Skip to main content

Kubernetes: 6. Imperative Commands

  • Imperative commands are useful in quickly creating the resources on Kubernetes
kubectl
--dry-run -> When created with this option, Kubernetes just validates the definition and does not actually create the resource
-o=yaml -> Gets the output in YAML format

kubectl run nginx-pod --image=nginx:alpine 
-> Create a pod with name nginx-pod and image nginx:alpine

kubectl run httpd --image=httpd:alpine 
-> By default, run implies run-a-pod

kubectl run redis --image=redis:alpine --labels=tier=db 
-> Create a pod with name redis and image redis:alpine and labels set to tier=db

kubectl run custom-nginx --image=nginx --port=8080 
-> Create a pod with name custom-nginx and image nginx to run on port 8080

kubectl expose pod redis --port=6379 --name=redis-service 
-> Create a service with name redis-service to expose pod named redis on service-port 6379

kubectl create deployment webapp --image=kodekloud/webapp-color --replicas=3 
-> Create a deployment with name webapp and image set with 3 replicas

kubectl create ns dev-ns
-> Create a nanespace dev-ns

kubectl create deployment redis-deploy --namespace=dev-ns --image=redis --replicas=2 
-> Create a deployment

kubectl expose pod httpd --name=httpd --type=ClusterIP --port=80 --target-port=8080 
-> Expose a pod as service of type ClusterIP on the specifed ports  
Labels:

Comments

Post a Comment

Popular posts from this blog

Azure Active Directory

Azure Active directory (AAD) is a Identity as a Service. This is a smaller subset of Active directory. This is not a replacement to active directory at all. Azure active directory provides the identity services to the mobile apps and web apps in Private cloud. These apps may be connected to on-premise applications. So an SSO is enabled for these apps. So Azure active directory has very simple functionality. Create Users, Groups. Map groups to network security groups and provide the authentication to the resources. When you login to Azure portal, right upper corner of the screen has username along with the domain. Domain or tenant or organization are used interchangeably. Management of Users and Groups: Cloud identity (create users manually)  Directory synchronized identifiers (users are synchronized)  Add users Adding a cloud identity users makes the user as Guest When you do directory synchronization on Premise AD Groups are synched up wi...
Post a Comment
Read more

Kubernetes: 19. Configure Application

Configuring application consists of Configuring commands and arguments on applications Configuring environment variables Configuring secrets Docker Commands docker run ubuntu  -> Runs ubuntu container and exit, container CMD is set to [bash], so the container quitely exits docker run ubuntu echo "Hello World" -> Runs ubuntu container, prints "Hello World" exits quitely. To update the default settings, create your own image from the base image lets call this ubuntu-sleeper image FROM ubuntu CMD sleep 5 CMD can also be mentioned in the JSON format like CMD ["sleep", "5"] Note that with JSON format the first element should always be the command to execute,  for eg, it CANNOT be ["sleep 5"] Run build the new ubuntu-sleeper image and run the new image docker build -t ubuntu-sleeper .  -> Build the image docker run ubuntu-sleeper -> Run the new image So the new image will launch ubuntu container, sleep for 5 seconds and quitely ex...
Post a Comment
Read more

Kubernetes: 5. Services

A  service  is a stable endpoint to connect to "something" An abstract way to expose an application running on a set of pods as a network service. Services enable communication between various components within and outside of the application With Kubernetes Services there is no need to configure the application for service discovery Kubernetes Service is an object just like Pod, ReplicaSet etc There is always a service running when Kubernetes is installed, Kubernetes API itself When a service is created, kubernetes creates the endpoints (kubectl get endpoints) The endpoints has all the pods associated with that service Headless Service A headless service is obtained by setting clusterIP  field to None Since there is no virtual IP address, there is no load balancer either The DNS service will return the pods' IP addresses as multiple A records This gives us an easy way to discover all the replicas for a deployment This is useful for creating stateful service...
Post a Comment
Read more