Sync MTU and check MTU valid values #149

w13915984028 · 2025-01-30T10:58:45Z

Problem:

Change of MTU on VlanConfig uplink is not updated to NAD.

Solution:

Check the input MTU on VlanConfig
Update the MTU to labels of ClusterNetwork when change happens
Sync NAD's MTU with the lables of ClusterNetwork when change happens

This solution does not change the APIs and UI, instead it propagates MTU from VlanConfig to ClusterNetwork when change happens; and makes sure all the VlanConfigs under the same ClusterNetwork will have the same MTU.

Related Issue:
harvester/harvester#4355
harvester/harvester#4752

HEP: harvester/harvester#6385
Doc PR: harvester/docs#640

Test plan:

MTU propogation
1.1 Create a clusternetwork
1.2 create a vlanconfig, the MTU from vlanconfig is synced to clusternetwork
1.3 create another vlanconfig, if MTU is different, it is denied by webhook
1.4 create nad, the MTU is inherited from clusternetwork/vlanconfig
Change the MTU of a clusternetwork
2.1 Stop all VMs attached to a specific clusternetwork
2.2 Delete all vlanconfigs until there is a last one; otherwise change MTU from any will be denied per 1.3
2.3 Change the last vlanconfig's MTU, then it is synced to clusternetwork; if there are any NADs attached to this clusternetwork, their MTU is changed automatically
2.4 Add more vlanconfig, each needs to fill the same MTU per 1.3

This way, if user plans to change the MTU of an existing clusternetwork, follow steps 2.

If VM is attached to clusternetwork, it is not allowed to change/delete vlannetwork:

MTU value validation:

Note: network-controller-harvester lacks many test code, need additional effort to add them, will add later.

w13915984028 · 2025-01-30T19:14:14Z

@mergify backport v0.5.x v0.6.x

mergify · 2025-01-30T19:14:18Z

backport v0.5.x v0.6.x

🟠 Waiting for conditions to match

merged [📌 backport requirement]

Signed-off-by: Jian Wang <jian.wang@suse.com>

ibrokethecloud · 2025-01-31T04:54:46Z

pkg/webhook/vlanconfig/validator.go

@@ -264,8 +270,8 @@ func (v *Validator) validateMTU(current *networkv1.VlanConfig) error {
 		if vc.Name == current.Name {


would it make sense to change it to just fetch the related cluster object crd and check the MTU from there?

A few considerations:

The current code has assumption that the clusternetwork may be created behind the vlanconfig, for logacy or other reasons

network-controller-harvester/pkg/controller/manager/vlanconfig/controller.go

Line 86 in ce3dd94

func (h Handler) ensureClusterNetwork(name string) error {

The MTU is synced to clusternetwork as a label, in extreme cases, if user hack it with an invalid value, the check may miss.

Signed-off-by: Jian Wang <jian.wang@suse.com>

rrajendran17 · 2025-02-03T07:04:04Z

Few points
1.Similar to vms,if MTU is updated after storage network configuration, it will be propagated to storage network nad, but LH pods interfaces will not have updated the new MTU.
A webhook check in needed to prevent updating the MTU when storage network is configured. The user has to disable storage network config before MTU change and enable storage network configuration after a new MTU change.
2.In case of storage network, the vlan network under the vlan config also has to be deleted if vlan config has to be deleted for any mismatch in MTU cases.Just a point to be noted while adding test cases.
3.Good to include a manual traffic test after MTU change in the test plan(either between VMs or LH pods with jumbo frames)

Signed-off-by: Jian Wang <jian.wang@suse.com>

w13915984028 · 2025-02-03T20:43:07Z

@rrajendran17 Thanks, the storagenetwork related cases need some additional processing, I will add.

rrajendran17 · 2025-02-03T21:47:16Z

pkg/controller/manager/nad/controller.go

 	return nil
 }

+// Sync cluster network MTU value to all attached NADs


Why not including this change during cluster network change inside pkg/controller/manager/clusternetwork/controller.go ?

rrajendran17 · 2025-02-03T21:53:55Z

pkg/utils/consts.go

+const (
+	DefaultMTU = 1500
+	MaxMTU     = 9000
+	MinMTU     = 1280 // IPv4 does not define this; IPv6 defines 1280; Harvester adopts it for both


IIUC, IPv4 defines 576 bytes as minimum MTU.

rrajendran17 · 2025-02-03T22:08:36Z

pkg/webhook/clusternetwork/validator.go

+			}
+			if mtu != oldMtu {
+				return fmt.Errorf(updateErr, newCn.Name, fmt.Errorf("label %v can't be updated", utils.KeyUplinkMTU))
+			}


Above two checks could be combined.

rrajendran17 · 2025-02-03T22:10:27Z

pkg/webhook/clusternetwork/validator_test.go

+		},
+		{
+			name:      "user can't add the MTU label",
+			returnErr: false,


since it will return error, returnErr should be true and errKey has error value.

rrajendran17 · 2025-02-03T22:15:38Z

pkg/webhook/clusternetwork/validator_test.go

+			},
+		},
+		{
+			name:      "ClusterNetwork is allowed to be deleted",


can you enhance the description ?

rrajendran17 · 2025-02-03T22:44:52Z

pkg/webhook/vlanconfig/validator_test.go

+
+		})
+	}
+}


If possible, can you also add unit tests for checking running vms and storage network nad configured when updating/deleting vlanconfigs ?

rrajendran17 · 2025-02-03T22:47:29Z

I also noticed,currently we do not have min-max MTU check in UI, we need to create a GH issue to add those changes to UI as well.

w13915984028 force-pushed the enh4355 branch 3 times, most recently from 3e4beb5 to dd3a7dc Compare January 30, 2025 14:19

w13915984028 mentioned this pull request Jan 30, 2025

Sync MTU and check MTU valid values #116

Closed

w13915984028 force-pushed the enh4355 branch 3 times, most recently from a76ad1e to db70af5 Compare January 30, 2025 18:15

w13915984028 requested review from rrajendran17, ihcsim and ibrokethecloud January 30, 2025 18:19

w13915984028 mentioned this pull request Jan 30, 2025

[ENHANCEMENT] Support configure MTU in the cluster network harvester/harvester#4355

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Sync MTU and check MTU valid values

1ae64ce

Signed-off-by: Jian Wang <jian.wang@suse.com>

w13915984028 force-pushed the enh4355 branch from db70af5 to 1ae64ce Compare January 30, 2025 19:15

ibrokethecloud reviewed Jan 31, 2025

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w13915984028 force-pushed the enh4355 branch 2 times, most recently from 5b393ff to dd757ea Compare January 31, 2025 08:26

Add vlanconfig validator test code

2a7d6a8

Signed-off-by: Jian Wang <jian.wang@suse.com>

w13915984028 force-pushed the enh4355 branch from dd757ea to 2a7d6a8 Compare January 31, 2025 08:28

Add clusternetwork test code

9df6c7c

Signed-off-by: Jian Wang <jian.wang@suse.com>

w13915984028 force-pushed the enh4355 branch 2 times, most recently from fd2db83 to 560c8b7 Compare January 31, 2025 08:55

Add nad validator test code

ce8ac01

Signed-off-by: Jian Wang <jian.wang@suse.com>

w13915984028 force-pushed the enh4355 branch from 560c8b7 to ce8ac01 Compare January 31, 2025 09:50

Enhance the validating on clusternetwork

201ce24

Signed-off-by: Jian Wang <jian.wang@suse.com>

w13915984028 force-pushed the enh4355 branch from 3c9c54c to 201ce24 Compare February 3, 2025 20:31

w13915984028 requested review from starbops and ibrokethecloud February 3, 2025 20:41

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Sync MTU and check MTU valid values #149

Sync MTU and check MTU valid values #149

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		@@ -264,8 +270,8 @@ func (v Validator) validateMTU(current networkv1.VlanConfig) error {
		if vc.Name == current.Name {

Sync MTU and check MTU valid values #149

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Sync MTU and check MTU valid values #149

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