Highly Recommend using repo here - Day9 to practice this project instead of code present in snippets, In case of confusion, Please do watch video that is explained in English, the code here in the blog is not changed to keep screenshots intact
To Put it in simple flow, we integrated Jenkins with Webhook from Github Repo,
and Jenkins server has SSH connection to Build Server , Build Server has SSH connection to Deploy Server.
Build Server has Docker and Ansible Installed.
Deploy Server has Kubernetes and Helm Charts Installed.
According to the way we designed this Project, whenever we push a commit to our code in Github, Jenkins gets triggered, and Jenkins runs Ansible Playbook in Build Server.
This Ansible Playbook is written to go and fetch this Repo - Bash Scripts
and once this task is done, now it runs deploy.sh script on Deploy Server, which deletes the existing pods and as a result latest image from the Docker Hub will be fetched again, the below script is written before helm charts
How to tag Docker Image with Git Commit Id
git rev-parse HEAD
As you can see from the above screenshot, we have improved our build.sh script to tag with commit id as we saved git commit id in variable git_commit and now we push it to Docker hub and now our images are formed with Tags as you can see in below screenshot
Now it is time, we have to get this commit id value to update in our Helm chart values, request you to complete Helm Charts chapter to understand what we are trying to do.
Helm Charts makes our kubernetes pods up and values.yaml files serves as the main and by default we have left the value of docker image tag as "latest'', this fetches recent image that is pushed to our docker hub, but we want to have this value as commit id, to track it better
We want this latest value to be updated with latest commit id that is pushed,and for this , we have created IAM role to give full s3 bucket access and we have attached this to both our Build Server and Deploy Server , also we have installed aws cli in both the servers, for this process, you can check the blog - Upload files to AWS EC2
Now we have created an s3 bucket and named it as gitcommitids
and we have created two empty files in it, one is new_value.txt and other is old_value.txt
Now we have updated our build.sh script to be in this way
#!/bin/bash
sudo docker container prune -f && sudo docker image prune -a -f && sudo docker volume prune -f && sudo docker network prune -f && sudo docker system prune -a -f
##this above step is not recommned step, i am deleting existing images to save space
sudo rm -r gold
sudo mkdir gold
cd gold/
sudo git clone https://github.com/Hari0o/Gold_Site_Ecommerce.git
cd Gold_Site_Ecommerce/
git_commit=$(sudo git rev-parse HEAD)
sudo docker build -t react-nginx:$git_commit -f golddockerfile .
sudo docker tag react-nginx:$git_commit sagarkakkala385/react-nginx:$git_commit ##make sure you did docker login
sudo docker push sagarkakkala385/react-nginx:$git_commit
aws s3 rm s3://gitcommitids/new_value.txt
sudo touch new_value.txt
sudo chmod 777 new_value.txt
sudo echo $git_commit > new_value.txt
aws s3 cp new_value.txt s3://gitcommitids/
sudo rm new_value.txt
Now if you see the above what we are doing is , whenever there is a new commit, it updates the commit value and pushed to docker hub, once that is done, since it has full access over s3 bucket , we have deleted new_value.txt file from s3 bucket, created new file "new_value.txt" in Build Server and updated it with git commit id value and pushed "new_value.txt" to s3 bucket , and removed the file that we created in Build Server
To put it simple, delete file "new_value.txt" in s3 bucket, create file "new_value.txt" and update file with git commit id in Build Server instance, send updated file "new_value.txt" to S3 Bucket
Now our deploy.sh script as well is updated in this way
#!/bin/bash
cd /home/ubuntu/react-chart/
aws s3 cp s3://gitcommitids/old_value.txt .
aws s3 cp s3://gitcommitids/new_value.txt .
old_value=$(cat old_value.txt)
new_value=$(cat new_value.txt)
sed -i "s/${old_value}/${new_value}/g" values.yaml
helm upgrade react-chart .
aws s3 rm s3://gitcommitids/old_value.txt
echo $new_value > old_value.txt
aws s3 cp old_value.txt s3://gitcommitids/
rm old_value.txt new_value.txt
Now we have updated deploy.sh, in such a way to get both the files old_value.txt and new_value.txt from s3 bucket to Deploy Server, and put them in variables like old_value and new_value, and we have used sed command to replace old value with new value , and then upgrade the helm, helm upgrade helps us in deploying latest image to our website, once helm upgrade is done, since we have deployed already with new git commit id, we are updating it as old value.txt
To put it simple, from above screenshot, we are pushing new generated git commit id value to s3 bucket in new_value.txt and after that we are asking deploy server to fetch the values of old_value.txt and new_value.txt, old_value.txt consists of tag which is now already running the website, which is deployed already, we are asking to fetch both old and new values, now using sed command we are asking to replace old value of tag in values.yaml with new value that is generated now, once helm is deployed , now updated the old_value.txt with the value that is already deployed.
Let us understand the logic better by deploying project, checking the values before commit and after commit
let us observe our old values before commiting,
Website:
d449a005a4bffd0328c5483d0b1827d2cb149560
Docker Hub:
S3 Bucket:
new_value.txt: d449a005a4bffd0328c5483d0b1827d2cb149560
old_value.txt: d449a005a4bffd0328c5483d0b1827d2cb149560
The values are same because, In logic we said once deployed, take new_value and update it in old_value.txt
Docker tag value in Helm Values.yaml:
let us observe our old values after commiting,
S3 Bucket :
To summarize what happened when we committed a new change:
sed -i "s/${old_value}/${new_value}/g" values.yaml
sed -i "s/d449a005a4bffd0328c5483d0b1827d2cb14956/e3676aa7d4090d8b2c2b6411e3db7c4d5a3c5b72/g" values.yaml
How does Docker tagging with git commit id help us
Now , using this commit id, i can check who committed it and can question on why these changes were pushed by him and justification for making changes that broke the production
This concludes the blog here
🔹 Important NoteAlso, before proceeding to the next session, please do the homework to understand the session better - DevOps Homework
Comments
Post a Comment