NodeLocalDNS#

NodeLocalDNS runs a local DNS caching agent on each node in the MKE cluster, improving performance by caching DNS responses locally and reducing latency compared to resolving external DNS records through a centralized CoreDNS service.

Prerequisites#

Before installing the NodeLocalDNS in an MKE 4k cluster, you must verify that:

The custom CNI provider is not enabled.
kube-proxy is running in iptables mode.

Configuration#

NodeLocalDNS is configured through the spec.nodeLocalDNS section of the mke4.yaml configuration file. The function is disabled by default, and thus to enable NodeLocalDNS, you must set the spec.nodeLocalDNS.enabled parameter to true.

NodeLocalDNS example configuration:

nodeLocalDNS:
    enabled: false
    nodeLocalConfigPersist: false
    resources:
      requests: {}

Parameter	Description	Default	Equivalent MKE 3 parameter
`enabled`	Enables the NodeLocalDNS service in the cluster. Valid values: `true`, `false`	`false`	`[cluster_config.node_local_dns]`
`nodeLocalConfigPersist`	Retains the NodeLocalDNS configmap.	`false`	[cluster_config.node_local_dns_config_persist]
`resources.requests.cpu`	Specifies the minimum CPU to guarantee for the NodeLocalDNS container.	`25m`	N/A
`resources.requests.memory`	Specifies the minimum memory to guarantee for the NodeLocalDNS container.	`5Mi`	N/A

To configure NodeLocalDNS:

Obtain the default mke4.yaml configuration file:
```
mkectl init
```
In the mke4.yaml configuration file, add the nodeLocalDNS section under spec and set the enabled parameter to true, as nodelocalDNS is disabled by default.
Apply the configuration:
```
mkectl apply -f mke4.yaml
```

Verify the successful deployment of NodeLocalDNS in the cluster:

kubectl get all,configmap -n kube-system | grep node

Example output:

pod/node-local-dns-7z5k9              1/1     Running   0          4m23s
pod/node-local-dns-8wgzc              1/1     Running   0          4m23s
pod/node-local-dns-xnr7q              1/1     Running   0          4m23s
service/node-local-dns                                       ClusterIP   None            <none>        9253/TCP                       4m24s
daemonset.apps/node-local-dns   3         3         3       3            3           kubernetes.io/os=linux   4m24s
configmap/node-local-dns                                         1      4m47s