Kassadin.moe
中文 ZH English EN 日本語 JA

Tutorial: Build a Personal Blog with Hexo + GitHub

Published on

Original language: Chinese . AI translations: English , Japanese .

This tutorial is for complete beginners with zero technical background. The goal is to help you build your own blog step by step.

It’s recommended to read the whole article once before you start.
(I’m using Windows 10 1903, so this tutorial is for Windows users.)

Motivation

I’d wanted to set up a blog for a long time, but never actually did it.
One weekend, while browsing around, I saw a tutorial about building a blog with Hexo + GitHub. On a whim, I decided to tinker with it.

While the “three-minute enthusiasm” lasted, I went from noon to night, spending 10+ hours, and finally built what the tutorial called “a personal site hosted on GitHub in 10 minutes”.
Of course, the tutorial itself is good, and if everything goes smoothly you really can set it up quickly.
But because my skill level was below zero, I stepped on a lot of weird beginner traps and wasted a ton of time.

Experienced people might miss some tiny details because in their eyes “everyone knows this”.
But those little details are exactly what trips up a lot of beginners who are ready to try.
So I’m writing this post to record my setup process and the pitfalls I hit, hoping it helps other beginners build their own site successfully.

Overall Flow

Now the main part: how to build a website using Hexo + GitHub.
Here’s the high-level workflow:

  • Preparation

    • Install Node.js and Git
    • Install Hexo

  • Build the blog locally

    • Create the site folder
    • Generate pages
    • Run locally

  • Host on GitHub

    • Create a GitHub account and repository
    • Connect Git and GitHub
    • Push the local site to GitHub

  • Celebrate

If you don’t know the terms above, here are brief introductions. Don’t worry if you still don’t get them; it won’t block the steps.

What is Hexo?
Hexo is a fast, simple, and efficient blog framework (Hexo docs).
You can think of it like applying a template when making slides: Hexo helps you generate a website locally, then you host the generated files on GitHub.

What is Node.js?
I don’t fully understand it. Here, it’s a runtime/component required for Hexo.

What is Git?
Git is a version control tool. In this tutorial, you can treat it as a terminal that helps control other tools.

What is GitHub?
GitHub is a hosted platform that uses Git for version control (Wikipedia).
For this tutorial, you can treat GitHub as a public cloud drive: you create a repository and upload your site there, and then others can access it.

Next, I’ll use Windows 10’s built-in Sandbox to demonstrate building a blog on a fresh Windows system.

Preparation

Install Node.js

Go to the Node.js website, click the left 10/16/0 LTS button to download.
Install with all defaults.

Install Git

Click the Git download link to download.
But for obvious reasons, the download may be slow. You can also use this mirror: Git for Windows (China mirror) and pick the latest 64-bit Git for Windows Setup.
Install with all defaults.

Install Hexo

With the required components installed, it’s time to install Hexo.
This step is very simple.
Right-click anywhere (for example, an empty area on the desktop), and select Git Bash Here.

This opens Git Bash. It looks like a scary command-line window, but you only need to type one command.

In the black window, you’ll see the cursor blinking after a $ symbol.

Type:
npm install -g hexo-cli

The window will look like this:

Press Enter. You’ll see… nothing change, and the cursor moves to the next line.

But Hexo is installing in the background. Wait for a while (depends on your network).
When it finishes, it will say something like: installed hexo-cli 2.0.0 in 105.03s.

Preparation is done. Next: build the blog locally.

Build Locally

Initialize the Folder

  • First, create a folder to store all blog files. You can put it anywhere you like. For example, I created a folder named Blog under Documents.
  • Open the empty folder, right-click, and click Git Bash Here.
  • Same black window again. This time it’s even simpler: type hexo init and press Enter.
    It will initialize the Blog folder and generate the skeleton files (think: the slide template). This can take a bit, so wait.
  • After a few minutes, initialization should be done. You’ll see many new files in the folder.
  • Next, don’t close the window. Type npm install and press Enter.
    It should be quick. You might see two warnings, but it seems fine.

Generate and Serve

  • Type hexo g and press Enter.
    (hexo g is short for hexo generate: it generates the static pages.)
  • The window prints a bunch of output.
  • Type hexo s and press Enter.
    (hexo s is short for hexo server: it serves the generated pages locally.)
  • Windows will pop up a prompt asking whether to allow Node.js network access. Allow it.
    In Git Bash you’ll see:
    Hexo is running at http://localhost:4000

Witness the Magic

  • Open a browser and type localhost:4000 in the address bar.
    You can also click: localhost:4000
  • WOW
  • Hexo has created your first post: Hello World

hexo s serves your site locally at localhost:4000. This is for debugging: check layout and content. If something is wrong, edit the post files, save, and refresh the page.

At this point, your blog works locally.
But if you want to put it online so others can read it, you need to upload the generated files to GitHub.
So let’s continue.

(Before continuing, it’s best to stop the running local server: press Ctrl+C in the Git Bash window.)

Host on GitHub

Create an Account and Repository

  • First, sign up for a GitHub account: Sign up
  • Then, create a new repository: New repository
  • Important: the repository name must be username.github.io.
    For example, if your username is KassadinL, the repo must be KassadinL.github.io.
    Case doesn’t matter: it will be treated as lowercase.
    Create the repo.
  • Open your repo, find Settings on the far right, and click it.
  • Scroll down to GitHub Pages and enable it.
    It should look like this.
    (I’m not sure whether this is strictly required, but I don’t want to create another GitHub account to test, so you can try it.)

Connect Git and GitHub

To push local files to GitHub, Git needs to authenticate with GitHub, proving you’re the owner of the account.
To finish that, we’ll do a few steps.

  • Open Git Bash, and set your GitHub username:
    git config --global user.name "YourGitHubUsername"
    For example, mine is KassadinL, so:
    git config --global user.name "KassadinL"
  • Then set your GitHub email:
    git config --global user.email "YourGitHubEmail"
    For example: git config --global user.email "sensensensan@gmail.com"
  • These two steps store your account info in Git. Next we generate an SSH key.
  • Type:
    ssh-keygen -t rsa -C "YourGitHubEmail"
    For example: ssh-keygen -t rsa -C "sensensensan@gmail.com"
    Press Enter, then press Enter three more times.
  • It will tell you where the key files are saved.
    Open C: -> Users -> <your username> -> .ssh, find id_rsa.pub, open it with Notepad, and copy all content.
  • Open GitHub Settings: SSH keys
    Click New SSH key.
    Fill Title with anything (e.g. Blog), paste what you copied into the Key box, then click Add SSH key.
  • Back to Git Bash, test whether the key works:
    ssh git@github.com
    Wait a moment. If it looks like the screenshot, it’s set up.

Push the Local Site to GitHub

  • To deploy to GitHub, Hexo needs to know where to push.
    Open your local Blog folder and find _config.yml (the site config file).
  • Open it with Notepad, and edit the end of the file:
deploy:
  type: git
  repo: Fill in the full repository URL you created on GitHub, and remember to add .git
  branch: master

  • Example change:

  • Notes:

    • Remember to add .git to the URL.
    • You must put a space after :. For example: type:git is wrong, type: git is correct.

  • Save and close.

  • Install the git deploy plugin (Hexo uses it to push files):

Terminal window
npm install hexo-deployer-git --save

Now you can publish your blog online.

Quoting 吴润 - GitHub+Hexo 搭建个人网站详细教程 on why we use SSH to connect Git and GitHub:
“The reason to set up GitHub keys is to use public/private key cryptography. You put the public key on GitHub and keep the private key on your computer. GitHub requires authentication for each push, so normally you’d need to enter username/password every time. To avoid that, we use SSH: when you push, Git matches your private key against the public key on GitHub; if they match, you’re considered a valid user and the push is allowed.”

Common Commands

When deploying with Hexo, you’ll often use these commands:

Terminal window
hexo s
ctrl c
hexo clean
hexo g
hexo d

Explanation:

  • hexo s (hexo server): serve locally. View the site at localhost:4000 to check layout and content. If something is wrong, edit the source files, save, and refresh.
  • Ctrl C: stop the local server.
  • hexo clean: remove generated files.
  • hexo g (hexo generate): generate static files under Blog\public.
  • hexo d (hexo deploy): deploy to GitHub.

2020/05/04 update
hexo clean can be shortened to hexo cl
hexo g and hexo d can be combined as hexo g -d

Usage

Customize the Blog

  • Change settings like title/subtitle/language.
    • Open _config.yml in your local blog folder, and edit title, subtitle, language, timezone, etc.
    • For example, changing title, subtitle, language updates the blog’s appearance.
    • For more settings, see other tutorials.

Write Posts

  • Use hexo n (hexo new) to create a new post file under Blog\source\_posts\.
    Open the file and start writing.
  • In that folder, you’ll see hello-world.md created by Hexo (your first post).
  • Usage: in Git Bash, run hexo n name. name is the filename. If it contains spaces, wrap it in double quotes.
  • Example: hexo n "the First Blog" creates the-First-Blog.md under Blog\source\_posts\.
  • Open the file and write.
  • Hexo uses Markdown by default. Markdown is a plain-text format with simple rules for formatting.
    See: Hexo Markdown 简明语法手册

The Correct Workflow

To summarize, here’s the correct workflow for writing and publishing a post:

  • hexo n "the First Blog": create a post
  • Edit content with a Markdown editor (or any editor; I use Notepad++)
  • hexo s: serve locally to preview
  • If it looks good, press Ctrl C to stop the server
  • hexo clean: clean old generated files
  • hexo g: generate new files
  • hexo d: deploy to GitHub
  • Done

2020/05/04 update
hexo cl cleans old files
hexo g -d generates and deploys in one go

Celebrate

At this point, your blog is fully built.
You can open username.github.io in the browser.
For example, my blog is kassadinl.github.io.

Try opening it on your phone or another computer too.
Feels kind of magical.

That’s the end of the main tutorial.

The End. Celebration. Celebration.

Appendix

  • About custom domains
  • Many tutorials explain how to bind a custom domain. I didn’t need it at the time, so I didn’t research it. If you do need it, check the tutorials I mentioned.
    This one is good: 吴润：GitHub+Hexo 搭建个人网站详细教程
  • About operating the command line window
  • In Git Bash, you can’t use Ctrl C / Ctrl V for copy/paste; Ctrl C is the Stop signal.
    Use Ctrl Shift C to copy, and Shift Insert to paste.
  • Left/right arrows move the cursor; up/down arrows browse history.
  • More pitfalls I hit:
  • When creating a GitHub repo, the name must be username.github.io. At first I wanted another name (e.g. MoriBlog.github.io instead of KassadinL.github.io) and wasted a lot of time. In hindsight it makes sense: the site uses username.github.io as the domain, and usernames are unique, so the repo name can’t be customized.
  • Use Git Bash rather than Windows CMD/PowerShell; the latter two sometimes fail to recognize commands.
  • After using hexo s to preview, stop it with Ctrl C promptly. I once had multiple Git Bash windows, one kept running, and later theme changes didn’t take effect.
  • When setting language in config, use language: zh-CN instead of language: zh-Hans from the official docs. The docs might be outdated; using the official value somehow made the blog language turn into German (no idea why).
  • About changing themes
  • Hexo is open source. If you’re not satisfied with the blog, you can modify anything.
    You can change themes (appearance) by editing config files.
    See: wangwlj—Hexo搭建的GitHub博客之优化大全

References

I mainly referenced these when building the blog:

Final Notes

Building a blog was a “three-minute enthusiasm” action, but the idea had existed for a long time, so I finally fulfilled a small wish.
The site still has many things I’m unhappy with, like not being familiar with Markdown and poor formatting, and I hadn’t had time to customize the theme further.

Besides satisfying my urge to tinker, I want this blog to be a place to log what I do.
Recently I’ve been learning Blender, so future posts may be about Blender: tutorials or works (if any…).

2019/07/15 AY

Updates

2019/07/17 Update

When organizing posts (renaming files/folders), sometimes the images associated with the post get deleted.
It happened twice, but thankfully I could restore them from Recycle Bin.

Today I suspect it might be because I forgot to stop hexo s while doing the operations…
(I’ve stepped on this trap many times.)

2019/07/25 Update

Added the “CC 4.0” license.
Referenced:
潘高—Hexo博客NexT主题美化之自定义文章底部版权声明
For a brief intro to Creative Commons:
漠伦—“知识共享”（CC协议）简单介绍

(I actually wanted to use CC BY-NC-SA, but most blogs I saw used CC BY-NC-ND, and many were version 3.0.
So I’m using this for now.)

2019/08/18 Update

Customize image size.
The NexT theme stretches images to full width by default, which isn’t great for reading.
I searched and found you can wrap images with a div to control scaling.

Insert <div style="width: 70%; margin: auto"> and </div> around the image.
width: can be pixels like 200px, or percentages like 70%.

2019/09/19 Update

Fixed a wrong copyright link.
Today I noticed the final copyright link was wrong: it showed http://yoursite.com/* instead of my site URL.
It didn’t seem to be a problem before.

I searched online and found the fix:
Moorez - hexo的next主题个性化配置教程

2019/09/25 Update

Embed Bilibili videos.
Bilibili’s default embed is bad: it only plays 360p, the embedded player is tiny, and the experience is terrible.
You can only adjust width/height with iframe, but there are many limitations.

<iframe
  src="//player.bilibili.com/player.html?aid=8854302&cid=19328137&page=1"
  scrolling="no"
  border="0"
  frameborder="no"
  framespacing="0"
  allowfullscreen="true"
>
</iframe>
<iframe
  src="//player.bilibili.com/player.html?aid=8854302&cid=19328137&page=1"
  width="100%"
  height="600"
  scrolling="no"
  border="0"
  frameborder="no"
  framespacing="0"
  allowfullscreen="true"
>
</iframe>
<iframe
  id="spkj"
  src="//player.bilibili.com/player.html?aid=8854302&cid=19328137&page=1"
  scrolling="no"
  border="0"
  frameborder="no"
  framespacing="0"
  allowfullscreen="true"
  width="100%"
>
</iframe>
<script type="text/javascript">
  document.getElementById('spkj').style.height =
    document.getElementById('spkj').scrollWidth * 0.76 + 'px';
</script>

The first snippet is Bilibili’s generated embed.
The second snippet adds responsive width.
The third snippet adds a responsive height script.

References:

Internal post links.
Usage:

{% post_link 001-how-to-deploy-blog-with-hexo-and-github %}

Reference:
Marshal@十万光年 - Hexo使用内链及文章中加入图片的方法

A brief Markdown syntax note.
I hit formatting issues while updating, searched, and learned on the fly.
Reference:
Hexo Markdown 简明语法手册

2019/09/26 Update

Add search.
Reference: hexo - Next 主题添加搜索功能

When installing the search module, I saw two errors saying dependency versions were too low, but search still worked.

2019/11/26 Update

I set up the blog once on Linux.
Re-reading this tutorial, I tweaked some wording.

Switched to the Fluid theme. It looks nice.
Reference: 使用指南 - Fluid

2019/11/29 Update

I tried to upgrade Hexo on Windows.
npm update seemed to do nothing.
Then I did something stupid: uninstalled Node.js (thinking reinstalling = latest).

Result: I got stuck at hexo init and npm install.
Git Bash output:

Terminal window
username@alias MINGW64 ~/Documents/Blog
$ hexo init
INFO  Cloning hexo-starter https://github.com/hexojs/hexo-starter.git
Cloning into 'C:\Users\username\Documents\Blog'...
remote: Enumerating objects: 22, done.
remote: Counting objects: 100% (22/22), done.
remote: Compressing objects: 100% (18/18), done.
remote: Total 153 (delta 8), reused 8 (delta 2), pack-reused 131
Receiving objects: 100% (153/153), 29.67 KiB | 660.00 KiB/s, done.
Resolving deltas: 100% (70/70), done.
Submodule 'themes/landscape' (https://github.com/hexojs/hexo-theme-landscape.git) registered for path 'themes/landscape'
Cloning into 'C:/Users/username/Documents/Blog/themes/landscape'...
remote: Enumerating objects: 32, done.
remote: Counting objects: 100% (32/32), done.
remote: Compressing objects: 100% (25/25), done.
remote: Total 1054 (delta 20), reused 13 (delta 7), pack-reused 1022
Receiving objects: 100% (1054/1054), 3.21 MiB | 851.00 KiB/s, done.
Resolving deltas: 100% (578/578), done.
Submodule path 'themes/landscape': checked out '73a23c51f8487cfcd7c6deec96ccc7543960d350'
INFO  Install dependencies
'npm' is not recognized as an internal or external command,
operable program or batch file.
WARN  Failed to install dependencies. Please run 'npm install' manually!


username@alias MINGW64 ~/Documents/Blog
$ npm install


> ejs@2.7.4 postinstall C:\Users\username\Documents\Blog\node_modules\ejs
> node ./postinstall.js


'node' is not recognized as an internal or external command,
operable program or batch file.
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@1.2.9 (node_modules\nunjucks\node_modules\fsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents@1.2.9: wanted {"os":"darwin","arch":"any"} (current: {"os":"win32","arch":"x64"})
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@2.1.2 (node_modules\fsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents@2.1.2: wanted {"os":"darwin","arch":"any"} (current: {"os":"win32","arch":"x64"})


npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! ejs@2.7.4 postinstall: `node ./postinstall.js`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the ejs@2.7.4 postinstall script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.


npm ERR! A complete log of this run can be found in:
npm ERR!     C:\Users\username\AppData\Roaming\npm-cache\_logs\2019-11-29T03_31_36_888Z-debug.log

I wasted two hours on this…

In the end, the fix was: run those two commands (hexo init and npm install) in Node.js’s built-in Node.js command prompt.
It was because environment variables weren’t set.

(Windows is hard to use I’m too noob.)

2019/12/23 Update

Bind a domain and enable HTTPS.

I thought I didn’t need this, but when I was tinkering with trojan I needed a domain, so I decided to bind the domain to the blog.
(I was too noob, so it was neither smooth nor convenient.)
I bought kassadin.moe.

My trojan tinkering log: Note: Deploying trojan (With Luck)

References:
Managing a custom domain for your GitHub Pages site - GitHub docs
GitHub Pages自定义域名开启HTTPS - Razeen
GitHub+Hexo 搭建个人网站详细教程 - 吴润

I ran into some issues (maybe because I’m too noob / early settings were wrong), for example:

  • In Cloudflare, A type record and CNAME type record seemed to be mutually exclusive for pointing to GitHub Pages.

    • If I used A type record, I got this error: invalid certificate.
    • I couldn’t figure it out, so I used CNAME type record.

  • In repo settings, under GitHub Pages, I couldn’t enable Enforce HTTPS.

    • I searched online. Some people said you need to wait 24 hours, but I waited 3 days and still couldn’t check Enforce HTTPS.
    • I followed GitHub Pages自定义域名开启HTTPS, and also enabled everything that looked useful in Cloudflare, and finally HTTPS could be enforced.
    • So I still don’t really know what made it work. It worked, so… fine.
    • The official guide suggests using dig to verify DNS after configuration. No matter how I configured, dig kassadin.moe looked wrong… whatever.
    • My guess is: I initially used a subdomain blog.kassadin.moe and configured it once, then later switched to kassadin.moe. And while troubleshooting Enforce HTTPS, I changed things frequently.
      Maybe that caused it? Weird.

2019/12/28 update
The blog should be using Cloudflare’s certificate now.

2019/12/28 Update

Add a comment system.

I used the gitalk comment system supported by the Fluid theme.
References:
gitalk - GitHub
NexT主题中集成gitalk评论系统
自动初始化 Gitalk 和 Gitment 评论

After setup, you still need to click Initialize Issue under each post.
(There’s a script mentioned above, but I don’t know how to use it.)

2020/05/04 Update

Command shortcuts.

  • hexo clean can be shortened to hexo cl
  • hexo g and hexo d can be combined as hexo g -d

Add RSS.

Ref:

After enabling it, the RSS icon didn’t show up (maybe due to the Fluid theme).
I searched through the config and found that in the Navigation bar menu section, you just add an RSS entry:

  # 导航栏菜单，可自行增减，key 用来关联 languages/*.yml，如不存在关联则显示 key 本身的值；icon 是 css class，可以省略；增加 name 可以强制显示指定名称
  # Navigation bar menu. `key` is used to associate languages/*.yml. If there is no association, the value of `key` itself will be displayed; if `icon` is a css class, it can be omitted; adding `name` can force the display of the specified name
  menu:
    - { key: "home", link: "/", icon: "iconfont icon-home-fill" }
    - { key: "archive", link: "/archives/", icon: "iconfont icon-archive-fill" }
    - { key: "tag", link: "/tags/", icon: "iconfont icon-tags-fill" }
    - { key: "about", link: "/about/", icon: "iconfont icon-user-fill" }
    - { key: "rss", link: "/atom.xml", icon: "iconfont icon-rss", name: "RSS" }

The last line is the RSS config.

2021/04/10 Update

Switched comment systems.

Recently I ran npm update and gitalk seemed to stop working, with Error: Request failed with status code 405.
I checked GitHub discussions: there were only a few posts about 405, while there were lots about 403.
It seemed related to a proxy parameter and looked complicated, so I gave up.

I switched to utterances, also supported by the Fluid theme. Like gitalk, it’s based on GitHub Issues.
Setup: utterances
It’s much simpler than gitalk, and also easier to use because you don’t need to Initialize Issue manually.
(But it seems there’s no anonymous commenting; you must use a GitHub account.)

2021/10/01 Update

SSH key errors.

When deploying (hexo d), I got various errors like:

Terminal window
git@ssh.github.com: Permission denied (publickey).


kex_exchange_identification: Connection closed by remote host
Connection closed by ...


git@ssh.github.com: Permission denied (publickey).
fatal: Could not read from remote repository.

At first I thought it was my proxy/VPN. Switching didn’t help.
I also tried various methods from
HEXO DEPLOY 时不断 Error: Permission denied (publickey). fatal: Could not read from remote repository. #1478
and
Win10使用ssh的hexo deploy到github報錯 #3339

Still didn’t work.

Then I saw this comment:

using cmd,type hexo d, Error: Permission denied (publickey). #2312

The ssh key doesn’t add to cmd environment.
Using ssh-add to add the key.
ssh-add ~/.ssh/id_rsa

Also GitHub docs:
Error: Permission denied (publickey) - Make sure you have a key that is being used

ssh-add -l returned The agent has no identities.
ssh-add returned Could not open a connection to your authentication agent.

Turns out my local environment wasn’t using any key at all…

Fix followed GitHub docs:
Generating a new SSH key and adding it to the ssh-agent

  • Start the ssh-agent in the background.

    Terminal window
    $ eval "$(ssh-agent -s)"
    > Agent pid 59566

    Depending on your environment, you may need to use a different command. For example, you may need to use root access by running sudo -s -H before starting the ssh-agent, or you may need to use exec ssh-agent bash or exec ssh-agent zsh to run the ssh-agent.

  • Add your SSH private key to the ssh-agent. If you created your key with a different name, or if you are adding an existing key that has a different name, replace id_ed25519 in the command with the name of your private key file.

    Terminal window
    ssh-add ~/.ssh/id_ed25519

Back then I saw this section but didn’t understand it, so I skipped it…
Now I wasted several hours.

2023/05/19 Update

SSH key error (2).

After a long time without updating the blog, today I wrote some notes and tried to deploy, and got this:

Terminal window
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that a host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
SHA256:uNiVztksCsDhcc0u9e8BujQXVUpKZIDTMczCvj3tD2s.
Please contact your system administrator.
Add correct host key in /home/***/.ssh/known_hosts to get rid of this message.
Offending RSA key in /home/***/.ssh/known_hosts:17
Host key for [ssh.github.com]:443 has changed and you have requested strict checking.
Host key verification failed.
...

I searched online and found GitHub’s post:
We updated our RSA SSH host key
I followed the steps there, but it still failed.

Reading the error carefully:

Terminal window
Add correct host key in /home/***/.ssh/known_hosts to get rid of this message.
Offending RSA key in /home/***/.ssh/known_hosts:17

Seems like my GitHub key config was wrong.

In ~/.ssh/config, add:

Host github.com
HostName github.com
PreferredAuthentications publickey
IdentityFile ~/.ssh/YourPrivateKeyFileName
User Yourname

Then it works.

I had actually configured it before, but I had two entries, and the first one was wrong.
SSH always used the first wrong entry, so it kept failing.

2023/05/19 Update 2

hexo d asks for username and password.

In the blog’s _config.yml, if the repo URL uses HTTPS, it will ask for username/password.
With a git (SSH) URL, it uses the key automatically.
So just switch back to the git URL.

Ref:
hexo d must enter pwd | hexo deploy的时候一直需要输入密码

2024/07/03 Update

I deployed to GitHub, but the blog didn’t update for a long time.
At one point I even thought Hexo was broken (time to migrate to Hugo).

On the blog repo page Settings -> Pages, it showed this error:

Actions is currently unavailable for your repository, and your Pages site requires a Jekyll build step.
To continue building your site on pushes, you need to enable Actions.

After messing around for a while, I realized GitHub changed Pages deployment to use GitHub Actions.

Fix:
Blog repo Settings -> Actions -> General
At the top, under Actions permissions, choose the 4th option Allow ... actions and reusable workflows, then check the first box Allow actions created by GitHub.
Save.

Then hexo deploy works again.
On the repo commit history, when the blog updates, after XXX committed xx minutes ago it shows a 3/3 check.
Before, it was 2/2.

(Deploy failures have no check mark.)

After I fixed it, I went back to GitHub docs and realized they had mentioned it:
In Troubleshooting Jekyll build errors for GitHub Pages sites, in the Who can use this feature? box, second paragraph:

All GitHub Pages builds will use GitHub Actions from June 30, 2024.
No other changes are required but GitHub Actions must be enabled in your repository for builds to continue.
For more information on enabling GitHub Actions, see “Managing GitHub Actions settings for a repository.”

They switched on June 30, and it had only been a few days. It really got me…

Also, putting this info inside the Who can use this feature? box feels odd.
The last few times I opened the doc I only skimmed the beginning, so I missed the second paragraph.