Kubernetes daily use commands

 Here is a quick view on k8 commands which are ideally useful for daily interaction work

• kubectl config get-contexts
• display list of contexts
• kubectx <env-name>
• to switch the env
• kubectl get nodes
• Get all nodes
• kubectl get namespaces
• Get all namespaces for a environment
• kubectl -n services get pod <pod-name>
• Get specific pod details
• kubectl -n services get pods
• Get all pods
• kubectl -n services delete pod <pod-name>
• Delete specific pod name
• -o wide
• To get data in more details like which node etc
• -o yaml
• To open specific file to see the details
• kubectl -n services describe pod <pod-name>
• To see description of the pod
• kubectl -n services exec -it  <pod-name> /bin/bash
• Logging into the pod to see details at code level
• kubectl -n services get hpa <hpd-pod-name>
• To check hpa details if hpa enabled
• kubectl -n services scale deploy <pod-name> --replicas=3
• To manual scale
• kubectl -n services get pods -o wide | grep ½
• Get all pods which are in unhealthy state
• kubectl -n services get deployment <pod-name> -o yaml
• To check min/max replicas or any other data point w.r.t deployment
• kubectl -n services get deployment <pod-name> -o yaml
• To edit min/max replicas or any resources
• kubectl -n services rollout restart deployment <po-name>
• To restart a service
• kubectl -n services logs <pod-name> -c install -f
• This could be used if our pod is in Init stage. Gives us the keys that are missing from config(Search for nil after running this command)
• kubectl -n configuration get pods
• Consul and Vault status
• stern -n configuration <name>
• Check logs of vault
• stern -n services <pod-name> -c <app-name> -t --since 1m
• Prints logs of all the pods of last 1 min
• stern -n services geolayers-api-primary -c geolayers-api -t --since 1m | grep '<text>' 
• Prints log only for the text that is in grep
• kubectl describe canary <pod-name> -n services
• To check canary deployment of specific pod
• kubectl get canary -n services
• To check all pods for which canary enabled

Kubectl commands complete cheatsheet : https://kubernetes.io/docs/reference/kubectl/cheatsheet/

Happy Learning !! :)

Design Parking Garage

 Let's discuss designing parking garage as a problem statement.

At high level what all we need to consider and think about while designing a parking garage.

Product Requirements:

• Need to be able to reserve a parking spot and receive some kind of ticket or receipt.
• Need to be able to pay for a parking spot.
• System needs to have a high consistency (no two people should be able to reseve the same spot at the same time).
• 3 types of vehicles (compact, regular and large).
• flat rate, but different rates depending of the type of parking.

APIs:

• Public Endpoints
• /reserve
• Params : garage_id, start_time, end_time
• Returns : (spot_id, reservation_id)
• /payment
• Params : reservation_id
• Note : Likely using an existing API to handle (Stripe, Square etc...)
• /cancel
• Params : reservation_id
• Internal Endpoints
• /calculate_payment
• Params : reservation_id
• /freespots
• Params : garage_id, vehicle_type, time
• Note : Smaller vehicles can fit into larger spots if necessary and therefore should be included in the overall number of spots
• /allocate_spot
• Params : garage_id, vehicle_type, time
• /create_account
• Params ; email, password, first_name, last_name
• /login
• Params : email, password

Data Schema:

• Reservations
• id : primary key
• garage_id : foreign key
• spot_id : foreign key
• start: timestamp
• end : timestamp
• paid : boolean
• Garage
• id : primary key
• zipcode : varchar
• rate_compact : decimal
• rate_regular : decimal
• rate_large : decimal
• Spots
• id : primary key
• garage_id : foreign key
• vehicle_type : enum
• status : enum
• Users
• id : primary key
• email : varchar
• password : varchar (note that this probably SHA-256 hash)
• first_name : varchar
• last_name : varchar
• Vehicles
• id : primary key
• user_id : foreign key
• licence : varchar