CoreDNS Configuration Consistency¶
Check Items¶
Check whether the current CoreDNS key configuration Corefile is different from the Helm release record. The difference may be overwritten during the add-on upgrade, affecting domain name resolution in the cluster.
Solution¶
You can upgrade CoreDNS separately after confirming the configuration differences.
Configure the kubectl command. For details, see Connecting to a Cluster Using kubectl.
Obtain the Corefile that takes effect currently.
kubectl get cm -nkube-system coredns -o jsonpath='{.data.Corefile}' > corefile_now.txt cat corefile_now.txt
Obtain the Corefile in the Helm Release records.
latest_release=`kubectl get secret -nkube-system -l owner=helm -l name=cceaddon-coredns --sort-by=.metadata.creationTimestamp | awk 'END{print $1}'` kubectl get secret -nkube-system $latest_release -o jsonpath='{.data.release}' | base64 -d | base64 -d | gzip -d | python -m json.tool | python -c " from __future__ import print_function import json,sys,re,yaml; manifests = json.load(sys.stdin)['manifest'] files = re.split('(?:^|\s*\n)---\s*',manifests) for file in files: if 'coredns/templates/configmap.yaml' in file and 'Corefile' in file: corefile = yaml.safe_load(file)['data']['Corefile'] print(corefile,end='') exit(0); print('error') exit(1); " > corefile_record.txt cat corefile_record.txt
Compare the output differences between 2 and 3.
diff corefile_now.txt corefile_record.txt -y;
Return to the CCE console and click the cluster name to access the cluster console. Choose Add-ons in the navigation pane, select CoreDNS, and click Upgrade.
To retain custom configurations, use either of the following methods:
(Recommended) Set parameterSyncStrategy to inherit. In this case, custom settings are automatically inherited. The system automatically parses, identifies, and inherits custom parameters.
Set parameterSyncStrategy to force. Manually enter the differential configuration. For details, see CoreDNS.
Click OK. After the add-on upgrade is complete, check whether all CoreDNS instances are available and whether Corefile meets the expectation.
kubectl get cm -nkube-system coredns -o jsonpath='{.data.Corefile}'
Change the value of parameterSyncStrategy to ensureConsistent to enable configuration consistency verification.
In addition, it is a good practice to use the parameter configuration function of CCE add-ons to modify the Corefile configuration for consistency.