Error when trying to run kubeadm join

ztrubow

At step 15 on section 3.2 (grow the cluster), when i run the command I am getting this output:

I0822 00:13:09.532678 3997 join.go:408] [preflight] found NodeName empty; using OS hostname as NodeName
I0822 00:13:09.532841 3997 initconfiguration.go:116] detected and using CRI socket: unix:///var/run/containerd/containerd.sock
[preflight] Running pre-flight checks
I0822 00:13:09.532920 3997 preflight.go:93] [preflight] Running general checks
I0822 00:13:09.532968 3997 checks.go:280] validating the existence of file /etc/kubernetes/kubelet.conf
I0822 00:13:09.533009 3997 checks.go:280] validating the existence of file /etc/kubernetes/bootstrap-kubelet.conf
I0822 00:13:09.533029 3997 checks.go:104] validating the container runtime
I0822 00:13:09.564730 3997 checks.go:329] validating the contents of file /proc/sys/net/bridge/bridge-nf-call-iptables
I0822 00:13:09.564803 3997 checks.go:329] validating the contents of file /proc/sys/net/ipv4/ip_forward
I0822 00:13:09.564875 3997 checks.go:644] validating whether swap is enabled or not
I0822 00:13:09.564929 3997 checks.go:370] validating the presence of executable crictl
I0822 00:13:09.564957 3997 checks.go:370] validating the presence of executable conntrack
I0822 00:13:09.564985 3997 checks.go:370] validating the presence of executable ip
I0822 00:13:09.565008 3997 checks.go:370] validating the presence of executable iptables
I0822 00:13:09.565033 3997 checks.go:370] validating the presence of executable mount
I0822 00:13:09.565057 3997 checks.go:370] validating the presence of executable nsenter
I0822 00:13:09.565080 3997 checks.go:370] validating the presence of executable ebtables
I0822 00:13:09.565104 3997 checks.go:370] validating the presence of executable ethtool
I0822 00:13:09.565124 3997 checks.go:370] validating the presence of executable socat
I0822 00:13:09.565150 3997 checks.go:370] validating the presence of executable tc
I0822 00:13:09.565171 3997 checks.go:370] validating the presence of executable touch
I0822 00:13:09.565200 3997 checks.go:516] running all checks
I0822 00:13:09.578345 3997 checks.go:401] checking whether the given node name is valid and reachable using net.LookupHost
I0822 00:13:09.580331 3997 checks.go:610] validating kubelet version
I0822 00:13:09.639145 3997 checks.go:130] validating if the "kubelet" service is enabled and active
I0822 00:13:09.648974 3997 checks.go:203] validating availability of port 10250
I0822 00:13:09.649179 3997 checks.go:280] validating the existence of file /etc/kubernetes/pki/ca.crt
I0822 00:13:09.649205 3997 checks.go:430] validating if the connectivity type is via proxy or direct
[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 execution phase preflight

If anyone could offer some insight, i've tried a few things found googling but nothing has helped at the moment. Happy to provide any other commands needed

fazlur.khan

@ztrubow

Looks like you have a missed few pre-requisite steps. Execute the below steps and re-try to grow the cluster.

Ensure Kernel has modules

sudo modprobe overlay
sudo modprobe br_netfilter

Update networking to allow traffic

cat <<EOF | sudo tee /etc/sysctl.d/kubernetes.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
EOF

sudo sysctl --system

Note: If you get port in use errors, reset and then retry. To reset run the command "kubeadm reset" on worker node.