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    Container Service for Kubernetes:Manage the BlazingDNS component

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    Container Service for Kubernetes:Manage the BlazingDNS component

    Last Updated:Jun 17, 2026

    Enable kernel-level DNS caching for ECI pods to reduce DNS latency—no dnsConfig changes required.

    Prerequisites

    Before you begin, make sure you have:

    How BlazingDNS works

    When a pod on an ECI sends a DNS query, BlazingDNS checks its kernel-level cache before forwarding to the upstream DNS server. Cached responses return immediately.

    Because caching runs at the kernel level, no changes to dnsConfig or DNS server settings are required.

    After installation, DNS requests from ECIs are cached automatically:

    image

    Limitations

    BlazingDNS is available only in ACK Serverless clusters and accelerates DNS resolution only for ECI pods. Additional limitations:

    • Supports DNS queries for A, AAAA, and CNAME records only.

    • Supports UDP-based DNS queries only.

    • Supports DNS responses up to 256 bytes.

    Important

    DNS cache acceleration applies only to pods created after BlazingDNS is installed. Existing pods are not affected.

    Install BlazingDNS

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

    2. On the Clusters page, click the cluster name. In the left-side navigation pane, choose Operations > Add-ons.

    3. On the Add-ons page, click the Networking tab. Find the BlazingDNS card, then click Install and follow the on-screen instructions.

    After installation:

    • A ConfigMap named blazing-dns is created in the kube-system namespace. Do not modify or delete this ConfigMap.

    • DNS cache acceleration automatically applies to new pods on ECIs.

    Verify that BlazingDNS is active

    Check the k8s.aliyun.com/dns-cache-enable annotation on the pod. true confirms DNS cache acceleration is active.

    Upgrade BlazingDNS

    On the Add-ons page, click the Networking tab. Find the BlazingDNS card, then click Upgrade and follow the on-screen instructions.

    Uninstall BlazingDNS

    Important

    Before uninstalling BlazingDNS, disable it for all running pods.

    Step 1: Identify pods with BlazingDNS enabled

    List pods with BlazingDNS enabled:

    kubectl get pod -o=jsonpath='{.items[?(@.metadata.annotations.k8s\.aliyun\.com/dns-cache-enable=="true")].metadata.name}' -A

    If jq is installed, print the namespace for each pod:

    kubectl get pod -o=jsonpath='{.items[?(@.metadata.annotations.k8s\.aliyun\.com/dns-cache-enable=="true")]}' | jq -rc ".metadata.namespace,.metadata.name"

    Step 2: Disable BlazingDNS for affected pods

    If the commands above return results, disable BlazingDNS before proceeding:

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

    2. On the Clusters page, click the cluster name. In the left-side navigation pane, choose Configurations > ConfigMaps.

    3. On the ConfigMap page, select the kube-system namespace. In the Actions column of the blazing-dns ConfigMap, click Edit. Set config to enabled: false.

    4. Delete and recreate the affected pods, then rerun the command from Step 1 until no pods are returned.

    Step 3: Uninstall the add-on

    On the Add-ons page, click the Networking tab. Find the BlazingDNS card, then click Uninstall and follow the on-screen instructions.