archlinux: Code cleanups (v2)

Cleanups:
1. Do not modify container's /etc/hosts (archlinux uses /etc/nsswitch.conf)
2. Remove duplicate lines from config
3. Print a nicer final message
4. Get rid of some grep's

Signed-off-by: Leonid Isaev <lisaev@umail.iu.edu>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

templates/lxc-archlinux.in

@@ -71,9 +71,10 @@ split_string() {
 
 # Arch-specific preconfiguration for container
 configure_arch() {
-    # read locale and timezone defaults from system rc.conf if running on Arch
+    # on ArchLinux, read defaults from host systemd configuration
     if [ "${is_arch}" ]; then
-        cp -p /etc/vconsole.conf /etc/locale.conf /etc/locale.gen "${rootfs_path}/etc/"
+        cp -p /etc/vconsole.conf /etc/locale.conf /etc/locale.gen \
+		"${rootfs_path}/etc/"
     else
         echo "LANG=${default_lang}" > "${rootfs_path}/etc/locale.conf"
         echo "KEYMAP=us" > "${rootfs_path}/etc/vconsole.conf"
@@ -89,22 +90,25 @@ EOF
             fi
         fi
     fi
+
+    # hostname and nameservers
     echo "${name}" > "${rootfs_path}/etc/hostname"
-    cat > "${rootfs_path}/etc/hosts" << EOF
-127.0.0.1   localhost.localdomain   localhost ${name}
-::1     localhost.localdomain   localhost
-EOF
-    grep nameserver /etc/resolv.conf > "${rootfs_path}/etc/resolv.conf"
+    while read r; do
+       [ "${r#nameserver}" = "$r" ] || echo "$r"
+    done < /etc/resolv.conf > "${rootfs_path}/etc/resolv.conf"
 
+    # chroot and configure system
     arch-chroot "${rootfs_path}" /bin/bash -s << EOF
 mkdir /run/lock
 locale-gen
 ln -s /usr/share/zoneinfo/${default_timezone} /etc/localtime
 # disable services unavailable for container
-ln -s /dev/null /etc/systemd/system/systemd-udevd.service
-ln -s /dev/null /etc/systemd/system/systemd-udevd-control.socket
-ln -s /dev/null /etc/systemd/system/systemd-udevd-kernel.socket
-ln -s /dev/null /etc/systemd/system/proc-sys-fs-binfmt_misc.automount
+for i in systemd-udevd.service \
+	systemd-udevd-control.socket \
+	systemd-udevd-kernel.socket \
+	proc-sys-fs-binfmt_misc.automount; do
+   ln -s /dev/null /etc/systemd/system/\$i
+done
 # set default systemd target
 ln -s /lib/systemd/system/multi-user.target /etc/systemd/system/default.target
 # initialize pacman keyring
@@ -141,7 +145,6 @@ lxc.cgroup.devices.allow = c 1:5 rwm
 lxc.cgroup.devices.allow = c 1:7 rwm
 lxc.cgroup.devices.allow = c 1:8 rwm
 lxc.cgroup.devices.allow = c 1:9 rwm
-lxc.cgroup.devices.allow = c 1:9 rwm
 lxc.cgroup.devices.allow = c 4:1 rwm
 lxc.cgroup.devices.allow = c 5:0 rwm
 lxc.cgroup.devices.allow = c 5:1 rwm
@@ -319,4 +322,8 @@ if [ -n "${root_passwd}" ]; then
     echo "root:${root_passwd}" | chroot "${rootfs_path}" chpasswd
 fi
 
-echo "container config is ${config_path}/config"
+cat << EOF
+ArchLinux container ${name} is successfully created! The configuration is
+stored in ${config_path}/config. Please refer to https://wiki.archlinux.org for
+information about configuring ArchLinux.
+EOF