<p>I'm trying to setup kubernetes (from the tutorials for centos7) on three VMs,
unfortunately the joining of the worker fails. I hope someone already had this problem (found it two times on the web with no answers), or might have a guess what's going wrong.</p>

<p>Here is what I get by kubeadm join:</p>

<pre><code>[preflight] running pre-flight checks
        [WARNING RequiredIPVSKernelModulesAvailable]: the IPVS proxier will not be used, because the following required kernel modules are not loaded: [ip_vs ip_vs_rr ip_vs_wrr ip_vs_sh] 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

I0902 20:31:15.401693    2032 kernel_validator.go:81] Validating kernel version
I0902 20:31:15.401768    2032 kernel_validator.go:96] Validating kernel config
        [WARNING SystemVerification]: docker version is greater than the most recently validated version. Docker version: 18.06.1-ce. Max validated version: 17.03
[discovery] Trying to connect to API Server "192.168.1.30:6443"
[discovery] Created cluster-info discovery client, requesting info from "https://192.168.1.30:6443"
[discovery] Requesting info from "https://192.168.1.30:6443" again to validate TLS against the pinned public key
[discovery] Cluster info signature and contents are valid and TLS certificate validates against pinned roots, will use API Server "192.168.1.30:6443"
[discovery] Successfully established connection with API Server "192.168.1.30:6443"
[kubelet] Downloading configuration for the kubelet from the "kubelet-config-1.11" ConfigMap in the kube-system namespace
[kubelet] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[preflight] Activating the kubelet service
[tlsbootstrap] Waiting for the kubelet to perform the TLS Bootstrap...
[kubelet-check] It seems like the kubelet isn't running or healthy.
[kubelet-check] The HTTP call equal to 'curl -sSL http://localhost:10248/healthz' failed with error: Get http://localhost:10248/healthz: dial tcp [::1]:10248: connect: connection refused.
[kubelet-check] It seems like the kubelet isn't running or healthy.
</code></pre>

<p>Though kublet is running:</p>

<pre><code>[root@k8s-worker1 nodesetup]# systemctl status kubelet -l
● kubelet.service - kubelet: The Kubernetes Node Agent
   Loaded: loaded (/etc/systemd/system/kubelet.service; enabled; vendor preset: disabled)
  Drop-In: /etc/systemd/system/kubelet.service.d
           └─10-kubeadm.conf
   Active: active (running) since So 2018-09-02 20:31:15 CEST; 19min ago
     Docs: https://kubernetes.io/docs/
 Main PID: 2093 (kubelet)
    Tasks: 7
   Memory: 12.1M
   CGroup: /system.slice/kubelet.service
           └─2093 /usr/bin/kubelet --bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubelet.conf --kubeconfig=/etc/kubernetes/kubelet.conf --config=/var/lib/kubelet/config.yaml --cgroup-driver=cgroupfs --cni-bin-dir=/opt/cni/bin --cni-conf-dir=/etc/cni/net.d --network-plugin=cni

Sep 02 20:31:15 k8s-worker1 systemd[1]: Started kubelet: The Kubernetes Node Agent.
Sep 02 20:31:15 k8s-worker1 systemd[1]: Starting kubelet: The Kubernetes Node Agent...
Sep 02 20:31:15 k8s-worker1 kubelet[2093]: Flag --cgroup-driver has been deprecated, This parameter should be set via the config file specified by the Kubelet's --config flag. See https://kubernetes.io/docs/tasks/administer-cluster/kubelet-config-file/ for more information.
Sep 02 20:31:15 k8s-worker1 kubelet[2093]: Flag --cgroup-driver has been deprecated, This parameter should be set via the config file specified by the Kubelet's --config flag. See https://kubernetes.io/docs/tasks/administer-cluster/kubelet-config-file/ for more information.
Sep 02 20:31:16 k8s-worker1 kubelet[2093]: I0902 20:31:16.440010    2093 server.go:408] Version: v1.11.2
Sep 02 20:31:16 k8s-worker1 kubelet[2093]: I0902 20:31:16.440314    2093 plugins.go:97] No cloud provider specified.
[root@k8s-worker1 nodesetup]# 
</code></pre>

<p>As far as I can see, the worker can connect to the master, but it tries to run a healthcheck on some local servlet which has not come up. Any ideas?</p>

<p>Here is what I did to configure my worker:</p>

<pre><code>exec bash
setenforce 0
sed -i --follow-symlinks 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/sysconfig/selinux


echo "Setting Firewallrules"
firewall-cmd --permanent --add-port=10250/tcp
firewall-cmd --permanent --add-port=10255/tcp
firewall-cmd --permanent --add-port=30000-32767/tcp
firewall-cmd --permanent --add-port=6783/tcp
firewall-cmd --reload


echo "And enable br filtering"
modprobe br_netfilter
echo '1' &gt; /proc/sys/net/bridge/bridge-nf-call-iptables


echo "disable swap"
swapoff -a
echo "### You need to edit /etc/fstab and comment the swapline!! ###"


echo "Adding kubernetes repo for download"
cat &lt;&lt;EOF &gt; /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg
        https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
EOF


echo "install the Docker-ce dependencies"
yum install -y yum-utils device-mapper-persistent-data lvm2

echo "add docker-ce repository"
yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo

echo "install docker ce"
yum install -y docker-ce

echo "Install kubeadm kubelet kubectl"
yum install kubelet kubeadm kubectl -y

echo "start and enable kubectl"
systemctl restart docker &amp;&amp; systemctl enable docker
systemctl restart kubelet &amp;&amp; systemctl enable kubelet

echo "Now we need to ensure that both Docker-ce and Kubernetes belong to the same control group (cgroup)"

echo "We assume that docker is using cgroupfs ... assuming kubelet does so too"
docker info | grep -i cgroup
grep -i cgroup /var/lib/kubelet/kubeadm-flags.env
#  old style
# sed -i 's/cgroup-driver=systemd/cgroup-driver=cgroupfs/g' /etc/systemd/system/kubelet.service.d/10-kubeadm.conf

systemctl daemon-reload
systemctl restart kubelet

# There has been an issue reported that traffic in iptable is been routed incorrectly.
# Below settings will make sure IPTable is configured correctly.
#
sudo bash -c 'cat &lt;&lt;EOF &gt;  /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF'

# Make changes effective
sudo sysctl --system
</code></pre>

<p>Thanks for any help in advance.</p>

<p><strong>Update I</strong></p>

<p>Journalctl Output from the worker:</p>

<pre><code>[root@k8s-worker1 ~]# journalctl -xeu kubelet
Sep 02 21:19:56 k8s-worker1 systemd[1]: Started kubelet: The Kubernetes Node Agent.
-- Subject: Unit kubelet.service has finished start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit kubelet.service has finished starting up.
-- 
-- The start-up result is done.
Sep 02 21:19:56 k8s-worker1 systemd[1]: Starting kubelet: The Kubernetes Node Agent...
-- Subject: Unit kubelet.service has begun start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit kubelet.service has begun starting up.
Sep 02 21:19:56 k8s-worker1 kubelet[3082]: Flag --cgroup-driver has been deprecated, This parameter should be set via the config file specified by the Kubelet's --confi
Sep 02 21:19:56 k8s-worker1 kubelet[3082]: Flag --cgroup-driver has been deprecated, This parameter should be set via the config file specified by the Kubelet's --confi
Sep 02 21:19:56 k8s-worker1 kubelet[3082]: I0902 21:19:56.788059    3082 server.go:408] Version: v1.11.2
Sep 02 21:19:56 k8s-worker1 kubelet[3082]: I0902 21:19:56.788214    3082 plugins.go:97] No cloud provider specified.
Sep 02 21:19:56 k8s-worker1 kubelet[3082]: F0902 21:19:56.814469    3082 server.go:262] failed to run Kubelet: cannot create certificate signing request: Unauthorized
Sep 02 21:19:56 k8s-worker1 systemd[1]: kubelet.service: main process exited, code=exited, status=255/n/a
Sep 02 21:19:56 k8s-worker1 systemd[1]: Unit kubelet.service entered failed state.
Sep 02 21:19:56 k8s-worker1 systemd[1]: kubelet.service failed.
</code></pre>

<p>And the get pods on the master side results in:</p>

<pre><code>[root@k8s-master ~]# kubectl get pods --all-namespaces=true
NAMESPACE     NAME                                 READY     STATUS    RESTARTS   AGE
kube-system   coredns-78fcdf6894-79n2m             0/1       Pending   0          1d
kube-system   coredns-78fcdf6894-tlngr             0/1       Pending   0          1d
kube-system   etcd-k8s-master                      1/1       Running   3          1d
kube-system   kube-apiserver-k8s-master            1/1       Running   0          1d
kube-system   kube-controller-manager-k8s-master   0/1       Evicted   0          1d
kube-system   kube-proxy-2x8cx                     1/1       Running   3          1d
kube-system   kube-scheduler-k8s-master            1/1       Running   0          1d
[root@k8s-master ~]# 
</code></pre>

<p><strong>Update II</strong>
As next step I generated a new token on the master side and used this one on the join command. Though the master token list displayed the the token as a valid one, the worker node insist that the master does not know about this token or it is expired....stop! Time to start all over, beginning with the master setup.</p>

<p>So here's what I did:</p>

<p>1) resetup the master VM, meaning a fresh centos7 (CentOS-7-x86_64-Minimal-1804.iso) installation on virtualbox. Configured networking von virtualbox: adapter1 as NAT to the host system (for being able to install the stuff) and adapter2 as internal network (same name to master and worker nodes for the kubernetes network).</p>

<p>2) With the fresh image installed the basis interface enp0s3 was not configured to run at boot time (so ifup enp03s, and reconfigured in /etc/sysconfig/network-script to run at boot time).</p>

<p>3) Configuring the second interface for the internal kubernetes network:</p>

<p><strong>/etc/hosts:</strong></p>

<pre><code>#!/bin/sh
echo '192.168.1.30 k8s-master' &gt;&gt; /etc/hosts
echo '192.168.1.40 k8s-worker1' &gt;&gt; /etc/hosts
echo '192.168.1.50 k8s-worker2' &gt;&gt; /etc/hosts
</code></pre>

<p>Identified my second interface via "ip -color -human addr" which showed me the enp0S8 in my case, so:</p>

<pre><code>#!/bin/sh
echo "Setting up internal Interface"
cat &lt;&lt;EOF &gt; /etc/sysconfig/network-scripts/ifcfg-enp0s8
DEVICE=enp0s8
IPADDR=192.168.1.30
NETMASK=255.255.255.0
NETWORK=192.168.1.0
BROADCAST=192.168.1.255
ONBOOT=yes
NAME=enp0s8
EOF

echo "Activate interface"
ifup enp0s8
</code></pre>

<p>4) Hostname, swap, disabling SELinux</p>

<pre><code>#!/bin/sh
echo "Setting hostname und deactivate SELinux"
hostnamectl set-hostname 'k8s-master'
exec bash
setenforce 0
sed -i --follow-symlinks 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/sysconfig/selinux

echo "disable swap"
swapoff -a

echo "### You need to edit /etc/fstab and comment the swapline!! ###"
</code></pre>

<p>Some remarks here: I rebooted as I saw that the later preflight checks seems to parse /etc/fstab to see that the swap does not exists. Also it seems that centos reactivates SElinux (I need to check this later on) as workaround I disabled it again after each reboot.</p>

<p>5) Establish the requires firewall settings</p>

<pre><code>#!/bin/sh
echo "Setting Firewallrules"
firewall-cmd --permanent --add-port=6443/tcp
firewall-cmd --permanent --add-port=2379-2380/tcp
firewall-cmd --permanent --add-port=10250/tcp
firewall-cmd --permanent --add-port=10251/tcp
firewall-cmd --permanent --add-port=10252/tcp
firewall-cmd --permanent --add-port=10255/tcp
firewall-cmd --reload

echo "And enable br filtering"
modprobe br_netfilter
echo '1' &gt; /proc/sys/net/bridge/bridge-nf-call-iptables
</code></pre>

<p>6) Adding the kubernetes repository</p>

<pre><code>#!/bin/sh
echo "Adding kubernetes repo for download"
cat &lt;&lt;EOF &gt; /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg
        https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
EOF
</code></pre>

<p>7) Install the required packages and configure the services</p>

<pre><code>#!/bin/sh

echo "install the Docker-ce dependencies"
yum install -y yum-utils device-mapper-persistent-data lvm2

echo "add docker-ce repository"
yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo

echo "install docker ce"
yum install -y docker-ce

echo "Install kubeadm kubelet kubectl"
yum install kubelet kubeadm kubectl -y

echo "start and enable kubectl"
systemctl restart docker &amp;&amp; systemctl enable docker
systemctl restart kubelet &amp;&amp; systemctl enable kubelet

echo "Now we need to ensure that both Docker-ce and Kubernetes belong to the same control group (cgroup)"
echo "We assume that docker is using cgroupfs ... assuming kubelet does so too"
docker info | grep -i cgroup
grep -i cgroup /var/lib/kubelet/kubeadm-flags.env
#  old style
# sed -i 's/cgroup-driver=systemd/cgroup-driver=cgroupfs/g' /etc/systemd/system/kubelet.service.d/10-kubeadm.conf

systemctl daemon-reload
systemctl restart kubelet

# There has been an issue reported that traffic in iptable is been routed incorrectly.
# Below settings will make sure IPTable is configured correctly.
#
sudo bash -c 'cat &lt;&lt;EOF &gt;  /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF'

# Make changes effective
sudo sysctl --system
</code></pre>

<p>8) Init the cluster</p>

<pre><code>#!/bin/sh
echo "Init kubernetes. Check join cmd in initProtocol.txt"
kubeadm init --apiserver-advertise-address=192.168.1.30 --pod-network-cidr=192.168.1.0/16 | tee initProtocol.txt
</code></pre>

<p>To verify here is the result of this command:</p>

<pre><code>Init kubernetes. Check join cmd in initProtocol.txt
[init] using Kubernetes version: v1.11.2
[preflight] running pre-flight checks
        [WARNING Firewalld]: firewalld is active, please ensure ports [6443 10250] are open or your cluster may not function correctly
I0904 21:53:15.271999    1526 kernel_validator.go:81] Validating kernel version
I0904 21:53:15.272165    1526 kernel_validator.go:96] Validating kernel config
        [WARNING SystemVerification]: docker version is greater than the most recently validated version. Docker version: 18.06.1-ce. Max validated version: 17.03
[preflight/images] Pulling images required for setting up a Kubernetes cluster
[preflight/images] This might take a minute or two, depending on the speed of your internet connection
[preflight/images] You can also perform this action in beforehand using 'kubeadm config images pull'
[kubelet] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[preflight] Activating the kubelet service
[certificates] Generated ca certificate and key.
[certificates] Generated apiserver certificate and key.
[certificates] apiserver serving cert is signed for DNS names [k8s-master kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 192.168.1.30]
[certificates] Generated apiserver-kubelet-client certificate and key.
[certificates] Generated sa key and public key.
[certificates] Generated front-proxy-ca certificate and key.
[certificates] Generated front-proxy-client certificate and key.
[certificates] Generated etcd/ca certificate and key.
[certificates] Generated etcd/server certificate and key.
[certificates] etcd/server serving cert is signed for DNS names [k8s-master localhost] and IPs [127.0.0.1 ::1]
[certificates] Generated etcd/peer certificate and key.
[certificates] etcd/peer serving cert is signed for DNS names [k8s-master localhost] and IPs [192.168.1.30 127.0.0.1 ::1]
[certificates] Generated etcd/healthcheck-client certificate and key.
[certificates] Generated apiserver-etcd-client certificate and key.
[certificates] valid certificates and keys now exist in "/etc/kubernetes/pki"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/admin.conf"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/kubelet.conf"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/controller-manager.conf"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/scheduler.conf"
[controlplane] wrote Static Pod manifest for component kube-apiserver to "/etc/kubernetes/manifests/kube-apiserver.yaml"
[controlplane] wrote Static Pod manifest for component kube-controller-manager to "/etc/kubernetes/manifests/kube-controller-manager.yaml"
[controlplane] wrote Static Pod manifest for component kube-scheduler to "/etc/kubernetes/manifests/kube-scheduler.yaml"
[etcd] Wrote Static Pod manifest for a local etcd instance to "/etc/kubernetes/manifests/etcd.yaml"
[init] waiting for the kubelet to boot up the control plane as Static Pods from directory "/etc/kubernetes/manifests" 
[init] this might take a minute or longer if the control plane images have to be pulled
[apiclient] All control plane components are healthy after 43.504792 seconds
[uploadconfig] storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config-1.11" in namespace kube-system with the configuration for the kubelets in the cluster
[markmaster] Marking the node k8s-master as master by adding the label "node-role.kubernetes.io/master=''"
[markmaster] Marking the node k8s-master as master by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[patchnode] Uploading the CRI Socket information "/var/run/dockershim.sock" to the Node API object "k8s-master" as an annotation
[bootstraptoken] using token: n4yt3r.3c8tuj11nwszts2d
[bootstraptoken] configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
[bootstraptoken] configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
[bootstraptoken] configured RBAC rules to allow certificate rotation for all node client certificates in the cluster
[bootstraptoken] creating the "cluster-info" ConfigMap in the "kube-public" namespace
[addons] Applied essential addon: CoreDNS
[addons] Applied essential addon: kube-proxy

Your Kubernetes master has initialized successfully!

To start using your cluster, you need to run the following as a regular user:

  mkdir -p $HOME/.kube
  sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
  sudo chown $(id -u):$(id -g) $HOME/.kube/config

You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
  https://kubernetes.io/docs/concepts/cluster-administration/addons/

You can now join any number of machines by running the following on each node
as root:

  kubeadm join 192.168.1.30:6443 --token n4yt3r.3c8tuj11nwszts2d --discovery-token-ca-cert-hash sha256:466e7972a4b6997651ac1197fdde68d325a7bc41f2fccc2b1efc17515af61172
</code></pre>

<p>Remark: looks fine for me so far, though I'm a bit worried that the latest docker-ce version might cause troubles here...</p>

<p>9) Deploying the pod network</p>

<pre><code>#!/bin/bash

echo "Configure demo cluster usage as root"
mkdir -p $HOME/.kube
cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
chown $(id -u):$(id -g) $HOME/.kube/config

# Deploy-Network using flanel
# Taken from first matching two tutorials on the web
# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/k8s-manifests/kube-flannel-rbac.yml

# taken from https://kubernetes.io/docs/setup/independent/create-cluster-kubeadm/#pod-network
kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/v0.10.0/Documentation/kube-flannel.yml
kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/c5d10c8/Documentation/kube-flannel.yml

echo "Try to run kubectl get pods --all-namespaces"
echo "After joining nodes: try to run kubectl get nodes to verify the status"
</code></pre>

<p>And here's the output of this command:</p>

<pre><code>Configure demo cluster usage as root
clusterrole.rbac.authorization.k8s.io/flannel created
clusterrolebinding.rbac.authorization.k8s.io/flannel created
serviceaccount/flannel created
configmap/kube-flannel-cfg created
daemonset.extensions/kube-flannel-ds created
clusterrole.rbac.authorization.k8s.io/flannel configured
clusterrolebinding.rbac.authorization.k8s.io/flannel configured
serviceaccount/flannel unchanged
configmap/kube-flannel-cfg unchanged
daemonset.extensions/kube-flannel-ds-amd64 created
daemonset.extensions/kube-flannel-ds-arm64 created
daemonset.extensions/kube-flannel-ds-arm created
daemonset.extensions/kube-flannel-ds-ppc64le created
daemonset.extensions/kube-flannel-ds-s390x created
Try to run kubectl get pods --all-namespaces
After joining nodes: try to run kubectl get nodes to verify the status
</code></pre>

<p>So I tried kubectl get pods --all-namespaces and I get</p>

<pre><code>[root@k8s-master nodesetup]# kubectl get pods --all-namespaces
NAMESPACE     NAME                                 READY     STATUS    RESTARTS   AGE
kube-system   coredns-78fcdf6894-pflhc             0/1       Pending   0          33m
kube-system   coredns-78fcdf6894-w7dxg             0/1       Pending   0          33m
kube-system   etcd-k8s-master                      1/1       Running   0          27m
kube-system   kube-apiserver-k8s-master            1/1       Running   0          27m
kube-system   kube-controller-manager-k8s-master   0/1       Evicted   0          27m
kube-system   kube-proxy-stfxm                     1/1       Running   0          28m
kube-system   kube-scheduler-k8s-master            1/1       Running   0          27m
</code></pre>

<p>and </p>

<pre><code>[root@k8s-master nodesetup]# kubectl get nodes
NAME         STATUS     ROLES     AGE       VERSION
k8s-master   NotReady   master    35m       v1.11.2
</code></pre>

<p>Hm...what's wrong with my master?</p>

<p>Some observations:</p>

<p>Sometime I got connection refused on running the kubectl in the beginning, I found out that it takes some minutes before the service is established. But because of this I was looking in the /var/log/firewalld and found a lot of these:</p>

<pre><code>2018-09-04 21:52:09 WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -t nat -D PREROUTING' failed: iptables: Bad rule (does a matching rule exist in that chain?).

2018-09-04 21:52:09 WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -t nat -D OUTPUT' failed: iptables: Bad rule (does a matching rule exist in that chain?).

2018-09-04 21:52:09 WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -t nat -F DOCKER' failed: iptables: No chain/target/match by that name.

2018-09-04 21:52:09 WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -t nat -X DOCKER' failed: iptables: No chain/target/match by that name.

2018-09-04 21:52:09 WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -t filter -F DOCKER' failed: iptables: No chain/target/match by that name.

2018-09-04 21:52:09 WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -t filter -X DOCKER' failed: iptables: No chain/target/match by that name.

2018-09-04 21:52:09 WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -t filter -F DOCKER-ISOLATION-STAGE-1' failed: iptables: No chain/target/match by that name.

2018-09-04 21:52:09 WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -t filter -X DOCKER-ISOLATION-STAGE-1' failed: iptables: No chain/target/match by that name.

2018-09-04 21:52:09 WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -t filter -F DOCKER-ISOLATION-STAGE-2' failed: iptables: No chain/target/match by that name.

2018-09-04 21:52:09 WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -t filter -X DOCKER-ISOLATION-STAGE-2' failed: iptables: No chain/target/match by that name.

2018-09-04 21:52:09 WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -t filter -F DOCKER-ISOLATION' failed: iptables: No chain/target/match by that name.

2018-09-04 21:52:09 WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -t filter -X DOCKER-ISOLATION' failed: iptables: No chain/target/match by that name.

2018-09-04 21:52:09 WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -t nat -n -L DOCKER' failed: iptables: No chain/target/match by that name.

2018-09-04 21:52:09 WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -t filter -n -L DOCKER' failed: iptables: No chain/target/match by that name.

2018-09-04 21:52:09 WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -t filter -n -L DOCKER-ISOLATION-STAGE-1' failed: iptables: No chain/target/match by that name.

2018-09-04 21:52:09 WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -t filter -n -L DOCKER-ISOLATION-STAGE-2' failed: iptables: No chain/target/match by that name.

2018-09-04 21:52:09 WARNING: COMMAND_FAILED: '/usr/sbin/iptables -w2 -t filter -C DOCKER-ISOLATION-STAGE-1 -j RETURN' failed: iptables: Bad rule (does a matching rule exist in that chain?).
</code></pre>

<p>Wrong docker version? The docker installation setup seems to be broken.</p>

<p>Anything else I can check on the master side...
It's gonna be late - tomorrow I'm trying to join my worker again (within the 24h range of the initial token period).</p>

<p><strong>Update III (After solving the docker issue)</strong></p>

<pre><code>[root@k8s-master ~]# kubectl get pods --all-namespaces=true
NAMESPACE     NAME                                 READY     STATUS    RESTARTS   AGE
kube-system   coredns-78fcdf6894-pflhc             0/1       Pending   0          10h
kube-system   coredns-78fcdf6894-w7dxg             0/1       Pending   0          10h
kube-system   etcd-k8s-master                      1/1       Running   0          10h
kube-system   kube-apiserver-k8s-master            1/1       Running   0          10h
kube-system   kube-controller-manager-k8s-master   1/1       Running   0          10h
kube-system   kube-flannel-ds-amd64-crljm          0/1       Pending   0          1s
kube-system   kube-flannel-ds-v6gcx                0/1       Pending   0          0s
kube-system   kube-proxy-l2dck                     0/1       Pending   0          0s
kube-system   kube-scheduler-k8s-master            1/1       Running   0          10h
[root@k8s-master ~]# 
</code></pre>

<p>And master looks happy now</p>

<pre><code>[root@k8s-master ~]# kubectl get nodes
NAME         STATUS    ROLES     AGE       VERSION
k8s-master   Ready     master    10h       v1.11.2
[root@k8s-master ~]# 
</code></pre>

<p>Stay tuned...after work I'm fixing docker/firewall on the worker, too and will try to join the cluster again (knowing now how to issue a new token if required). So Update IV will follow in about 10hours</p>

<p>It seems that your <code>kubeadm token</code> has been expired as per <code>kubelet</code> logs attached.</p>

<blockquote>
  <p>Sep 02 21:19:56 k8s-worker1 kubelet[3082]: F0902 21:19:56.814469<br>
  3082 server.go:262] failed to run Kubelet: cannot create certificate
  signing request: Unauthorized</p>
</blockquote>

<p>TTL for this token remains 24 hours after command <code>kubeadm init</code> released, check this <a href="https://kubernetes.io/docs/reference/setup-tools/kubeadm/kubeadm-token/" rel="nofollow noreferrer">link</a> for more information.</p>

<p>The master node’s system runtime components look unhealthy, not sure whether the cluster can be running fine. Although <code>CoreDNS</code> services are in pending state, take a look at <code>kubeadm</code> troubleshooting <a href="https://kubernetes.io/docs/setup/independent/troubleshooting-kubeadm/#coredns-or-kube-dns-is-stuck-in-the-pending-state" rel="nofollow noreferrer">document</a> in order to check whether any of <a href="https://kubernetes.io/docs/setup/independent/create-cluster-kubeadm/#pod-network" rel="nofollow noreferrer">Pod network</a> providers have been installed on your cluster.</p>

<p>I recommend rebuilding cluster in order to refresh <code>kubeadm token</code> and bootstrap cluster system modules from scratch.</p>
