<p>when using kubeadm join token to join worker node to a k8 master. Iam receiving following errors.</p>

<pre><code>[preflight] running pre-flight checks
[preflight] WARNING: Couldn't create the interface used for talking to the container runtime: docker is required for container runtime: exec: "docker": executable file not found in $PATH
        [WARNING RequiredIPVSKernelModulesAvailable]: the IPVS proxier will not be used, because the following required kernel modules are not loaded: [ip_vs_sh nf_conntrack_ipv4 ip_vs ip_vs_rr ip_vs_wrr] or no builtin kernel ipvs support: map[ip_vs:{} ip_vs_rr:{} ip_vs_wrr:{} ip_vs_sh:{} nf_conntrack_ipv4:{}]
you can solve this problem with following methods:
 1. Run 'modprobe -- ' to load missing kernel modules;
2. Provide the missing builtin kernel ipvs support

[preflight] Some fatal errors occurred:
        [ERROR FileContent--proc-sys-net-bridge-bridge-nf-call-iptables]: /proc/sys/net/bridge/bridge-nf-call-iptables does not exist
        [ERROR FileContent--proc-sys-net-ipv4-ip_forward]: /proc/sys/net/ipv4/ip_forward 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=...`

*********************
error 2 : when run modprobe_nrfilter
modprobe: FATAL: Module br_netfilter not found.
</code></pre>

<p>It seems like docker is not installed or not in your <code>PATH</code>:</p>

<pre><code>Couldn't create the interface used for talking to the container runtime: docker is required for container runtime: exec: "docker": executable file not found in $PATH
</code></pre>

<p>This can be fixed by installing docker and ensuring the docker executable is in your PATH.</p>
