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bump cni version to v0.8.0

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bump cni dependencies so we can benefits from its
bugfixes and improvements

Signed-off-by: Antonio Ojea <antonio.ojea.garcia@gmail.com>
This commit is contained in:
Antonio Ojea
2020-06-07 23:21:37 +02:00
committed by Antonio Ojea
parent 412378ff02
commit e3d27f9ed8
18 changed files with 508 additions and 237 deletions
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15
vendor/github.com/containernetworking/plugins/pkg/ns/README.md generated vendored
View File

@@ -12,10 +12,6 @@ For example, you cannot rely on the `ns.Set()` namespace being the current names
The `ns.Do()` method provides **partial** control over network namespaces for you by implementing these strategies. All code dependent on a particular network namespace (including the root namespace) should be wrapped in the `ns.Do()` method to ensure the correct namespace is selected for the duration of your code. For example:
```go
targetNs, err := ns.NewNS()
if err != nil {
return err
}
err = targetNs.Do(func(hostNs ns.NetNS) error {
dummy := &netlink.Dummy{
LinkAttrs: netlink.LinkAttrs{
@@ -26,11 +22,16 @@ err = targetNs.Do(func(hostNs ns.NetNS) error {
})
```
Note this requirement to wrap every network call is very onerous - any libraries you call might call out to network services such as DNS, and all such calls need to be protected after you call `ns.Do()`. The CNI plugins all exit very soon after calling `ns.Do()` which helps to minimize the problem.
Note this requirement to wrap every network call is very onerous - any libraries you call might call out to network services such as DNS, and all such calls need to be protected after you call `ns.Do()`. All goroutines spawned from within the `ns.Do` will not inherit the new namespace. The CNI plugins all exit very soon after calling `ns.Do()` which helps to minimize the problem.
Also: If the runtime spawns a new OS thread, it will inherit the network namespace of the parent thread, which may have been temporarily switched, and thus the new OS thread will be permanently "stuck in the wrong namespace".
When a new thread is spawned in Linux, it inherits the namespace of its parent. In versions of go **prior to 1.10**, if the runtime spawns a new OS thread, it picks the parent randomly. If the chosen parent thread has been moved to a new namespace (even temporarily), the new OS thread will be permanently "stuck in the wrong namespace", and goroutines will non-deterministically switch namespaces as they are rescheduled.
In short, **there was no safe way to change network namespaces, even temporarily, from within a long-lived, multithreaded Go process**. If you wish to do this, you must use go 1.10 or greater.
### Creating network namespaces
Earlier versions of this library managed namespace creation, but as CNI does not actually utilize this feature (and it was essentially unmaintained), it was removed. If you're writing a container runtime, you should implement namespace management yourself. However, there are some gotchas when doing so, especially around handling `/var/run/netns`. A reasonably correct reference implementation, borrowed from `rkt`, can be found in `pkg/testutils/netns_linux.go` if you're in need of a source of inspiration.
In short, **there is no safe way to change network namespaces from within a long-lived, multithreaded Go process**. If your daemon process needs to be namespace aware, consider spawning a separate process (like a CNI plugin) for each namespace.
### Further Reading
- https://github.com/golang/go/wiki/LockOSThread

108
vendor/github.com/containernetworking/plugins/pkg/ns/ns_linux.go generated vendored
View File

@@ -15,10 +15,8 @@
package ns
import (
"crypto/rand"
"fmt"
"os"
"path"
"runtime"
"sync"
"syscall"
@@ -38,82 +36,6 @@ func getCurrentThreadNetNSPath() string {
return fmt.Sprintf("/proc/%d/task/%d/ns/net", os.Getpid(), unix.Gettid())
}
// Creates a new persistent network namespace and returns an object
// representing that namespace, without switching to it
func NewNS() (NetNS, error) {
const nsRunDir = "/var/run/netns"
b := make([]byte, 16)
_, err := rand.Reader.Read(b)
if err != nil {
return nil, fmt.Errorf("failed to generate random netns name: %v", err)
}
err = os.MkdirAll(nsRunDir, 0755)
if err != nil {
return nil, err
}
// create an empty file at the mount point
nsName := fmt.Sprintf("cni-%x-%x-%x-%x-%x", b[0:4], b[4:6], b[6:8], b[8:10], b[10:])
nsPath := path.Join(nsRunDir, nsName)
mountPointFd, err := os.Create(nsPath)
if err != nil {
return nil, err
}
mountPointFd.Close()
// Ensure the mount point is cleaned up on errors; if the namespace
// was successfully mounted this will have no effect because the file
// is in-use
defer os.RemoveAll(nsPath)
var wg sync.WaitGroup
wg.Add(1)
// do namespace work in a dedicated goroutine, so that we can safely
// Lock/Unlock OSThread without upsetting the lock/unlock state of
// the caller of this function
var fd *os.File
go (func() {
defer wg.Done()
runtime.LockOSThread()
var origNS NetNS
origNS, err = GetNS(getCurrentThreadNetNSPath())
if err != nil {
return
}
defer origNS.Close()
// create a new netns on the current thread
err = unix.Unshare(unix.CLONE_NEWNET)
if err != nil {
return
}
defer origNS.Set()
// bind mount the new netns from the current thread onto the mount point
err = unix.Mount(getCurrentThreadNetNSPath(), nsPath, "none", unix.MS_BIND, "")
if err != nil {
return
}
fd, err = os.Open(nsPath)
if err != nil {
return
}
})()
wg.Wait()
if err != nil {
unix.Unmount(nsPath, unix.MNT_DETACH)
return nil, fmt.Errorf("failed to create namespace: %v", err)
}
return &netNS{file: fd, mounted: true}, nil
}
func (ns *netNS) Close() error {
if err := ns.errorIfClosed(); err != nil {
return err
@@ -124,16 +46,6 @@ func (ns *netNS) Close() error {
}
ns.closed = true
if ns.mounted {
if err := unix.Unmount(ns.file.Name(), unix.MNT_DETACH); err != nil {
return fmt.Errorf("Failed to unmount namespace %s: %v", ns.file.Name(), err)
}
if err := os.RemoveAll(ns.file.Name()); err != nil {
return fmt.Errorf("Failed to clean up namespace %s: %v", ns.file.Name(), err)
}
ns.mounted = false
}
return nil
}
@@ -180,9 +92,8 @@ type NetNS interface {
}
type netNS struct {
file *os.File
mounted bool
closed bool
file *os.File
closed bool
}
// netNS implements the NetNS interface
@@ -267,7 +178,16 @@ func (ns *netNS) Do(toRun func(NetNS) error) error {
if err = ns.Set(); err != nil {
return fmt.Errorf("error switching to ns %v: %v", ns.file.Name(), err)
}
defer threadNS.Set() // switch back
defer func() {
err := threadNS.Set() // switch back
if err == nil {
// Unlock the current thread only when we successfully switched back
// to the original namespace; otherwise leave the thread locked which
// will force the runtime to scrap the current thread, that is maybe
// not as optimal but at least always safe to do.
runtime.UnlockOSThread()
}
}()
return toRun(hostNS)
}
@@ -282,6 +202,10 @@ func (ns *netNS) Do(toRun func(NetNS) error) error {
var wg sync.WaitGroup
wg.Add(1)
// Start the callback in a new green thread so that if we later fail
// to switch the namespace back to the original one, we can safely
// leave the thread locked to die without a risk of the current thread
// left lingering with incorrect namespace.
var innerError error
go func() {
defer wg.Done()