{"record":{"id":"1b7f17f96bcd1b27","repo":"cilium/cilium","slug":"multicast-not-enabled","errorCode":null,"errorMessage":"multicast not enabled","messagePattern":"multicast not enabled","errorType":"console","errorClass":null,"httpStatus":null,"severity":"error","filePath":"cilium-dbg/cmd/bpf_multicast_groups.go","lineNumber":136,"sourceCode":"\t\t}\n\n\t\tgroupV4Map, err := getMulticastGroupMap(log)\n\t\tif err != nil {\n\t\t\tFatalf(\"failed to get multicast bpf map: %s\", err)\n\t\t}\n\n\t\terr = groupV4Map.Delete(group)\n\t\tif err != nil {\n\t\t\tFatalf(\"Error deleting multicast group: %s\", err)\n\t\t}\n\t},\n}\n\nfunc getMulticastGroupMap(logger *slog.Logger) (*maps_multicast.GroupV4OuterMap, error) {\n\tgroupV4Map, err := maps_multicast.OpenGroupV4OuterMap(logger, maps_multicast.GroupOuter4MapName)\n\tif err != nil {\n\t\tif errors.Is(err, fs.ErrNotExist) {\n\t\t\treturn nil, fmt.Errorf(\"multicast not enabled\")\n\t\t}\n\t\treturn nil, fmt.Errorf(\"cannot open multicast bpf maps: %w\", err)\n\t}\n\n\treturn groupV4Map, nil\n}\n\nfunc parseMulticastGroupArgs(args []string) (netip.Addr, error) {\n\tif len(args) != 1 {\n\t\treturn netip.Addr{}, fmt.Errorf(\"expecting group IP as argument, got %d arguments\", len(args))\n\t}\n\n\tgroup, err := netip.ParseAddr(args[0])\n\tif err != nil {\n\t\treturn netip.Addr{}, fmt.Errorf(\"invalid IP address format: %w\", err)\n\t}\n\n\t// check group is multicast and ipv4 address","sourceCodeStart":118,"sourceCodeEnd":154,"githubUrl":"https://github.com/cilium/cilium/blob/ac7b90affa4baf0642e6685319d56907b3a73a6d/cilium-dbg/cmd/bpf_multicast_groups.go#L118-L154","documentation":"getMulticastGroupMap tries to open the pinned multicast group outer map (GroupOuter4MapName). If the open fails with fs.ErrNotExist it means the pinned BPF map file is absent, i.e. multicast support was not enabled in the Cilium agent, so the CLI reports 'multicast not enabled'.","triggerScenarios":"Running any `cilium-dbg bpf multicast ...` command (groups list, subscribers add/remove/list) on a node where the multicast feature flag is off, so OpenGroupV4OuterMap cannot find the pinned map file.","commonSituations":"Multicast not enabled via the Cilium Helm/ConfigMap option (e.g. multicast.enabled or enableMulticast-related config); running the CLI against an older Cilium version without the feature; checking maps on a node before the agent created them at startup.","solutions":["Enable multicast in the Cilium agent config (Helm value / ConfigMap) and restart the agent so the pinned maps are created","Verify the map pin exists: `ls /sys/fs/bpf/tc/globals/cilium_mc_group_v4*` or `bpftool map list | grep -i multicast`","Check the Cilium version supports the multicast BPF maps feature; upgrade if needed","Confirm cilium-dbg is pointing at the correct node/agent where multicast is enabled"],"exampleFix":"// before: run multicast CLI against agent with feature disabled\ncilium-dbg bpf multicast groups list\n// after: enable the feature first, then run\nhelm upgrade cilium cilium/cilium --set multicast.enabled=true\ncilium-dbg bpf multicast groups list","handlingStrategy":"validation","validationCode":"// check the pinned multicast group map exists before invoking the command\nif ! ls /sys/fs/bpf/tc/globals/cilium_mc_group_v4* >/dev/null 2>&1; then\n  echo \"multicast not enabled: enable the multicast option in the Cilium agent config and restart\"\nfi","typeGuard":null,"tryCatchPattern":"groupMap, err := getMulticastGroupMap(logger)\nif err != nil {\n\tif errors.Is(err, fs.ErrNotExist) || strings.Contains(err.Error(), \"multicast not enabled\") {\n\t\treturn fmt.Errorf(\"multicast is disabled on this agent; set the multicast config option and restart Cilium\")\n\t}\n\treturn err\n}","preventionTips":["Enable multicast in Helm/ConfigMap before using any `bpf multicast` commands","Confirm the pinned map exists in /sys/fs/bpf after agent startup","Check `cilium-dbg status` for feature availability on the target node","Version-check Cilium for multicast BPF map support"],"tags":["cilium","bpf","multicast","feature-disabled","ebpf-map"],"backgroundTag":"feature-not-enabled","analyzedSha":"ac7b90affa4baf0642e6685319d56907b3a73a6d","analyzedAt":"2026-08-31T18:27:15.868Z","schemaVersion":2},"datasetVersion":"2026-08-31T19:17:28.585Z"}