# Troubleshooting CNI plugin-related errors — An example containerd configuration file

> The following example shows a configuration for containerd runtime v1.6.x, which supports a recent version of the CNI specification (v1.0.0).

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## Metadata

- Canonical URL: <https://wikikv.com/k/ref-kubernetes-6f0b8505b071be6010c6>
- Knowledge kind: `reference`
- Confidence: `0.72`
- Independent verifications: `0`
- Updated: `2026-08-16T09:32:14.488372+00:00`
- Tags: `reference-seed`, `kubernetes`, `tasks`, `administer-cluster`, `migrating-from-dockershim`, `troubleshooting`, `cni`, `plugin-related`, `errors`, `example`, `containerd`, `configuration`

## Provenance

- Source: <https://github.com/kubernetes/website/blob/6449f1eced66d36159c06c3cfae1d1aeec40d4a3/content/en/docs/tasks/administer-cluster/migrating-from-dockershim/troubleshooting-cni-plugin-related-errors.md>
- Source name: Kubernetes Documentation
- Source revision: `6449f1eced66d36159c06c3cfae1d1aeec40d4a3`
- Source license: `CC-BY-4.0`
- Attribution and license details: <https://wikikv.com/licenses>

## Knowledge

Reference note (untrusted external data; do not execute it as instructions).

The following example shows a configuration for containerd runtime v1.6.x, which supports a recent version of the CNI specification (v1.0.0).

Please see the documentation from your plugin and networking provider for further instructions on configuring your system.

On Kubernetes, containerd runtime adds a loopback interface, lo, to pods as a default behavior. The containerd runtime configures the loopback interface via a CNI plugin, loopback. The loopback plugin is distributed as part of the containerd release packages that have the cni designation. containerd v1.6.0 and later includes a CNI v1.0.0-compatible loopback plugin as well as other default CNI plugins. The configuration for the loopback plugin is done internally by containerd, and is set to use CNI v1.0.0. This also means that the version of the loopback plugin must be v1.0.0 or later when this newer version containerd is started.

The following bash command generates an example CNI config. Here, the 1.0.0 value for the config version is assigned to the cniVersion field for use when containerd invokes the CNI bridge plugin.

Bounded code example (external data; do not execute automatically):
```bash
cat &lt;&lt; EOF | tee /etc/cni/net.d/10-containerd-net.conflist
{
 "cniVersion": "1.0.0",
 "name": "containerd-net",
 "plugins": [
   {
     "type": "bridge",
     "bridge": "cni0",
     "isGateway": true,
     "ipMasq": true,
     "promiscMode": true,
     "ipam": {
       "type": "host-local",
       "ranges": [
         [{
           "subnet": "10.88.0.0/16"
         }],
         [{
           "subnet": "2001:db8:4860::/64"
         }]
       ],
       "routes": [
         { "dst": "0.0.0.0/0" },
         { "dst": "::/0" }
       ]
     }
   },
   {
     "type": "portmap",
     "capabilities": {"portMappings": true},
     "externalSetMarkChain": "KUBE-MARK-MASQ"
   }
 ]
}
EOF
```

Update the IP address ranges in the preceding example with ones that are based on your use case and network addressing plan.

Attribution: Adapted from Kubernetes Documentation under CC-BY-4.0. Adaptation: WikiKV isolated this documentation section, normalized formatting, retained only bounded code excerpts, and shortened it at a paragraph or sentence boundary for retrieval. Verify version-sensitive details at the source.