vl3-dns

vL3 dns single cluster example

This example shows how is working DNS in the vl3 network.

Diagram:

NOTE: Forwarder and NSMmgr are not added in the diagram for the simplicity

By this example we are using by defeault the next go-template for DNS records generating:

{{ index .Labels \"podName\" }}.{{ .NetworkService }}

The vl3 dns server handles the incoming connection and uses the template to generate DNS record.

For example, nsc.netsvc-1 will be generated for the next conntection:{"labels":{"podName": "nsc"}, "networkservice": "netsvc-1"}.

The template could be changed via env variable of cmd-nse-vl3-vpp: NSM_DNS_TEMPLATES.

Run

Deploy network service, nsc and vl3 nses (See at kustomization.yaml):

kubectl apply -k https://github.com/networkservicemesh/deployments-k8s/examples/features/vl3-dns?ref=7a2735f6f8c8ed02d058c1a6a2f04846a3d88cad

Wait for clients to be ready:

kubectl wait --for=condition=ready --timeout=2m pod -l app=alpine -n ns-vl3-dns

Find all nscs:

nscs=$(kubectl  get pods -l app=alpine -o go-template --template="{{range .items}}{{.metadata.name}} {{end}}" -n ns-vl3-dns)
[[ ! -z $nscs ]]

Ping each client by each client via DNS:

(
for nsc in $nscs
do
    for pinger in $nscs
    do
        kubectl exec $pinger -n ns-vl3-dns -- ping -c2 -i 0.5 $nsc.vl3-dns -4 || exit
    done
done
)

Check NSCs PTR records:

(
for nsc in $nscs
do
    for pinger in $nscs
    do
        # Get IP address for PTR request
        nscAddr=$(kubectl exec $pinger -n ns-vl3-dns -- nslookup -type=a $nsc.vl3-dns | grep -A1 Name | tail -n1 | sed 's/Address: //')
        kubectl exec $pinger -n ns-vl3-dns -- nslookup $nscAddr || exit
    done
done
)

Find vl3-nses:

nses=$(kubectl get pods -l app=nse-vl3-vpp -o go-template --template="{{range .items}}{{.metadata.name}} {{end}}" -n ns-vl3-dns)
[[ ! -z nses ]]

Ping each vl3-nse by each client via DNS:

(
for nse in $nses
do
    for pinger in $nscs
    do
        kubectl exec $pinger -n ns-vl3-dns -- ping -c2 -i 0.5 $nse.vl3-dns -4 || exit
    done
done
)

Check NSEs PTR records:

(
for nse in $nses
do
    for pinger in $nscs
    do
        # Get IP address for PTR request
        nseAddr=$(kubectl exec $pinger -n ns-vl3-dns -- nslookup -type=a $nse.vl3-dns | grep -A1 Name | tail -n1 | sed 's/Address: //')
        kubectl exec $pinger -n ns-vl3-dns -- nslookup $nseAddr || exit
    done
done
)

Cleanup

To cleanup the example just follow the next command:

kubectl delete ns ns-vl3-dns