Merge pull request #2827 from weaveworks/issues/2799-peer-disco

Peer Discovery via cloud service
2017-04-11 14:59:28 +01:00
commit bc47866880
@@ -124,3 +124,9 @@
 [submodule "vendor/github.com/containernetworking/cni"]
 	path = vendor/github.com/containernetworking/cni
 	url = https://github.com/containernetworking/cni
+[submodule "vendor/golang.org/x/net"]
+	path = vendor/golang.org/x/net
+	url = https://go.googlesource.com/net
+[submodule "vendor/google.golang.org/grpc"]
+	path = vendor/google.golang.org/grpc
+	url = https://github.com/grpc/grpc-go
@@ -198,17 +198,6 @@ func (alloc *Allocator) HandleHTTP(router *mux.Router, defaultSubnet address.CID
 		w.WriteHeader(204)
 	})

-	router.Methods("DELETE").Path("/peer").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		alloc.Shutdown()
-		w.WriteHeader(204)
-	})
-
-	router.Methods("DELETE").Path("/peer/{id}").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		ident := mux.Vars(r)["id"]
-		transferred := alloc.AdminTakeoverRanges(ident)
-		fmt.Fprintf(w, "%d IPs taken over from %s\n", transferred, ident)
-	})
-
 	router.Methods("GET").Path("/ipinfo/tracker").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		fmt.Fprintf(w, tracker)
 	})
@@ -82,3 +82,25 @@ func findInterface(ifaceName string) (iface *net.Interface, err error) {
 	}
 	return
 }
+
+func LocalAddresses() ([]*net.IPNet, error) {
+	links, err := netlink.LinkList()
+	if err != nil {
+		return nil, err
+	}
+
+	retval := []*net.IPNet{}
+	for _, link := range links {
+		if _, isBridge := link.(*netlink.Bridge); isBridge || (link.Attrs().Flags&net.FlagLoopback) != 0 {
+			continue
+		}
+		addrs, err := netlink.AddrList(link, netlink.FAMILY_V4)
+		if err != nil {
+			return nil, err
+		}
+		for _, addr := range addrs {
+			retval = append(retval, addr.IPNet)
+		}
+	}
+	return retval, nil
+}
@@ -0,0 +1,104 @@
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"time"
+
+	"github.com/gorilla/mux"
+
+	"github.com/weaveworks/weave/ipam"
+)
+
+// TODO: move these definitions somewhere more shareable
+type PeerUpdateRequest struct {
+	Name      string   `json:"peername"`
+	Nickname  string   `json:"nickname"`  // optional
+	Addresses []string `json:"addresses"` // can be empty
+}
+
+type PeerUpdateResponse struct {
+	Addresses []string `json:"addresses"`
+	PeerCount int      `json:"peercount"`
+}
+
+var httpClient = &http.Client{Timeout: 30 * time.Second}
+
+func do(verb string, discoveryEndpoint, token string, request interface{}, response interface{}) error {
+	body := new(bytes.Buffer)
+	err := json.NewEncoder(body).Encode(request)
+	if err != nil {
+		return err
+	}
+	req, err := http.NewRequest(verb, discoveryEndpoint+"/peer", body)
+	if err != nil {
+		return err
+	}
+	req.Header.Set("Authorization", fmt.Sprintf("Scope-Probe token=%s", token))
+	req.Header.Set("X-Weave-Net-Version", version)
+	req.Header.Set("Content-Type", "application/json")
+	Log.Printf("Calling peer discovery %s with %s", req.URL, request)
+	resp, err := httpClient.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		rbody, _ := ioutil.ReadAll(resp.Body)
+		return errors.New(resp.Status + ": " + string(rbody))
+	}
+	if response == nil {
+		return nil
+	}
+	err = json.NewDecoder(resp.Body).Decode(response)
+	Log.Printf("peer discovery result: (%v) %v", err, response)
+	return err
+}
+
+func peerDiscoveryUpdate(discoveryEndpoint, token, peername, nickname string, addresses []string) ([]string, int, error) {
+	request := PeerUpdateRequest{
+		Name:      peername,
+		Nickname:  nickname,
+		Addresses: addresses,
+	}
+	var updateResponse PeerUpdateResponse
+	err := do("POST", discoveryEndpoint, token, request, &updateResponse)
+	return updateResponse.Addresses, updateResponse.PeerCount, err
+}
+
+func peerDiscoveryDelete(discoveryEndpoint, token, peername string) error {
+	request := PeerUpdateRequest{Name: peername}
+	return do("DELETE", discoveryEndpoint, token, request, nil)
+}
+
+func HandleHTTPPeer(router *mux.Router, alloc *ipam.Allocator, discoveryEndpoint, token, peername string) {
+	router.Methods("DELETE").Path("/peer").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if discoveryEndpoint != "" {
+			if err := peerDiscoveryDelete(discoveryEndpoint, token, peername); err != nil {
+				Log.Errorf("Error while deleting self from peer discovery: %s", err)
+			}
+		}
+		if alloc != nil {
+			alloc.Shutdown()
+		}
+		w.WriteHeader(204)
+	})
+
+	router.Methods("DELETE").Path("/peer/{id}").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		ident := mux.Vars(r)["id"]
+		if discoveryEndpoint != "" {
+			// TODO: deal with this being either a peername or a nickname
+			if err := peerDiscoveryDelete(discoveryEndpoint, token, ident); err != nil {
+				Log.Errorf("Error while deleting self from peer discovery: %s", err)
+			}
+		}
+		if alloc != nil {
+			transferred := alloc.AdminTakeoverRanges(ident)
+			fmt.Fprintf(w, "%d IPs taken over from %s\n", transferred, ident)
+		}
+	})
+}
@@ -53,7 +53,7 @@ type dnsConfig struct {
 func (c *ipamConfig) Enabled() bool {
 	var (
 		hasPeerCount = c.PeerCount > 0
-		hasMode      = len(c.Mode) > 0
+		hasMode      = c.HasMode()
 		hasRange     = c.IPRangeCIDR != ""
 		hasSubnet    = c.IPSubnetCIDR != ""
 	)
@@ -75,6 +75,10 @@ func (c *ipamConfig) Enabled() bool {
 	return true
 }

+func (c ipamConfig) HasMode() bool {
+	return len(c.Mode) > 0
+}
+
 func (c *ipamConfig) parseMode() error {
 	modeAndParam := strings.SplitN(c.Mode, "=", 2)

@@ -143,6 +147,9 @@ func main() {
 		trustedSubnetStr   string
 		dbPrefix           string
 		isAWSVPC           bool
+		discoveryEndpoint  string
+		token              string
+		advertiseAddress   string

 		defaultDockerHost = "unix:///var/run/docker.sock"
 	)
@@ -184,6 +191,9 @@ func main() {
 	mflag.StringVar(&trustedSubnetStr, []string{"-trusted-subnets"}, "", "comma-separated list of trusted subnets in CIDR notation")
 	mflag.StringVar(&dbPrefix, []string{"-db-prefix"}, "/weavedb/weave", "pathname/prefix of filename to store data")
 	mflag.BoolVar(&isAWSVPC, []string{"-awsvpc"}, false, "use AWS VPC for routing")
+	mflag.StringVar(&discoveryEndpoint, []string{"-peer-discovery-url"}, "https://cloud.weave.works/api/net", "url for peer discovery")
+	mflag.StringVar(&token, []string{"-token"}, "", "token for peer discovery")
+	mflag.StringVar(&advertiseAddress, []string{"-advertise-address"}, "", "address to advertise for peer discovery")

 	// crude way of detecting that we probably have been started in a
 	// container, with `weave launch` --> suppress misleading paths in
@@ -257,7 +267,24 @@ func main() {
 	router := weave.NewNetworkRouter(config, networkConfig, name, nickName, overlay, db)
 	Log.Println("Our name is", router.Ourself)

-	if peers, err = router.InitialPeers(resume, peers); err != nil {
+	if token != "" {
+		var addresses []string
+		if advertiseAddress == "" {
+			localAddrs, err := weavenet.LocalAddresses()
+			checkFatal(err)
+			for _, addr := range localAddrs {
+				addresses = append(addresses, addr.IP.String())
+			}
+		} else {
+			addresses = strings.Split(advertiseAddress, ",")
+		}
+		discoveredPeers, count, err := peerDiscoveryUpdate(discoveryEndpoint, token, name.String(), nickName, addresses)
+		checkFatal(err)
+		if !ipamConfig.HasMode() {
+			ipamConfig.PeerCount = len(peers) + count
+		}
+		peers = append(peers, discoveredPeers...)
+	} else if peers, err = router.InitialPeers(resume, peers); err != nil {
 		Log.Fatal("Unable to get initial peer set: ", err)
 	}

@@ -352,6 +379,7 @@ func main() {
 		}
 		router.HandleHTTP(muxRouter)
 		HandleHTTP(muxRouter, version, router, allocator, defaultSubnet, ns, dnsserver)
+		HandleHTTPPeer(muxRouter, allocator, discoveryEndpoint, token, name.String())
 		muxRouter.Methods("GET").Path("/metrics").Handler(metricsHandler(router, allocator, ns, dnsserver))
 		http.Handle("/", common.LoggingHTTPHandler(muxRouter))
 		Log.Println("Listening for HTTP control messages on", httpAddr)
@@ -376,7 +404,7 @@ func options() map[string]string {
 	mflag.Visit(func(f *mflag.Flag) {
 		value := f.Value.String()
 		name := canonicalName(f)
-		if name == "password" {
+		if name == "password" || name == "token" {
 			value = "<redacted>"
 		}
 		options[name] = value
@@ -135,5 +135,6 @@ Weave Net supports *any* protocol, and it doesn't have to be over TCP/IP. For ex
 **See Also** 

 * [Installing Weave Net](/site/installing-weave.md)
+ * [Using Weave Cloud to get started with Weave Net](/site/using-weave/weave-cloud.md)
 * [Using Fastdp With Weave Net](/site/using-weave/fastdp.md)
 * [Using the Weave Net Docker Network Plugin](/site/plugin.md)
@@ -0,0 +1,126 @@
+---
+title: Using Weave Cloud to get started with Weave Net
+menu_order: 10
+---
+
+Weave Net provides a simple to deploy networking solution for containerized apps. Here, we describe how to manage a Weave container network using a sample application which consists of two simple `netcat` services deployed to containers on two separate hosts.
+
+This section contains the following topics:
+
+ * [Signing in to Weave Cloud](#signing-in)
+ * [Launching Weave Net](#launching)
+ * [Launching on Additional Hosts](#peer-connections)
+ * [How Peer Discovery Works](#how-it-works)
+
+### <a name="signing-in"></a>Signing in to Weave Cloud
+
+Weave Cloud is a fast and simple way to visualize, manage and monitor
+containers and microservices.  In order to use Weave Cloud to set up
+Weave Net, you must sign up to Weave Cloud and create an "Instance".
+
+The instance will have a Service Token which is a 32-character string
+used to uniquely identify it.  Get hold of the Service Token for your
+Instance, as shown below:
+
+![UI to get a Service Token](weave-cloud-token.png)
+
+For the purpose of these instructions we will use a dummy Service
+Token `dk6hz1acdd58aea6b75migoy4axqasdf`.
+
+
+### <a name="launching"></a>Launching Weave Net
+
+Before launching Weave Net and deploying your apps, ensure that Docker
+is [installed](https://docs.docker.com/engine/installation/) on both
+hosts.
+
+On `$HOST1` run:
+
+    host1$ weave launch --token=dk6hz1acdd58aea6b75migoy4axqasdf
+    host1$ eval $(weave env)
+    host1$ docker run --name a1 -ti weaveworks/ubuntu
+
+Where,
+
+ * The first line runs Weave Net.
+
+* The second line configures the Weave Net environment, so that containers launched via the Docker command line are automatically attached to the Weave network, and,
+ * The third line runs the [application container](/site/faq.md#own-image) using [a Docker command](https://docs.docker.com/engine/reference/run/).
+
+> **Note** If the first command results in an error like
+> ```
+> Cannot connect to the Docker daemon. Is the docker daemon running on this host?
+> ```
+> then you likely need to be 'root' in order to connect to the Docker
+> daemon. If so, run the above and all subsequent commands in a
+> *single* root shell:
+> ```
+> host1$ sudo -s
+> host1# weave launch --token=dk6hz1acdd58aea6b75migoy4axqasdf
+> host1# eval $(weave env)
+> host1# docker run --name a1 -ti weaveworks/ubuntu
+> ```
+> Do *not* prefix individual commands with `sudo`, since some commands
+> modify environment entries and hence they all need to be executed from
+> the same shell.
+
+Weave Net must be launched once per host. The relevant container images will be pulled down from Docker Hub on demand during `weave launch`.
+
+You can also preload the images by running `weave setup`. Preloaded images are useful for automated deployments, and ensure there are no delays during later operations.
+
+If you are deploying an application that consists of more than one container to the same host, launch them one after another using `docker run`, as appropriate.  
+
+
+### <a name="peer-connections"></a>Launching on Additional Hosts
+
+To launch Weave Net on an additional host and create a peer
+connection, run exactly the same commands as on the first host:
+
+    host2$ weave launch --token=dk6hz1acdd58aea6b75migoy4axqasdf
+    host2$ eval $(weave env)
+    host2$ docker run --name a2 -ti weaveworks/ubuntu
+
+Because you are using Weave Cloud, the second peer will discover the
+first and automatically create a connection to it.
+
+>**Note:** If there is a firewall between `$HOST1` and `$HOST2`,  you must permit traffic to flow through TCP 6783 and UDP 6783/6784, which are Weave’s control and data ports.
+
+Now you can proceed to [test container communications](site/using-weave#testing)
+
+### <a name="how-it-works"></a>How Peer Discovery Works
+
+The Weave Cloud back-end maintains a database of all the peers that
+have registered in each instance. You can create as many instances as
+you like in the Weave Cloud console: for different projects, or to
+separate test and production.
+
+As each peer starts up, it looks for all network instances that
+another peer might be able to contact it on, and registers those with the back-end.
+If you want to control which addresses are used, add the `--advertise-address` flag:
+
+    host1$ weave launch --token=dk6hz1acdd58aea6b75migoy4axqasdf --advertise-address=192.0.2.1,198.51.100.4
+
+When the new peer registers itself, it also fetches a list of all
+other peers in the instance, and begins to contact them.
+
+If the peer cannot contact the Weave Cloud back-end it will print an
+error message in its log and exit. To check the logs run:
+
+    host1$ docker logs weave
+
+When a Weave Net instance is formed for the first time, the peers must
+initialize the [IP Allocation Manager](site/ipam.md). This process,
+and the configuration options available, are unchanged when using
+Weave Cloud.
+
+When you shut down a peer for good, use [the `weave reset`
+command](site/ipam/stop-remove-peers-ipam.md) and it will be removed
+from the Weave Cloud database so future peers will not attempt to
+connect to it.
+
+**See Also**
+
+ * [Installing Weave Net](/site/installing-weave.md)
+ * [Using Weave Net](/site/using-weave.md)
+ * [Using Fastdp With Weave Net](/site/using-weave/fastdp.md)
+ * [Using the Weave Net Docker Network Plugin](/site/plugin.md)