Kubernetes 1.12 and flannel does not work out of the box

[outcoldman]

Seems like a new behavior with kubeadm, after I created a master, I see two taints on the master node:

Taints:             node-role.kubernetes.io/master:NoSchedule
                    node.kubernetes.io/not-ready:NoSchedule

But https://raw.githubusercontent.com/coreos/flannel/v0.10.0/Documentation/kube-flannel.yml has toleration only to

- key: node-role.kubernetes.io/master
        operator: Exists
        effect: NoSchedule

I added a toleration to kube-flannel.yml to solve the issue:

      - key: node-role.kubernetes.io/master
        operator: Exists
        effect: NoSchedule
      - key: node.kubernetes.io/not-ready
        operator: Exists
        effect: NoSchedule

Expected Behavior

The docs should work with flannel out of the box
https://kubernetes.io/docs/setup/independent/create-cluster-kubeadm/

Current Behavior

Possible Solution

Maybe instead it should use a toleration without a key?

tolerations:
        - effect: NoSchedule
          operator: Exists

Steps to Reproduce (for bugs)

1. Bootstrap master node with kubeadm
2. Apply as suggested https://raw.githubusercontent.com/coreos/flannel/v0.10.0/Documentation/kube-flannel.yml from the docs.

Context

Your Environment

• Flannel version: v0.10.0
• Backend used (e.g. vxlan or udp):
• Etcd version:
• Kubernetes version (if used): 1.12
• Operating System and version: Linux master1 4.4.0-134-generic #160-Ubuntu SMP Wed Aug 15 14:58:00 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux, "Ubuntu 16.04.5 LTS"
• Link to your project (optional):

[geerlingguy]

I can confirm as well—on 1.11.3 the configuration applies correctly. On 1.12.0 it does not.

[Balonno]

usign the toleration without a key worked for me. Would this be the solution?

[caseydavenport]

usign the toleration without a key worked for me. Would this be the solution?

That sounds fine to me - flannel should probably tolerate all NoSchedule taints, since it's a critical piece of infrastructure.

Anyone want to submit a PR?

[outcoldman]

@caseydavenport I have submitted PR against master https://github.com/coreos/flannel/pull/1045/files

But it will be good to have the same fix for the tag v0.10.0, considering that in a lot of places there is a reference to this path https://raw.githubusercontent.com/coreos/flannel/v0.10.0/Documentation/kube-flannel.yml

Considering that this is just a configuration change, maybe make a release v0.10.1 and update the Kubernetes documentation?

[jmyung]

thanks @outcoldman. it helps :)

[adhipati-blambangan]

thanks @outcoldman ! it works like a charm. ;)

[mauilion]

Flannel should probably set

tolerations:
        - operator: Exists

as the default tolerations set. This will ensure that the flannel ds tolerates all taints.

[ReSearchITEng]

For anyone willing to test the flannel fix for 1.12 ,
kubectl -n kube-system apply -f https://raw.githubusercontent.com/coreos/flannel/bc79dd1505b0c8681ece4de4c0d86c5cd2643275/Documentation/kube-flannel.yml

[NerdyShawn]

For anyone willing to test the flannel fix for 1.12 ,
kubeadm -n kube-system apply -f https://raw.githubusercontent.com/coreos/flannel/bc79dd1505b0c8681ece4de4c0d86c5cd2643275/Documentation/kube-flannel.yml

#trying on a pi2 b+ master
`HypriotOS/armv7: root@piNode01 in ~

kubeadm -n kube-system apply -f https://raw.githubusercontent.com/coreos/flannel/bc79dd1505b0c8681ece4de4c0d86c5cd2643275/Documentation/kube-flannel.yml

Error: unknown command "apply" for "kubeadm"
Run 'kubeadm --help' for usage.
error: unknown command "apply" for "kubeadm"
`

[cablespaghetti]

Try with kubectl rather than kubeadm. I think that was a typo. Unfortunately I don't have a 1.12 cluster at the moment. I'll test this when I do though.

…

On Fri, 5 Oct 2018, 16:25 NerdyShawn, ***@***.***> wrote: For anyone willing to test the flannel fix for 1.12 , kubeadm -n kube-system apply -f https://raw.githubusercontent.com/coreos/flannel/bc79dd1505b0c8681ece4de4c0d86c5cd2643275/Documentation/kube-flannel.yml #trying on a pi2 b+ master `HypriotOS/armv7: ***@***.***Node01 in ~ kubeadm -n kube-system apply -f https://raw.githubusercontent.com/coreos/flannel/bc79dd1505b0c8681ece4de4c0d86c5cd2643275/Documentation/kube-flannel.yml Error: unknown command "apply" for "kubeadm" Run 'kubeadm --help' for usage. error: unknown command "apply" for "kubeadm" ` — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#1044 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AKoi5ounjV64Fz2gZD0SGvXbTrK-4JHxks5uh3nagaJpZM4W9xBu> .

[rberg2]

Hello,
I can confirm this fixes flannel on my 1.12 test cluster. https://raw.githubusercontent.com/coreos/flannel/bc79dd1505b0c8681ece4de4c0d86c5cd2643275/Documentation/kube-flannel.yml

[NerdyShawn]

So that got me closer, but still no dice, here is the docker output the apiserver container seems no bueno. Sorry I'm struggling with text formatting so here is the screenshot.

[cablespaghetti]

Hi @NerdyShawn,

I don't think you've got your kubectl configured correctly to connect to your cluster. As it seems like @rberg2 has managed to get this working, maybe it would be good to continue this on one of the support channels like slack rather than this issue.

[ReSearchITEng]

Sorry, it was a typo, it's kubectl.

For those interested, k8s 1.12 deployment with all the goodies (ingress, dashboard, optional vsphere*, etc) automated with ansible and maintained here: github.com/ReSearchITEng/kubeadm-playbook/
The above has been scripted there as well.

[tallaxes]

@ReSearchITEng, confirm works (1.12.1).
The link to ansible playbook is broken.

[hegdedarsh]

Hello,
Even with the tolerations, it still says , i used the below link to run the flannel

https://raw.githubusercontent.com/coreos/flannel/bc79dd1505b0c8681ece4de4c0d86c5cd2643275/Documentation/kube-flannel.yml

Please find the output of the pods:-

[user@darshan-p-hegde-89ca8c531 ~]$ kubectl get pods -n kube-system
NAME READY STATUS RESTARTS AGE
coredns-576cbf47c7-9r27x 0/1 ContainerCreating 0 6m
coredns-576cbf47c7-qc4tm 0/1 ContainerCreating 0 6m
etcd-darshan-p-hegde-89ca8c531.mylabserver.com 1/1 Running 0 4m54s
kube-apiserver-darshan-p-hegde-89ca8c531.mylabserver.com 1/1 Running 0 5m2s
kube-controller-manager-darshan-p-hegde-89ca8c531.mylabserver.com 1/1 Running 0 5m2s
kube-flannel-ds-amd64-gm5z7 0/1 CrashLoopBackOff 5 4m56s
kube-proxy-mbtcj 1/1 Running 0 6m
kube-scheduler-darshan-p-hegde-89ca8c531.mylabserver.com 1/1 Running 0 5m13s

I have described the flannel pod and and the output is below:-

Name: kube-flannel-ds-amd64-gm5z7
Namespace: kube-system
Priority: 0
PriorityClassName:
Node: darshan-p-hegde-89ca8c531.mylabserver.com/172.31.42.12
Start Time: Sun, 07 Oct 2018 06:37:31 +0000
Labels: app=flannel
controller-revision-hash=6697bf5fc6
pod-template-generation=1
tier=node
Annotations:
Status: Running
IP: 172.31.42.12
Controlled By: DaemonSet/kube-flannel-ds-amd64
Init Containers:
install-cni:
Container ID: docker://b085e4a7d80b26730dc795d4a72b8a278ddc4ba71e5c463bfcd0172b793de349
Image: quay.io/coreos/flannel:v0.10.0-amd64
Image ID: docker-pullable://quay.io/coreos/flannel@sha256:88f2b4d96fae34bfff3d46293f7f18d1f9f3ca026b4a4d288f28347fcb6580ac
Port:
Host Port:
Command:
cp
Args:
-f
/etc/kube-flannel/cni-conf.json
/etc/cni/net.d/10-flannel.conflist
State: Terminated
Reason: Completed
Exit Code: 0
Started: Sun, 07 Oct 2018 06:37:33 +0000
Finished: Sun, 07 Oct 2018 06:37:33 +0000
Ready: True
Restart Count: 0
Environment:
Mounts:
/etc/cni/net.d from cni (rw)
/etc/kube-flannel/ from flannel-cfg (rw)
/var/run/secrets/kubernetes.io/serviceaccount from flannel-token-llwn4 (ro)
Containers:
kube-flannel:
Container ID: docker://a8096a56009a0566b53e4b0aac09430b75120979e63dbe32eb8ed91053666a77
Image: quay.io/coreos/flannel:v0.10.0-amd64
Image ID: docker-pullable://quay.io/coreos/flannel@sha256:88f2b4d96fae34bfff3d46293f7f18d1f9f3ca026b4a4d288f28347fcb6580ac
Port:
Host Port:
Command:
/opt/bin/flanneld
Args:
--ip-masq
--kube-subnet-mgr
State: Waiting
Reason: CrashLoopBackOff
Last State: Terminated
Reason: Error
Exit Code: 1
Started: Sun, 07 Oct 2018 06:43:46 +0000
Finished: Sun, 07 Oct 2018 06:43:48 +0000
Ready: False
Restart Count: 6
Limits:
cpu: 100m
memory: 50Mi
Requests:
cpu: 100m
memory: 50Mi
Environment:
POD_NAME: kube-flannel-ds-amd64-gm5z7 (v1:metadata.name)
POD_NAMESPACE: kube-system (v1:metadata.namespace)
Mounts:
/etc/kube-flannel/ from flannel-cfg (rw)
/run from run (rw)
/var/run/secrets/kubernetes.io/serviceaccount from flannel-token-llwn4 (ro)
Conditions:
Type Status
Initialized True
Ready False
ContainersReady False
PodScheduled True
Volumes:
run:
Type: HostPath (bare host directory volume)
Path: /run
HostPathType:
cni:
Type: HostPath (bare host directory volume)
Path: /etc/cni/net.d
HostPathType:
flannel-cfg:
Type: ConfigMap (a volume populated by a ConfigMap)
Name: kube-flannel-cfg
Optional: false
flannel-token-llwn4:
Type: Secret (a volume populated by a Secret)
SecretName: flannel-token-llwn4
Optional: false
QoS Class: Guaranteed
Node-Selectors: beta.kubernetes.io/arch=amd64
Tolerations: :NoSchedule
node.kubernetes.io/disk-pressure:NoSchedule
node.kubernetes.io/memory-pressure:NoSchedule
node.kubernetes.io/network-unavailable:NoSchedule
node.kubernetes.io/not-ready:NoExecute
node.kubernetes.io/unreachable:NoExecute
node.kubernetes.io/unschedulable:NoSchedule
Events:
Type Reason Age From Message

---

Normal Scheduled 6m57s default-scheduler Successfully assigned kube-system/kube-flannel-ds-amd64-gm5z7 to darshan-p-hegde-89ca8c531.mylabserver.com
Normal Pulling 6m57s kubelet, darshan-p-hegde-89ca8c531.mylabserver.com pulling image "quay.io/coreos/flannel:v0.10.0-amd64"
Normal Pulled 6m55s kubelet, darshan-p-hegde-89ca8c531.mylabserver.com Successfully pulled image "quay.io/coreos/flannel:v0.10.0-amd64"
Normal Created 6m55s kubelet, darshan-p-hegde-89ca8c531.mylabserver.com Created container
Normal Started 6m55s kubelet, darshan-p-hegde-89ca8c531.mylabserver.com Started container
Normal Started 6m5s (x4 over 6m53s) kubelet, darshan-p-hegde-89ca8c531.mylabserver.com Started container
Normal Pulled 5m11s (x5 over 6m54s) kubelet, darshan-p-hegde-89ca8c531.mylabserver.com Container image "quay.io/coreos/flannel:v0.10.0-amd64" already present on machine
Normal Created 5m11s (x5 over 6m53s) kubelet, darshan-p-hegde-89ca8c531.mylabserver.com Created container
Warning BackOff 105s (x23 over 6m48s) kubelet, darshan-p-hegde-89ca8c531.mylabserver.com Back-off restarting failed container

Please find the output of the coreos pods:-

Warning FailedCreatePodSandBox 7m50s kubelet, darshan-p-hegde-89ca8c531.mylabserver.com Failed create pod sandbox: rpc error: code = Unknown desc = failed to set up sandbox container "5f6770d9dfcb53738a0dd428b86e815d4d85e9b71a76d17b10b1f764f102fb61" network for pod "coredns-576cbf47c7-9r27x": NetworkPlugin cni failed to set up pod "coredns-576cbf47c7-9r27x_kube-system" network: open /run/flannel/subnet.env: no such file or directory
Warning FailedCreatePodSandBox 7m49s kubelet, darshan-p-hegde-89ca8c531.mylabserver.com Failed create pod sandbox: rpc error: code = Unknown desc = failed to set up sandbox container "009e9e0099f993086300649a89995a28a0fdf1a128863f7a71e3ff1973788c26" network for pod "coredns-576cbf47c7-9r27x": NetworkPlugin cni failed to set up pod "coredns-576cbf47c7-9r27x_kube-system" network: open /run/flannel/subnet.env: no such file or directory
Warning FailedCreatePodSandBox 7m48s kubelet, darshan-p-hegde-89ca8c531.mylabserver.com Failed create pod sandbox: rpc error: code = Unknown desc = failed to set up sandbox container "ea0ddaf5c411dd026cfd23366e49424526b7cc547652ca262a346f4c800f0c04" network for pod "coredns-576cbf47c7-9r27x": NetworkPlugin cni failed to set up pod "coredns-576cbf47c7-9r27x_kube-system" network: open /run/flannel/subnet.env: no such file or directory

[outcoldman]

@hegdedarsh possible that it is a different problem, but I would suggest using a released version https://raw.githubusercontent.com/coreos/flannel/v0.10.0/Documentation/kube-flannel.yml, modify the tolerations and give it a try.

[pkeuter]

This fixes the issue for me. Thanks for the PR!

[telecodani]

Adding the toleration in the Flannel yaml works for me also. Tested on v1.12.1 Kubernetes. Thanks.

[benn0r]

I am using the yaml file recommended in this issue. But for me nodePort and "externalIps" doesn't work anymore unless its from the same node that the pods are located on. If i try to telnet via the master ip i get a timeout.
this is since the upgrade to kubernetes 1.12.

Is this a problem with flannel?

[sarlacpit]

I am on a fresh install of k8s 1.12 and have just tried downloading v0.10 and the tolerations seem to exist already. So I applied the yml

      - key: node-role.kubernetes.io/master
        operator: Exists
        effect: NoSchedule

It tried creating the flannel pod but came up with 'Error' and eventually "CrashLoopBackOff".
Still very new to k8s. Any debug I can provide let me know.