k8s management tool

Deployment  Helm, use charts to deploy complex applications 

CLi tool, kubectl, kube-shell which can auto-completiion commands. 

monitoring : cAdvisor.

kompose: move docker compose to kubenets

loadtest: Fortio

CD: Arog  https://www.youtube.com/watch?v=2WSJF7d8dUg&list=RDCMUCFe9-V_rN9nLqVNiI8Yof3w&index=11 , it watch the target app yaml change in the repo,  and apply it once a change detected in the gitlab

Pod Deleting

1 pod deleted by kubectl with default grace period (30sec)

2 API server make the pod as terminating ;

3 kubectl in the node which running the pod notice the terminating, it will 

   a) if prestop is set, it will run prestop hook, 

    b) send Term signal to process to the  containers for that pod;

4 at same time, service will be updated to delete this pod; the iptable route will be changed. 

5  after grace period expire, kubectl send sigkill to force stop. 

6 remove pod object 

 

Hybrid Cloud:

connect from onprem to cloud can be vpn or PoP (e.g aws direct link). PoP is private, VPN needs internet. 

Service Mesh:  Istio, connect mutiple cluster. Istio can be used to define policy of route traffic. 

Intergration 

Security: layer3 K8s Netowrk Policy/Calico, Layer3 Istio for traffic between user to K8s (north and south)

              Istil TLS  can be used to secure traffic between pods (authentication); RBAC (aurth); 

 

service mesh config example for carnary deployment

kubectl apply -f - <<EOF
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: helloworld
spec:
  hosts:
    - helloworld
  http:
  - route:
    - destination:
        host: helloworld
        subset: v1
      weight: 90
    - destination:
        host: helloworld
        subset: v2
      weight: 10
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: helloworld
spec:
  host: helloworld
  subsets:
  - name: v1
    labels:
      version: v1
  - name: v2
    labels:
      version: v2
EOF