Add IPVS input plugin (#4890)

plugins/inputs/ipvs/README.md

@@ -0,0 +1,26 @@
+# IPVS Input Plugin (Linux)
+
+The IPVS input plugin uses the linux kernel netlink socket interface to gather
+metrics about ipvs virtual and real servers.
+
+## Configuration
+
+[[inputs.ipvs]]
+  # no configuration
+
+## Permissions
+
+Assuming you installed the telegraf package via one of the published packages,
+the process will be running as the `telegraf` user. However, in order for this
+plugin to communicate over netlink sockets it needs the telegraf process to be
+running as `root` (or some user with `CAP_NET_ADMIN` and `CAP_NET_RAW`). Be sure
+to ensure these permissions before running telegraf with this plugin included.
+
+## Sample Output
+
+This is what you can expect the emitted metrics to look like
+
+```
+ipvs_virtual_server,address=172.18.64.234,address_family=inet,netmask=32,port=9000,protocol=tcp,sched=mh_418 bytes_out=0i,pps_in=0i,pps_out=0i,cps=0i,pkts_in=0i,pkts_out=0i,connections=0i,bytes_in=0i 1540407540000000000
+ipvs_virtual_server,address_family=inet,fwmark=47,netmask=32,sched=mh_418 connections=0i,pkts_in=0i,bytes_out=0i,pps_in=0i,pps_out=0i,pkts_out=0i,bytes_in=0i,cps=0i 1540407540000000000
+```

plugins/inputs/ipvs/ipvs.go

@@ -0,0 +1,112 @@
+// +build linux
+
+package ipvs
+
+import (
+	"errors"
+	"fmt"
+	"math/bits"
+	"strconv"
+	"syscall"
+
+	"github.com/docker/libnetwork/ipvs"
+	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/plugins/inputs"
+)
+
+// IPVS holds the state for this input plugin
+type IPVS struct {
+	handle *ipvs.Handle
+}
+
+// Description returns a description string
+func (i *IPVS) Description() string {
+	return "Collect virtual and real server stats from Linux IPVS"
+}
+
+// SampleConfig returns a sample configuration for this input plugin
+func (i *IPVS) SampleConfig() string {
+	return ``
+}
+
+// Gather gathers the stats
+func (i *IPVS) Gather(acc telegraf.Accumulator) error {
+	if i.handle == nil {
+		h, err := ipvs.New("") // TODO: make the namespace configurable
+		if err != nil {
+			return errors.New("Unable to open IPVS handle")
+		}
+		i.handle = h
+	}
+
+	services, err := i.handle.GetServices()
+	if err != nil {
+		i.handle.Close()
+		i.handle = nil // trigger a reopen on next call to gather
+		return errors.New("Failed to list IPVS services")
+	}
+	for _, s := range services {
+		fields := map[string]interface{}{
+			"connections": s.Stats.Connections,
+			"pkts_in":     s.Stats.PacketsIn,
+			"pkts_out":    s.Stats.PacketsOut,
+			"bytes_in":    s.Stats.BytesIn,
+			"bytes_out":   s.Stats.BytesOut,
+			"pps_in":      s.Stats.PPSIn,
+			"pps_out":     s.Stats.PPSOut,
+			"cps":         s.Stats.CPS,
+		}
+		acc.AddGauge("ipvs_virtual_server", fields, serviceTags(s))
+	}
+
+	return nil
+}
+
+// helper: given a Service, return tags that identify it
+func serviceTags(s *ipvs.Service) map[string]string {
+	ret := map[string]string{
+		"sched":          s.SchedName,
+		"netmask":        fmt.Sprintf("%d", bits.OnesCount32(s.Netmask)),
+		"address_family": addressFamilyToString(s.AddressFamily),
+	}
+	// Per the ipvsadm man page, a virtual service is defined "based on
+	// protocol/addr/port or firewall mark"
+	if s.FWMark > 0 {
+		ret["fwmark"] = strconv.Itoa(int(s.FWMark))
+	} else {
+		ret["protocol"] = protocolToString(s.Protocol)
+		ret["address"] = s.Address.String()
+		ret["port"] = strconv.Itoa(int(s.Port))
+	}
+	return ret
+}
+
+// helper: convert protocol uint16 to human readable string (if possible)
+func protocolToString(p uint16) string {
+	switch p {
+	case syscall.IPPROTO_TCP:
+		return "tcp"
+	case syscall.IPPROTO_UDP:
+		return "udp"
+	case syscall.IPPROTO_SCTP:
+		return "sctp"
+	default:
+		return fmt.Sprintf("%d", p)
+	}
+}
+
+// helper: convert addressFamily to a human readable string
+func addressFamilyToString(af uint16) string {
+	switch af {
+	case syscall.AF_INET:
+		return "inet"
+	case syscall.AF_INET6:
+		return "inet6"
+	default:
+		return fmt.Sprintf("%d", af)
+	}
+}
+
+func init() {
+	inputs.Add("ipvs", func() telegraf.Input { return &IPVS{} })
+}

plugins/inputs/ipvs/ipvs_notlinux.go

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+// +build !linux
+
+package ipvs