Config Maps

• ConfigMaps are used to provide configuration information for Workloads.
• This can either be fine-grained information or a composite value in the form of file.
• ConfigMap is a k8s object that defines a small file system.
• Another way is a set of variables that can be used when defining the environment or command line for your containers
• Lets create a sample configuration
  
• Using a ConfigMap: There are three main ways to use a ConfigMap
  • FileSystem: you can mount a ConfigMap into a Pod. A file is create for each entry based of key name and the contents of the file are set to the value
  • Environment variable:
  • A ConfigMap can be used to dynamically set the value of an environmental variable
  • Command-line argument:
  • K8s supports dynamically creating commnad line for a container using ConfigMap Values
• Refer Here for the changes
  
  
  

Secrets

• If you have a configuration value with sensitive information, we use secrets in k8s
• Secrets can be mounted exactly similar to config maps
  
  
  
• Refer Here

Init Containers in Pod

• In Pod we have two types of containers
• init container:
  • Init container always runs to completion
  • Each init container must complete successfully before the next one starts
  • If Pod’s init container fails, kubelet will restart repeately
  • If init container fails k8s treats the overall Pod as failed
• regular containers:
  • run our application
• Refer Here for the changes done
  

Health Checks

• K8s introduced health checks for application liveness.
• Liveness health checks run application-specific log to verify that the application is not just still running , but functioning properly
• Liveness Probe:
• We need a way to confirm that our application is actually healty & shouldn’t be restarted.
• Liveness probes are defined per container which means each container inside a Pod is health-checked seperated
• Refer Here
• Refer Here for the changes done
• Readiness Probe:
• This probe determinse whether the container is ready to serve the user requests
• container that fail readiness checks are removed from service load balancers
• Refer Here for the changes done

Resoruce Constraints

• Refer Here for resource constraints on Docker.

Waiting for 10 mins for you do create a docker container with cpu and memory restrictions.

• Resource Management in k8s is dealt with two major aspects
• Resource Requests => Minimum Required Resources
• Resource Limits => Maximum Required Resources
• Lets create a Pod with limits and request. Refer Here for the official docs
• Refer Here