Manually upgrade unmanaged CoreDNS

Console

1. Log on to the ACK console. In the left navigation pane, click Clusters.

2. On the Clusters page, click the name of your cluster. In the left navigation pane, click Workloads > Deployments.

3. At the top of the Deployments page, set Namespace to kube-system. In the list of deployments, find the coredns deployment and check the Image column to confirm that the current CoreDNS image version is coredns:1.6.2.

kubectl

Run the following command to check the current CoreDNS version:

kubectl get deployment coredns -n kube-system -o jsonpath="{.spec.template.spec.containers[0].image}"

The following is an example of the output:

registry-vpc.cn-hangzhou.aliyuncs.com/acs/coredns:1.6.2

Console

1. (Optional) Replace the proxy plugin with the forward plugin.

   The proxy plugin was deprecated in CoreDNS v1.6.2. If you are upgrading from an earlier version, you must replace the proxy plugin with the forward plugin in your CoreDNS configuration.

   Change the CoreDNS configuration

   1. Log on to the ACK console. In the left navigation pane, click Clusters.

   2. On the Clusters page, click the name of your cluster. In the left navigation pane, click Configurations > ConfigMaps.

   3. On the ConfigMaps page, set Namespace to kube-system. Find coredns and click Edit YAML in the Actions column.

   4. In the View in YAML panel, change proxy to forward, and then click OK. This replaces the deprecated proxy plugin with the forward plugin. The final ConfigMap should look similar to the following:

      apiVersion: v1
      data:
        Corefile: |-
          .:53 {
            autopath @kubernetes
            cache 30
            errors
            forward . /etc/resolv.conf
            health
            kubernetes cluster.local in-addr.arpa ip6.arpa {
                pods verified
                fallthrough in-addr.arpa ip6.arpa
            }
            loadbalance
            loop
            prometheus :9153
            ready
            reload
          }
      kind: ConfigMap

2. Update the CoreDNS image version.

   1. Log on to the ACK console. In the left navigation pane, click Clusters.

   2. On the Clusters page, click the name of your cluster. In the left navigation pane, click Workloads > Deployments.

   3. On the Deployments page, set the Namespace to kube-system. Find coredns and in the Actions column, choose > Edit YAML.

   4. In the Edit YAML panel, find and update the image field to your target version, and then click Update. In the YAML editor, find the CoreDNS deployment configuration and change the value of the image field to your target version, for example, v1.9.3.10-5e7ba42d-aliyun. The following is a key YAML snippet:

      labelSelector:
                matchExpressions:
                  - key: k8s-app
                    operator: In
                    values:
                      - kube-dns
              topologyKey: kubernetes.io/hostname
            weight: 100
        containers:
        - args:
          - '-conf'
          - /etc/coredns/Corefile
          image: 'registry-cn-hangzhou-vpc.ack.aliyuncs.com/acs/coredns:v1.9.3.10-5e7ba42d-aliyun'
          imagePullPolicy: IfNotPresent
          livenessProbe:
            failureThreshold: 5
            httpGet:
              ...

3. Verify that the upgrade is successful.

   1. Run the following command to check the current CoreDNS version.

      kubectl get deployment coredns -n kube-system -o jsonpath="{.spec.template.spec.containers[0].image}"

      Expected output:

      registry-cn-hangzhou-vpc.ack.aliyuncs.com/acs/coredns:v1.9.3.10-5e7ba42d-aliyun

   2. Run the following command to check whether all CoreDNS pods in the cluster are in the Running state.

      kubectl get pods -n kube-system | grep coredns

      Expected output:

      coredns-78d4b8****-6g62w                           1/1     Running   0          9d
      coredns-78d4b8****-n6wjm                           1/1     Running   0          9d

kubectl

1. (Optional) Replace the proxy plugin with the forward plugin.

   The proxy plugin was deprecated in CoreDNS v1.6.2. If you are upgrading from an earlier version, you must replace the proxy plugin with the forward plugin in your CoreDNS configuration.

   Change the CoreDNS configuration

   1. Run the following command to edit the CoreDNS configuration file, change proxy to forward, and then save the file and exit.

      kubectl edit configmap/coredns -n kube-system

   2. Run the following command to view the logs of a CoreDNS pod and confirm that the configuration is reloaded.

      kubectl logs coredns-78d4b8bd88-n6wjm -n kube-system

      The expected output is as follows. The presence of plugin/reload indicates that the CoreDNS configuration has been reloaded successfully.

      .:53
      [INFO] plugin/reload: Running configuration MD5 = 71c5f1ff539d304c630521f315dc2ac2
      CoreDNS-1.6.7
      linux/amd64, go1.13.6, da7f65b
      [INFO] 127.0.0.1:48329 - 42313 "HINFO IN 1108347002237365533.4506541768939609094. udp 57 false 512" NXDOMAIN qr,rd,ra 132 0.008874794s

2. Run the following command to edit the CoreDNS configuration, update the version in the image field, and then save and exit.

   kubectl edit deployment/coredns -n kube-system

3. Verify that the upgrade is successful.

   1. Run the following command to check the current CoreDNS version.

      kubectl get deployment coredns -n kube-system -o jsonpath="{.spec.template.spec.containers[0].image}"

      Expected output:

      registry-cn-hangzhou-vpc.ack.aliyuncs.com/acs/coredns:v1.9.3.10-5e7ba42d-aliyun

   2. Run the following command to check whether all CoreDNS pods in the cluster are in the Running state.

      kubectl get pods -n kube-system | grep coredns

      Expected output:

      coredns-78d4b8****-6g62w                           1/1     Running   0          9d
      coredns-78d4b8****-n6wjm                           1/1     Running   0          9d