How to Deploy a Static Site on Linode Kubernetes Engine

Linode Kubernetes Engine (LKE) allows you to easily create, scale, and manage Kubernetes clusters to meet your application’s demands, reducing the often complicated cluster set-up process to just a few clicks. Linode manages your Kubernetes master node, and you select how many Linodes you want to add as worker nodes to your cluster.

Deploying a static site using an LKE cluster is a great example to follow when learning Kubernetes. A container image for a static site can be written in less than ten lines, and only one container image is needed. Therefore, it’s often less complicated to deploy a static site on Kubernetes than some other applications that require multiple components.

Caution

Following the instructions in this guide creates billable resources on your account in the form of Linodes and NodeBalancers. You are billed an hourly rate for the time that these resources exist on your account. Be sure to follow the tear-down section at the end of this guide if you do not wish to continue using these resources.

This guide shows you how to:

• On your workstation, create a site with Hugo, a static site generator (SSG).
• Containerize the static site using Docker.
• Deploy the container to your LKE cluster.

• You should have a working knowledge of Kubernetes’ key concepts, including master and worker nodes, Pods, Deployments, and Services. For more information on Kubernetes, see our Beginner’s Guide to Kubernetes series.

• You also need to prepare your workstation with some prerequisite software:

  • Install kubectl (your client’s version should be at least 1.13)
  • Install Git
  • Install Docker
  • Sign up for a Docker Hub Account
  • Install Hugo

• Finally, you need to create a cluster on LKE, if you do not already have one:

  • To create a cluster in the Linode Cloud Manager, review the Deploy a Cluster with Linode Kubernetes Engine guide.

    Note

    Specifically, follow the Create an LKE Cluster and Connect to your LKE Cluster with kubectl sections.

  • To create a cluster from the Linode API, review the Deploy and Manage a Cluster with Linode Kubernetes Engine and the Linode API tutorial.

    Note

    Specifically, follow the Create an LKE Cluster section.

You should have kubectl installed on your local workstation. kubectl is the command line interface for Kubernetes, and allows you to remotely connect to your Kubernetes cluster to perform tasks.

macOS:

Install via Homebrew:

brew install kubectl

If you don’t have Homebrew installed, visit the Homebrew home page for instructions. Alternatively, you can manually install the binary; visit the Kubernetes documentation for instructions.

Linux:

1. Download the latest kubectl release:

   curl -LO "https://dl.k8s.io/release/$(curl -L -s https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl"
   

2. Make the downloaded file executable:

   chmod +x ./kubectl
   

3. Move the command into your PATH:

   sudo mv ./kubectl /usr/local/bin/kubectl
   

Note

You can also install kubectl via your package manager; visit the Kubernetes documentation for instructions.

Windows:

Visit the Kubernetes documentation for a link to the most recent Windows release.

To perform some of the commands in this guide you need to have Git installed on your workstation. Git is a version control system that allows you to save your codebase in various states to ease development and deployment. Follow our How to Install Git on Linux, Mac or Windows guide for instructions on how to install Git.

To install Docker CE (Community Edition), follow the instructions within one of the guides below:

• Installing and Using Docker on Ubuntu and Debian

• Installing and Using Docker on CentOS and Fedora

For complete instructions on even more Linux distributions, reference the Install Docker Engine section of Docker’s official documentation.

You use Docker Hub to store your Docker image. If you don’t already have a Docker Hub account, create one now.

A static site generator (SSG) is usually a command line tool that takes text files written in a markup language like Markdown, applies a stylized template to the content, and produces valid HTML, CSS, and JavaScript files. Static sites are prized for their simplicity and speed, as they do not generally have to interact with a database.

The Linode documentation website, and this guide, employ Hugo. Hugo is a powerful and fast SSG written in the Go programming language, but you can choose one that best suits your needs by reading our How to Choose a Static Site Generator guide.

The steps in this guide are generally the same across SSGs: install a static site generator, create some content in a text file, and then generate your site’s HTML through a build process.

To download and install Hugo, you can use a package manager.

• For Debian and Ubuntu:

    sudo apt-get install hugo
  

• For Red Hat, Fedora, and CentOS:

    sudo dnf install hugo
  

• For macOS, use Homebrew:

    brew install hugo
  

• For Windows, use Chocolatey:

    choco install hugo
  

For more information on downloading Hugo, you can visit the official Hugo website.

In this section you creates a static site on your workstation using Hugo.

1. Use Hugo to scaffold a new site. This command creates a new directory with the name you provide, and inside that directory it creates the default Hugo directory structure and configuration files:

   hugo new site lke-example
   

2. Move into the new directory:

   cd lke-example
   

3. Initialize the directory as a Git repository. This allows you to track changes to your website and save it in version control.

    git init
   

4. Hugo allows for custom themes. For the sake of this example, you install the Ananke theme as a Git submodule.

   git submodule add https://github.com/budparr/gohugo-theme-ananke.git themes/ananke
   

   Note

   Git submodules allow you to include one Git repository within another, each maintaining their own version history. To view a collection of Hugo themes, visit the Hugo theme collection.

5. In the text editor of your choice, open the config.toml file and add the following line to the end:

   theme = "ananke"
   

   This line instructs Hugo to search for a folder named ananke in the themes directory and applies the templating it finds to the static site.

6. Add an example first post to your Hugo site:

   hugo new posts/first_post.md
   

   This creates a Markdown file in the content/posts/ directory with the name first_post.md. You see output like the following:

   /Users/linode/k8s/lke/lke-example/content/posts/first_post.md created

7. Open the first_post.md file in the text editor of your choosing. You see a few lines of front matter, a format Hugo uses for extensible metadata, at the top of the file:

   File: lke-example/content/posts/first_post.md

   1 2 3 4 5

   --- title: "First_post" date: 2019-07-29T14:22:04-04:00 draft: false ---

   Change the title to your desired value, and change draft to false. Then, add some example Markdown text to the bottom of the file, like the example below:

   File: lke-example/content/posts/first_post.md

   1 2 3 4 5 6 7 8 9 10 11 12 13

   --- title: "First Post About LKE Clusters" date: 2019-07-29T14:22:04-04:00 draft: false --- ## LKE Clusters Linode Kubernetes Engine (LKE) clusters are: - Fast - Affordable - Scalable

8. You can preview your changes by starting the local Hugo server:

   hugo server
   

   You should see output like the following:

   .                  | EN
   +------------------+----+
     Pages              |  8
     Paginator pages    |  0
     Non-page files     |  0
     Static files       |  3
     Processed images   |  0
     Aliases            |  0
     Sitemaps           |  1
     Cleaned            |  0
   
   Total in 6 ms
   Watching for changes in /Users/linode/k8s/lke/lke-example/{content,data,layouts,static,themes}
   Watching for config changes in /Users/linode/k8s/lke/lke-example/config.toml
   Serving pages from memory
   Running in Fast Render Mode. For full rebuilds on change: hugo server --disableFastRender
   Web Server is available at http://localhost:1313/ (bind address 127.0.0.1)
   Press Ctrl+C to stop

9. Visit the URL that Hugo is running on. In the above example, the URL is http://localhost:1313. This server automatically updates whenever you make a change to a file in the Hugo site directory. To stop this server, enter CTRL-C on your keyboard in your terminal.

10. When you are satisfied with your static site, you can generate the HTML, CSS, and JavaScript for your site by building the site:

    hugo -v
    

    Hugo creates the site’s files in the public/ directory. View the files by listing them:

    ls public
    

11. You can build the site at any time from your source Markdown content files, so it’s common practice to keep built files out of a Git repository. This practice keeps the size of the repository to a minimum.

    You can instruct Git to ignore certain files within a repository by adding them to a .gitignore file. Add the public/ directory to your .gitignore file to exclude these files from the repository:

    echo 'public/' >> .gitignore
    

12. Add and commit the source files to the Git repository:

    git add .
    git commit -m "Initial commit. Includes all of the source files, configuration, and first post."
    

    You are now ready to create a Docker image from the static site you’ve just created.

In this section you create a Docker container for your static site, which you then run on your LKE cluster. Before deploying it on your cluster, you test its functionality on your workstation.

1. In your Hugo static site folder, create a new text file named Dockerfile and open it in the text editor of your choosing. A Dockerfile tells Docker how to create the container.

2. Add the following contents to the Dockerfile. Each command has accompanying comments that describe their function:

   File: lke-example/Dockerfile

   1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

   # Install the latest Debian operating system. FROM alpine:3.12.0 as HUGO # Install Hugo. RUN apk update && apk add hugo # Copy the contents of the current working directory to the # static-site directory. COPY . /static-site # Command Hugo to build the static site from the source files, # setting the destination to the public directory. RUN hugo -v --source=/static-site --destination=/static-site/public # Install NGINX, remove the default NGINX index.html file, and # copy the built static site files to the NGINX html directory. FROM nginx:stable-alpine RUN mv /usr/share/nginx/html/index.html /usr/share/nginx/html/old-index.html COPY --from=HUGO /static-site/public/ /usr/share/nginx/html/ # Instruct the container to listen for requests on port 80 (HTTP). EXPOSE 80

   Save the Dockerfile and return to the command prompt.

3. Create a new text file named .dockerignore in your Hugo static site folder and add the following lines:

   File: lke-example/.dockerignore

   1 2 3 4

   public/ .git/ .gitmodules/ .gitignore

   Note

   This file, similar to the .gitignore file you created in the previous section, allows you to ignore certain files within the working directory that you want to leave out of the container. Because you want the container to be the smallest size possible, the .dockerignore file includes the public/ folder and some hidden folders that Git creates.

4. Run the Docker build command. Replace mydockerhubusername with your Docker Hub username. The period at the end of the command tells Docker to use the current directory as its build context.

   docker build -t mydockerhubusername/lke-example:v1 .
   

   Note

   In the example below, the container image is named lke-example and has been given a version tag of v1. Feel free to change these values.

5. Docker downloads the required Debian and NGINX images, as well as install Hugo into the image. Once complete, you should see output similar to the following:

   Successfully built 320ae416c940
   Successfully tagged mydockerhubusername/lke-example:v1

6. You can view the image by listing all local images:

   docker images
   

   REPOSITORY                       TAG   IMAGE ID       CREATED             SIZE
   mydockerhubusername/lke-example  v1    320ae416c940   About an hour ago   20.8MB

1. You can test your new image by creating a container with it locally. To do so, enter the following run command:

   docker run -p 8080:80 -d mydockerhubusername/lke-example:v1
   

   The -p flag instructs Docker to forward port 8080 on localhost to port 80 on the container. The -d flag instructs Docker to run in detached mode so that you are returned to the command prompt once the container initializes.

2. Once the container has started, open your browser and navigate to localhost:8080. You should see your static site.

3. You can stop the running container by finding the ID of the container and issuing the stop command. To find the ID of the container, use the ps command:

   docker ps
   

   You should see a list of actively running containers, similar to the following:

   b4a7b959a6c7        mydockerhubusername/lke-example:v1         "nginx -g 'daemon of…"   5 hours ago         Up 5 hours          0.0.0.0:8080->80/tcp        romantic_mahavira

4. Note the random string of numbers and letters next to the image name. In the above example, the string is b4a7b959a6c7. Issue the stop command, supplying the string of numbers and letters:

   docker stop b4a7b959a6c7
   

1. Now that you have a working container image, you can push that image to Docker Hub. First, log in to Docker Hub from your workstation’s terminal:

   docker login
   

2. Next, push the image, with version tag, to Docker Hub, using the push command:

   docker push mydockerhubusername/lke-example:v1
   

   You can now view your image on Docker Hub as a repository. To view all of your repositories, navigate to the Docker Hub repository listing page.

3. Lastly, add the Dockerfile and .dockerignore file to your Git repository:

   git add .
   git commit -m "Add Dockerfile and .dockerignore."
   

   You are now ready to deploy the container to your LKE cluster.

In this section, you create a Deployment from the container you created in the previous section, and a Service to load balance the deployment.

1. Begin by navigating to a location outside of your static site directory. You do not need your static site directory for the remainder of this guide.

   cd ..
   

2. Create a new directory to house your Kubernetes manifests, and move into that directory:

   mkdir manifests && cd manifests
   

1. In the text editor of your choice, create a new YAML manifest file for your Deployment. Name the file static-site-deployment.yaml, save it to your manifests directory, and enter the contents of this snippet:

   File: manifests/static-site-deployment.yaml

   1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

   apiVersion: apps/v1 kind: Deployment metadata: name: static-site-deployment labels: app: static-site spec: replicas: 3 selector: matchLabels: app: static-site template: metadata: labels: app: static-site spec: containers: - name: static-site image: mydockerhubusername/lke-example:v1 imagePullPolicy: Always ports: - containerPort: 80

   • In this example the number of replica Pods is set to 3 on line 8. This value can be changed to meet the needs of your website.
   • The spec.containers.image field on line 19 should be changed to match the name of the container image you pushed to Docker Hub. Be sure to include the proper version tag at the end of the container name.
   • imagePullPolicy: Always on line 20 ensures that each time a Pod is created, the most recent version of the container image will be pulled from Docker Hub.

2. Once you have a Deployment manifest, you can apply the deployment to the LKE cluster with kubectl:

   kubectl apply -f static-site-deployment.yaml
   

3. You can check on the progress of your Deployment by listing the available pods:

   kubectl get pods
   

   If your Deployment was successful, you should see output like the following:

   NAME                                    READY   STATUS   RESTARTS   AGE
   static-site-deployment-cdb88b5bb-7pbjc  1/1     Running  0          1h
   static-site-deployment-cdb88b5bb-gx9h5  1/1     Running  0          1h
   static-site-deployment-cdb88b5bb-lzdvh  1/1     Running  0          1h

1. Create a Service manifest file to provide load balancing for the deployment. Load balancing ensures that traffic is balanced efficiently across multiple backend nodes, improving site performance and ensuring that your static site is accessible should a node go down.

   Specifically, the Service manifest that is used in this guide triggers the creation of a Linode NodeBalancer.

   Note

   The NodeBalancer’s creation is controlled through the Linode Cloud Controller Manager (CCM). The CCM provides a number of settings, called annotations, that allow you to control the functionality of the NodeBalancer. To learn more about the CCM, read our Installing the Linode CCM on an Unmanaged Kubernetes Cluster guide.

2. Name the file static-site-service.yaml, save it to your manifests directory, and enter the contents of this snippet:

   File: manifests/static-site-service.yaml

   1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

   apiVersion: v1 kind: Service metadata: name: static-site-service annotations: service.beta.kubernetes.io/linode-loadbalancer-throttle: "4" labels: app: static-site spec: type: LoadBalancer ports: - name: http port: 80 protocol: TCP targetPort: 80 selector: app: static-site sessionAffinity: None

3. Once you’ve created your Service manifest file, you can apply it to the LKE cluster:

   kubectl apply -f static-site-service.yaml
   

4. You can check on the status of your Service by listing the Services currently running on your server:

   kubectl get services
   

   You should see output similar to the following:

   NAME                 TYPE          CLUSTER-IP     EXTERNAL-IP      PORT(S)        AGE
   kubernetes           ClusterIP     10.128.0.1     <none>           443/TCP        20h
   static-site-service  LoadBalancer  10.128.99.240  192.0.2.1        80:32648/TCP   100m

5. Note the external IP address of the Service you created. This is the IP address of the NodeBalancer, and you can use it to view your static site.

6. In the above example, the IP address is 192.0.2.1. Navigate to the external IP address in the browser of your choice to view your static site. You should see the same content as when you tested your Docker image on your workstation.

In an LKE cluster, some entities and services are only accessible from within that cluster while others are publicly accessible (reachable from the internet).

Private (accessible only within the cluster)

• Pod IPs, which use a per-cluster virtual network in the range 10.2.0.0/16
• ClusterIP Services, which use a per-cluster virtual network in the range 10.128.0.0/16

Public (accessible over the internet)

• NodePort Services, which listen on all Nodes with ports in the range 30000-32768.
• LoadBalancer Services, which automatically deploy and configure a NodeBalancer.
• Any manifest which uses hostNetwork: true and specifies a port.
• Most manifests which use hostPort and specify a port.

Exposing workloads to the public internet through the above methods can be convenient, but this can also carry a security risk. You may wish to manually install firewall rules on your cluster nodes. The following policies are needed to allow communication between the node pools and the control plane and block unwanted traffic:

• ALlow kubelet health checks: TCP port 10250 from 192.168.128.0/17 Accept
• Allow Wireguard tunneling for kubectl proxy: UDP port 51820 from 192.168.128.0/17 Accept
• Allow Calico BGP traffic: TCP port 179 from 192.168.128.0/17 Accept
• Allow NodePorts for workload services: TCP/UDP port 30000 - 32767 192.168.128.0/17 Accept
• Block all other TCP traffic: TCP All Ports All IPv4/All IPv6 Drop
• Block all other UDP traffic: UDP All Ports All IPv4/All IPv6 Drop
• Block all ICMP traffic: ICMP All Ports All IPv4/All IPv6 Drop
• IPENCAP for IP ranges 192.168.128.0/17 for internal communication between node pools and control plane.

For additional information, please see this community post. Future LKE release may allow greater flexibility for the network endpoints of these types of workloads.

Please note, at this time, nodes should be removed from the Cloud Firewall configuration before removing/recycling of node pools within the Kubernetes configuration. Also, when adding node pools to the Kubernetes cluster, Cloud Firewall must be updated with the new node pool(s). Failure to add the new nodes creates a security risk.

Note

All new LKE clusters create a service named Kubernetes in the default namespace designed to ease interactions with the control plane. This is a standard service for LKE clusters.

If you’d like to continue using the static site that you created in this guide, you may want to assign a domain to it. Review the DNS Records: An Introduction and DNS Manager guides for help with setting up DNS. When setting up your DNS record, use the external IP address that you noted at the end of the previous section.

If you would rather not continue using the cluster you just created, review the tear-down section to remove the billable Linode resources that were generated.

• To remove the NodeBalancer you created, all you need to do is delete the underlying Service. From your workstation:

    kubectl delete service static-site-service
  

  Alternatively, you can use the manifest file you created to delete the Service. From your workstation:

    kubectl delete -f static-site-service.yaml
  

• To remove the LKE Cluster and the associated nodes from your account, navigate to the Linode Cloud Manager:

  1. Click on the Kubernetes link in the sidebar. A new page with a table which lists your clusters appears.

  2. Click on the more options elipsis next to the cluster you would like to delete, and select Delete.

  3. You are prompted to enter the name of the cluster to confirm the action. Enter the cluster name and click Delete.

• Lastly, remove the KUBECONFIG line you added to your Bash profile to remove the LKE cluster from your available contexts.

More Information

You may wish to consult the following resources for additional information on this topic. While these are provided in the hope that they will be useful, please note that we cannot vouch for the accuracy or timeliness of externally hosted materials.

• Install and Set Up kubectl