When running in ipvs mode, unable to update kube-proxy to 1.15

[lbernail]

What happened:
When updating to 1.15 in IPVS mode, kube-proxy fails to start

What you expected to happen:
kube-proxy updates ok

How to reproduce it (as minimally and precisely as possible):
Deploy kube-proxy <1.15 in ipvs mode and update to 1.15

Anything else we need to know?:
Error message in kube-proxy:

E0430 10:05:53.783443       1 ipset.go:162] Failed to make sure ip set: &{{KUBE-NODE-PORT-LOCAL-SCTP hash:ip,port inet 1024 65536 0-65535 Kubernetes nodeport SCTP port with externalTrafficPolicy=local} map[] 0xc00032e830} exist, error: error creating ipset KUBE-NODE-PORT-LOCAL-SCTP, error: exit status 1

I think the reason is the change of ipset type (bitmap to hash) in PR #74341. The 2 sets that creates the problem are:

• KUBE-NODE-PORT-SCTP
• KUBE-NODE-PORT-LOCAL-SCTP

Removing the sets manually works but is not a great solution for in-place updates.
I think we should fix this before the 1.15 release (not sure what the best approach is: delete the set if it exists with the wrong type? Use a different name to avoid the collision?)

Environment:

• Kubernetes version (use kubectl version): 1.14 => 1.15
• Cloud provider or hardware configuration: AWS
• OS (e.g: cat /etc/os-release): ubuntu 18.04
• Kernel (e.g. uname -a): 4.4

/sig network
/area ipvs
/assign @m1093782566

[athenabot]

/triage unresolved

Comment /remove-triage unresolved when the issue is assessed and confirmed.

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[andrewsykim]

Great catch! Looks like a breaking change. One solution like you mentioned is to add support for replacing ipsets in pkg/util/ipset if a similar ipset already exists? Thoughts @m1093782566?

[andrewsykim]

I noticed we pass in -exists for ipsets but that only checks for identical ipset types. Maybe pkg/util/ipset needs to be smarter and do a full diff

[andrewsykim]

Use a different name to avoid the collision?)

This could work as well 🤔

[andrewsykim]

Opened a fix for it here #77371, let's chat there :)

[athenabot]

@m1093782566 @andrewsykim
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[andrewsykim]

/remove-triage unresolved