prototype dns config helper

designed to help out when adding domains and subdomains to DNS, especially geared towards a vm configuration we're working with (multiple domains served on same vm with one ip address, vm provides dns servers to host computer).

diff --git a/scripts/system/add_domain.sh b/scripts/system/add_domain.sh
new file mode 100644 (file)
index 0000000..00cf6de
--- /dev/null
+++ b/scripts/system/add_domain.sh
@@ -0,0 +1,162 @@
+#!/bin/bash
+
+# this set of functions serve the main purpose of adding new domains or subdomains to the bind9 DNS server on the current host.
+# it is currently highly specific to running a bunch of domains on a linux VM, where the VM has one IP address.
+# note that bind 'named' must already be configured.
+# also, it is assumed that if a subdomain is being added, then the containing domain has already been configured and is 
+# configured in a file similar to "blah.com.conf" in /etc/bind.
+#
+# Author: Chris Koeritz
+
+# some defaults that are convenient for current purposes.
+# hmmm: these would need to be parameterized somehow for this script to become really general.
+
+# in our scheme, the single IP address that all our domains map to.
+IP_ADDRESS="10.28.42.20"
+# the email address (where first dot is replaced by @) for the administrator of the domain.
+SERVER_ADMIN="fred.cakelampvm.com"
+# the name of the name server for the new domains (should already be configured).
+MAIN_NAME_SERVER="ns.cakelampvm.com"
+# the name of the mail server for a new domain (should already be configured).
+MAIL_SERVER="mail.cakelampvm.com"
+# the distribution name to be listed in info for the new domain or subdomain.
+DISTRO="ubuntu"
+
+# creates a totally new domain config file for DNS.
+function write_new_domain_file()
+{
+  local domain_name="$1"; shift
+
+  local domain_file="/etc/bind/${domain_name}.conf"
+
+  echo "adding a totally new domain called $domain_name"
+  echo "using the config file: $domain_file"
+
+  if [ -f $domain_file ]; then
+    echo "The domain configuration file already exists at:"
+    echo "  $domain_file"
+    echo "Please remove this file before proceeding, if it is junk.  For example:"
+    echo "  sudo rm $domain_file"
+    exit 1
+  fi
+
+  echo "
+\$TTL 1W
+@      IN SOA  @       ${SERVER_ADMIN}. (
+               2017100801 ; serial
+               2H ; refresh
+               8M ; retry
+               14D ; expiry
+               6H ) ; minimum
+
+       IN NS           ${MAIN_NAME_SERVER}.
+       IN MX   10      ${MAIL_SERVER}.
+
+${domain}.     IN A    ${IP_ADDRESS}
+       IN HINFO        \"linux server\" \"${DISTRO}\"
+"
+#fix
+# >"$domain_file"
+}
+
+function add_zone_for_new_domain()
+{
+  local domain_name="$1"; shift
+
+  local domain_file="/etc/bind/${domain_name}.conf"
+
+  echo "adding a new domain configured by ${domain_file} into"
+  echo "the named.conf.local configuration file."
+
+# need to write the reference to the new conf file in the zone list.
+
+echo "
+zone \"${domain_name}\" in {
+       file \"${domain_file}\";
+       type master;
+       allow-query { any; };
+};
+"
+#fix
+#>> /etc/bind9/named.conf.local
+
+}
+
+# adds a new subdomain under a containing domain.
+function add_new_subdomain()
+{
+  local new_domain="$1"; shift
+
+  # split up the full domain name into subdomain portion and containing domain.
+  local subdomain="${new_domain%.*.*}"
+  local containing_domain="${new_domain#*.}"
+
+  echo "adding a subdomain $subdomain to containing domain $containing_domain"
+
+  local domain_file="/etc/bind/${containing_domain}.conf"
+  # see if config file already exists; if not, complain.
+  if [ ! -f "$domain_file" ]; then
+    echo "The domain configuration file for $new_domain is missing."
+    echo "It should already be present in: $domain_file"
+    echo "Please add the containing domain before trying to add a subdomain."
+    exit 1
+  fi
+
+  # see if subdomain already present in config.
+  if [ $(grep -q "$new_domain" "$domain_file") ]; then
+    echo "The subdomain $subdomain already seems to exist in the domain"
+    echo "configuration file: $domain_file"
+    echo "Please edit the config file to remove the subdomain before trying"
+    echo "to re-add the subdomain."
+    exit 1
+  fi
+
+  # append the new subdomain into the config file.
+  echo "
+${subdomain}.${containing_domain}.    IN A    ${IP_ADDRESS}
+        IN HINFO \"linux server\" \"${DISTRO}\"
+"
+#fix
+#>> /etc/bind/${containing_domain}.conf
+
+}
+
+function restart_bind()
+{
+  echo restarting DNS server.
+  service bind9 restart
+  if [ $? -ne 0 ]; then
+    echo "The bind service did not restart properly.  Please check the error logs."
+    exit 1
+  fi
+  echo DNS server restarted.
+}
+
+# main body of script.
+
+if (( $EUID != 0 )); then
+  echo "This script must be run as root or sudo."
+  exit 1
+fi
+
+new_domain="$1"; shift
+
+if [ -z "$new_domain" ]; then
+  echo "This script needs a domain name to add to DNS." 
+  exit 1
+fi
+
+# if domain name has three or more components, then add a subdomain.
+# otherwise, add a full new domain.
+if [[ $new_domain == *"."*"."* ]]; then
+  # add a subdomain to the containing domain.
+  add_new_subdomain "$new_domain"
+  restart_bind
+else
+  # create a totally new domain in DNS.
+  write_new_domain_file "$new_domain"
+  add_zone_for_new_domain "$new_domain"
+  restart_bind
+fi
+
+