> For the complete documentation index, see [llms.txt](https://atomoh.gitbook.io/kubernetes/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://atomoh.gitbook.io/kubernetes/en/quiz-collection/service-mesh/linkerd/installation.md).
# Installation Quiz
This quiz tests your understanding of Linkerd installation and setup.
## Quiz Questions
### 1. What is the correct command to install the Linkerd CLI?
A. `apt-get install linkerd` B. `curl --proto '=https' --tlsv1.2 -sSfL https://run.linkerd.io/install | sh` C. `kubectl install linkerd` D. `helm install linkerd`
Show Answer
**Answer: B. `curl --proto '=https' --tlsv1.2 -sSfL https://run.linkerd.io/install | sh`**
**Explanation:** The Linkerd CLI is installed through the official installation script. This script detects the operating system and downloads the appropriate binary. Homebrew (`brew install linkerd`) or Chocolatey (`choco install linkerd2`) can also be used, but the official script is the most common method.
### 2. What command verifies cluster requirements before Linkerd installation?
A. `linkerd check` B. `linkerd check --pre` C. `linkerd verify` D. `linkerd install --dry-run`
Show Answer
**Answer: B. `linkerd check --pre`**
**Explanation:** The `linkerd check --pre` command verifies that the cluster meets requirements before Linkerd installation. It validates Kubernetes API accessibility, version compatibility, and necessary permissions. After installation, use `linkerd check` to verify full status.
### 3. What must be provided when installing Linkerd with Helm?
A. Envoy proxy image B. Trust Anchor and Identity Issuer certificates C. Prometheus configuration file D. Kubernetes version information
Show Answer
**Answer: B. Trust Anchor and Identity Issuer certificates**
**Explanation:** Unlike CLI installation, Helm installation does not auto-generate certificates. Users must create and provide Trust Anchor (Root CA) and Identity Issuer (Intermediate CA) certificates themselves. This allows better control over certificate management in production environments.
### 4. What is the recommended number of control plane replicas for Linkerd HA installation?
A. 1 B. 2 C. 3 D. 5
Show Answer
**Answer: C. 3**
**Explanation:** HA configuration recommends 3 replicas each for Destination, Identity, and Proxy Injector. Three replicas can maintain quorum even if one fails and ensure availability during rolling updates.
### 5. Which is NOT a main feature of the Viz extension?
A. Web dashboard B. Prometheus metrics collection C. Automatic canary deployment D. Real-time traffic tap
Show Answer
**Answer: C. Automatic canary deployment**
**Explanation:** The Viz extension provides web dashboard, Prometheus-based metrics collection, Grafana dashboards, and real-time traffic tap functionality. Automatic canary deployment is implemented through separate tools like Flagger.
### 6. What load balancer type is recommended for Multicluster gateway on EKS?
A. Classic Load Balancer B. Application Load Balancer (ALB) C. Network Load Balancer (NLB) D. Internal Load Balancer
Show Answer
**Answer: C. Network Load Balancer (NLB)**
**Explanation:** NLB is optimized for TCP/TLS traffic, making it suitable for Linkerd's mTLS gateway traffic. ALB is optimized for HTTP/HTTPS, and since the Linkerd gateway operates at the TCP level, NLB is recommended.
### 7. What is the correct order for Linkerd upgrade?
A. Data plane → CRD → Control plane B. CRD → Control plane → Data plane C. Control plane → CRD → Data plane D. CRD → Data plane → Control plane
Show Answer
**Answer: B. CRD → Control plane → Data plane**
**Explanation:** The correct upgrade order is: 1) CLI upgrade, 2) CRD upgrade, 3) Control plane upgrade, 4) Data plane (proxy) upgrade. CRDs must be upgraded first to use new API versions.
### 8. What is the purpose of the `linkerd install --crds` command?
A. Install Linkerd CLI B. Install Custom Resource Definitions C. Generate certificates D. Inject proxies
Show Answer
**Answer: B. Install Custom Resource Definitions**
**Explanation:** `linkerd install --crds` installs only the CRDs (Custom Resource Definitions) used by Linkerd. This includes CRDs for ServiceProfile, Server, ServerAuthorization, etc. The control plane is installed separately with `linkerd install`.
### 9. What is the command to install the Jaeger extension?
A. `linkerd install jaeger` B. `linkerd jaeger install | kubectl apply -f -` C. `kubectl apply -f jaeger.yaml` D. `helm install jaeger linkerd/jaeger`
Show Answer
**Answer: B. `linkerd jaeger install | kubectl apply -f -`**
**Explanation:** Linkerd extensions generate manifests in the format `linkerd install` and apply them with kubectl. The Jaeger extension provides distributed tracing functionality.
### 10. What is the correct order to completely remove Linkerd?
A. Control plane → Extensions → CRD B. Extensions → Control plane → CRD C. CRD → Control plane → Extensions D. All can be removed simultaneously
Show Answer
**Answer: B. Extensions → Control plane → CRD**
**Explanation:** The removal order is the reverse of installation: 1) Remove extensions like Viz, Jaeger, Multicluster, 2) Remove control plane, 3) Remove CRDs. This is because extensions depend on the control plane, and the control plane depends on CRDs.
### 11. What does the `linkerd check` command NOT verify?
A. Kubernetes API connection B. Certificate validity C. Application business logic D. Control plane Pod status
Show Answer
**Answer: C. Application business logic**
**Explanation:** `linkerd check` only verifies Linkerd infrastructure status: Kubernetes API connection, certificate validity, control plane Pod status, proxy status, etc. It does not verify application business logic or functionality.
### 12. What annotation must be added to a namespace for automatic proxy injection?
A. `linkerd.io/inject: enabled` B. `linkerd.io/proxy: true` C. `sidecar.linkerd.io/inject: true` D. `linkerd/auto-inject: yes`
Show Answer
**Answer: A. `linkerd.io/inject: enabled`**
**Explanation:** Adding the `linkerd.io/inject: enabled` annotation to a namespace automatically injects linkerd-proxy into all new Pods in that namespace. The same annotation can be used on individual Pods.