content): Merge conflict in pkg/userdata/centos/provider.go error: Failed to merge in the changes. hint: Use 'git am --show-current-patch=diff' to see the failed patch Patch failed at 0001 Fix releasever to 7 for RHEL and CentOS in yum docker repository When you have resolved this problem, run "git am --continue". If you prefer to skip this patch, run "git am --skip" instead. To restore the original branch and stop patching, run "git am --abort". 

In response to this:

/cherry-pick release/v1.14

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.