I am new at kubeletes and I can´t run "kubeadm init" with success.

Let me show you step by step what I did:

1. I installed last version dockers using yum following dockers documentation (I have configurated 'Environment="HTTP_PROXY=http://usuario:password@proxy:port/" "HTTPS_PROXY=http://usuario:password@proxy:port/"' in /etc/systemd/system/docker.service.d/http-proxy.conf).

2. I have disabled SELINUXTYPE, disabled Swap with the command "swapoff -a" and commented "#/dev/mapper/centos-swap swap swap defaults 0 0" in /etc/fstab.

3. I used "modprobe br_netfilter" and "echo '1' > /proc/sys/net/bridge/bridge-nf-call-iptables" to activate the module called "br_netfilter".

4. "kubernetes.repo" file to install "kubelet kubeadm kubectl" using yum:

   [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
   

5. Opened ports:

    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

6. I created "10-kubeadm.conf" file:

    [Service]
    Environment="KUBELET_KUBECONFIG_ARGS=--bootstrap kubeconfig=/etc/kubernetes/bootstrap-kubelet.conf --kubeconfig=/etc/kubernetes/kubelet.conf"
    Environment="KUBELET_CONFIG_ARGS=--config=/var/lib/kubelet/config.yaml"
    # This is a file that "kubeadm init" and "kubeadm join" generates at runtime, populating the KUBELET_KUBEADM_ARGS variable dynamically
    EnvironmentFile=-/var/lib/kubelet/kubeadm-flags.env
    # This is a file that the user can use for overrides of the kubelet args as a last resort. Preferably, the user should use
    # the .NodeRegistration.KubeletExtraArgs object in the configuration files instead. KUBELET_EXTRA_ARGS should be sourced from this file.
    EnvironmentFile=-/etc/sysconfig/kubelet
    ExecStart=
    ExecStart=/usr/bin/kubelet $KUBELET_KUBECONFIG_ARGS $KUBELET_CONFIG_ARGS $KUBELET_KUBEADM_ARGS $KUBELET_EXTRA_ARGS

7. Reload and enable services:

    systemctl daemon-reload
    systemctl restart docker
    systemctl enable docker
    systemctl restart kubelet
    systemctl enable kubelet

   (both services with status: active(running))

Error:

[wait-control-plane] Waiting for the kubelet to boot up the control plane as static Pods from directory "/etc/kubernetes/manifests". This can take up to 4m0s
[kubelet-check] Initial timeout of 40s passed.

Unfortunately, an error has occurred:
    timed out waiting for the condition

This error is likely caused by:
    - The kubelet is not running
    - The kubelet is unhealthy due to a misconfiguration of the node in some way (required cgroups disabled)

If you are on a systemd-powered system, you can try to troubleshoot the error with the following commands:
    - 'systemctl status kubelet'
    - 'journalctl -xeu kubelet'

Additionally, a control plane component may have crashed or exited when started by the container runtime.
To troubleshoot, list all containers using your preferred container runtimes CLI, e.g. docker.
Here is one example how you may list all Kubernetes containers running in docker:
    - 'docker ps -a | grep kube | grep -v pause'
    Once you have found the failing container, you can inspect its logs with:
    - 'docker logs CONTAINERID'
error execution phase wait-control-plane: couldn't initialize a Kubernetes cluster

Thanks in advance for the help.

Best Regards.