Error while deploying k8s cluster using the instructions https://docs.openstack.org/openstack-helm/latest/install/kubernetes-gate.html and command ``make dev-deploy k8s multinode``
error log:
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....
....
PLAY [all] *********************************************************************
TASK [Gathering Facts] *********************************************************
ok: [/mnt/rootfs]
TASK [deploy-kubeadm-node : base kubeadm deploy] *******************************
ok: [/mnt/rootfs] => (item=/etc/kubernetes/)
ok: [/mnt/rootfs] => (item=/etc/systemd/system/kubelet.service.d/)
ok: [/mnt/rootfs] => (item=/var/lib/kubelet/)
TASK [deploy-kubeadm-node : copying kubeadm binary to host] ********************
changed: [/mnt/rootfs]
TASK [deploy-kubeadm-node : debug] *********************************************
ok: [/mnt/rootfs] => {
"msg": "kubeadm join --tls-bootstrap-token bkhsj3.t44o9wu43bfwsht0 --discovery-token kbeuk6.qt62e8fo1ooki1t7 --discovery-token-ca-cert-hash sha256:35de8f5d6178e517a84df0b191c78e6a94a5776b1deba233f38c6ff9c826cd89 10.0.1.112:6443"
}
TASK [deploy-kubeadm-node : running kubeadm join command] **********************
fatal: [/mnt/rootfs]: FAILED! => {"changed": true, "cmd": ["kubeadm", "join", "--tls-bootstrap-token", "bkhsj3.t44o9wu43bfwsht0", "--discovery-token", "kbeuk6.qt62e8fo1ooki1t7", "--discovery-token-ca-cert-hash", "sha256:35de8f5d6178e517a84df0b191c78e6a94a5776b1deba233f38c6ff9c826cd89", "10.0.1.112:6443"], "delta": "0:00:00.456285", "end": "2018-07-24 21:30:25.396365", "failed": true, "msg": "non-zero return code", "rc": 2, "start": "2018-07-24 21:30:24.940080", "stderr": "[preflight] Some fatal errors occurred:\n\t/proc/sys/net/bridge/bridge-nf-call-iptables does not exist\n[preflight] If you know what you are doing, you can skip pre-flight checks with `--skip-preflight-checks`", "stderr_lines": ["[preflight] Some fatal errors occurred:", "\t/proc/sys/net/bridge/bridge-nf-call-iptables does not exist", "[preflight] If you know what you are doing, you can skip pre-flight checks with `--skip-preflight-checks`"], "stdout": "[kubeadm] WARNING: kubeadm is in beta, please do not use it for production clusters.\n[preflight] Running pre-flight checks", "stdout_lines": ["[kubeadm] WARNING: kubeadm is in beta, please do not use it for production clusters.", "[preflight] Running pre-flight checks"]}
to retry, use: --limit @/opt/playbooks/kubeadm-aio-deploy-node.retry
PLAY RECAP *********************************************************************
/mnt/rootfs : ok=4 changed=1 unreachable=0 failed=1
