[k8s] Fix docker storage of Fedora CoreOS

In commit I1a75f1bf12747508a3497293650d3cc668202de6 the worker node
is missed to add the docker storage support. And the current systemd
unit is not really working. So this patch fixes it by removing the
hardcode for /dev/vdb and using xfs instead of ext4 (the same way
for Fedora Atomic) to make it simpler and solid.

Task: 39331
Story: 2005201

Change-Id: I4c465664eb19f1992df95750dd7b2d99688c6cae
(cherry picked from commit c2439ca1)

doc/source/user/index.rst

@@ -1124,6 +1124,8 @@ Storage driver (docker-storage-driver)
   default is 'devicemapper'. Refer to the `Storage`_ section for more
   details.
 
+  **NOTE:** For Fedora CoreOS driver, devicemapper is not supported.
+
 Image (image)
   Specified in the ClusterTemplate to indicate the image to boot the servers.
   The image binary is loaded in Glance with the attribute
@@ -2929,6 +2931,12 @@ of Docker storage drivers available.
   container isolation, although it still runs in enforcing mode on the
   cluster compute instances.
 
+* 'overlay2' is the preferred storage driver, for all currently supported
+  Linux distributions, and requires no extra configuration. When possible,
+  overlay2 is the recommended storage driver. When installing Docker for
+  the first time, overlay2 is used by default.
+
+
 Persistent storage
 ------------------
 

magnum/drivers/common/templates/fragments/configure_docker_storage_driver_fedora_coreos.sh

 ssh_cmd="ssh -F /srv/magnum/.ssh/config root@localhost"
 
-configure_storage_driver_generic() {
-
-    cat > /etc/systemd/system/var-lib-docker.mount <<EOF
-[Unit]
-Description=Mount ephemeral to /var/lib/docker
-
-[Mount]
-What=/dev/vdb
-Where=/var/lib/docker
-Type=ext4
+runtime=${CONTAINER_RUNTIME}
+if [ ${CONTAINER_RUNTIME} = "containerd"  ] ; then
+    storage_dir="/var/lib/containerd"
+else
+    storage_dir="/var/lib/docker"
+    runtime="docker"
+fi
 
-[Install]
-WantedBy=local-fs.target
-EOF
+clear_docker_storage () {
+    # stop docker
+    $ssh_cmd systemctl stop ${runtime}
+    # clear storage graph
+    $ssh_cmd rm -rf ${storage_dir}
+    $ssh_cmd mkdir -p ${storage_dir}
+}
 
+# Configure generic docker storage driver.
+configure_storage_driver_generic() {
+    clear_docker_storage
 
-    cat > /etc/sysconfig/enable-docker-mount.sh <<EOF
-#!/bin/sh
-. /etc/sysconfig/heat-params
     if [ -n "$DOCKER_VOLUME_SIZE" ] && [ "$DOCKER_VOLUME_SIZE" -gt 0 ]; then
-    if [[ "$(blkid -o value -s TYPE /dev/vdb)" -eq 0 ]]; then
-        systemctl daemon-reload
-        systemctl start var-lib-docker.mount
-        systemctl enable var-lib-docker.mount
-    else
-        mkfs -t ext4 /dev/vdb
-        systemctl daemon-reload
-        systemctl start var-lib-docker.mount
-        systemctl enable var-lib-docker.mount
+        $ssh_cmd mkfs.xfs -f ${device_path}
+        echo "${device_path} ${storage_dir} xfs defaults 0 0" >> /etc/fstab
+        $ssh_cmd mount -a
+        $ssh_cmd restorecon -R ${storage_dir}
     fi
+    if [ ${CONTAINER_RUNTIME} = "host-docker"  ] ; then
+        sed -i -E 's/^OPTIONS=("|'"'"')/OPTIONS=\1--storage-driver='$1' /' /etc/sysconfig/docker
     fi
-EOF
-
-    chmod +x /etc/sysconfig/enable-docker-mount.sh
-
-    cat > /etc/systemd/system/enable-docker-mount.service <<EOF
-[Unit]
-Description=Mount docker volume
-
-[Service]
-Type=oneshot
-EnvironmentFile=/etc/sysconfig/heat-params
-ExecStart=/etc/sysconfig/enable-docker-mount.sh
-
-[Install]
-RequiredBy=multi-user.target
-EOF
-
 }
 
 configure_devicemapper() {
     configure_storage_driver_generic
 }
+

magnum/drivers/k8s_fedora_coreos_v1/templates/kubecluster.yaml

@@ -269,7 +269,9 @@ parameters:
   docker_storage_driver:
     type: string
     description: docker storage driver name
-    default: "devicemapper"
+    default: "overlay2"
+    constraints:
+      - allowed_pattern: "^(?!devicemapper$).*"
 
   cgroup_driver:
     type: string

magnum/drivers/k8s_fedora_coreos_v1/templates/kubeminion.yaml

@@ -468,7 +468,10 @@ resources:
             - get_file: ../../common/templates/fragments/configure-docker-registry.sh
             - get_file: ../../common/templates/kubernetes/fragments/configure-kubernetes-minion.sh
             - get_file: ../../common/templates/kubernetes/fragments/add-proxy.sh
-              # TODO add docker_storage_setup
+            - str_replace:
+                template: {get_file: ../../common/templates/fragments/configure-docker-storage.sh}
+                params:
+                  $configure_docker_storage_driver: {get_file: ../../common/templates/fragments/configure_docker_storage_driver_fedora_coreos.sh}
             - get_file: ../../common/templates/kubernetes/fragments/enable-services-minion.sh
             - get_file: ../../common/templates/fragments/enable-docker-registry.sh