What is your question about the text? Do you need help with setting up a Blue/Green deployment using Route53/DNS or ELB/ASG approach? Or do you have some other questions regarding the setup and configuration of the services mentioned in the text?
Kubernetes storage explained: Persistent Volumes, Claims, Storage Classes, Volume Modes & Access Modes. Essential for CKA exam domains
np1.yaml & np2.yaml differ by 1 tiny typo! np1 allows DNS traffic on ports 53 (TCP/UDP) OR namespace space2 match. np2 allows DNS traffic on ports 53 AND namespace space2 match, due to single rule with both constraints.
Kubernetes basics: SVC, NodePort, ClusterIP, Ingress & NetworkPolicy. Expose services with `kubectl expose`, access with `curl` and port-forwarding. Understand ingress rules, YAML files and network policies for secure traffic flow.
Ingress vs NetworkPolicy: Ingress provides HTTP/HTTPS routing & domain-based routing, while NodePort exposes a service on each node's port, but lacks advanced features like TLS termination or path-based routing.
Quick recap for logs & configs: /var/log/, /etc/kubernetes/ & /var/lib/kubelet/. Use kubectl, journalctl or grep to view logs. Check config files in /etc/kubernetes/ & /var/lib/kubelet/
Pod scheduling in Kubernetes explained: affinity (node & pod), nodeName/nodeSelector, taint/tolerations, priority & priorityclass. Learn how to schedule pods with specific requirements.
Confusion between `/var/lib/etcd` on hostPath & mountVolume in `etcd.yaml`. Restoring etcd snapshot: `etcdctl snapshot save` & `etcdctl snapshot restore` with correct data-dir paths.
Node in NotReady state due to resource insufficiency, kubelet problems, networking issues or control plane connectivity issues. Debug with `kubectl describe`, `systemctl status` & `journalctl` logs. Cordon and drain nodes for maintenance.
1. File Synchronization 2. Initialization with InitContainer
Update etcd.yaml to restore etcd: update hostPath in manifest to match new data directory. Example: `- hostPath: path: /root/default.etcd type: DirectoryOrCreate name: etcd-data
Stop all API servers, restore etcd state, then restart API servers. Use crictl to interact with containers if containerd is used.
Backup Etcd: Set env vars for etcdctl, export ETCDCTL_API=3 & correct paths to CA, server.crt & key. Backup with `etcdctl snapshot save /opt/cluster_backup.db > /opt/backup.txt 2>&1
RBAC explained in 250 characters: Service Account is like an identity card, Role defines permissions, RoleBinding grants access to resources. Use `kubectl auth can-i` for quick verification of permissions.
Create deployments with `kubectl create deploy NAME --image=IMAGE --replica NUM`. Scale or change image with `kubectl scale`/`kubectl set image`. Rollback with `k rollout undo`.
kubectl expose deployment nginx --name nginx-svc --port 8080 --target-port 80` exposes a ClusterIP service, while `--type NodePort` exposes it to all nodes on port 8081. Access via SVC_IP:SVC_Port or curl NODE_IP:NodePort.
HostPath & Local Type Persistent Volumes in Kubernetes explained with simplified demos. HostPath ephemeral, no PVC needed. Local type requires PVC & StorageClass, nodeAffinity & automatic pod assignment.
Kubernetes config files & locations: `/etc/kubernetes/manifests`, `/var/lib/kubelet/config.yaml`, `/etc/systemd/system/kubelet.service.d/10-kubeadm.conf`, `.kube/` directory, `pki/` folder for certificates and keys.
ConfigMaps in Kubernetes allow you to decouple configuration from code. They can be used as environment variables or mounted as files within a container, making it easy to manage application configurations.
Decode a secret using base64: `k get secrets database-data -n database-ns -o jsonpath='{.data.*}' | base64 -d
