TL;DR: The url for this blog has been updated; it used to be hojin-kim.github.io and is now blog.hojin.kim. Also, hojin.kim/blog or hojin-kim.github.io/blog will redirect to the new url.

There is a .kim top-level domain

I discovered that .kim exists as a top-level domain. I checked that hojin.kim was not taken, and I bought it.

And then I was confused about what to do with it. Finally, after a lot of trial and error, I decided and set up the following urls:

  • hojin.kim for the academic homepage hosted by my affiliation, and
  • blog.hojin.kim for this blog.

This took much longer than it should have, so I’m writing this post to summarize the process and to remind myself in the future (or to help someone else who is in the same situation).

Setting up the hojin.kim domain

I bought the domain from Porkbun; one of my friends said that the price here is good. (I didn’t double-check if it is, so you might want to check other providers as well).

I decided to use hojin.kim for my academic homepage mathsci.kaist.ac.kr/~hjkim. Here are the steps I took:

  • The domain provider said that I needed an IPv4 address for the root domain setting. I had no idea about this; after some research, I came to know that the tilde home directory generally does not have a dedicated IP address.
  • It seemed that some web server configurations might do this; after checking the corresponding Apache2 configurations on [dept webserver]:[...]/apache2/sites-available/ (with my read-only permission), I concluded that the server policy did not seem to allow such configurations for individuals. This means that I cannot link my personal domain directly to the academic homepage.
  • A quick workaround is a redirection. Instead of having another web server like AWS, I decided to use the GitHub page.

  • hojin-kim.github.io was already taken for this blog. After some more trial and error, I renamed the repository from hojin-kim.github.io to blog, so the blog url at that point was hojin-kim.github.io/blog.

    I was stuck at this point for a while, especially with the site.baseurl feature.

    Say the url for a post in the blog is hojin-kim.github.io/blog/math/20200101-title. Then hojin-kim.github.io is url, and /blog is the baseurl, which means that all urls are follwed by url+baseurl. (The followed /math/20200101-title stands for the precise location of the post, relative to the url+baseurl).

    Since my original plan was to set the blog url to hojin.kim/blog, I changed the repository name into blog, and also set the baseurl : /blog in [repo-root]\_config.yml. (Note that some repository is published under github-id.github.io/some). Because of this change, I had to do the overall fix of several Jekyll files and posts, since I haven’t take care of baseurl feature before (as it was empty).

    However, at last, the blog url is set to blog.hojin.kim, and site.baseurl is set to be empty again.

  • Then I created the new repository hojin-kim.github.io for the root GitHub page, published it, and set the custom domain to hojin.kim.
  • I made some settings on the domain provider website. I set the CNAME record to
    • TYPE: CNAME,
    • HOST: www.hojin.kim,
    • ANSWER: hojin-kim.github.io..
  • The apex domain (hojin.kim) was automatically set by the domain provider; if you did it manually, it would be look like this:
    • TYPE: A,
    • HOST: hojin.kim,
    • ANSWER: The IPv4 address of the GitHub page, 185.199.[x].153 with $108 \le x \le 111$. (I have four items for the setting.)
  • Everything worked fine at that point. This resulted in
    • hojin.kim for hojin-kim.github.io, which redirects to the academic homepage, and
    • hojin.kim/blog for this blog hojin-kim.github.io/blog.

Setting up the subdomain

Up until this moment, I was thinking of using hojin.kim/blog for this blog. However, I realized that it would be better to use blog.hojin.kim for the blog. The reasons are:

  • Inconsistent physical directory structure.

    hojin.kim/blog makes me think that the blog is a subdirectory of the homepage, which is not true (although I know that this is technically irrelevant).

  • The permanent url for the posts will be confusing.

    The url for the posts will be hojin.kim/blog/categoryname/subcatname/YYYYMMDD-post-title which is not only too long but also consists of too deep directories. This was tolerable, but there was a more serious problem; since I have a category called blog, some posts would have urls like hojin.kim/blog/blog/YYYYMMDD-post-title, which is super ugly.

So I decided to use blog.hojin.kim for the blog. I spent other hours on this, which shouldn’t take that long. Actually, the steps are simple.

  • Edit your Jekyll files again if needed. For example, I changed the url of _config.yml.

    I checked that everything worked fine when tested locally, but there were still some problems when hosted on GitHub. You might have to check the source code for the rendered html files, and check that each asset file (like css files) is linked correctly.

  • Publish the repository, and set the custom domain to blog.hojin.kim.
  • Make some settings on the domain provider. I set the CNAME record to
    • TYPE: CNAME,
    • HOST: blog.hojin.kim,
    • ANSWER: hojin-kim.github.io.,

    This was another time-consuming step for me. First I set the ANSWER slot to hojin.kim/blog. Since the DNS check failed, I tried hojin-kim.github.io/blog and so on. I thought the DNS propagation would take some time, so I waited for hours, and the problem was not solved. After some research, I realized that the ANSWER slot should be hojin-kim.github.io.. Note the dot at the end; this indicates that the domain is a Fully Qualified Domain Name (FQDN).

Remaining TODOs

  • The Google search result now points to the outdated urls; I should check the Google Search Console and update the Sitemap. – However, who cares? I mean, I know this site is very rarely visited.
  • Some minor settings, like Disqus comments etc.
    • Disqus
    • Sitemap.xml
    • Robots.txt
    • Google Analytics
    • Broken links in previous posts or etc?
    • Some other?
  • Check if the baseurl thing was necessary. The existence of two working urls, blog.[...] and [...]/blog, is not pleasant and I want to check if I can get rid of the baseurl setting and deprecate the [...]/blog url. Maybe I should check the settings url (for the base hostname) and baseurl on \_config.yml.
    • Updated: baseurl is now removed again, with url: blog.hojin.kim.