WIP: Add serverless GPU compute support to SSH tunnel

experimental/ssh/cmd/connect.go

@@ -1,6 +1,7 @@
 package ssh
 
 import (
+	"errors"
 	"time"
 
 	"github.com/databricks/cli/cmd/root"
@@ -18,10 +19,18 @@ func newConnectCommand() *cobra.Command {
 This command establishes an SSH connection to Databricks compute, setting up
 the SSH server and handling the connection proxy.
 
+For dedicated clusters:
+  databricks ssh connect --cluster=<cluster-id>
+
+For serverless compute:
+  databricks ssh connect --name=<connection-name> [--accelerator=<accelerator>]
+
 ` + disclaimer,
 	}
 
 	var clusterID string
+	var connectionName string
+	var accelerator string
 	var proxyMode bool
 	var serverMetadata string
 	var shutdownDelay time.Duration
@@ -30,9 +39,11 @@ the SSH server and handling the connection proxy.
 	var releasesDir string
 	var autoStartCluster bool
 	var userKnownHostsFile string
+	var liteswap string
 
-	cmd.Flags().StringVar(&clusterID, "cluster", "", "Databricks cluster ID (required)")
-	cmd.MarkFlagRequired("cluster")
+	cmd.Flags().StringVar(&clusterID, "cluster", "", "Databricks cluster ID (for dedicated clusters)")
+	cmd.Flags().StringVar(&connectionName, "name", "", "Connection name (for serverless compute)")
+	cmd.Flags().StringVar(&accelerator, "accelerator", "", "GPU accelerator type for serverless compute (GPU_1xA10 or GPU_8xH100)")
 	cmd.Flags().DurationVar(&shutdownDelay, "shutdown-delay", defaultShutdownDelay, "Delay before shutting down the server after the last client disconnects")
 	cmd.Flags().IntVar(&maxClients, "max-clients", defaultMaxClients, "Maximum number of SSH clients")
 	cmd.Flags().BoolVar(&autoStartCluster, "auto-start-cluster", true, "Automatically start the cluster if it is not running")
@@ -50,6 +61,9 @@ the SSH server and handling the connection proxy.
 	cmd.Flags().StringVar(&userKnownHostsFile, "user-known-hosts-file", "", "Path to user known hosts file for SSH client")
 	cmd.Flags().MarkHidden("user-known-hosts-file")
 
+	cmd.Flags().StringVar(&liteswap, "liteswap", "", "Liteswap header value for traffic routing (dev/test only)")
+	cmd.Flags().MarkHidden("liteswap")
+
 	cmd.PreRunE = func(cmd *cobra.Command, args []string) error {
 		// CLI in the proxy mode is executed by the ssh client and can't prompt for input
 		if proxyMode {
@@ -64,20 +78,40 @@ the SSH server and handling the connection proxy.
 	cmd.RunE = func(cmd *cobra.Command, args []string) error {
 		ctx := cmd.Context()
 		wsClient := cmdctx.WorkspaceClient(ctx)
+
+		if !proxyMode && clusterID == "" && connectionName == "" {
+			return errors.New("please provide --cluster flag with the cluster ID, or --name flag with the serverless connection name")
+		}
+
+		if accelerator != "" && connectionName == "" {
+			return errors.New("--accelerator flag can only be used with serverless compute (--name flag)")
+		}
+
+		// Remove when we add support for serverless CPU
+		if connectionName != "" && accelerator == "" {
+			return errors.New("--name flag requires --accelerator to be set (e.g. for now we only support serverless GPU compute)")
+		}
+
+		// TODO: validate connectionName if provided
+
 		opts := client.ClientOptions{
 			Profile:              wsClient.Config.Profile,
 			ClusterID:            clusterID,
+			ConnectionName:       connectionName,
+			Accelerator:          accelerator,
 			ProxyMode:            proxyMode,
 			ServerMetadata:       serverMetadata,
 			ShutdownDelay:        shutdownDelay,
 			MaxClients:           maxClients,
 			HandoverTimeout:      handoverTimeout,
 			ReleasesDir:          releasesDir,
 			ServerTimeout:        serverTimeout,
+			TaskStartupTimeout:   taskStartupTimeout,
 			AutoStartCluster:     autoStartCluster,
 			ClientPublicKeyName:  clientPublicKeyName,
 			ClientPrivateKeyName: clientPrivateKeyName,
 			UserKnownHostsFile:   userKnownHostsFile,
+			Liteswap:             liteswap,
 			AdditionalArgs:       args,
 		}
 		return client.Run(ctx, wsClient, opts)

experimental/ssh/cmd/constants.go

@@ -9,6 +9,7 @@ const (
 	defaultHandoverTimeout = 30 * time.Minute
 
 	serverTimeout        = 24 * time.Hour
+	taskStartupTimeout   = 10 * time.Minute
 	serverPortRange      = 100
 	serverConfigDir      = ".ssh-tunnel"
 	serverPrivateKeyName = "server-private-key"

experimental/ssh/cmd/server.go

@@ -26,12 +26,15 @@ and proxies them to local SSH daemon processes.
 	var maxClients int
 	var shutdownDelay time.Duration
 	var clusterID string
+	var sessionID string
 	var version string
 	var secretScopeName string
 	var authorizedKeySecretName string
 
 	cmd.Flags().StringVar(&clusterID, "cluster", "", "Databricks cluster ID")
 	cmd.MarkFlagRequired("cluster")
+	cmd.Flags().StringVar(&sessionID, "session-id", "", "Session identifier (cluster ID or serverless connection name)")
+	cmd.MarkFlagRequired("session-id")
 	cmd.Flags().StringVar(&secretScopeName, "secret-scope-name", "", "Databricks secret scope name to store SSH keys")
 	cmd.MarkFlagRequired("secret-scope-name")
 	cmd.Flags().StringVar(&authorizedKeySecretName, "authorized-key-secret-name", "", "Name of the secret containing the client public key")
@@ -56,6 +59,7 @@ and proxies them to local SSH daemon processes.
 		wsc := cmdctx.WorkspaceClient(ctx)
 		opts := server.ServerOptions{
 			ClusterID:               clusterID,
+			SessionID:               sessionID,
 			MaxClients:              maxClients,
 			ShutdownDelay:           shutdownDelay,
 			Version:                 version,