add network create funcs

pkg/drivers/kic/oci/errors.go

@@ -39,12 +39,27 @@ var ErrWindowsContainers = &FailFastError{errors.New("docker container type is w
 // ErrCPUCountLimit is thrown when docker daemon doesn't have enough CPUs for the requested container
 var ErrCPUCountLimit = &FailFastError{errors.New("not enough CPUs is available for container")}
 
+// ErrIPinUse is thrown when the container been given an IP used by another container
+var ErrIPinUse = &FailFastError{errors.New("can't create with that IP, address already in use")}
+
 // ErrExitedUnexpectedly is thrown when container is created/started without error but later it exists and it's status is not running anymore.
 var ErrExitedUnexpectedly = errors.New("container exited unexpectedly")
 
 // ErrDaemonInfo is thrown when docker/podman info is failing or not responding
 var ErrDaemonInfo = errors.New("daemon info not responding")
 
+// ErrNetworkSubnetTaken is thrown when a subnet is taken by another network
+var ErrNetworkSubnetTaken = errors.New("subnet is taken")
+
+// ErrNetworkNotFound is when given network was not found
+var ErrNetworkNotFound = errors.New("kic network not found")
+
+// ErrNetworkGatewayTaken is when given network gatway is taken
+var ErrNetworkGatewayTaken = errors.New("network gateway is taken")
+
+// ErrNetworkInUse is when trying to delete a network which is attached to another container
+var ErrNetworkInUse = errors.New("can't delete network attached to a running container")
+
 // LogContainerDebug will print relevant docker/podman infos after a container fails
 func LogContainerDebug(ociBin string, name string) string {
 	rr, err := containerInspect(ociBin, name)

pkg/drivers/kic/oci/network_create.go

@@ -0,0 +1,125 @@
+/*
+Copyright 2019 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package oci
+
+import (
+	"fmt"
+	"net"
+	"os/exec"
+	"strings"
+
+	"github.com/golang/glog"
+	"github.com/pkg/errors"
+)
+
+// DefaultSubnet subnet to be used on first cluster
+const defaultSubnet = "192.168.39.0/24"
+
+// CreateNetwork creates a network returns gateway and error, minikube creates one network per cluster
+func CreateNetwork(ociBin string, name string) (net.IP, error) {
+	if ociBin != Docker {
+		return nil, fmt.Errorf("%s network not implemented yet", ociBin)
+	}
+	return createDockerNetwork(name)
+}
+
+func createDockerNetwork(name string) (net.IP, error) {
+	// check if the network already exists
+	subnet, gateway, err := dockerNetworkInspect(name)
+	if err == nil {
+		glog.Infof("Found existing network with subnet %s and gateway %s.", subnet, gateway)
+		return gateway, nil
+	}
+	// simple way to create networks, subnet is taken, try one bigger
+	attempt := 0
+	_, subnet, err = net.ParseCIDR(defaultSubnet)
+	if err != nil {
+		return nil, errors.Wrapf(err, "parse default subnet %s", defaultSubnet)
+	}
+
+	gateway, err = tryCreateDockerNetwork(subnet, name)
+	if err != nil {
+		if err != ErrNetworkSubnetTaken {
+			return nil, errors.Wrapf(err, "error creating network")
+		}
+		// try up to 13 times
+		// we can try up to 255
+		for attempt < 13 {
+			attempt++
+			glog.Infof("Couldn't create network %q at %q subnet will try again with a new subnet ...", name, subnet)
+			// increase 3nd digit by 10 each time
+			// 13 times adding 10 defaultSubnet "192.168.39.0/24"
+			// at most it will add up to 169 which is still less than max allowed 255
+			// this is large enough to try more and not too small to not try enough
+			// can be tuned in the next iterations
+			subnet.IP.To4()[2] += 10
+			gateway, err := tryCreateDockerNetwork(subnet, name)
+			if err == nil {
+				return gateway, nil
+			}
+			if err == ErrNetworkSubnetTaken {
+				continue
+			}
+		}
+
+	}
+	return gateway, nil
+}
+
+func tryCreateDockerNetwork(subnet *net.IPNet, name string) (net.IP, error) {
+	gateway := subnet.IP.To4()
+	gateway[3]++ // first ip for gateway
+	glog.Infof("attempt to create network %q with subnet: %s and gateway %s...", subnet, name, gateway)
+	// options documentation https://docs.docker.com/engine/reference/commandline/network_create/#bridge-driver-options
+	rr, err := runCmd(exec.Command(Docker, "network", "create", "--driver=bridge", fmt.Sprintf("--subnet=%s", subnet), fmt.Sprintf("--gateway=%s", gateway), "-o", "--ip-masq", "-o", "--icc", fmt.Sprintf("--label=%s=%s", CreatedByLabelKey, "true"), name))
+	if err != nil {
+		if strings.Contains(rr.Output(), "Pool overlaps with other one on this address space") {
+			return nil, ErrNetworkSubnetTaken
+		}
+		if strings.Contains(rr.Output(), "failed to allocate gateway") && strings.Contains(rr.Output(), "Address already in use") {
+			return nil, ErrNetworkGatewayTaken
+		}
+		return nil, errors.Wrapf(err, "error creating network")
+	}
+	return gateway, nil
+}
+
+// returns subnet and gate if exists
+func dockerNetworkInspect(name string) (*net.IPNet, net.IP, error) {
+	rr, err := runCmd(exec.Command(Docker, "network", "inspect", name, "--format", "{{(index .IPAM.Config 0).Subnet}},{{(index .IPAM.Config 0).Gateway}}"))
+	if err != nil {
+		if strings.Contains(rr.Output(), "No such network:") {
+			return nil, nil, ErrNetworkNotFound
+		}
+		return nil, nil, err
+	}
+	// results looks like 172.17.0.0/16,172.17.0.1
+	ips := strings.Split(strings.TrimSpace(rr.Stdout.String()), ",")
+	if len(ips) == 0 {
+		return nil, nil, fmt.Errorf("invalid network info")
+	}
+
+	_, subnet, err := net.ParseCIDR(ips[0])
+	if err != nil {
+		return nil, nil, errors.Wrapf(err, "parse subnet for %s", name)
+	}
+	var gateway net.IP
+	if len(ips) > 0 {
+		gateway = net.ParseIP(ips[1])
+	}
+	return subnet, gateway, nil
+}