Summary - Multi-cluster
- Docker & Kubernetes course
- Expert
- Lesson 30/47
- 5 min
Combine kubeconfig and cross-cluster service to switch contexts.
Summary: multi-cluster
In this group:
- Multiple clusters are used for isolation, availability, regulation and scale; the cost is operational load.
- Distribution: GitOps (Argo CD ApplicationSet, Flux) or managers like Karmada; KubeFed was abandoned.
- Kubeconfig: clusters + users + contexts;
--context,KUBECONFIGmerging, exec-based credentials. - Cross-cluster services: MCS (
ServiceExport,clusterset.local), a mesh or an internal LB; CIDRs must not overlap. - A cluster registry is a set of labelled records; the ApplicationSet cluster generator deploys by label.
for c in uretim-eu uretim-tr; do kubectl --context $c get deploy -n magaza; donePractice Checking all clusters
Write a one-line shell loop: for c in uretim-eu uretim-tr; do kubectl --context $c get deploy -n magaza; done. Then, on a separate line, print the ready replica count of the api deployment in magaza in the uretim-tr context with jsonpath='{.status.readyReplicas}'.
Starter code
# buraya yazSample solution
for c in uretim-eu uretim-tr; do kubectl --context $c get deploy -n magaza; done
kubectl --context uretim-tr get deploy api -n magaza -o jsonpath='{.status.readyReplicas}'Expected output
NAME READY UP-TO-DATE AVAILABLE AGE api 4/4 4 4 12d web 3/3 3 3 12d NAME READY UP-TO-DATE AVAILABLE AGE api 2/2 2 2 9d web 2/2 2 2 9d 2
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 What is a good way to reduce the risk of running a command on the wrong cluster?
- Giving the clusters the same name
- Writing --context explicitly on every command in scripts Correct answer
- Sharing a single kubeconfig
- Relying on current-context
Explanation: The active context may have been changed in another terminal.
2 Run the command on a specific cluster.
Question
kubectl ____ uretim-tr get pods -n magaza
Answer
kubectl --context uretim-tr get pods -n magazaExplanation: --context picks a target without changing the active context.
3 Match.
| Term | Meaning |
|---|---|
--context |
Single-command target |
ApplicationSet |
Multi-cluster deployment |
ServiceExport |
Cross-cluster service |
kubeconfig |
Connection info |