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Move AWS hostname support behind new flag
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For now, the new flag is automatically set when cloud-provider-name=aws, but this will be removed in the future following our normal deprecation timeline.

This also adds IMDSv2 support, and support for setting the hostname on windows.

Signed-off-by: Brad Davidson <[email protected]>
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@brandond
brandond committed Nov 26, 2024
1 parent eb5768b commit 030b9d2
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Showing 4 changed files with 118 additions and 50 deletions.
6 changes: 6 additions & 0 deletions pkg/cli/cmds/root.go
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Original file line number Diff line number Diff line change
Expand Up @@ -82,6 +82,12 @@ var (
EnvVar: "RKE2_CLOUD_PROVIDER_CONFIG",
Destination: &config.CloudProviderConfig,
},
&cli.BoolFlag{
Name: "node-name-from-cloud-provider-metadata",
Usage: "(cloud provider) Set node name from instance metadata service hostname",
EnvVar: "RKE2_NODE_NAME_FROM_CLOUD_PROVIDER_METADATA",
Destination: &config.CloudProviderMetadataHostname,
},
&cli.StringFlag{
Name: "profile",
Usage: "(security) Validate system configuration against the selected benchmark (valid items: cis)",
Expand Down
55 changes: 55 additions & 0 deletions pkg/rke2/rke2.go
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Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,7 @@ import (
"context"
"fmt"
"io/ioutil"
"net/http"
"os"
"os/exec"
"path/filepath"
Expand Down Expand Up @@ -36,6 +37,7 @@ type Config struct {
PodSecurityAdmissionConfigFile string
CloudProviderConfig string
CloudProviderName string
CloudProviderMetadataHostname bool
Images images.ImageOverrideConfig
KubeletPath string
ControlPlaneResourceRequests cli.StringSlice
Expand Down Expand Up @@ -406,3 +408,56 @@ func terminateRunningContainers(ctx context.Context, containerRuntimeEndpoint st
return len(disabledItems) == 0, nil
})
}

func hostnameFromMetadataEndpoint(ctx context.Context) string {
var token string

// Get token, required for IMDSv2
tokenCtx, tokenCancel := context.WithTimeout(ctx, time.Second)
defer tokenCancel()
if req, err := http.NewRequestWithContext(tokenCtx, http.MethodPut, "http://169.254.169.254/latest/api/token", nil); err != nil {
logrus.Debugf("Failed to create request for token endpoint: %v", err)
} else {
req.Header.Add("x-aws-ec2-metadata-token-ttl-seconds", "60")
if resp, err := http.DefaultClient.Do(req); err != nil {
logrus.Debugf("Failed to get token from token endpoint: %v", err)
} else {
defer resp.Body.Close()
if resp.StatusCode != http.StatusOK {
logrus.Debugf("Token endpoint returned unacceptable status code %d", resp.StatusCode)
} else {
if b, err := ioutil.ReadAll(resp.Body); err != nil {
logrus.Debugf("Failed to read response body from token endpoint: %v", err)
} else {
token = string(b)
}
}
}
}

// Get hostname from IMDS, with token if available
metaCtx, metaCancel := context.WithTimeout(ctx, time.Second)
defer metaCancel()
if req, err := http.NewRequestWithContext(metaCtx, http.MethodGet, "http://169.254.169.254/latest/meta-data/local-hostname", nil); err != nil {
logrus.Debugf("Failed to create request for metadata endpoint: %v", err)
} else {
if token != "" {
req.Header.Add("x-aws-ec2-metadata-token", token)
}
if resp, err := http.DefaultClient.Do(req); err != nil {
logrus.Debugf("Failed to get hostname from metadata endpoint: %v", err)
} else {
defer resp.Body.Close()
if resp.StatusCode != http.StatusOK {
logrus.Debugf("Metadata endpoint returned unacceptable status code %d", resp.StatusCode)
} else {
if b, err := ioutil.ReadAll(resp.Body); err != nil {
logrus.Debugf("Failed to read response body from metadata endpoint: %v", err)
} else {
return strings.TrimSpace(string(b))
}
}
}
}
return ""
}
67 changes: 20 additions & 47 deletions pkg/rke2/rke2_linux.go
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Original file line number Diff line number Diff line change
Expand Up @@ -7,13 +7,10 @@ import (
"bytes"
"context"
"fmt"
"io/ioutil"
"net/http"
"os/exec"
"path/filepath"
"strconv"
"strings"
"time"

"github.com/k3s-io/k3s/pkg/agent/config"
"github.com/k3s-io/k3s/pkg/cli/cmds"
Expand Down Expand Up @@ -92,22 +89,29 @@ func initExecutor(clx *cli.Context, cfg Config, isServer bool) (*podexecutor.Sta
return nil, fmt.Errorf("--cloud-provider-config requires --cloud-provider-name to be provided")
}
if cfg.CloudProviderName != "" {
cpConfig = &podexecutor.CloudProviderConfig{
Name: cfg.CloudProviderName,
Path: cfg.CloudProviderConfig,
}
if clx.String("node-name") == "" && cfg.CloudProviderName == "aws" {
fqdn := hostnameFromMetadataEndpoint(context.Background())
if fqdn == "" {
hostFQDN, err := hostnameFQDN()
if err != nil {
return nil, err
}
fqdn = hostFQDN
if cfg.CloudProviderName == "aws" {
logrus.Warnf("--cloud-provider-name=aws is deprecated due to removal of the in-tree aws cloud provider; if you want the legacy hostname behavior associated with this flag please use --node-name-from-cloud-provider-metadata")
cfg.CloudProviderMetadataHostname = true
cfg.CloudProviderName = ""
} else {
cpConfig = &podexecutor.CloudProviderConfig{
Name: cfg.CloudProviderName,
Path: cfg.CloudProviderConfig,
}
if err := clx.Set("node-name", fqdn); err != nil {
}
}

if cfg.CloudProviderMetadataHostname {
fqdn := hostnameFromMetadataEndpoint(context.Background())
if fqdn == "" {
hostFQDN, err := hostnameFQDN()
if err != nil {
return nil, err
}
fqdn = hostFQDN
}
if err := clx.Set("node-name", fqdn); err != nil {
return nil, err
}
}

Expand Down Expand Up @@ -502,34 +506,3 @@ func hostnameFQDN() (string, error) {

return strings.TrimSpace(b.String()), nil
}

func hostnameFromMetadataEndpoint(ctx context.Context) string {
ctx, cancel := context.WithTimeout(ctx, time.Second)
defer cancel()

req, err := http.NewRequestWithContext(ctx, http.MethodGet, "http://169.254.169.254/latest/meta-data/local-hostname", nil)
if err != nil {
logrus.Debugf("Failed to create request for metadata endpoint: %v", err)
return ""
}

resp, err := http.DefaultClient.Do(req)
if err != nil {
logrus.Debugf("Failed to get local-hostname from metadata endpoint: %v", err)
return ""
}
defer resp.Body.Close()

if resp.StatusCode != http.StatusOK {
logrus.Debugf("Metadata endpoint returned unacceptable status code %d", resp.StatusCode)
return ""
}

b, err := ioutil.ReadAll(resp.Body)
if err != nil {
logrus.Debugf("Failed to read response body from metadata endpoint: %v", err)
return ""
}

return strings.TrimSpace(string(b))
}
40 changes: 37 additions & 3 deletions pkg/rke2/rke2_windows.go
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Original file line number Diff line number Diff line change
Expand Up @@ -4,8 +4,10 @@
package rke2

import (
"context"
"fmt"
"path/filepath"
"unsafe"

"github.com/k3s-io/k3s/pkg/agent/config"
"github.com/k3s-io/k3s/pkg/cli/cmds"
Expand All @@ -15,7 +17,9 @@ import (
"github.com/rancher/rke2/pkg/cli/defaults"
"github.com/rancher/rke2/pkg/images"
"github.com/rancher/rke2/pkg/pebinaryexecutor"
"github.com/sirupsen/logrus"
"github.com/urfave/cli"
"golang.org/x/sys/windows"
)

func initExecutor(clx *cli.Context, cfg Config, isServer bool) (*pebinaryexecutor.PEBinaryConfig, error) {
Expand Down Expand Up @@ -48,9 +52,29 @@ func initExecutor(clx *cli.Context, cfg Config, isServer bool) (*pebinaryexecuto
return nil, fmt.Errorf("--cloud-provider-config requires --cloud-provider-name to be provided")
}
if cfg.CloudProviderName != "" {
cpConfig = &pebinaryexecutor.CloudProviderConfig{
Name: cfg.CloudProviderName,
Path: cfg.CloudProviderConfig,
if cfg.CloudProviderName == "aws" {
logrus.Warnf("--cloud-provider-name=aws is deprecated due to removal of the in-tree aws cloud provider; if you want the legacy node-name behavior associated with this flag please use --node-name-from-cloud-provider-metadata")
cfg.CloudProviderMetadataHostname = true
cfg.CloudProviderName = ""
} else {
cpConfig = &pebinaryexecutor.CloudProviderConfig{
Name: cfg.CloudProviderName,
Path: cfg.CloudProviderConfig,
}
}
}

if cfg.CloudProviderMetadataHostname {
fqdn := hostnameFromMetadataEndpoint(context.Background())
if fqdn == "" {
hostFQDN, err := hostnameFQDN()
if err != nil {
return nil, err
}
fqdn = hostFQDN
}
if err := clx.Set("node-name", fqdn); err != nil {
return nil, err
}
}

Expand Down Expand Up @@ -78,3 +102,13 @@ func initExecutor(clx *cli.Context, cfg Config, isServer bool) (*pebinaryexecuto
CNIName: "",
}, nil
}

func hostnameFQDN() (string, error) {
var domainName *uint16
var domainNameLen uint32 = 256
err := windows.GetComputerNameEx(windows.ComputerNameDnsFullyQualified, &domainName, &domainNameLen)
if err != nil {
return "", err
}
return windows.UTF16ToString((*[1 << 16]uint16)(unsafe.Pointer(domainName))[:domainNameLen-1]), nil
}

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