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estradiol.cloud/content/posts/hugo-on-k8s-nginx/index.md
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2024-03-12 22:33:12 -07:00

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+++ title = 'Hugo on Kubernetes & NGINX' date = 2024-03-12T16:45:59-07:00 description = 'kubernetes is for girls' series = ['wtf'] categories = ['Tutorial'] tags = ['meta', 'k8s', 'flux', 'hugo'] toc = true +++

i decided to make a website. a static one. this one. with Hugo. the main reason i have for needing a website is as a vanity project, so i have some stuff to host in a Kubernetes cluster i'm running. the k8s cluster is also a vanity project.

because i don't like software, i wanted a way to deploy my site that doesn't involve much of it. this post is about that.

Getting Started

i built my site by following the straight-forward Getting Started guide in the Hugo documentation.

i did hugo new site estradiol.cloud. and then cd estradiol.cloud; git init. and then i picked a ridiculous theme "inspired by terminal ricing aesthetics", installing it like git submodule add https://github.com/joeroe/risotto.git themes/risotto; echo "theme = 'risotto'" >> hugo.toml.1

at this point, my website is basically finished (i also changed the title in hugo.toml). i probably won't be putting anything on it, so there's no point fiddling with other details.

about deployment, the Hugo guide's Basic Usage page has this to offer:

Most of our users deploy their sites using a CI/CD workflow, where a push{{< sup "1" >}} to their GitHub or GitLab repository triggers a build and deployment. Popular providers include AWS Amplify, CloudCannon, Cloudflare Pages, GitHub Pages, GitLab Pages, and Netlify.

  1. The Git repository contains the entire project directory, typically excluding the public directory because the site is built after the push.

importantly, you can't make a post about deploying this way. everyone deploys this way. if i deploy this way, this site will have no content.

this approach also involves a build system somewhere that can run Hugo to compile the code and assets and push them onto my host. i definitely already need Hugo installed on my laptop if i'm going to post anything.2 so now i'm running Hugo in two places. there's surely going to be other complex nonsense like webhooks involved.

diagram: deploy w/ GitHub Pages & Actions

and hang on. let's look at this again:

  1. The Git repository contains the entire project directory, typically excluding the public directory because the site is built after the push.

you're telling me i'm going to build a nice static site and not check the actual content into version control? couldn't be me.

Getting Static

suppose i instead check my content in exactly as i intend to serve it? then i could shell into my server box, pull the site, and nifty-galifty! isn't this the way it has always been done?

my problem is that i don't have a server box. i have a container orchestration system. there are several upsides to this3 but it means that somehow my generated content needs to end up in a container. because Pods are ephemeral and i'd like to run my site with horizontal scalability4, i don't want my container to retain runtime state across restarts or replicas.

i could run a little pipeline that builds a container image wrapping my content and pushes it to a registry. when i deploy, the cluster pulls the image, content and all. all ready to go. but now i've got software again: build stages and webhooks and, to make matters worse, now i'm hosting and versioning container images.

diagram: deploy w/ container build

i don't want any of this. i just want to put some HTML and static assets behind a web server.

instead, i'd like to deploy a popular container image from a public registry and deliver my content to it continuously.

a minimal setup to achieve this might look like:

  • a Pod with:
    • an nginx container to serve the content;
    • a git-pull sidecar that loops, pulling the content;
    • an initContainer to do the initial checkout;
    • an emptyDir volume to share between the containers.
  • a ConfigMap to store the nginx config.

diagram: minimal pod/configmap setup

when a new Pod comes up, the initContainer mounts the emptyDir at /www and clones the repository into it. i use git sparse-checkout to avoid pulling repository contents i don't want to serve out:

# git-clone command
git clone https://code.estradiol.cloud/tamsin/estradiol.cloud.git --no-checkout --branch trunk /tmp/www;
cd /tmp/www;
git sparse-checkout init --cone;
git sparse-checkout set public;
git checkout;
shopt -s dotglob
mv /tmp/www/* /www

for the sidecar, i script up a git pull loop:

# git-pull command
while true; do
  cd /www && git -c safe.directory=/www pull origin trunk
  sleep 60
done

and i create a ConfigMap with a server block to configure nginx to use Hugo's public/ as root:

# ConfigMap; data: default.conf
server {
  listen 80;
  location / {
    root   /www/public;
    index  index.html;
  }
}

the rest of this is pretty much boilerplate:

{{< code-details summary="kubectl apply -f https://estradiol.cloud/posts/hugo-on-k8s/site.yaml" lang="yaml" details=`

estradiol-cloud.yaml

apiVersion: v1 kind: ConfigMap metadata: labels: app.kubernetes.io/instance: estradiol-cloud app.kubernetes.io/name: nginx name: nginx-server-block data: default.conf: |- server { listen 80; location / { root /www/public; index index.html; } }

apiVersion: v1 kind: Pod metadata: name: nginx labels: app.kubernetes.io/instance: estradiol-cloud app.kubernetes.io/name: nginx spec: containers:

  • name: nginx image: nginx:1.25.4 ports:
    • containerPort: 80 volumeMounts:
    • mountPath: /www name: www
    • mountPath: /etc/nginx/conf.d name: nginx-server-block
  • name: git-pull image: bitnami/git command:
    • /bin/bash
    • -ec
    • | while true; do cd /www && git -c safe.directory=/www pull origin trunk sleep 60 done volumeMounts:
    • mountPath: /www name: www initContainers:
  • name: git-clone image: bitnami/git command:
    • /bin/bash
    • -c
    • | shopt -s dotglob git clone https://code.estradiol.cloud/tamsin/estradiol.cloud.git --no-checkout --branch trunk /tmp/www; cd /tmp/www; git sparse-checkout init --cone; git sparse-checkout set public; git checkout; mv /tmp/www/* /www volumeMounts:
    • mountPath: /www name: www volumes:
  • name: www emptyDir: {}
  • name: nginx-server-block configMap: name: nginx-server-block ` >}}

my Hugo workflow now looks like:

  1. make changes to source;
  2. run hugo --gc --minify;5
  3. git commit & push.

my git pull control loop takes things over from here and i'm on easy street.

Getting Web

this is going great! my Pod is running. it's serving out my code. i get Continuous Deployment™ for the low price of 11 lines bash. i mean... no one can actually browse to my website6 but that will be an easy fix, right? yes. networking is always the easy part.

first, i need a Service. this gives me a proxy to my several replicas7 and in-cluster service discovery.

{{< code-details summary="kubectl apply -f https://estradiol.cloud/posts/hugo-on-k8s-nginx/service.yaml" lang="yaml" details=`

service.yaml

apiVersion: v1 kind: Service metadata: labels: app.kubernetes.io/instance: estradiol-cloud app.kubernetes.io/name: nginx name: nginx spec: type: ClusterIP selector: app.kubernetes.io/instance: estradiol-cloud app.kubernetes.io/name: nginx ports:

  • name: http port: 80 protocol: TCP targetPort: http ` >}}

next, i need an Ingress to handle traffic inbound to the cluster and direct it to the Service:

{{< code-details summary="kubectl apply -f https://estradiol.cloud/posts/hugo-on-k8s-nginx/ingress.yaml" lang="yaml" details=`

ingress.yaml

apiVersion: networking.k8s.io/v1 kind: Ingress metadata: labels: app.kubernetes.io/instance: estradiol-cloud app.kubernetes.io/name: nginx name: nginx spec: rules:

  • host: estradiol.cloud http: paths:
    • backend: service: name: nginx port: name: http path: / pathType: Prefix ` >}}

this part expresses a routing rule: traffic reaching the cluster via estradiol.cloud should go to my Service, and then to one of its backend Pods. to actually apply this rule, i need an ingress controller. mine is ingress-nginx.

when i deployed controller in my cluster, it created some more nginx Pods. these update their configuration dynamically based on the rules in my Ingress resource(s). the controller also creates a Service of type LoadBalancer, which magically creates a load balancer appliance in my cloud provider. off-screen, i can point DNS to that appliance to finish the setup.

diagram: kubernetes ingress

you can tell it's working by looking at your browser bar.

as this has come together, i've gotten increasingly anxious about how much YAML i've had to write. this is a problem because YAML is software and, as established, i'm hoping not to have much of that. it's also annoying that most of this YAML really is just boilerplate.

conveniently, Bitnami maintains a Helm Chart that templates out all the boilerplate and does exactly what i've just been doing.8 i can replace all my YAML with a call out to this chart and a few lines of configuration, assuming i have helm client installed:

{{< code-details summary="helm upgrade --install --create-namespace --namespace estradiol-cloud -f https://estradiol.cloud/posts/hugo-on-k8s-nginx/values.yaml oci://registry-1.docker.io/bitnamicharts/nginx" lang="yaml" details=`

values.yaml

cloneStaticSiteFromGit: enabled: true repository: "https://code.estradiol.cloud/tamsin/estradiol.cloud.git" branch: trunk gitClone: command: - /bin/bash - -ec - | -f "/opt/bitnami/scripts/git/entrypoint.sh" && source "/opt/bitnami/scripts/git/entrypoint.sh" git clone {{ .Values.cloneStaticSiteFromGit.repository }} --no-checkout --branch {{ .Values.cloneStaticSiteFromGit.branch }} /tmp/app "$?" -eq 0 && cd /tmp/app && git sparse-checkout init --cone && git sparse-checkout set public && git checkout && shopt -s dotglob && rm -rf /app/* && mv /tmp/app/* /app/ ingress: enabled: true hostname: estradiol.cloud ingressClassName: nginx tls: true annotations: { cert-manager.io/cluster-issuer: letsencrypt-prod } serverBlock: |- server { listen 8080; root /app/public; index index.html; } service: type: ClusterIP `>}}

diagram: helm setup

configuration for the git-clone script and our custom server block are added via values.yaml. the git-pull loop configured by the chart works as-is. by using the chart, we get a few other nicities. for instance, my Pods are now managed by a Deployment.9 this will make my grand scale-out plans a breeze.

Getting Flux'd

by now, i'm riding high. my whole setup is my static site code and <30 lines of YAML.

i do have a bunch of stuff deployed into my cluster, and none of this is very reproducible without all of that. my workflow has also expanded to:

  1. for routine site deploys:
    1. make changes to source;
    2. run hugo --gc --minify;5
    3. git commit & push.
  2. to update nginx, the chart version, or change config:
    1. make changes to values.yaml
    2. helm upgrade

i could do without the extra helm client dependency on my laptop. i'm also pretty git push-pilled, and i really want the solution to all my problems to take the now familiar shape: put a control loop in my cluster and push to a git repository.

enter flux.

with flux, i decide on a repository (and maybe a path within it) to act as a source for my Kubernetes YAML. i go through a short bootstrap process which installs the flux controllers and add them to repository. to make a change to a resource in my cluster, i edit the YAML and push to the repository. flux listens and applies the changes.

flux supports Helm deploys, so i can get that helm client off my laptop. i can also use it to manage my ingress controller, cert-manager, flux itself and whatever other infrastructural junk i may end up needing.

to move my web stack into flux, i create a HelmRepository resource for the bitnami Helm charts:

# bitnami-helm.yaml
apiVersion: source.toolkit.fluxcd.io/v1beta2
kind: HelmRepository
metadata:
  name: bitnami
  namespace: default
spec:
  url: https://charts.bitnami.com/bitnami

and add a HelmRelease pointing to the repository/chart version and containing my values.yaml:

{{< code-details summary="release.yaml" lang="yaml" details=apiVersion: helm.toolkit.fluxcd.io/v2beta1 kind: HelmRelease metadata: name: web namespace: estradiol-cloud spec: interval: 5m chart: spec: chart: nginx version: '15.12.2' sourceRef: kind: HelmRepository name: bitnami namespace: default interval: 1m values: cloneStaticSiteFromGit: enabled: true repository: "https://code.estradiol.cloud/tamsin/estradiol.cloud.git" branch: trunk gitClone: command: - /bin/bash - -ec - | [[ -f "/opt/bitnami/scripts/git/entrypoint.sh" ]] && source "/opt/bitnami/scripts/git/entrypoint.sh" git clone {{ .Values.cloneStaticSiteFromGit.repository }} --no-checkout --branch {{ .Values.cloneStaticSiteFromGit.branch }} /tmp/app [[ "$?" -eq 0 ]] && cd /tmp/app && git sparse-checkout init --cone && git sparse-checkout set public && git checkout && shopt -s dotglob && rm -rf /app/* && mv /tmp/app/* /app/ ingress: enabled: true hostname: estradiol.cloud ingressClassName: nginx tls: true annotations: { cert-manager.io/cluster-issuer: letsencrypt-prod } serverBlock: |- server { listen 8080; root /app/public; index index.html; } service: type: ClusterIP>}}

when i push these to my flux source repository, the Helm release rolls out.

diagram: flux git push/deploy sequence

A Note About Software

in the end, i'm forced to admit there's still a lot of software involved in all of this. setting aside the stuff that provisions and scales my cluster nodes, and the magic LoadBalancer, i have:

  • nginx (running from a stock image);
  • git & bash (running from a stock image);
  • a remote git server (i'm running gitea10, but github dot com is fine here);
  • Kubernetes (oops!);
    • flux, especially kustomize-controller and helm-controller;
    • ingress-nginx controller;
    • cert-manager and Let's Encrypt;
  • the bitnami/nginx Helm chart;

the bulk of this i'll be able to reuse for the other things i deploy on the cluster11. and it replaces SASS black-boxes like "AWS Amplify, CloudCannon, Cloudflare Pages, GitHub Pages, GitLab Pages, and Netlify" in the recommended Hugo deployment.

to actually deploy my site, i get to maintain a bash scripts for git-clone, my NGINX config, and a couple of blobs of YAML.

at least there are no webhooks.

fin

  1. i appreciate the culinary branding. ↩︎

  2. unlikely. ↩︎

  3. few of which could be considered relevant for my project. ↩︎

  4. i absolutely will not need this ↩︎

  5. i added disableHTML = true and disableXML = true to [minify] configuration in hugo.toml to keep HTML and RSS diffs readable. ↩︎

  6. i can check that its working, at least, with a port-forward. ↩︎

  7. lmao ↩︎

  8. what incredible luck! (obviously, until now i've been working backward from this chart) ↩︎

  9. i also snuck a TLS certificate configuration via Let's Encrypt with cert-manager into this iteration. if you're following along at home and don't have cert-manager installed, this should still work fine (but with no HTTPS). ↩︎

  10. because i'm running gitea in my cluster and i want to avoid a circular dependency for my flux source repository, i also depend on GitLab dot com. ↩︎

  11. i won't. ↩︎