istio/istio · error

plugin type %v not a string

Error message

plugin type %v not a string

What it means

While indexing each plugin in the Istio CNI conflist by its 'type' field, istio-cni found a plugin whose 'type' is not a JSON string (null, number, boolean, or missing). The '%v' prints the offending value. This is a strict schema check: every CNI plugin entry must have a string 'type'.

Source

Thrown at cni/pkg/install/install.go:365

		if err != nil {
			return err
		}
		plugins, err := util.GetPlugins(cniConfigMap)
		if err != nil {
			return fmt.Errorf("%s: %w", cniConfigFilepath, err)
		}

		// Create a map to index plugins by their "type" field
		pluginMap := make(map[string]map[string]any)
		for _, rawPlugin := range plugins {
			plugin, err := util.GetPlugin(rawPlugin)
			if err != nil {
				return fmt.Errorf("%s: %w", cniConfigFilepath, err)
			}
			if pluginType, ok := plugin["type"].(string); ok {
				pluginMap[pluginType] = plugin
			} else {
				return fmt.Errorf("plugin type %v not a string", plugin["type"])
			}
		}

		// Verify that the Istio CNI config exists in the CNI config plugin map
		if _, exists := pluginMap["istio-cni"]; !exists {
			return fmt.Errorf("istio-cni plugin not found in Istio CNI config at %s", cniConfigFilepath)
		}

		if useIstioOwnedCNIConfig(cfg) {
			// Verifies the Istio CNI config contains all non istio-cni plugins from the primary CNI config
			// and checks that the plugins are equivalent
			primaryCNIConfigFilepath, err := getCNIConfigFilepath(ctx, cfg.CNIConfName, cfg.MountedCNINetDir, cfg.ChainedCNIPlugin)
			if err != nil {
				return err
			}
			primaryCniConfigMap, err := util.ReadCNIConfigMap(primaryCNIConfigFilepath)
			if err != nil {
				return err

View on GitHub (pinned to 8dc789c5cf)

Solutions

1. Open the file named in the preceding context and find the plugin entry whose 'type' is wrong: jq '.plugins[] | select((.type|type) != "string")' <file>.
2. Set a proper string type (e.g. "istio-cni", "portmap", "calico") or remove the invalid entry.
3. Restart istio-cni-node to re-verify, or delete the file to let it be regenerated.

Example fix

// before:
{ "name": "bad", "type": null }
// after:
{ "name": "portmap", "type": "portmap", "capabilities": {"portMappings": true} }

jq -e '.plugins | all(.[]; (.type | type) == "string")' /host/etc/cni/net.d/istio-cni-conflist

func pluginTypeIsString(p map[string]any) (string, bool) {
    t, ok := p["type"].(string)
    return t, ok && t != ""
}

When it happens

Trigger: A plugin entry in the 'plugins' array of the Istio-owned conflist lacks 'type' or has a non-string value, hit during the per-plugin loop in checkCNIConfig after util.GetPlugin succeeds.

Common situations: Hand-edited or templated conflist with a typo (e.g. type: 032 or a commented-out field parsed wrong); a CNI chaining tool injecting a malformed plugin stanza; YAML-to-JSON conversion mistakes when users author the file from a ConfigMap.

Related errors

• %s: %w
• istio-cni plugin not found in Istio CNI config at %s
• istio-cni CNI config file modified: %s
• no valid networks found in %s
• existing CNI config: %v

AI-assisted analysis of istio/istio@8dc789c5cf (2026-08-15). Data as JSON: /api/errors/7a585793317d78ef. Report an issue: GitHub.