Kubernetes :4

DevOps Classroom Series – 08/Apr/2021

Pod

• This is smallest deployable units of computing in k8s
• A Pod consists of one or more containers with shared network and storage resources
• Each Pod will recieve a unique ip address
• To create any object in k8s we need to create a template
• To write the spec navigate to api reference Refer Here
• Refer Here for the pods specs created
• Now lets try to apply the pod spec created 
• Each pod will get one ip address  

kubernetes namespace

• K8s supports multiple virtual cluster backed by same physical cluster and these virtual clusters are called as namespace
• In k8s for any object we have two kinds of scopes
  • cluster scope
  • namespace scope

Commonly used kubectl commands

• get object: In the resources which are scoped to namespace we can use -n to specify the namespace

kubectl get pods -n default

• describe object-type object-name: 
• logs object-name: 
• apply -f filename.yaml
• Other Commands 
• We can use short names 
• To get to know the information of cluster 

Kubernetes HTTP Request Flow

• HTTP Request flow 
• Restful api Refer Here

The K8s API

• K8s api uses JSON over http for its requests and responses.
• k8s api allows clients to create, update, delete or read the description of object via standard http methods    
• Trace the HTTP requests: To trace http request we will be using kubectl get pods -n kube-system. To this we will be adding verbose level –v=8

kubectl get pods -n kube-system --v=8

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