Files
k3s/pkg/cli/agent/agent.go
Brad Davidson 992e64993d Add support for kubeadm token and client certificate auth
Allow bootstrapping with kubeadm bootstrap token strings or existing
Kubelet certs. This allows agents to join the cluster using kubeadm
bootstrap tokens, as created with the `k3s token create` command.

When the token expires or is deleted, agents can successfully restart by
authenticating with their kubelet certificate via node authentication.
If the token is gone and the node is deleted from the cluster, node auth
will fail and they will be prevented from rejoining the cluster until
provided with a valid token.

Servers still must be bootstrapped with the static cluster token, as
they will need to know it to decrypt the bootstrap data.

Signed-off-by: Brad Davidson <brad.davidson@rancher.com>
2023-02-07 14:55:04 -08:00

81 lines
2.2 KiB
Go

package agent
import (
"crypto/tls"
"fmt"
"os"
"path/filepath"
"runtime"
"github.com/erikdubbelboer/gspt"
"github.com/k3s-io/k3s/pkg/agent"
"github.com/k3s-io/k3s/pkg/cli/cmds"
"github.com/k3s-io/k3s/pkg/datadir"
"github.com/k3s-io/k3s/pkg/netutil"
"github.com/k3s-io/k3s/pkg/token"
"github.com/k3s-io/k3s/pkg/version"
"github.com/rancher/wrangler/pkg/signals"
"github.com/sirupsen/logrus"
"github.com/urfave/cli"
)
func Run(ctx *cli.Context) error {
// hide process arguments from ps output, since they may contain
// database credentials or other secrets.
gspt.SetProcTitle(os.Args[0] + " agent")
// Evacuate cgroup v2 before doing anything else that may fork.
if err := cmds.EvacuateCgroup2(); err != nil {
return err
}
// Initialize logging, and subprocess reaping if necessary.
// Log output redirection and subprocess reaping both require forking.
if err := cmds.InitLogging(); err != nil {
return err
}
if runtime.GOOS != "windows" && os.Getuid() != 0 && !cmds.AgentConfig.Rootless {
return fmt.Errorf("agent must be run as root, or with --rootless")
}
if cmds.AgentConfig.TokenFile != "" {
token, err := token.ReadFile(cmds.AgentConfig.TokenFile)
if err != nil {
return err
}
cmds.AgentConfig.Token = token
}
clientKubeletCert := filepath.Join(cmds.AgentConfig.DataDir, "agent", "client-kubelet.crt")
clientKubeletKey := filepath.Join(cmds.AgentConfig.DataDir, "agent", "client-kubelet.key")
_, err := tls.LoadX509KeyPair(clientKubeletCert, clientKubeletKey)
if err != nil && cmds.AgentConfig.Token == "" {
return fmt.Errorf("--token is required")
}
if cmds.AgentConfig.ServerURL == "" {
return fmt.Errorf("--server is required")
}
if cmds.AgentConfig.FlannelIface != "" && len(cmds.AgentConfig.NodeIP) == 0 {
cmds.AgentConfig.NodeIP.Set(netutil.GetIPFromInterface(cmds.AgentConfig.FlannelIface))
}
logrus.Info("Starting " + version.Program + " agent " + ctx.App.Version)
dataDir, err := datadir.LocalHome(cmds.AgentConfig.DataDir, cmds.AgentConfig.Rootless)
if err != nil {
return err
}
cfg := cmds.AgentConfig
cfg.Debug = ctx.GlobalBool("debug")
cfg.DataDir = dataDir
contextCtx := signals.SetupSignalContext()
return agent.Run(contextCtx, cfg)
}