GH#35793 Update minimum storage requirements for all providers from 120GB -> 100GB

[codyhoag]

Resolves #35793

Updates were made in the machine requirement section for all providers that specified that table. For example:

• RHEL KVM on IBM Z and LinuxONE machine requirements
• z/VM on IBM Z and LinuxONE machine requirements
• bare metal machine requirements

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[codyhoag]

@miabbott can you verify? Thanks!

[miabbott]

LGTM

[codyhoag]

Due to our docs support policy, this will require several ACKs from stakeholders before merging.

@nstielau @xltian @sferich888 @makentenza @vikram-redhat can you ACK this documentation update for minimum storage requirements for a cluster VM? Thanks!

[vikram-redhat]

LGTM

[sferich888]

ACK (and ill proxy @nstielau via #35793 (comment) and #35793 (comment))

[nstielau]

LGTM, thanks!

[holgwolf]

one comment from Z and LinuxONE side. The documentation above considers the off-prem side of things for KVM. We should change the minimum for all Z related docs including z/VM as well. I appreciate the lower minimum.

[SNiemann15]

I've verified 100 GB also show in the z/VM on IBM Z and LinuxONE machine requirements now.

[makentenza]

LGTM

[holgwolf]

I think we should not have a statement about IOPS for z and LinuxONE since this is not commonly used by our customers.

[codyhoag]

I think we should not have a statement about IOPS for z and LinuxONE since this is not commonly used by our customers.

@nstielau wanted to check with you on this recommendation. Are you OK with hiding the IOPS column for IBM Z and LinuxONE?

[makentenza]

I think we should not have a statement about IOPS for z and LinuxONE since this is not commonly used by our customers.

@nstielau wanted to check with you on this recommendation. Are you OK with hiding the IOPS column for IBM Z and LinuxONE?

Is there any technical reason why a Z or LinuxONE customer should have any issues to satisfy the required IOPS? From my point of view not having a high demand on these platforms is not a reason to avoid these requirements.

[pamoedom]

My 2 cents:

100GB is more than sufficient for a bare minimum installation, some examples:

[IPI AWS]

[root@ip-10-0-141-49 /]# df -h /
Filesystem      Size  Used Avail Use% Mounted on
/dev/nvme0n1p4  100G   12G   89G  12% /

[root@ip-10-0-155-85 /]# df -h /
Filesystem      Size  Used Avail Use% Mounted on
/dev/nvme0n1p4  100G  8.1G   92G   9% /

[UPI BM]

[root@master-00 /]# df -h /
Filesystem      Size  Used Avail Use% Mounted on
/dev/sdc4       112G   14G   98G  13% /

[root@worker-00 /]# df -h /
Filesystem      Size  Used Avail Use% Mounted on
/dev/sda4       224G   15G  209G   7% /

However, please note that IOPS could be critical for ETCD performance and cluster stability, I remember cases in the past where the default type of disks being used had very poor performance (e.g. Azure).

Additional references:

• ETCD backend performance requirements for OpenShift
• OCP 4 - Performance degradation on AZURE

Best Regards.

[holgwolf]

I think we should not have a statement about IOPS for z and LinuxONE since this is not commonly used by our customers.

@nstielau wanted to check with you on this recommendation. Are you OK with hiding the IOPS column for IBM Z and LinuxONE?

Is there any technical reason why a Z or LinuxONE customer should have any issues to satisfy the required IOPS? From my point of view not having a high demand on these platforms is not a reason to avoid these requirements.

There is not a issue to satisfy those requirements - all testing do show no problems on the setup. I do agree that IO bandwidth needs to be available and the setup needs to be done that the required demand is satisfied.

We verify before each release that all requirements are satisfied and would document anything the customer needs to perform to get the correct setup done.

The IOPS metric is just not really used on Z and LinuxONE and if we introduce this to the documentation we would need to tell the customer how they can find out how to verify what IOPS they have. This would mean service questions. Therefore we would need a whole chapter to tell the customer how he can get this verified.

Therefore I suggest keep the model as we have it right now and do not introduce this part of the table for Z and LinuxONE.

[yunjiang29]

@codyhoag confirmed on AWS platform, LGTM.

[jinyunma]

I verified 100G on vSphere platform, it works well.

[makentenza]

@codyhoag can we use this PR to reflect this change as well on the provided templates for UPI deployments? At least for AWS we provide 120 fixed sizes (https://docs.openshift.com/container-platform/4.8/installing/installing_aws/installing-aws-user-infra.html#installation-cloudformation-control-plane_installing-aws-user-infra
) but might be others as well

[codyhoag]

Because the UPI templates are auto-generated from the openshift/installer repo, once the templates are updated there by Engineering, the changes will be reflected in the docs 👍

[codyhoag]

@nstielau can you confirm the action to hide the new IOPS column for IBM Z?
@xltian are there any other verifications this needs from a QE perspective?

[xltian]

@jianlinliu Can you check if we complete all the verification?

[jianlinliu]

Thanks for @pamoedom mentioned IOPS, especially for azure platform, that is really a good point. I totally agree with that. cc @mgahagan73 and @Amoghrd to notice this.

After go through the PR, sound like the minimum requirement does not link to azure install, so I think this PR is safe to merge.

[codyhoag]

@jianlinliu is Azure the only provider you have concerns for these adjustments applying to? We have a follow-up planned to add this table to providers that don't have it (AWS, Azure, GCP). So we'd like to confirm this information is applicable everywhere (or gather what needs to be adjusted per provider).

[jianlinliu]

@codyhoag for gcp/aws/azure, as far as I know, installer do some minimum requirement check when running installation, especially for control-plane, I guess the minimum requirement on those cloud platforms should be aligned with the ones installer required.

[nstielau]

Let's replace the Z IOPS requirement with "N/A". Of course disk performance is still a consideration, but if "iops
isn't the usual metric on Z we can leave it blank. Thanks @holgwolf

[codyhoag]

Thanks, all! I have made the recommended changes. We have all the necessary ACKs to get this merged. I'll wait until EOD tomorrow (EST) and proceed with merging if there are no other comments.

[kalexand-rh]

This looks like it's all rendering right. :) I have a style pick, then it's good to go.

[codyhoag]

/cherrypick enterprise-4.9

[codyhoag]

/cherrypick enterprise-4.8

[codyhoag]

/cherrypick enterprise-4.7

[codyhoag]

/cherrypick enterprise-4.6

[openshift-cherrypick-robot]

@codyhoag: new pull request created: #36523

In response to this:

/cherrypick enterprise-4.9

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.

[openshift-cherrypick-robot]

@codyhoag: #36226 failed to apply on top of branch "enterprise-4.8":

Applying: Update storage requirements for all providers from 120GB -> 100GB
Using index info to reconstruct a base tree...
M	modules/installation-requirements-user-infra.adoc
Falling back to patching base and 3-way merge...
Auto-merging modules/installation-requirements-user-infra.adoc
CONFLICT (content): Merge conflict in modules/installation-requirements-user-infra.adoc
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
Patch failed at 0001 Update storage requirements for all providers from 120GB -> 100GB
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:

/cherrypick enterprise-4.8

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.

[openshift-cherrypick-robot]

@codyhoag: #36226 failed to apply on top of branch "enterprise-4.7":

Applying: Update storage requirements for all providers from 120GB -> 100GB
Using index info to reconstruct a base tree...
M	modules/installation-requirements-user-infra-ibm-z-kvm.adoc
M	modules/installation-requirements-user-infra.adoc
Falling back to patching base and 3-way merge...
Auto-merging modules/installation-requirements-user-infra.adoc
CONFLICT (content): Merge conflict in modules/installation-requirements-user-infra.adoc
Auto-merging modules/installation-requirements-user-infra-ibm-z-kvm.adoc
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
Patch failed at 0001 Update storage requirements for all providers from 120GB -> 100GB
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:

/cherrypick enterprise-4.7

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.

[openshift-cherrypick-robot]

@codyhoag: #36226 failed to apply on top of branch "enterprise-4.6":

Applying: Update storage requirements for all providers from 120GB -> 100GB
Using index info to reconstruct a base tree...
A	modules/installation-requirements-user-infra-ibm-z-kvm.adoc
M	modules/installation-requirements-user-infra.adoc
Falling back to patching base and 3-way merge...
Auto-merging modules/installation-requirements-user-infra.adoc
CONFLICT (content): Merge conflict in modules/installation-requirements-user-infra.adoc
CONFLICT (modify/delete): modules/installation-requirements-user-infra-ibm-z-kvm.adoc deleted in HEAD and modified in Update storage requirements for all providers from 120GB -> 100GB. Version Update storage requirements for all providers from 120GB -> 100GB of modules/installation-requirements-user-infra-ibm-z-kvm.adoc left in tree.
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
Patch failed at 0001 Update storage requirements for all providers from 120GB -> 100GB
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:

/cherrypick enterprise-4.6

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.