setup_{RedHat,Debian}.sh, make more idempotent

Previously, when either setup_{RedHat,Debian}.sh was ran
multiple times a mess was created due to multiple loop
devices being setup.

This change now looks to see if '/docker' or '/swapfile'
already exist, and not re-create them if they do.

*However*, /var/lib/docker (/docker) is still wiped - but it
means that the script can run and bring the system into a
constant vanilla state.

Change-Id: I169662fa04c2bf644672ca75c3ee579795943727
Closes-Bug: #1586563
Signed-off-by: Dave Walker (Daviey) <email@daviey.com>

tools/setup_Debian.sh

@@ -20,15 +20,19 @@ function add_key {
 }
 
 function setup_disk {
-    sudo swapoff -a
-    sudo dd if=/dev/zero of=/swapfile bs=1M count=4096
-    sudo chmod 0600 /swapfile
-    sudo mkswap /swapfile
-    sudo /sbin/swapon /swapfile
+    if [ ! -f /swapfile ]; then
+        sudo swapoff -a
+        sudo dd if=/dev/zero of=/swapfile bs=1M count=4096
+        sudo chmod 0600 /swapfile
+        sudo mkswap /swapfile
+        sudo /sbin/swapon /swapfile
+    fi
 
-    sudo dd if=/dev/zero of=/docker bs=1M count=10240
-    losetup -f /docker
-    DEV=$(losetup -a | awk -F: '/\/docker/ {print $1}')
+    if [ ! -f /docker ]; then
+        sudo dd if=/dev/zero of=/docker bs=1M count=10240
+        losetup -f /docker
+        DEV=$(losetup -a | awk -F: '/\/docker/ {print $1}')
+    fi
 
     # Format Disks and setup Docker to use BTRFS
     sudo parted ${DEV} -s -- mklabel msdos

tools/setup_RedHat.sh

@@ -4,15 +4,19 @@ set -o xtrace
 set -o errexit
 
 function setup_disk {
-    sudo swapoff -a
-    sudo dd if=/dev/zero of=/swapfile bs=1M count=4096
-    sudo chmod 0600 /swapfile
-    sudo mkswap /swapfile
-    sudo /sbin/swapon /swapfile
-
-    sudo dd if=/dev/zero of=/docker bs=1M count=20480
-    losetup -f /docker
-    DEV=$(losetup -a | awk -F: '/\/docker/ {print $1}')
+    if [ ! -f /swapfile ]; then
+        sudo swapoff -a
+        sudo dd if=/dev/zero of=/swapfile bs=1M count=4096
+        sudo chmod 0600 /swapfile
+        sudo mkswap /swapfile
+        sudo /sbin/swapon /swapfile
+    fi
+
+    if [ ! -f /docker ]; then
+        sudo dd if=/dev/zero of=/docker bs=1M count=20480
+        losetup -f /docker
+        DEV=$(losetup -a | awk -F: '/\/docker/ {print $1}')
+    fi
 
     # Format Disks and setup Docker to use BTRFS
     sudo parted ${DEV} -s -- mklabel msdos
@@ -53,7 +57,7 @@ sudo systemctl start docker
 sudo docker info
 
 # disable ipv6 until we're sure routes to fedora mirrors work properly
-sudo sh -c 'echo "net.ipv6.conf.all.disable_ipv6 = 1" >> /etc/sysctl.conf'
+sudo sh -c 'echo "net.ipv6.conf.all.disable_ipv6 = 1" > /etc/sysctl.d/disable_ipv6.conf'
 sudo /usr/sbin/sysctl -p
 
 echo "Completed $0."