Attempting to update Amazon Route53 using a script, but domain is not being updated

Question

I have several Amazon EC2 instances, running Ubuntu 10.04, with which I'd like to use Amazon's Route53. I setup a script as described in Shlomo Swidler's article, but I'm still missing something.

When the script runs, it doesn't return any output, which I initially assumed meant it ran correctly. However, when I check the DNS records using MyR53DNS, there are no entries for my instances. Here's my script:

#!/bin/tcsh -f

set root=`dirname $0`
setenv EC2_HOME /usr/lib/ec2-api-tools
setenv EC2_CERT /etc/cron.route53/ec2_x509_cert.pem
setenv EC2_PRIVATE_KEY /etc/cron.route53/ec2_x509_private.pem
setenv AWS_ACCESS_KEY_ID myaccesskeyid
setenv AWS_SECRET_ACCESS_KEY myaccesskey

/usr/bin/ec2-describe-instances | \
perl -ne '/^INSTANCE\s+(i-\S+).*?(\S+\.amazonaws\.com)/ \
and do { $dns = $2; print "$1 $dns\n" }; /^TAG.+\sShortName\s+(\S+)/ \
and print "$1 $dns\n"' | \
perl -ane 'print "$F[0] CNAME $F[1] --replace\n"' | \
xargs -n 4 /etc/cron.route53/cli53/cli53.py \
rrcreate -x 60 mydomain.com

Does anyone see a problem with this script? If its not the script, what else could be preventing my Route53 domain from being updated?

I am using the Security Groups to IP-restrict the instances. I've tried opening port 53, but that didn't seem to have an effect. Is there another port that Route53 uses?

I'd appreciate any help or guidance the Unix & Linux community can offer. Let me know if you need any further info.

---

Here is the results of running: tcsh -f -x /etc/cron.route53/aws-route53.sh

set root=`dirname $0`
dirname /etc/cron.route53/aws-route53.sh
setenv EC2_HOME /usr/lib/ec2-api-tools
setenv EC2_CERT /etc/cron.route53/ec2_x509_cert.pem
setenv EC2_PRIVATE_KEY /etc/cron.route53/ec2_x509_private.pem
setenv AWS_ACCESS_KEY_ID myaccesskeyid
setenv AWS_SECRET_ACCESS_KEY myaccesskey

I receive the same output whether the last 7 lines are commented or uncommented.

---

> cat -A  /etc/cron.route53/aws-route53.sh
#!/bin/tcsh -f$
$
set root=`dirname $0`$
setenv EC2_HOME /usr/lib/ec2-api-tools$
setenv EC2_CERT /etc/cron.route53/ec2_x509_cert.pem$
setenv EC2_PRIVATE_KEY /etc/cron.route53/ec2_x509_private.pem$
setenv AWS_ACCESS_KEY_ID myaccesskeyid$
setenv AWS_SECRET_ACCESS_KEY myaccesskey$
$
/usr/bin/ec2-describe-instances | \$
perl -ne '/^INSTANCE\s+(i-\S+).*?(\S+\.amazonaws\.com)/ \$
and do { $dns = $2; print "$1 $dns\n" }; /^TAG.+\sShortName\s+(\S+)/ \$
and print "$1 $dns\n"' | \$
perl -ane 'print "$F[0] CNAME $F[1] --replace\n"' | \$
xargs -n 4 /etc/cron.route53/cli53/cli53.py \$
rrcreate -x 60 mydomain.com

> cat /etc/cron.route53/aws-route53.sh
#!/bin/tcsh -f

set root=`dirname $0`
setenv EC2_HOME /usr/lib/ec2-api-tools
setenv EC2_CERT /etc/cron.route53/ec2_x509_cert.pem
setenv EC2_PRIVATE_KEY /etc/cron.route53/ec2_x509_private.pem
setenv AWS_ACCESS_KEY_ID myaccesskeyid
setenv AWS_SECRET_ACCESS_KEY myaccesskey

/usr/bin/ec2-describe-instances | \
perl -ne '/^INSTANCE\s+(i-\S+).*?(\S+\.amazonaws\.com)/ \
and do { $dns = $2; print "$1 $dns\n" }; /^TAG.+\sShortName\s+(\S+)/ \
and print "$1 $dns\n"' | \
perl -ane 'print "$F[0] CNAME $F[1] --replace\n"' | \
xargs -n 4 /etc/cron.route53/cli53/cli53.py \
rrcreate -x 60 mydomain.com

Answer 1

Aha! Your script is missing a newline at the end. Unix text files (such as scripts) are sequences of line, and each line (even the last) must be terminated by a newline.

Most modern unix tools can cope with malformed text files, but tcsh doesn't count as modern: it looks like it ignores the last, unterminated, logical line (everything after the last newline that's not preceded by a backslash).

A good editor (such as Emacs or Vi(m)) automatically makes sure that csh scripts are terminated by a newline.¹ It looks like your editor is not doing the right thing, so make sure your scripts do end with a newline (cat /path/to/script must show the last script line above the next prompt, not next to it).

¹ _{In a really good editor, such as Emacs, this doesn't apply to other kinds of files that may legitimately be not newline-terminated.}