Flannel: Flannel + etcdv3?

[bhouse]

Hi!

I'm wondering what the compatibility of flannel with etcdv3 is? If I upgrade to etcdv3 and migrate the storage backend, will that get used by flannel? When I tried it, there seem to still be two storage backends, one for etcdv2 that flannel uses, and etcdv3 that's empty.

My apologies if this is in the docs/code somewhere, I wasn't able to grep for it. Thanks for all your work on this project!

[mgoodness]

This is a somewhat pressing question with etcd v3 becoming the default store in Kubernetes 1.6. This blog post seems to indicate that the v2 API will keep working after the data has been migrated to v3, but confirmation would be nice.

[tomdee]

Flannel still uses the etcdv2 API. It can still talk to a etcd V3 server and share it will Kubernetes even if kubernetes is using etcdv3.

So it works, but it's not ideal so I would like to update flannel to use etcdv3 when I get a chance.

[chulkilee]

Okay, @tomdee closed #542 mentioning this, so I guess this will be a placeholder for using etcv3.

Although flannel is working with etcv3, I see lots of warning when using etcd behind Amazon ELB since etcdv2 API does not send heart beat (while etcdv3 does). Although it does not break anything (I guess flannel will just reconnect), but it's annoying :)

[tomdee]

Yes, I hear and understand the need for etcdv3 for the heartbeat support.

[ravilr]

Does flannel continue to work even after etcdctl migrate of v2 data to v3 data. @hongchaodeng @xiang90 does migrate keep around v2 data. Can someone confirm, if they have gone through this process. Thanks.

[ravilr]

https://github.com/coreos/etcd/issues/7406 confirms that etcdctl migrate leaves the existing v2 data as-is.

[nesc58]

Is anyone working on this issue? There's huge issue to create backups for v2 (flannel) and v3 (e.g. kubernetes). The clientv3 for etcd is in the official repo. Are there unsolved issues or is this a personal/timing problem to solve this issue in one of the next versions?
And it's right. Flannel still works with etcdv3.

[andyxning]

@nesc58 Seems like flannel has updated the etcd dep version to 3.1.x. @tomdee could you please confirm this?

See #759 for more info.

[tomdee]

That PR just updates the library version - flannel still only works with the etcdv2 API for now

[andyxning]

Any plan to upgrade etcd support to etcd v3? @tomdee

[alapidas]

@tomdee Would there be interest in accepting a contribution that added this feature?

[RuiGuo34]

@tomdee I'd like to know if the latest flannel version v0.9.0 supports etcd v3 now?

[tomdee]

@alapidas yes
@dxdeidara Sorry, it's still not supported

[372046933]

Still not supportted?

[calvix]

Are there any plans for adding support for etcdv3 ever?

[fabifrank]

+1

[robinsondan87]

Kubectl 1.13 will be dropping any support for the v2 api so we need flannel to support the v3 api, are there any plans to introduce this soon as 1.13 is currently in alpha status with a RC due soon.

[unteem]

I'm a bit confused here, can someone confirm that compatibility between flannel and kubernetes 1.13 is broken or it sill works? Thanks

[dannyk81]

@unteem @robinsondan87 FYI --> https://github.com/kubernetes/kubernetes/issues/57354#issuecomment-451679688