Docker

We can deploy applications to VPS / Cloud Instances to avail it in the public internet. When deploying for production we need some standard practices to ensure application is easy to manage. Some of the feature to consider are: Auto TLS Easy image building and deployment Rolling updates Rollback when needed Preparing VPS for deployment Setup a brand new VPS with SSH and Necessary settings example Install Docker on VPS ssh into VPS using ssh vps1.example.com install docker curl -fsSL https://get.docker.com | sudo sh Setting up Docker Context We can use docker context to configure docker client to connect to the VPS. We can create a context using: ...

I had been using docker compose for a while to deploy, I started noticing there is a slight downtime while deploying docker compose. Moreover, If there is some error while deploying it could be disruptive. I finally started using docker swarm, It’s not very different from docker compose, It is good for rolling updates. Running docker in swarm mode is just a single command docker swarm init which will spin up the manager node. And we can add more nodes to the swarm later on. ...

Certbot is a very useful tool to setup auto renewal of certificates. Here is how I’m setting up certbot and nginx quick and easy. Initial Setup Here is the docker-compose.yaml file with nginx and certbot services: nginx: image: "nginx:alpine" container_name: app_nginx ports: - 80:80 - 443:443 volumes: - ./platform/config/nginx/nginx.conf:/etc/nginx/nginx.conf:ro - ./platform/config/certbot/www:/var/www/certbot:ro - ./platform/config/certbot/conf:/etc/letsencrypt:ro restart: always certbot: image: certbot/certbot container_name: app_certbot volumes: - ./platform/config/certbot/www:/var/www/certbot:rw - ./platform/config/certbot/conf:/etc/letsencrypt:rw Every file that’s generated by certbot will be stored in ./platform/config/certbot ...

Gofiber is a fast lightweight web framework with simple api, inspired by expressjs. The simplicity of the api makes it easy to get started with. It’s also fast and has a lot of features. Setup Create a new project Create a new directory and initialize a go module. go mod init github.com/adharshmk96/gofiber-init Install gofiber go get -u github.com/gofiber/fiber/v2 a main.go with hello world touch main.go package main import "github.com/gofiber/fiber/v2" func main() { // gofiber with default settings app := fiber.New() // handler for root path app.Get("/", func(c *fiber.Ctx) error { return c.SendString("Hello, World 👋!") }) // start server on port 3000 app.Listen(":3000") fmt.Println("Server started on port 3000") } Dockerfile for building the app ...

Steps I follow to setup a CI CD workflow. Write Dockerfile in the code repo. Write a k8s Manifest file using kustomize template. Following this tree structure. ├── base │ └── app │ ├── deployment.yaml │ ├── kustomization.yaml │ └── service.yaml └── overlay ├── production │ └── kustomization.yaml └── staging └── kustomization.yaml Write a skaffold file ( skaffold init will auto initialize itself ). Build Docker image and Render the k8s manifest using skaffold. skaffold build && \ skaffold render --digest-source='tag' -p staging -o ../path-to/manifest.yml Manually push the rendered k8s to the manifest repository. Setup the k8s to access the private repository kubectl create secret generic <secret-name> \ --from-file=.dockerconfigjson=~/.docker/config.json \ --type=kubernetes.io/dockerconfigjson Update the K8s manifest with spec: template: spec: imagePullSecrets: - name: <secret-name> Setup argo cd in the target k8s cluster. ArgoCD Getting Started kubectl create namespace argocd kubectl apply -n argocd -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/install.yaml kubectl patch svc argocd-server -n argocd -p '{"spec": {"type": "LoadBalancer"}}' kubectl -n argocd get secret argocd-initial-admin-secret -o jsonpath="{.data.password}" | base64 -d; echo Login and Link repository to argocd. Create an app in argocd and configure to access the repository and the cluster to deploy.

Docker compose is a tool that helps us define and run multiple services together. We declare the services and their attributes in a configuration file and the docker compose tool reads it and issues the command to docker CLI in order to start and run the services. It helps us abstract all the creation of different components, building or pulling images etc… To run multiple services for a project. Once a compose-file is declared, we can run everything all at once with a single run command, we can also manage them via the docker compose interface. ...

Docker images are built from a Dockerfile, which is a blueprint for how to prepare a ready-to-run image. We can relate it to steps we perform in a computer to get something installed and running. We can start with a base image that corresponds to an OS (like ubuntu, alpine, Debian etc…) or we can even start from essentials installed in an OS. Basic steps are Start from the base image Run commands Specify default run command Here’s a basic example from nodejs ...

Docker is a platform that provides lightweight isolated runtimes for software. It helps us to package the software and its dependencies in a ready to run format. We can say its sort of works like VMs except, docker uses the kernel of our base OS. This is achieved by few techniques done with docker, File system snapshot - Dockerfile is used to build a filesystem snapshot that contains all the required files to run the software. Namespacing - Docker isolates the resources for the running processes using the Namespacing feature. It is a linux feature which partitions resources and control access between processes on resources. Control groups - The volume of resources used by a process can also be limited by docker. It is achieved by cgroups features which is another linux feature that helps define resource limits for a process. Why use Docker? As docker enables packaging and running software in a lightweight way, It solves the problem of setting up and configuring an environment to run the software. ...