f49145d5ff
Allow users to tune net network parameters such as somaxconn.
With this patch, users can add a new network configuration:
> {
> "name": "mytuning",
> "type": "tuning",
> "sysctl": {
> "net.core.somaxconn": "500"
> }
> }
The value /proc/sys/net/core/somaxconn will be set to 500 in the network
namespace but will remain unchanged on the host.
Only sysctl parameters that belong to the network subsystem can be
modified.
Related to: https://github.com/coreos/rkt/pull/2140
84 lines
2.3 KiB
Go
84 lines
2.3 KiB
Go
// Copyright 2016 CNI authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// This is a "meta-plugin". It reads in its own netconf, it does not create
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// any network interface but just changes the network sysctl.
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package main
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import (
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"encoding/json"
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"fmt"
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"io/ioutil"
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"os"
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"path/filepath"
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"strings"
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"github.com/appc/cni/pkg/ns"
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"github.com/appc/cni/pkg/skel"
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"github.com/appc/cni/pkg/types"
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)
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// TuningConf represents the network tuning configuration.
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type TuningConf struct {
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types.NetConf
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SysCtl map[string]string `json:"sysctl"`
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}
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func cmdAdd(args *skel.CmdArgs) error {
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tuningConf := TuningConf{}
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if err := json.Unmarshal(args.StdinData, &tuningConf); err != nil {
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return fmt.Errorf("failed to load netconf: %v", err)
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}
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// The directory /proc/sys/net is per network namespace. Enter in the
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// network namespace before writing on it.
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err := ns.WithNetNSPath(args.Netns, false, func(hostNS *os.File) error {
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for key, value := range tuningConf.SysCtl {
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fileName := filepath.Join("/proc/sys", strings.Replace(key, ".", "/", -1))
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fileName = filepath.Clean(fileName)
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// Refuse to modify sysctl parameters that don't belong
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// to the network subsystem.
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if !strings.HasPrefix(fileName, "/proc/sys/net/") {
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return fmt.Errorf("invalid net sysctl key: %q", key)
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}
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content := []byte(value)
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err := ioutil.WriteFile(fileName, content, 0644)
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if err != nil {
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return err
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}
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}
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return nil
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})
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if err != nil {
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return err
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}
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result := types.Result{}
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return result.Print()
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}
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func cmdDel(args *skel.CmdArgs) error {
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// TODO: the settings are not reverted to the previous values. Reverting the
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// settings is not useful when the whole container goes away but it could be
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// useful in scenarios where plugins are added and removed at runtime.
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return nil
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}
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func main() {
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skel.PluginMain(cmdAdd, cmdDel)
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}
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