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moby--moby/libnetwork
Martin Dojcak feab0cca9f libnetwork/overlay:fix join sandbox deadlock
Operations performed on overlay network sandboxes are handled by
dispatching operations send through a channel. This allows for
asynchronous operations to be performed which, since they are
not called from within another function, are able to operate in
an idempotent manner with a known/measurable starting state from
which an identical series of iterative actions can be performed.

However, it was possible in some cases for an operation dispatched
from this channel to write a message back to the channel in the
case of joining a network when a sufficient volume of sandboxes
were operated on.

A goroutine which is simultaneously reading and writing to an
unbuffered channel can deadlock if it sends a message to a channel
then waits for it to be consumed and completed, since the only
available goroutine is more or less "talking to itself". In order
to break this deadlock, in the observed race, a goroutine is now
created to send the message to the channel.

Signed-off-by: Martin Dojcak <martin.dojcak@lablabs.io>
Signed-off-by: Ryan Barry <rbarry@mirantis.com>
2022-03-22 11:15:14 -04:00
..
bitseq refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
cluster
cmd refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
config libnetwork: remove more config bits related to external k/v stores 2022-01-06 18:45:45 +01:00
datastore libnetwork: remove etcd-related code and tests 2022-01-06 18:45:43 +01:00
diagnostic
discoverapi
docs libnetwork: remove consul-related code and tests 2022-01-06 18:45:41 +01:00
driverapi
drivers libnetwork/overlay:fix join sandbox deadlock 2022-03-22 11:15:14 -04:00
drvregistry
etchosts refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
idm
internal
ipam refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
ipamapi libnetwork/ipamapi: godoc fixes 2021-08-27 16:52:46 +02:00
ipams refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
ipamutils
iptables
netlabel
netutils
networkdb libnetwork/networkdb: remove some redundant fmt.Sprintf()'s 2022-02-15 12:56:23 +01:00
ns
options
osl refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
portallocator
portmapper refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
resolvconf refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
support
test/integration libnetwork: remove etcd-related code and tests 2022-01-06 18:45:43 +01:00
testutils
types libnetwork/types: remove TransportPort.FromString() as it's unused 2021-08-27 14:16:32 +02:00
.dockerignore
.gitignore
agent.go
agent.pb.go
agent.proto
CHANGELOG.md
controller.go libnetwork: remove more config bits related to external k/v stores 2022-01-06 18:45:45 +01:00
default_gateway.go
default_gateway_freebsd.go
default_gateway_linux.go
default_gateway_windows.go
drivers_freebsd.go
drivers_ipam.go
drivers_linux.go
drivers_windows.go
endpoint.go libnetwork: remove more config bits related to external k/v stores 2022-01-06 18:45:45 +01:00
endpoint_cnt.go
endpoint_info.go
endpoint_info_unix.go
endpoint_info_windows.go
endpoint_test.go refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
error.go
errors_test.go
firewall_linux.go
firewall_linux_test.go
firewall_others.go
libnetwork_internal_test.go
libnetwork_linux_test.go refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
libnetwork_test.go libnetwork: fix unhandled errors in tests (ineffassign) 2022-02-08 09:43:27 +01:00
libnetwork_unix_test.go
libnetwork_windows_test.go
network.go libnetwork: remove more config bits related to external k/v stores 2022-01-06 18:45:45 +01:00
network_unix.go
network_windows.go
README.md
resolver.go libnetwork: some minor refactoring / cleanup 2021-10-15 15:26:15 +02:00
resolver_test.go
resolver_unix.go
resolver_windows.go
sandbox.go
sandbox_dns_unix.go refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
sandbox_dns_windows.go
sandbox_externalkey.go
sandbox_externalkey_unix.go refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
sandbox_externalkey_windows.go
sandbox_store.go
sandbox_test.go
service.go
service_common.go
service_common_test.go
service_linux.go refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
service_unsupported.go
service_windows.go Windows: require Windows Server RS5 / ltsc2019 (build 17763) as minimum 2022-02-18 22:58:28 +01:00
store.go libnetwork: remove etcd-related code and tests 2022-01-06 18:45:43 +01:00
store_linux_test.go
store_test.go refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00

libnetwork - networking for containers

Libnetwork provides a native Go implementation for connecting containers

The goal of libnetwork is to deliver a robust Container Network Model that provides a consistent programming interface and the required network abstractions for applications.

Design

Please refer to the design for more information.

Using libnetwork

There are many networking solutions available to suit a broad range of use-cases. libnetwork uses a driver / plugin model to support all of these solutions while abstracting the complexity of the driver implementations by exposing a simple and consistent Network Model to users.

package main

import (
	"fmt"
	"log"

	"github.com/docker/docker/pkg/reexec"
	"github.com/docker/docker/libnetwork"
	"github.com/docker/docker/libnetwork/config"
	"github.com/docker/docker/libnetwork/netlabel"
	"github.com/docker/docker/libnetwork/options"
)

func main() {
	if reexec.Init() {
		return
	}

	// Select and configure the network driver
	networkType := "bridge"

	// Create a new controller instance
	driverOptions := options.Generic{}
	genericOption := make(map[string]interface{})
	genericOption[netlabel.GenericData] = driverOptions
	controller, err := libnetwork.New(config.OptionDriverConfig(networkType, genericOption))
	if err != nil {
		log.Fatalf("libnetwork.New: %s", err)
	}

	// Create a network for containers to join.
	// NewNetwork accepts Variadic optional arguments that libnetwork and Drivers can use.
	network, err := controller.NewNetwork(networkType, "network1", "")
	if err != nil {
		log.Fatalf("controller.NewNetwork: %s", err)
	}

	// For each new container: allocate IP and interfaces. The returned network
	// settings will be used for container infos (inspect and such), as well as
	// iptables rules for port publishing. This info is contained or accessible
	// from the returned endpoint.
	ep, err := network.CreateEndpoint("Endpoint1")
	if err != nil {
		log.Fatalf("network.CreateEndpoint: %s", err)
	}

	// Create the sandbox for the container.
	// NewSandbox accepts Variadic optional arguments which libnetwork can use.
	sbx, err := controller.NewSandbox("container1",
		libnetwork.OptionHostname("test"),
		libnetwork.OptionDomainname("docker.io"))
	if err != nil {
		log.Fatalf("controller.NewSandbox: %s", err)
	}

	// A sandbox can join the endpoint via the join api.
	err = ep.Join(sbx)
	if err != nil {
		log.Fatalf("ep.Join: %s", err)
	}

	// libnetwork client can check the endpoint's operational data via the Info() API
	epInfo, err := ep.DriverInfo()
	if err != nil {
		log.Fatalf("ep.DriverInfo: %s", err)
	}

	macAddress, ok := epInfo[netlabel.MacAddress]
	if !ok {
		log.Fatalf("failed to get mac address from endpoint info")
	}

	fmt.Printf("Joined endpoint %s (%s) to sandbox %s (%s)\n", ep.Name(), macAddress, sbx.ContainerID(), sbx.Key())
}

Contributing

Want to hack on libnetwork? Docker's contributions guidelines apply.

Code and documentation copyright 2015 Docker, inc. Code released under the Apache 2.0 license. Docs released under Creative commons.