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PostgreSQL is one of the most popular open-source databases, offering flexibility and powerful configuration options. As a PostgreSQL DBA or developer, understanding configuration files is essential for performance tuning, troubleshooting, and database administration. In this article, we will explore PostgreSQL configuration files, learn how to modify parameters manually, use the ALTER SYSTEM…

1. What is Startup Probe? 👉 Startup probe = check if application has started successfully Runs only during startup (not continuous) Used for slow-starting apps (Java, Spring Boot, DB-heavy apps) Until it passes: ❌ Liveness NOT executed ❌ Readiness NOT executed ✅ This prevents Kubernetes from killing app too early. 2. Why we need Startup Probe (real problem) Without startup probe: App…

What is restartPolicy in Kubernetes restartPolicy tells Kubernetes: 👉 “What should I do when a container inside a Pod stops?” Kubernetes uses this for self-healing (auto restart). Types of restartPolicy There are 3 values only: 1. Always (default) Container will restart every time it stops Even if it exited successfully ✅ 👉 Used for: Web apps APIs Long running services 2.…

What is Init Container in Kubernetes? An Init Container is a special container that runs before your main application container starts. 👉 Think of it like setup/initialization stepBefore your app starts, something must be ready → init container handles that. Key Points (Very Important) Runs before main container Runs only once and completes Runs in sequence (if multiple init containers) If…

A Static Pod is a pod that is directly managed by the kubelet (node agent) instead of the Kubernetes API server. It is managed locally by kubelet by creating YAML file directly on the Node by connecting node and create static pod with yaml file directly by using Kubectl apply command. 👉 Normal pods: Created using kubectl apply Managed by API server, scheduler, etc. 👉 Static pods: Created by…

AWR (Automatic Workload Repository) is one of the most important Oracle DBA tools for performance analysis. It captures database workload statistics and helps identify bottlenecks such as slow SQL, high CPU usage, I/O issues, waits, and memory problems. Types of AWR Reports 1. Single Instance AWR Report Used for standalone databases. @$ORACLE_HOME/rdbms/admin/awrrpt.sql 2. RAC AWR Report…

What is terminationGracePeriodSeconds in Kubernetes? In Kubernetes, terminationGracePeriodSeconds defines how much time (in seconds) a Pod gets to shut down gracefully before it is forcefully killed. When Kubernetes decides to stop a Pod (for example during scaling down, deployment update, or manual deletion), it does not immediately kill the container. Instead, it gives the application some…

What is Node Selector in Kubernetes? Kubernetes uses labels on nodes Pod uses nodeSelector to match those labels Pod will only run on nodes that match labels In Kubernetes, both nodes and pods use labels to control where workloads run. A node is first assigned a label such as disktype=ssd, which describes its characteristics. Then, when creating a pod, you specify a nodeSelector with the same…

For using the bash shell of POD kubectl exec -it <podname> -- /bin/bashExample kubectl exec -it POD1 -- /bin/bash -- In case of POD has multi container pod then we specify the container namekubectl exec -it <podname> --container <containername> -- /bin/bash example: kubectl exec -it POD1 --container CONTAINER1 -- /bin/bash Check Logs of POD kubectl logs <podname>Example: kubectl logs POD1 To…

Enhance SQL Queries Using Oracle Access Advisor SQL Access Advisor is a performance tuning tool provided by Oracle that analyzes your SQL workload and recommends structures such as: Indexes Materialized Views Materialized View Logs Partitions These recommendations help improve SQL performance and reduce query execution time. SQL Access Advisor helps Oracle DBAs identify missing indexes,…

ReplicaSet = Controller that keeps N Pods always running. We define the number of Pods running then kubenet keep this no of POD in running state. We set 3 POD to run then ReplicaSet ensures: ✅ Always 3 pods are running ✅ If 1 pod dies → creates new pod ✅ If extra pods exist → deletes extra Example of a manifest file: It defines 3 pods to run. If a pod dies or has issues, a new pod is created…

Kubernetes Labels Explained: Grouping and Managing Resources What are Labels in Kubernetes? 👉 Labels are key = value pairs attached to Kubernetes objects (Pods, Nodes, Deployments, etc.). Used for: Grouping resources Filtering objects Connecting services to pods Scheduling workloads Example: app=frontendenv=prodtier=backend Example (YAML with labels) apiVersion: v1kind: Podmetadata:…

Manage the Namespace in Kubernetes What is Namespace? In Kubernetes, namespaces help separate groups of resources within a single cluster. They function like virtual clusters, improving organization, resource management, and access control. Namespaces are especially beneficial in environments with many users from different teams or projects. Get a list of all namespaces in Cluster…

Create a manifest file with command for deployment in Kubernet To deploy an Nginx application in Kubernetes, create a manifest file using the command “kubectl create deployment ngnix –image=ngnix –dry-run=client -o yaml > deploymentngnix.yaml.” Deploy the pod with “kubectl apply -f deploymentngnix.yaml,” verify using “kubectl get pods,” and delete resources with “kubectl delete -f…

What is Dry Run? kubectl --dry-run lets you test a command without actually creating/updating resources. Types of Dry Run 1. Client Side (--dry-run=client) Use kubectl dry-run for client side validation of a manifest. Runs locally (no cluster call) Just checks syntax Does NOT validate with Kubernetes server kubectl create deployment my-app --image=nginx --dry-run=client -o yamlORKubectl…

Essentials of Managing Kubernetes Contexts Get information about our current cluster context. Ensure we are login to correct cluster. Note: * mark on cluster which we are on in output of the command kubectl config get-contexts Change our context if needed by specify name kubectl config use-context <name> Get information about the API server for our current context kubectl cluster-info Get…

To display all configured Docker network subnets: docker network inspect $(docker network ls -q) | grep Subnet You can also list available Docker networks: docker network ls Inspect a specific network: docker network inspect <network_name> Example: docker network inspect bridge Choosing a Free Subnet Each interconnect network must use a unique subnet. Example: docker network create \…