diff --git a/modules/install-consul/README.md b/modules/install-consul/README.md
index e8f2647b..dea1258e 100644
--- a/modules/install-consul/README.md
+++ b/modules/install-consul/README.md
@@ -44,7 +44,7 @@ example](https://github.com/hashicorp/terraform-aws-consul/tree/master/examples/
 The `install-consul` script accepts the following arguments:
 
 * `version VERSION`: Install Consul version VERSION. Optional if download-url is provided.
-* `dowload-url URL`: Install the Consul package hosted in this url. Optional if version is provided.
+* `download-url URL`: Install the Consul package hosted in this url. Optional if version is provided.
 * `path DIR`: Install Consul into folder DIR. Optional.
 * `user USER`: The install dirs will be owned by user USER. Optional.
 * `ca-file-path PATH`: Path to a PEM-encoded certificate authority used to encrypt and verify authenticity of client and server connections. Optional.
diff --git a/modules/install-consul/install-consul b/modules/install-consul/install-consul
index 03b856aa..ac53a779 100755
--- a/modules/install-consul/install-consul
+++ b/modules/install-consul/install-consul
@@ -41,30 +41,30 @@ function print_usage {
 }
 
 function log {
-  local readonly level="$1"
-  local readonly message="$2"
-  local readonly timestamp=$(date +"%Y-%m-%d %H:%M:%S")
+  local -r level="$1"
+  local -r message="$2"
+  local -r timestamp=$(date +"%Y-%m-%d %H:%M:%S")
   >&2 echo -e "${timestamp} [${level}] [$SCRIPT_NAME] ${message}"
 }
 
 function log_info {
-  local readonly message="$1"
+  local -r message="$1"
   log "INFO" "$message"
 }
 
 function log_warn {
-  local readonly message="$1"
+  local -r message="$1"
   log "WARN" "$message"
 }
 
 function log_error {
-  local readonly message="$1"
+  local -r message="$1"
   log "ERROR" "$message"
 }
 
 function assert_not_empty {
-  local readonly arg_name="$1"
-  local readonly arg_value="$2"
+  local -r arg_name="$1"
+  local -r arg_value="$2"
 
   if [[ -z "$arg_value" ]]; then
     log_error "The value for '$arg_name' cannot be empty"
@@ -74,10 +74,10 @@ function assert_not_empty {
 }
 
 function assert_either_or {
-  local readonly arg1_name="$1"
-  local readonly arg1_value="$2"
-  local readonly arg2_name="$3"
-  local readonly arg2_value="$4"
+  local -r arg1_name="$1"
+  local -r arg1_value="$2"
+  local -r arg2_name="$3"
+  local -r arg2_value="$4"
 
   if [[ -z "$arg1_value" && -z "$arg2_value" ]]; then
     log_error "Either the value for '$arg1_name' or '$arg2_name' must be passed, both cannot be empty"
@@ -86,6 +86,30 @@ function assert_either_or {
   fi
 }
 
+# A retry function that attempts to run a command a number of times and returns the output
+function retry {
+  local -r cmd="$1"
+  local -r description="$2"
+
+  for i in $(seq 1 5); do
+    log_info "$description"
+
+    # The boolean operations with the exit status are there to temporarily circumvent the "set -e" at the
+    # beginning of this script which exits the script immediatelly for error status while not losing the exit status code
+    output=$(eval "$cmd") && exit_status=0 || exit_status=$?
+    log_info "$output"
+    if [[ $exit_status -eq 0 ]]; then
+      echo "$output"
+      return
+    fi
+    log_warn "$description failed. Will sleep for 10 seconds and try again."
+    sleep 10
+  done;
+
+  log_error "$description failed after 5 attempts."
+  exit $exit_status
+}
+
 # Install steps are based on: http://unix.stackexchange.com/a/291098/215969
 function install_supervisord_debian {
   sudo apt-get install -y supervisor
@@ -166,12 +190,12 @@ function install_dependencies {
 }
 
 function user_exists {
-  local readonly username="$1"
+  local -r username="$1"
   id "$username" >/dev/null 2>&1
 }
 
 function create_consul_user {
-  local readonly username="$1"
+  local -r username="$1"
 
   if $(user_exists "$username"); then
     echo "User $username already exists. Will not create again."
@@ -182,8 +206,8 @@ function create_consul_user {
 }
 
 function create_consul_install_paths {
-  local readonly path="$1"
-  local readonly username="$2"
+  local -r path="$1"
+  local -r username="$2"
 
   log_info "Creating install dirs for Consul at $path"
   sudo mkdir -p "$path"
@@ -198,24 +222,25 @@ function create_consul_install_paths {
 }
 
 function fetch_binary {
-  local readonly version="$1"
+  local -r version="$1"
   local download_url="$2"
 
   if [[ -z "$download_url" && -n "$version" ]];  then
     download_url="https://releases.hashicorp.com/consul/${version}/consul_${version}_linux_amd64.zip"
   fi
 
-  log_info "Downloading Consul to $DOWNLOAD_PACKAGE_PATH"
-  curl -o "$DOWNLOAD_PACKAGE_PATH" "$download_url" --location --silent --fail --show-error
+  retry \
+    "curl -o '$DOWNLOAD_PACKAGE_PATH' '$download_url' --location --silent --fail --show-error" \
+    "Downloading Consul to $DOWNLOAD_PACKAGE_PATH"
 }
 
 function install_binary {
-  local readonly install_path="$1"
-  local readonly username="$2"
+  local -r install_path="$1"
+  local -r username="$2"
 
-  local readonly bin_dir="$install_path/bin"
-  local readonly consul_dest_path="$bin_dir/consul"
-  local readonly run_consul_dest_path="$bin_dir/run-consul"
+  local -r bin_dir="$install_path/bin"
+  local -r consul_dest_path="$bin_dir/consul"
+  local -r run_consul_dest_path="$bin_dir/run-consul"
 
   unzip -d /tmp "$DOWNLOAD_PACKAGE_PATH"
 
@@ -224,7 +249,7 @@ function install_binary {
   sudo chown "$username:$username" "$consul_dest_path"
   sudo chmod a+x "$consul_dest_path"
 
-  local readonly symlink_path="$SYSTEM_BIN_DIR/consul"
+  local -r symlink_path="$SYSTEM_BIN_DIR/consul"
   if [[ -f "$symlink_path" ]]; then
     log_info "Symlink $symlink_path already exists. Will not add again."
   else
@@ -239,14 +264,14 @@ function install_binary {
 }
 
 function install_tls_certificates {
-  local readonly path="$1"
-  local readonly user="$2"
-  local readonly ca_file_path="$3"
-  local readonly cert_file_path="$4"
-  local readonly key_file_path="$5"
-
-  local readonly consul_tls_certs_path="$path/tls"
-  local readonly ca_certs_path="$consul_tls_certs_path/ca"
+  local -r path="$1"
+  local -r user="$2"
+  local -r ca_file_path="$3"
+  local -r cert_file_path="$4"
+  local -r key_file_path="$5"
+
+  local -r consul_tls_certs_path="$path/tls"
+  local -r ca_certs_path="$consul_tls_certs_path/ca"
 
   log_info "Moving TLS certs to $consul_tls_certs_path and $ca_certs_path"
 
diff --git a/modules/install-dnsmasq/install-dnsmasq b/modules/install-dnsmasq/install-dnsmasq
index c4797c4b..ee8e007e 100755
--- a/modules/install-dnsmasq/install-dnsmasq
+++ b/modules/install-dnsmasq/install-dnsmasq
@@ -34,30 +34,30 @@ function print_usage {
 }
 
 function log {
-  local readonly level="$1"
-  local readonly message="$2"
-  local readonly timestamp=$(date +"%Y-%m-%d %H:%M:%S")
+  local -r level="$1"
+  local -r message="$2"
+  local -r timestamp=$(date +"%Y-%m-%d %H:%M:%S")
   >&2 echo -e "${timestamp} [${level}] [$SCRIPT_NAME] ${message}"
 }
 
 function log_info {
-  local readonly message="$1"
+  local -r message="$1"
   log "INFO" "$message"
 }
 
 function log_warn {
-  local readonly message="$1"
+  local -r message="$1"
   log "WARN" "$message"
 }
 
 function log_error {
-  local readonly message="$1"
+  local -r message="$1"
   log "ERROR" "$message"
 }
 
 function assert_not_empty {
-  local readonly arg_name="$1"
-  local readonly arg_value="$2"
+  local -r arg_name="$1"
+  local -r arg_value="$2"
 
   if [[ -z "$arg_value" ]]; then
     log_error "The value for '$arg_name' cannot be empty"
@@ -75,7 +75,7 @@ function has_apt_get {
 }
 
 function install_dnsmasq {
-  local readonly consul_ip="$1"
+  local -r consul_ip="$1"
 
   log_info "Installing Dnsmasq"
 
@@ -95,9 +95,9 @@ function install_dnsmasq {
 }
 
 function write_consul_config {
-  local readonly consul_domain="$1"
-  local readonly consul_ip="$2"
-  local readonly consul_port="$3"
+  local -r consul_domain="$1"
+  local -r consul_ip="$2"
+  local -r consul_port="$3"
 
   log_info "Configuring Dnsmasq to forward lookups of the '$consul_domain' domain to $consul_ip:$consul_port in $CONSUL_DNS_MASQ_CONFIG_FILE"
   mkdir -p "$DNS_MASQ_CONFIG_DIR"
diff --git a/modules/run-consul/run-consul b/modules/run-consul/run-consul
index 9ae89f4b..a8352648 100755
--- a/modules/run-consul/run-consul
+++ b/modules/run-consul/run-consul
@@ -70,37 +70,37 @@ function print_usage {
 }
 
 function log {
-  local readonly level="$1"
-  local readonly message="$2"
-  local readonly timestamp=$(date +"%Y-%m-%d %H:%M:%S")
+  local -r level="$1"
+  local -r message="$2"
+  local -r timestamp=$(date +"%Y-%m-%d %H:%M:%S")
   >&2 echo -e "${timestamp} [${level}] [$SCRIPT_NAME] ${message}"
 }
 
 function log_info {
-  local readonly message="$1"
+  local -r message="$1"
   log "INFO" "$message"
 }
 
 function log_warn {
-  local readonly message="$1"
+  local -r message="$1"
   log "WARN" "$message"
 }
 
 function log_error {
-  local readonly message="$1"
+  local -r message="$1"
   log "ERROR" "$message"
 }
 
 # Based on code from: http://stackoverflow.com/a/16623897/483528
 function strip_prefix {
-  local readonly str="$1"
-  local readonly prefix="$2"
+  local -r str="$1"
+  local -r prefix="$2"
   echo "${str#$prefix}"
 }
 
 function assert_not_empty {
-  local readonly arg_name="$1"
-  local readonly arg_value="$2"
+  local -r arg_name="$1"
+  local -r arg_value="$2"
 
   if [[ -z "$arg_value" ]]; then
     log_error "The value for '$arg_name' cannot be empty"
@@ -110,12 +110,12 @@ function assert_not_empty {
 }
 
 function lookup_path_in_instance_metadata {
-  local readonly path="$1"
+  local -r path="$1"
   curl --silent --show-error --location "$EC2_INSTANCE_METADATA_URL/$path/"
 }
 
 function lookup_path_in_instance_dynamic_data {
-  local readonly path="$1"
+  local -r path="$1"
   curl --silent --show-error --location "$EC2_INSTANCE_DYNAMIC_DATA_URL/$path/"
 }
 
@@ -132,8 +132,8 @@ function get_instance_region {
 }
 
 function get_instance_tags {
-  local readonly instance_id="$1"
-  local readonly instance_region="$2"
+  local -r instance_id="$1"
+  local -r instance_region="$2"
   local tags=""
   local count_tags=""
 
@@ -159,8 +159,8 @@ function get_instance_tags {
 }
 
 function get_asg_size {
-  local readonly asg_name="$1"
-  local readonly aws_region="$2"
+  local -r asg_name="$1"
+  local -r aws_region="$2"
   local asg_json=""
 
   log_info "Looking up the size of the Auto Scaling Group $asg_name in $aws_region"
@@ -169,8 +169,8 @@ function get_asg_size {
 }
 
 function get_cluster_size {
-  local readonly instance_tags="$1"
-  local readonly aws_region="$2"
+  local -r instance_tags="$1"
+  local -r aws_region="$2"
 
   local asg_name=""
   asg_name=$(get_tag_value "$instance_tags" "$AWS_ASG_TAG_KEY")
@@ -185,14 +185,14 @@ function get_cluster_size {
 # Get the value for a specific tag from the tags JSON returned by the AWS describe-tags:
 # https://docs.aws.amazon.com/cli/latest/reference/ec2/describe-tags.html
 function get_tag_value {
-  local readonly tags="$1"
-  local readonly tag_key="$2"
+  local -r tags="$1"
+  local -r tag_key="$2"
 
   echo "$tags" | jq -r ".Tags[] | select(.Key == \"$tag_key\") | .Value"
 }
 
 function assert_is_installed {
-  local readonly name="$1"
+  local -r name="$1"
 
   if [[ ! $(command -v ${name}) ]]; then
     log_error "The binary '$name' is required by this script but is not installed or in the system's PATH."
@@ -208,26 +208,26 @@ function join_by {
 }
 
 function generate_consul_config {
-  local readonly server="${1}"
-  local readonly config_dir="${2}"
-  local readonly user="${3}"
-  local readonly cluster_tag_key="${4}"
-  local readonly cluster_tag_value="${5}"
-  local readonly datacenter="${6}"
-  local readonly enable_gossip_encryption="${7}"
-  local readonly gossip_encryption_key="${8}"
-  local readonly enable_rpc_encryption="${9}"
-  local readonly ca_path="${10}"
-  local readonly cert_file_path="${11}"
-  local readonly key_file_path="${12}"
-  local readonly cleanup_dead_servers="${13}"
-  local readonly last_contact_threshold="${14}"
-  local readonly max_trailing_logs="${15}"
-  local readonly server_stabilization_time="${16}"
-  local readonly redundancy_zone_tag="${17}"
-  local readonly disable_upgrade_migration="${18}"
-  local readonly upgrade_version_tag=${19}
-  local readonly config_path="$config_dir/$CONSUL_CONFIG_FILE"
+  local -r server="${1}"
+  local -r config_dir="${2}"
+  local -r user="${3}"
+  local -r cluster_tag_key="${4}"
+  local -r cluster_tag_value="${5}"
+  local -r datacenter="${6}"
+  local -r enable_gossip_encryption="${7}"
+  local -r gossip_encryption_key="${8}"
+  local -r enable_rpc_encryption="${9}"
+  local -r ca_path="${10}"
+  local -r cert_file_path="${11}"
+  local -r key_file_path="${12}"
+  local -r cleanup_dead_servers="${13}"
+  local -r last_contact_threshold="${14}"
+  local -r max_trailing_logs="${15}"
+  local -r server_stabilization_time="${16}"
+  local -r redundancy_zone_tag="${17}"
+  local -r disable_upgrade_migration="${18}"
+  local -r upgrade_version_tag=${19}
+  local -r config_path="$config_dir/$CONSUL_CONFIG_FILE"
 
   local instance_id=""
   local instance_ip_address=""
@@ -316,14 +316,14 @@ EOF
 }
 
 function generate_supervisor_config {
-  local readonly supervisor_config_path="$1"
-  local readonly consul_config_dir="$2"
-  local readonly consul_data_dir="$3"
-  local readonly consul_log_dir="$4"
-  local readonly consul_bin_dir="$5"
-  local readonly consul_user="$6"
+  local -r supervisor_config_path="$1"
+  local -r consul_config_dir="$2"
+  local -r consul_data_dir="$3"
+  local -r consul_log_dir="$4"
+  local -r consul_bin_dir="$5"
+  local -r consul_user="$6"
   shift 6
-  local readonly environment=("$@")
+  local -r environment=("$@")
 
   log_info "Creating Supervisor config file to run Consul in $supervisor_config_path"
   cat > "$supervisor_config_path" <<EOF
@@ -349,7 +349,7 @@ function start_consul {
 
 # Based on: http://unix.stackexchange.com/a/7732/215969
 function get_owner_of_path {
-  local readonly path="$1"
+  local -r path="$1"
   ls -ld "$path" | awk '{print $3}'
 }