remove atomic support because reached end of live (#5783)

docs/_sidebar.md

@@ -23,9 +23,9 @@
   * [Packet](/docs/packet.md)
   * [vSphere](/docs/vsphere.md)
 * Operating Systems
-  * [Atomic](docs/atomic.md)
   * [Debian](docs/debian.md)
   * [Coreos](docs/coreos.md)
+  * [Fedora CoreOS](docs/fcos.md)  
   * [OpenSUSE](docs/opensuse.md)
 * Advanced
   * [Proxy](/docs/proxy.md)

docs/atomic.md

@@ -1,22 +0,0 @@
-# Atomic host bootstrap
-
-Atomic host testing has been done with the network plugin flannel. Change the inventory var `kube_network_plugin: flannel`.
-
-Note: Flannel is the only plugin that has currently been tested with atomic
-
-## Vagrant
-
-* For bootstrapping with Vagrant, use box centos/atomic-host or fedora/atomic-host
-* Update VagrantFile variable `local_release_dir` to `/var/vagrant/temp`.
-* Update `vm_memory = 2048` and `vm_cpus = 2`
-* Networking on vagrant hosts has to be brought up manually once they are booted.
-
-    ```ShellSession
-    vagrant ssh
-    sudo /sbin/ifup enp0s8
-    ```
-
-* For users of vagrant-libvirt download centos/atomic-host qcow2 format from <https://wiki.centos.org/SpecialInterestGroup/Atomic/Download/>
-* For users of vagrant-libvirt download fedora/atomic-host qcow2 format from <https://dl.fedoraproject.org/pub/alt/atomic/stable/>
-
-Then you can proceed to [cluster deployment](#run-deployment)