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Merge pull request #532 from dverbeir/flannel_ipam_routes

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flannel: allow input ipam parameters as basis for delegate
This commit is contained in:
Casey Callendrello 2020-10-07 17:55:41 +02:00 committed by GitHub
commit 6df03d7937
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4 changed files with 134 additions and 13 deletions
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7
plugins/meta/flannel/README.md
View File

@ -68,6 +68,8 @@ To use `ipvlan` instead of `bridge`, the following configuration can be specifie
}
```
The `ipam` part of the network configuration generated for the delegated plugin, can also be customized by adding a base `ipam` section to the input flannel network configuration. This `ipam` element is then updated with the flannel subnet, a route to the flannel network and, unless provided, an `ipam` `type` set to `host-local` before being provided to the delegated plugin.
## Network configuration reference
* `name` (string, required): the name of the network
@ -75,11 +77,12 @@ To use `ipvlan` instead of `bridge`, the following configuration can be specifie
* `subnetFile` (string, optional): full path to the subnet file written out by flanneld. Defaults to /run/flannel/subnet.env
* `dataDir` (string, optional): path to directory where plugin will store generated network configuration files. Defaults to `/var/lib/cni/flannel`
* `delegate` (dictionary, optional): specifies configuration options for the delegated plugin.
* `ipam` (dictionary, optional, Linux only): when specified, is used as basis to construct the `ipam` section of the delegated plugin configuration.
flannel plugin will always set the following fields in the delegated plugin configuration:
* `name`: value of its "name" field.
* `ipam`: "host-local" type will be used with "subnet" set to `$FLANNEL_SUBNET`.
* `ipam`: based on the received `ipam` section if present, with a `type` defaulting to `host-local`, a `subnet` set to `$FLANNEL_SUBNET` and (Linux only) a `routes` element assembled from the routes listed in the received `ipam` element and a route to the flannel network. Other fields present in the input `ipam` section will be transparently provided to the delegate.
flannel plugin will set the following fields in the delegated plugin configuration if they are not present:
* `ipMasq`: the inverse of `$FLANNEL_IPMASQ`
@ -87,6 +90,8 @@ flannel plugin will set the following fields in the delegated plugin configurati
Additionally, for the bridge plugin, `isGateway` will be set to `true`, if not present.
One use case of the `ipam` configuration is to allow adding back the routes to the cluster services and/or to the hosts when using `isDefaultGateway=false`. In that case, the bridge plugin does not install a default route and, as a result, only pod-to-pod connectivity would be available.
## Windows Support (Experimental)
This plugin supports delegating to the windows CNI plugins (overlay.exe, l2bridge.exe) to work in conjunction with [Flannel on Windows](https://github.com/coreos/flannel/issues/833).
Flannel sets up an [HNS Network](https://docs.microsoft.com/en-us/virtualization/windowscontainers/container-networking/architecture) in L2Bridge mode for host-gw and in Overlay mode for vxlan.

14
plugins/meta/flannel/flannel.go
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@ -46,6 +46,8 @@ const (
type NetConf struct {
types.NetConf
// IPAM field "replaces" that of types.NetConf which is incomplete
IPAM map[string]interface{} `json:"ipam,omitempty"`
SubnetFile string `json:"subnetFile"`
DataDir string `json:"dataDir"`
Delegate map[string]interface{} `json:"delegate"`
@ -89,6 +91,18 @@ func loadFlannelNetConf(bytes []byte) (*NetConf, error) {
return n, nil
}
func getIPAMRoutes(n *NetConf) ([]types.Route, error) {
rtes := []types.Route{}
if n.IPAM != nil && hasKey(n.IPAM, "routes") {
buf, _ := json.Marshal(n.IPAM["routes"])
if err := json.Unmarshal(buf, &rtes); err != nil {
return rtes, fmt.Errorf("failed to parse ipam.routes: %w", err)
}
}
return rtes, nil
}
func loadFlannelSubnetEnv(fn string) (*subnetEnv, error) {
f, err := os.Open(fn)
if err != nil {

38
plugins/meta/flannel/flannel_linux.go
View File

@ -22,12 +22,36 @@ import (
"context"
"encoding/json"
"fmt"
"os"
"github.com/containernetworking/cni/pkg/invoke"
"github.com/containernetworking/cni/pkg/skel"
"github.com/containernetworking/cni/pkg/types"
"os"
)
// Return IPAM section for Delegate using input IPAM if present and replacing
// or complementing as needed.
func getDelegateIPAM(n *NetConf, fenv *subnetEnv) (map[string]interface{}, error) {
ipam := n.IPAM
if ipam == nil {
ipam = map[string]interface{}{}
}
if !hasKey(ipam, "type") {
ipam["type"] = "host-local"
}
ipam["subnet"] = fenv.sn.String()
rtes, err := getIPAMRoutes(n)
if err != nil {
return nil, fmt.Errorf("failed to read IPAM routes: %w", err)
}
rtes = append(rtes, types.Route{Dst: *fenv.nw})
ipam["routes"] = rtes
return ipam, nil
}
func doCmdAdd(args *skel.CmdArgs, n *NetConf, fenv *subnetEnv) error {
n.Delegate["name"] = n.Name
@ -55,15 +79,11 @@ func doCmdAdd(args *skel.CmdArgs, n *NetConf, fenv *subnetEnv) error {
n.Delegate["cniVersion"] = n.CNIVersion
}
n.Delegate["ipam"] = map[string]interface{}{
"type": "host-local",
"subnet": fenv.sn.String(),
"routes": []types.Route{
{
Dst: *fenv.nw,
},
},
ipam, err := getDelegateIPAM(n, fenv)
if err != nil {
return fmt.Errorf("failed to assemble Delegate IPAM: %w", err)
}
n.Delegate["ipam"] = ipam
return delegateAdd(args.ContainerID, n.DataDir, n.Delegate)
}

88
plugins/meta/flannel/flannel_linux_test.go
View File

@ -14,6 +14,7 @@
package main
import (
"encoding/json"
"fmt"
"io/ioutil"
"os"
@ -50,9 +51,25 @@ var _ = Describe("Flannel", func() {
"name": "cni-flannel",
"type": "flannel",
"subnetFile": "%s",
"dataDir": "%s"
"dataDir": "%s"%s
}`
const inputIPAMTemplate = `
"unknown-param": "unknown-value",
"routes": [%s]%s`
const inputIPAMType = "my-ipam"
const inputIPAMNoTypeTemplate = `
{
"unknown-param": "unknown-value",
"routes": [%s]%s
}`
const inputIPAMRoutes = `
{ "dst": "10.96.0.0/12" },
{ "dst": "192.168.244.0/24", "gw": "10.1.17.20" }`
const flannelSubnetEnv = `
FLANNEL_NETWORK=10.1.0.0/16
FLANNEL_SUBNET=10.1.17.1/24
@ -68,6 +85,26 @@ FLANNEL_IPMASQ=true
return file.Name()
}
var makeInputIPAM = func(ipamType, routes, extra string) string {
c := "{\n"
if len(ipamType) > 0 {
c += fmt.Sprintf(" \"type\": \"%s\",", ipamType)
}
c += fmt.Sprintf(inputIPAMTemplate, routes, extra)
c += "\n}"
return c
}
var makeInput = func(inputIPAM string) string {
ipamPart := ""
if len(inputIPAM) > 0 {
ipamPart = ",\n \"ipam\":\n" + inputIPAM
}
return fmt.Sprintf(inputTemplate, subnetFile, dataDir, ipamPart)
}
BeforeEach(func() {
var err error
// flannel subnet.env
@ -76,7 +113,7 @@ FLANNEL_IPMASQ=true
// flannel state dir
dataDir, err = ioutil.TempDir("", "dataDir")
Expect(err).NotTo(HaveOccurred())
input = fmt.Sprintf(inputTemplate, subnetFile, dataDir)
input = makeInput("")
})
AfterEach(func() {
@ -108,7 +145,7 @@ FLANNEL_IPMASQ=true
})
Expect(err).NotTo(HaveOccurred())
By("check that plugin writes to net config to dataDir")
By("check that plugin writes the net config to dataDir")
path := fmt.Sprintf("%s/%s", dataDir, "some-container-id")
Expect(path).Should(BeAnExistingFile())
@ -213,4 +250,49 @@ FLANNEL_IPMASQ=true
})
})
})
Describe("getDelegateIPAM", func() {
Context("when input IPAM is provided", func() {
BeforeEach(func() {
inputIPAM := makeInputIPAM(inputIPAMType, inputIPAMRoutes, "")
input = makeInput(inputIPAM)
})
It("configures Delegate IPAM accordingly", func() {
conf, err := loadFlannelNetConf([]byte(input))
Expect(err).ShouldNot(HaveOccurred())
fenv, err := loadFlannelSubnetEnv(subnetFile)
Expect(err).ShouldNot(HaveOccurred())
ipam, err := getDelegateIPAM(conf, fenv)
Expect(err).ShouldNot(HaveOccurred())
podsRoute := "{ \"dst\": \"10.1.0.0/16\" }\n"
subnet := "\"subnet\": \"10.1.17.0/24\""
expected := makeInputIPAM(inputIPAMType, inputIPAMRoutes+",\n"+podsRoute, ",\n"+subnet)
buf, _ := json.Marshal(ipam)
Expect(buf).Should(MatchJSON(expected))
})
})
Context("when input IPAM is provided without 'type'", func() {
BeforeEach(func() {
inputIPAM := makeInputIPAM("", inputIPAMRoutes, "")
input = makeInput(inputIPAM)
})
It("configures Delegate IPAM with 'host-local' ipam", func() {
conf, err := loadFlannelNetConf([]byte(input))
Expect(err).ShouldNot(HaveOccurred())
fenv, err := loadFlannelSubnetEnv(subnetFile)
Expect(err).ShouldNot(HaveOccurred())
ipam, err := getDelegateIPAM(conf, fenv)
Expect(err).ShouldNot(HaveOccurred())
podsRoute := "{ \"dst\": \"10.1.0.0/16\" }\n"
subnet := "\"subnet\": \"10.1.17.0/24\""
expected := makeInputIPAM("host-local", inputIPAMRoutes+",\n"+podsRoute, ",\n"+subnet)
buf, _ := json.Marshal(ipam)
Expect(buf).Should(MatchJSON(expected))
})
})
})
})