# Fleet Management
## Overview
Fleet Management is a feature that helps group Kubernetes clusters across multiple **zones/regions** , allowing flexible traffic management between clusters. When using **Global Load Balancer (GLB)** , there are two main traffic distribution mechanisms:
1. **North-South Traffic Management with GLB**
* **How it works** : A single **GLB will route traffic to clusters** by geographic region (eg: HAN, HCM...), helping to optimize performance and reduce costs compared to using multiple individual Load Balancers.
* **Support for clusters with Network Type:**
✅ Calico Overlay ✅ Cilium Overlay ✅ Cilium VPC Native
2. **East-West Traffic Management with MCS**
* **How it works** : If a backend service in a cluster fails, traffic will **failover** to the backends of other clusters in **the fleet** , ensuring **no downtime** .
* **Only supports clusters with Network Type** :
✅ Cilium VPC Native
***
## Create fleet
Follow these instructions to create a Fleet and manage traffic distribution with GLB:
**Step 1:** Log in to **VKS Portal** at the link:
**Step 2:** Select **Fleet Management**
**Step 3:** Select **Create a fleet**
**Step 4:** Enter a memorable name for the fleet in the **Fleet Name** field . The **Fleet** name must be between 5 and 50 characters long, including the characters a-z, 0-9, '-'
**Step 5:** Select **the Region** containing your **Cluster**
**Step 6:** Select the cluster list you want to add to the fleet and select **Register** .
**Step 7:** In the list of added **Clusters , you need to specify a cluster** as **host** . The remaining **Clusters will be members** . For example, in the picture, I specify the cluster named demo-fleet-03 as host and the cluster named demo-cluster-04 as member.
**Step 8:** Select the type of **Traffic flow** you want, depending on the **Network type** of the **cluster** you have selected, the type of **Traffic flow** you can choose will be displayed accordingly.
**Step 9:** Select **Create**
**Step 10:** Deploy a service on the host cluster. First, you need to download **the KubeConfig** of **the Host Cluster** and connect to this host cluster. After downloading the **KubeConfig** file and updating it to a **config** file in the directory `~/.kube`, you can check the connection to the cluster with the command:
```
kubectl get nodes
```
Next, let's implement a service, which:
* With Traffic Flow: **East West Traffic Management with Multi Cluster Service** : you can create service type **LoadBalancer, NodePort or ClusterIP.**
* With Traffic Flow: **North South Traffic Management with GLB** : you can create service type **LoadBalance or NodePort** .
For example below, I create a file `nginx.yaml`containing nginx service type LoadBalancer at namespace `default`:
```yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-app
spec:
selector:
matchLabels:
app: nginx
replicas: 1
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:1.18.0
ports:
- containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
name: nginx-service
spec:
selector:
app: nginx
type: LoadBalancer
ports:
- protocol: TCP
port: 80
targetPort: 80
```
```
kubectl apply -f nginx.yaml
```
**Step 11:** Create a file `glb-nginx.yaml`containing the GLB service using the following sample YAML:
```yaml
apiVersion: vks.vngcloud.vn/v1alpha1
kind: VngcloudGlobalLoadBalancer
metadata:
name: nginx-service
namespace: default
```
**Step 12:** Apply GLB configuration using command:
```
kubectl apply -f glb-nginx.yaml
```
Replace `glb-nginx.yaml`with your YAML file name.
At this time, the system will create a new vGLB on the vGLB system, you can check the created vGLB [here](https://glb.console.vngcloud.vn/glb/list) .
{% hint style="info" %}
**Attention:**
* A **vGLB** can only be used for **a single Fleet** .
* However, if you have a vGLB **that is not used in any Fleet** , you can **reuse** it by **adding annotations to the YAML file** when creating the vGLB.
{% endhint %}
**Step 13:** Check the status of GLB with the command:
```
kubectl get vngcloudgloballoadbalancer -n default
```
You will see a list of created GLBs along with their status.
For example:
```
NAME FLEET ID GLB ID ADDRESS
AGE
nginx-service fl-cadc9e8c-0930-44aa-a37f-cb330a8c4af9 glb-09108dcc-5d3d-4067-8700-02941acd7d68 vks-fl-cadc9e8-default-nginx-serv-33be0-53461-2354c.glb.vngcloud.vn 4h30m
```
**Step 14:** Get the IP address or hostname of GLB to access the service using the command:
**Step 15:** Test Fleet's performance by sending a request to GLB:
```
curl http://
```
Replace ``with the IP address or hostname obtained from the step above.
For example:
```sh
curl http://vks-fl-25757a5-default-nginx-serv-33a00-53461-38e3a.glb.vngcloud.vn
StatusCode : 200
StatusDescription : OK
Content :
Welcome to nginx!
<...
RawContent : HTTP/1.1 200 OK
Connection: keep-alive
Accept-Ranges: bytes
Content-Length: 612
Content-Type: text/html
Date: Fri, 28 Feb 2025 08:48:50 GMT
ETag: "5e9efe7d-264"
Last-Modified: Tue, 21 Apr 2020 ...
Forms : {}
Headers : {[Connection, keep-alive], [Accept-Ranges, bytes], [Content-Length, 612], [Content-Type, text/html]...}
Images : {}
InputFields : {}
Links : {@{innerHTML=nginx.org; innerText=nginx.org; outerHTML=nginx.org; outerText=nginx.org; tagName=A; href=http://nginx.org/}, @{innerHTML=nginx.com;
innerText=nginx.com; outerHTML=nginx.com; outerText=nginx.com; tagName=A; href=http://nginx.com/}}
ParsedHtml : mshtml.HTMLDocumentClass
RawContentLength : 612
```
Or access directly as picture:
### **Check North-South Traffic with GLB**
Suppose, you have initialized Fleet with 2 clusters on 2 regions HAN, HCM and selected Flow Traffic as GLB. The general steps to perform the test are as follows:
1. First, on Host Cluster, you need to deploy glb-nginx.yaml to create GLB via command:
```
kubectl apply -f glb-nginx.yaml
```
1. Next, on each Cluster A, B, you create a deploy nginx service but you need to edit the service output to Hello Nginx HAN, Hello Nginx HCM to easily observe how traffic is distributed.
* **On Cluster A in Region HCM:**
* Create files `nginx-configmap.yaml` and `nginx.yaml`following the pattern, deploy them on cluster A:
```yaml
apiVersion: v1
kind: ConfigMap
metadata:
name: nginx-custom-page
namespace: default
data:
index.html: |
Hello Nginx HCM
```
```
kubectl apply -f nginx-configmap.yaml
```
```yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-app
spec:
selector:
matchLabels:
app: nginx
replicas: 1
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx
volumeMounts:
- name: nginx-html
mountPath: /usr/share/nginx/html/
volumes:
- name: nginx-html
configMap:
name: nginx-custom-page
---
apiVersion: v1
kind: Service
metadata:
name: nginx-service
spec:
selector:
app: nginx
type: LoadBalancer
ports:
- protocol: TCP
port: 80
targetPort: 80
```
```
kubectl apply -f nginx.yaml
```
* **On Cluster B in Region HAN:**
* Create files `nginx-configmap.yaml` and `nginx.yaml`following the pattern, deploy them on cluster A:
```yaml
apiVersion: v1
kind: ConfigMap
metadata:
name: nginx-custom-page
namespace: default
data:
index.html: |
Hello Nginx HAN
```
```
kubectl apply -f nginx-configmap.yaml
```
```yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-app
spec:
selector:
matchLabels:
app: nginx
replicas: 1
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx
volumeMounts:
- name: nginx-html
mountPath: /usr/share/nginx/html/
volumes:
- name: nginx-html
configMap:
name: nginx-custom-page
---
apiVersion: v1
kind: Service
metadata:
name: nginx-service
spec:
selector:
app: nginx
type: LoadBalancer
ports:
- protocol: TCP
port: 80
targetPort: 80
```
```
kubectl apply -f nginx.yaml
```
3. Finally, on ClusterA, B, do curl to GLB\_Domain.
* **On Cluster A in Region HCM:**
```
kubectl get pod
NAME READY STATUS RESTARTS AGE
nginx-app-5dc57d48b6-phtz4 1/1 Running 0 23m
```
```
kubectl exec nginx-app-5dc57d48b6-phtz4 -it -- curl vks-fl-c4289d0-default-nginx-serv-82e59-53461-93a04.glb.vngcloud.vn
```
The curl result will be as follows:
```
Hello Nginx HCM
```
* **On Cluster B in Region HAN:**
```
kubectl get pod
NAME READY STATUS RESTARTS AGE
nginx-app-5dc57d48b6-tvc5f 1/1 Running 0 16h
```
Copy
```
kubectl exec nginx-app-5dc57d48b6-tvc5f -it -- curl vks-fl-c4289d0-default-nginx-serv-82e59-53461-93a04.glb.vngcloud.vn
```
The curl result will be as follows:
```
Hello Nginx HAN
```
### **Check** East-West Traffic with MCS
Test failover by shutting down the backend service in one cluster and observing how traffic is distributed to another cluster in Fleet:
* For example, on a Cluster belonging to Region HAN, I perform scale deployment with the command:
```
kubectl scale deployment nginx-app --replicas=0 -n default
```
* At this time, all traffic will be transferred to the cluster in Region HCM, you can check by curling to GLB Endpoint:
```
curl vks-fl-c4289d0-default-nginx-serv-82e59-53461-93a04.glb.vngcloud.vn
```
The curl result will be as follows:
```
Hello Nginx HCM
```
After completing the above steps, you have successfully set up Fleet Management on VKS with Global Load Balancer to effectively manage traffic between clusters.
***
## Register and unregister a cluster to the fleet
After creating a Fleet, you can add existing Kubernetes clusters to the Fleet in two ways:
* **Method 1:** In **Fleet Management** , select **Edit Fleet** then select a cluster from the available list and click **"Register"** to add to Fleet.
* **Method 2:** Register the cluster directly to Fleet during the cluster creation process.
If you no longer need a cluster in Fleet, you can **Unregister it** by:
**Step 1:** Access the **Fleet Management** section .
**Step 2:** Select the cluster to remove.
**Step 3:** Click **"Remove"** or **"Unregister"** (only delete cluster from Fleet, not delete cluster from VKS system).
***
## Changing host clusters within a fleet
Once you create a Fleet, you can edit its configuration:
* **Change Host Cluster** in existing Fleet.
* **Add or remove cluster members** as needed, but always ensure Fleet has at least one cluster host.
***
## Delete a fleet
When you no longer need a Fleet, you can delete it by:
**Step 1:** Access **Fleet Management** .
**Step 2:** Select **the Fleet** to delete.
**Step 3:** Click **"Delete"** and confirm.
{% hint style="info" %}
**Attention:**
* Each Fleet needs to have at least **one host cluster** , the remaining clusters will act as **member clusters** . After the Fleet is created, you can **add/remove member clusters** or **change host clusters** .
* A cluster cannot register to **multiple Fleets at the same time** . If you want to change Fleet, you need **to Unregister from the old Fleet** before adding to the new Fleet.
* You cannot delete a cluster if it is a host cluster in a Fleet. If you want to delete a cluster that is **a host** , you need to **transfer the host role to another cluster** before deleting it. Without a host cluster, Fleet will not function properly.
* If you want to use Private cluster for Fleet, you **are required to set up NAT** to communicate with GLB because we currently do not support Private Service Endpoint to GLB.
* When a Fleet is deleted, **the clusters within the Fleet still exist** and can be used independently or added to another Fleet.
{% endhint %}
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