解決kubeadm init /proc/sys/net/bridge/bridge-nf-call-iptables contents are not set to 1

起因

$ sudo  kubeadm init --kubernetes-version=v1.14.1 --pod-network-cidr=192.168.0.0/16
[init] Using Kubernetes version: v1.14.1
[preflight] Running pre-flight checks
error execution phase preflight: [preflight] Some fatal errors occurred:
        [ERROR CRI]: container runtime is not running: output: Cannot connect to the Docker daemon at tcp://localhost:2375. Is the docker daemon running?
, error: exit status 1
        [ERROR IsDockerSystemdCheck]: cannot execute 'docker info': exit status 1
        [ERROR FileContent--proc-sys-net-bridge-bridge-nf-call-iptables]: /proc/sys/net/bridge/bridge-nf-call-iptables contents are not set to 1
[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`
[root@master vagrant]# sudo kubeadm init --kubernetes-version=v1.14.1 --pod-network-cidr=192.168.33.10/24
[init] Using Kubernetes version: v1.14.1
[preflight] Running pre-flight checks
error execution phase preflight: [preflight] Some fatal errors occurred:
        [ERROR FileContent--proc-sys-net-bridge-bridge-nf-call-iptables]: /proc/sys/net/bridge/bridge-nf-call-iptables contents are not set to 1
[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`

解決方案

$ echo 1 > /proc/sys/net/bridge/bridge-nf-call-iptables
$ echo 1 > /proc/sys/net/bridge/bridge-nf-call-ip6tables