ref(*): format devices as ext4 instead of btrfs

We also set the inode and block size here as recommended by CoreOS,
so the Docker volume has the maximum inodes available.

Author: carmstrong

contrib/azure/azure-user-data-template

@@ -11,7 +11,7 @@ coreos:
         Type=oneshot
         RemainAfterExit=yes
         ExecStart=/usr/sbin/wipefs -f /dev/sdc
-        ExecStart=/usr/sbin/mkfs.btrfs -f /dev/sdc
+        ExecStart=/usr/sbin/mkfs.ext4 -i 4096 -b 4096 /dev/sdc
         ExecStart=/bin/touch /etc/azure-formatted
     - name: var-lib-docker.mount
       command: start
@@ -24,4 +24,4 @@ coreos:
         [Mount]
         What=/dev/sdc
         Where=/var/lib/docker
-        Type=btrfs
+        Type=ext4

contrib/ec2/gen-json.py

@@ -14,7 +14,7 @@
   Type=oneshot
   RemainAfterExit=yes
   ExecStart=/usr/sbin/wipefs -f /dev/xvdb
-  ExecStart=/usr/sbin/mkfs.ext4 /dev/xvdb
+  ExecStart=/usr/sbin/mkfs.ext4 -i 4096 -b 4096 /dev/xvdb
   ExecStart=/bin/touch /etc/ephemeral-volume-formatted
 '''
 MOUNT_EPHEMERAL_VOLUME = '''
@@ -47,7 +47,7 @@
   Type=oneshot
   RemainAfterExit=yes
   ExecStart=/usr/sbin/wipefs -f /dev/xvdf
-  ExecStart=/usr/sbin/mkfs.btrfs -f /dev/xvdf
+  ExecStart=/usr/sbin/mkfs.ext4 -i 4096 -b 4096 /dev/xvdf
   ExecStart=/bin/touch /etc/docker-volume-formatted
 '''
 MOUNT_DOCKER_VOLUME = '''
@@ -59,7 +59,7 @@
   [Mount]
   What=/dev/xvdf
   Where=/var/lib/docker
-  Type=btrfs
+  Type=ext4
 '''
 
 new_units = [

contrib/gce/gce-user-data-template

@@ -11,7 +11,7 @@ coreos:
         Type=oneshot
         RemainAfterExit=yes
         ExecStart=/usr/sbin/wipefs -f /dev/disk/by-id/scsi-0Google_PersistentDisk_coredocker
-        ExecStart=/usr/sbin/mkfs.btrfs -f /dev/disk/by-id/scsi-0Google_PersistentDisk_coredocker
+        ExecStart=/usr/sbin/mkfs.ext4 -i 4096 -b 4096 /dev/disk/by-id/scsi-0Google_PersistentDisk_coredocker
         ExecStart=/bin/touch /etc/gce-formatted
     - name: var-lib-docker.mount
       command: start
@@ -24,4 +24,4 @@ coreos:
         [Mount]
         What=/dev/disk/by-id/scsi-0Google_PersistentDisk_coredocker
         Where=/var/lib/docker
-        Type=btrfs
+        Type=ext4