Fixing URL-based Redirect Errors for AWS Route 53 and S3

Transcription

1 Fixing URL-based Redirect Errors for AWS Route 53 and S3 Many of the typical DNS providers offer what we call URL-based redirects. This is something where a 301 HTTP response is applied to the DNS query and an answer of a new DNS name is sent back in order to forward you to the new URL. This is not something that is natively available in AWS Route 53, but I ve written about the solution here in the past where we can use S3 buckets and the website hosting and redirection option. The flow that the client will see is: request URL (e.g. gcondemand.io) DNS responds with record from Route 53 with an S3 alias S3 redirects to the new URL using HTTP 301 response Domains No Longer Forwarding using Route 53 and S3 The only challenge comes when you set up a domain on Route 53 and you are asked which DNS servers are the authoritative NS records to inject. New zones work automatically by injecting AWS name servers which will be dynamic within the AWS environment. When a zone is transferred, the question will be presented if you want to keep your existing NS settings from the original registrar or if you want to specify your own NS settings which means setting up some NS records that you assume are all good. Here s the trick: your NS records must contain the same entry as the SOA (Start of Authority) or else bad things will happen in time. This is an example of a domain that was transferred over, given NS entries, and worked for quite a while. Suddenly, this is what will happen: But, it worked for a while DNS is a magical thing (spoiler: it s not really magic), and will work for quite a while as the internet continues to dynamically find your zone redirect on the previous name servers. At some point, you will bump into the issue where the records will age out on other servers and when downstream DNS servers go hunting for your records, the zone is pointing to differing NS records. Fixing your Simple Redirects using Route 53 and S3 Fire up your Route 53 console, choose your hosted zone, and then select the Go To Record Sets button to edit the zone.

2 You can see by our entries here that we have a mismatch from the SOA and the NS records: I ve gotten four AWS DNS servers that I will use here: ns-1881.awsdns-43.co.uk ns-875.awsdns-45.net ns-134.awsdns-16.com ns-1457.awsdns-54.org That will fix the first issue of the mismatched NS records and the SOA being different: For the second part of the fix, go to the Registered Domains section in the Route 53 console, and select the Add or Edit Name Servers section under your zone. Now, make sure to replace the four records with the matching set of four NS records you ve used within the Hosted Zone section:

3 That will get you all sorted out. Don t forget that DNS is a cached both locally and on remote DNS servers, so it may take up to 5-15 minutes for your local cache to expire and it may take up to a few hours for the remote entries to become corrected. Hopefully that gets you all fixed up if you ve had a similar issue! Setting up a GitBook for a Custom Domain If you haven t already looked at the GitBook platform, you definitely should. There are a number of very interesting ways that you can use this for creating easy-to-use documentation sites using simple markdown and the hosted platform. SaaS FTW! Let s view a simple way to add a custom domain name to an existing GitBook site. For this example, I m using: A GitBook site AWS Route53 hosted zone About 15 minutes of wait time for the DNS propagation Start by looking at your existing GitBook site under the Settings Domains section: The first thing to do is to make sure that you get your DNS configured. Open up your AWS Route53 console, select the radio button for your domain, and click the Go to Record Sets button:

4 Create a new CNAME entry using the Create Record Set button. Choose www for the Name field, CNAME as the Type, and for the value, choose to redirect the request: You also need to set a redirect for the root domain which is turbonomicguidetothegalaxy.com in this case. That naked domain redirect can be done in some DNS hosting platforms using a URL Redirect, however that is not available with AWS Route53. Luckily, I ve covered how to use S3 and Route53 for simple redirects in the past here. You will just need to configure the redirect of the root to in the S3 configuration. Route53 will take over from

5 there. On your GitBooks settings page, enter the newly assigned domain name to match the changes you just made in Route53. This is done using the Domain for content field: Save the settings and you ll be given a confirmation on screen: This is where the wait time comes in. DNS can take a little while to update across all of the internet, so it s best to wait about 15 minutes to complete the last step. To confirm your changes, type in the domain name for your GitBook that you have just configured and watch the magic happen! The sample you can see at TurbonomicGuideToTheGalaxy.com is a simple GitBooks site that is being updated. Now all that I have to do is give out the FQDN and update my book as I go. If the book repository is updated, the redirection can be configured at the new repo and you never have to worry about people having to update their links and bookmarks. Enjoy!

6 AWS Route53 Step-by-Step Redirecting Domains GUI While I ve covered this one before with a specific two-step approach to do simple redirect. This will repeat some of those steps with a new domain pointing to an alternate web site URL. This is a real use-case example where I ve bought a new domain that I want redirected to DiscoPosse.com as the target. Sample source zone: EricWright.ca Sample target website: DiscoPosse.com Using Route53 to Redirect to a New URL My sample domain was registered with Route53. You can see the registration message here: A Hosted Zone is created automatically as part of the registration process: Highlight the radio button and use the Go to Record Sets button. That lets us create a new entry with the Create Record Set button. Because we want to redirect the default www zone, let s create a CNAME record for that and directly assign discoposse.com in the Value field:

7 We need to redirect the root domain of ericwright.ca as well, but we can t use a CNAME for a root record. This means we need to create a S3 bucket for the root zone. Name it after the domain you re redirecting:

8 Set up the Static Website Hosting section in the properties window for the S3 bucket, and put the target domain under the Redirect all requests to another host name section: We may have to exit and reenter the Route53 zone to refresh, so once you re done with that, set up a new A record, click the Alias radio button to Yes, and click the Alias Target field to trigger the drop down list where you can select the S3 website endpoint that matches the domain root:

9 Wait for a few minutes minutes will ensure that the TTL for the zone and record are passed and it forces a fresh request to the root domain. Using the AWS CLI (aka AWS Shell) to Query Route53 Hosted Zones You will need to install the AWS CLI on your machine, or you can also use my sandbox method to run it inside a VirtualBox VM to save installing in your workstation. Once configured, we will use the following command to list all of the zones: aws route53 list-hosted-zones-by-name

10 You will see all of the available zones come back. Clearly that is more detail than we want, so let s add a couple of parameters which will reduce the output to just the zone we want --dns-name ericwright.ca. (note the trailing dot is important). That still returns a series of zones, so we also add the --max-items 1 parameter as well: We can confirm the redirects using the curl command for both domain names using the curl command and the -IL parameter to show the HTTP response details:

11 In our next post, we will be doing some DNS record management using the AWS CLI to emulate the changes we did in the GUI in this article. Simple HTTP Redirects Using AWS Route 53 and S3 Let s just say that you want to create a redirect for a root domain while using Route 53 on Amazon Web Services. Many of the popular domain registration and web hosting providers (e.g. GoDaddy, Domain.com, etc.) have baked in settings to redirect to another URL. In Route 53, there is no native way to do this, but luckily it s a couple of simple steps away and you also get to learn a little about web site hosting on AWS S3 (Simple Storage Service) at the same time.

12 My example is for which has been redirected to as you can see by clicking the link. Now, let s learn how to do that easily with AWS Route 53 DNS service and S3. Our assumption is that you ve registered the domain with Route 53 or are at least hosting the DNS zone and have set the SOA (Start of Authority) record and NS (Name Server) records to AWS DNS settings. Setting up Your S3 Buckets The reason that I say buckets as a plural, is that we will want to have a working DNS for both the root domain virtualdesignmaster.com and also the which is normally a CNAME entry to point to the root domain. Open up your AWS S3 and click the Create Bucket button. Name your S3 bucket the same as your domain name. In my case for the example is virtualdesignmaster.com. I ve chose to put it in the US Standard region because it s the closest to the majority of my traffic for the site: After you click the create button, you need to click the Properties button on the upper right side of the page. Expand the section which says Static Website Hosting, select the Redirect all requests to another host name radio button, and type the URL that you want to redirect to. In my case it is

13 Save the changes and repeat the process, but this time you will name the S3 bucket as the www name for your domain. My example uses Open the Properties section, expand the section which says Static Website Hosting, select the Redirect all requests to another host name radio button, and type the URL that you want to redirect to:

14 That is your S3 configuration. Next up is the DNS settings. Route 53 Configuration for S3 Targets Open up your Route 53 configuration in the AWS console. Select the Hosted Zones area, choose the radio button for the zone we are working on and click Go to Record Sets: Click Create Record Set. Leave the Name section empty, choose A IPv4 address as the Type:

15 Change the Alias from the default of No to Yes: Click in the Alias Target field which brings up a droplist. It may take up to 20 or more seconds to populate the list. Under the S3 website endpoints you will see the one you ve created. Select that and click the Create button at the bottom: Repeat the process of adding a new record. This time put www in the Name section. Keep A-IPv4 address as the Type, and click the Alias Target section to select the S3 website endpoint which matches the A record name:

16 DNS is a rather magical system, but it will take up to 15 minutes or more update. Once some time has passed, you can confirm te redirection is in place by trying the URL in a browser. It should redirect you to the web site that you ve assigned in your S3 configuration. You can confirm from the command line using curl as well. Type curl --head yourdomain.com which will show you the output below, and then you can also type curl yourdomain.com which will show you the redirect in the output: Note that this is different than a 301 or 302 redirect. The method used by the S3 redirection is a META tag instead. I m also assuming that you re aware that there is a cost for the S3 usage.

17 Costs of Using S3 for Web Site Hosting and Redirection As listed on the S3 and storage pricing site, the S3 usage qualifies for a Free Tier to AWS users up to the first 20,000 HTTP GET requests per month for the first year of usage. After your Free Tier usage expires, you are charged 0.004$ per 10,000 HTTP GET requests per month in the US East region. Pricing across regions can be different, so make sure to take that into account when you choose the location of your S3 buckets: Hopefully this helps, plus it s also handy to know as part of your study towards the AWS Solutions Architect Associate exam.