Default config won't work with kubelet 1.16+

[wk8]

kubernetes/kubernetes#80482 added CNI validation to the kubelet, which results in the kubelet choking on the current default config for flannel, with errors along the line of:

Aug 27 23:28:44 wk-k8s kubelet[16814]: W0827 23:28:44.567137   16814 cni.go:202] Error validating CNI config &{cbr0  false [0xc000cb9580 0xc000cb9600] [123 10 32 32 34 110 97 109 101 34 58 32 34 99 98 114 48 34 44 10 32 32 34 112 108 117 103 105 110 115 34 58 32 91 10 32 32 32 
Aug 27 23:28:44 wk-k8s kubelet[16814]: W0827 23:28:44.567244   16814 cni.go:237] Unable to update cni config: no valid networks found in /etc/cni/net.d
Aug 27 23:28:45 wk-k8s kubelet[16814]: E0827 23:28:45.801717   16814 kubelet.go:2182] Container runtime network not ready: NetworkReady=false reason:NetworkPluginNotReady message:docker: network plugin is not ready: cni config uninitialized

Adding a

"cniVersion": "0.3.1"

line to https://github.com/coreos/flannel/blob/ecb6db314e40094a43144b57f29b3ec2164d44c9/Documentation/kube-flannel.yml#L107-L131 or https://github.com/coreos/flannel-cni/blob/master/flannel.conflist.default fixes the issue.

[uniuuu]

Hi Jean Rougé,

I experienced the same issue.
I confirm the fix provided by you above has solved it.

Sep 19 06:33:49 master-1 kubelet[2168]: W0919 06:33:49.140365    2168 cni.go:202] Error validating CNI config &{cbr0  false [0xc000331b00 0xc000331c20] [123 10 32 32 34 110 97 109 101 34 58 32 34 99 98 114 48 34 44 10 32 32 34 112 108 117 103 105 110 115 34 58 32 91 10 32 32 32 32 123 10 32 32 32 32 32 32 34 116 121 112 101 34 58 32 34 102 108 97 110 110 101 108 34 44 10 32 32 32 32 32 32 34 100 101 108 101 103 97 116 101 34 58 32 123 10 32 32 32 32 32 32 32 32 34 104 97 105 114 112 105 110 77 111 100 101 34 58 32 116 114 117 101 44 10 32 32 32 32 32 32 32 32 34 105 115 68 101 102 97 117 108 116 71 97 116 101 119 97 121 34 58 32 116 114 117 101 10 32 32 32 32 32 32 125 10 32 32 32 32 125 44 10 32 32 32 32 123 10 32 32 32 32 32 32 34 116 121 112 101 34 58 32 34 112 111 114 116 109 97 112 34 44 10 32 32 32 32 32 32 34 99 97 112 97 98 105 108 105 116 105 101 115 34 58 32 123 10 32 32 32 32 32 32 32 32 34 112 111 114 116 77 97 112 112 105 110 103 115 34 58 32 116 114 117 101 10 32 32 32 32 32 32 125 10 32 32 32 32 125 10 32 32 93 10 125 10]}: [plugin flannel does not support config version "" plugin portmap does not support config version ""]
Sep 19 06:33:49 master-1 kubelet[2168]: W0919 06:33:49.140577    2168 cni.go:237] Unable to update cni config: no valid networks found in /etc/cni/net.d
Sep 19 06:33:49 master-1 kubelet[2168]: E0919 06:33:49.612844    2168 kubelet.go:2187] Container runtime network not ready: NetworkReady=false reason:NetworkPluginNotReady message:docker: network plugin is not ready: cni config uninitialized

Created pull request flannel-io/flannel#1179

[uniuuu]

Hi @wk8

Please test use of "cniVersion": "0.2.0", as it in the issue flannel-io/flannel#1173

[jethrogb]

I think this can be closed as it is fixed in flannel-io/flannel#1183?