Maintenance Page

Well this part of Maintenance Page does not contribute much to DevOps learnings but having this page can impact Business and their revenue. May be the page resembles it is a simple one but companies having one maintenance page can have a huge impact, lets understand this impact by example

For Suppose, you wanted to buy a Mobile in Amazon website and you are a regular customer of Amazon, you have your gift cards or some promo codes, and you wanted to buy a Mobile, since Amazon is your favorite website, first thing you do is to check website, lets assume 2 scenarios here

Scenario 1:

Website takes forver to load or it shows 404 error , or there is no website, You will now route to other webistes. You might raise a customer ticket via mail for amazon customer support or you can even route to Flipkart website,. This scenario caused Amazon to loose one potential customer like you, imagine amazon as world wide used e-commere site how much business could it loose ?

Scenario 2:

When you opened Amazon website, you get page there most like maintenance page which might inform the website is currently under maintenance and website will be back in one hour or text includes specific time and time zone. This makes you understand that you can re-visit website after one hour. And you will not be raising support tickets too.

So based on scenarios, we might have to understand impact it makes to business, Having Maintenance page helps business to reduce less Production support tickets and as well not to loose potential customers

Why Maintenance is Required?

Sometimes there might be updates which might require Kubernetes Node Restart, Most Updates or Upgrades are done post business hours, But we will imagine a situation where we are going to do in business hours, it can be underlying server restart or some upgrades that require restart, or sometime servers are restarted as regular maintenance

Before Maintenance is planned, customers will be notified in applications or via mail as well, but having this page would help someone understand who misses to read mails

Here, Before going further, i would recommend to complete till Day3 in Contents of Blog

Now if you have completed till Day3, you might be familiar that our website is now running on kubernetes

Here basic scenario we want to achieve is whenever customer tries to access our website via internet , it must show maintenance page.

As you know already, we had specified our domain hari-dev.shop in Ingress

As from above diagram, whenever user access our domain which is in ingress, Ingress targets service and from service it targets deployment.

Here simple route we are going to follow is , for our Ingress (where domain is specified) to reroute to different service and deployment which has Maintenance page

Now you can imagine, our scenario , we are trying to achieve would be something like this as shown in below diagram

Now let us get into the Project, for it to have Mainatence Page, we will create a Docker Image

You can clone this repo - Maintanence Repo

The Repo consists of both components like Docker and Kubernetes, since the explanations of files have been given in Docker and Kubernetes sessions, will skip explaining in detail

Now let us create a Docker image for our Maintenance Page.

Once you open the repo and navigate to Docker , you will be able to find three files, maintainence page.png, which is actually background image, You can choose to upload or experiment any image of your choice

In case, you want to use different image, make sure to point that image name in index.html , as shown in below screenshot, rename .png file with the name of your image

Also since it is a simple image, we don't need to build any code, we will just deploy this index.html file inside our docker container, As you can see from Docker file

Now let us get into implementation of Maintenance page, here, let us do it in two steps, Building docker image and Deploying it in Kubernetes

Please do refer Day2 and Day3 blogs of Docker and Kubernetes for initial setup

Step1: Building Docker image

Considering, you have already Docker installed and Docker Hub account is created, we will proceed as follows

git clone https://github.com/sagarkakkalasworld/maintenance.git

cd maintenance/Docker/

sudo docker build -t maintanence-page -f maintanencepagedockerfile .

sudo docker images

Docker image is successfully created, now let us push this into docker hub account

sudo docker login

Now let us tag our local image to docker hub account

sudo docker tag maintanence-page:latest sagarkakkalasworld/maintanence-page:latest

Note: Please do replace sagarkakkalasworld to your docker hub username in the above command

and now push the image now to docker hub

Now verify your docker hub account

Now before going to step2, it is recommended to stop the instance where docker is running

Step2: Deploying in Kubernetes

Now considering that microk8s is already installed and an application is already running inside your instance,

there are few important changes that needs to be done, you can use same ingress, deployment and service manifest files that you used for application but make sure to make the following changes

In deployment file, make sure to update the changes of image and as well labels

Now in service.yaml file, use the same labels that you used for deployment

Now at ingress file, lets make the changes of pointing out to this service

Once the changes are done, let us pull the code

git clone https://github.com/sagarkakkalasworld/maintenance.git

since our application is already running, before applying changes, make sure to remove existing ingress

 kubectl get ingress -n react-microk8s

kubectl delete ingress react-ingress -n react-microk8s

Now let us get into our maintenance kubernetes manifest files

cd maintenance/Kubernetes/

since we have all the required manifest files here in the directory, we can just run a single command to apply all three files

kubectl apply -f .

check if the maintenance pods are up

kubectl get pods -n react-microk8s

As seen from above, since maintenance pods are up, we are free to make changes in our application

And also check domain, after updating AWS EC2 public IP in GoDaddy

also do not forget to add Inbound rules to 80 in security groups

once updated, check domain, If you have done already, just refresh the page

Before refreshing browser

After refreshing the browser

Feel free to choose your own image and make the project live

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