ITQC/containernetworking-plugins
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Add -hostprefix in DHCP daemon to run the daemon as container

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This diff adds -hostprefix option in dhcp daemon. This option
could be used to run dhcp daemon as container because container
cannot touch host's netns directly. The diff changes dhcp daemon
to touch procfs mounted to another path, like '/hostfs/proc'.
This commit is contained in:
Tomofumi Hayashi 2018-01-23 12:59:03 +09:00
parent d228f980e1
commit 9604565b22
3 changed files with 11 additions and 5 deletions
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1
plugins/ipam/dhcp/README.md
View File

@ -18,6 +18,7 @@ $ ./dhcp daemon
If given `-pidfile <path>` arguments after 'daemon', the dhcp plugin will write
its PID to the given file.
If given `-hostprefix <prefix>` arguments after 'daemon', the dhcp plugin will use this prefix for netns as `<prefix>/<original netns>`. It could be used in case of running dhcp daemon as container.
Alternatively, you can use systemd socket activation protocol.
Be sure that the .socket file uses /run/cni/dhcp.sock as the socket path.

7
plugins/ipam/dhcp/daemon.go
View File

@ -41,6 +41,7 @@ var errNoMoreTries = errors.New("no more tries")
type DHCP struct {
mux sync.Mutex
leases map[string]*DHCPLease
hostNetnsPrefix string
}
func newDHCP() *DHCP {
@ -58,7 +59,8 @@ func (d *DHCP) Allocate(args *skel.CmdArgs, result *current.Result) error {
}
clientID := args.ContainerID + "/" + conf.Name
l, err := AcquireLease(clientID, args.Netns, args.IfName)
hostNetns := d.hostNetnsPrefix + args.Netns
l, err := AcquireLease(clientID, hostNetns, args.IfName)
if err != nil {
return err
}
@ -140,7 +142,7 @@ func getListener() (net.Listener, error) {
}
}
func runDaemon(pidfilePath string) error {
func runDaemon(pidfilePath string, hostPrefix string) error {
// since other goroutines (on separate threads) will change namespaces,
// ensure the RPC server does not get scheduled onto those
runtime.LockOSThread()
@ -161,6 +163,7 @@ func runDaemon(pidfilePath string) error {
}
dhcp := newDHCP()
dhcp.hostNetnsPrefix = hostPrefix
rpc.Register(dhcp)
rpc.HandleHTTP()
http.Serve(l, nil)

4
plugins/ipam/dhcp/main.go
View File

@ -33,11 +33,13 @@ const socketPath = "/run/cni/dhcp.sock"
func main() {
if len(os.Args) > 1 && os.Args[1] == "daemon" {
var pidfilePath string
var hostPrefix string
daemonFlags := flag.NewFlagSet("daemon", flag.ExitOnError)
daemonFlags.StringVar(&pidfilePath, "pidfile", "", "optional path to write daemon PID to")
daemonFlags.StringVar(&hostPrefix, "hostprefix", "", "optional prefix to netns")
daemonFlags.Parse(os.Args[2:])
if err := runDaemon(pidfilePath); err != nil {
if err := runDaemon(pidfilePath, hostPrefix); err != nil {
log.Printf(err.Error())
os.Exit(1)
}