Add `--ssh-hostkey-algos` flag to bootstrap command

Allow configuring the list of host key algorithms to use for
SSH connections initialized by the CLI during bootstrap.

Signed-off-by: Stefan Prodan <stefan.prodan@gmail.com>

cmd/flux/bootstrap.go

@@ -22,6 +22,7 @@ import (
 	"fmt"
 	"strings"
 
+	"github.com/fluxcd/pkg/git"
 	"github.com/manifoldco/promptui"
 	"github.com/spf13/cobra"
 	"k8s.io/apimachinery/pkg/api/errors"
@@ -64,6 +65,7 @@ type bootstrapFlags struct {
 	sshHostname          string
 	caFile               string
 	privateKeyFile       string
+	sshHostKeyAlgorithms []string
 
 	watchAllNamespaces bool
 	networkPolicy      bool
@@ -124,6 +126,7 @@ func init() {
 	bootstrapCmd.PersistentFlags().StringVar(&bootstrapArgs.secretName, "secret-name", rootArgs.defaults.Namespace, "name of the secret the sync credentials can be found in or stored to")
 	bootstrapCmd.PersistentFlags().Var(&bootstrapArgs.keyAlgorithm, "ssh-key-algorithm", bootstrapArgs.keyAlgorithm.Description())
 	bootstrapCmd.PersistentFlags().Var(&bootstrapArgs.keyRSABits, "ssh-rsa-bits", bootstrapArgs.keyRSABits.Description())
+	bootstrapCmd.PersistentFlags().StringSliceVar(&bootstrapArgs.sshHostKeyAlgorithms, "ssh-hostkey-algos", nil, "list of host key algorithms to be used by the CLI for SSH connections")
 	bootstrapCmd.PersistentFlags().Var(&bootstrapArgs.keyECDSACurve, "ssh-ecdsa-curve", bootstrapArgs.keyECDSACurve.Description())
 	bootstrapCmd.PersistentFlags().StringVar(&bootstrapArgs.sshHostname, "ssh-hostname", "", "SSH hostname, to be used when the SSH host differs from the HTTPS one")
 	bootstrapCmd.PersistentFlags().StringVar(&bootstrapArgs.caFile, "ca-file", "", "path to TLS CA file used for validating self-signed certificates")
@@ -192,6 +195,10 @@ func bootstrapValidate() error {
 		return fmt.Errorf("invalid --registry-creds format, expected 'user:password'")
 	}
 
+	if len(bootstrapArgs.sshHostKeyAlgorithms) > 0 {
+		git.HostKeyAlgos = bootstrapArgs.sshHostKeyAlgorithms
+	}
+
 	return nil
 }
 

cmd/flux/bootstrap_git.go

@@ -66,7 +66,7 @@ command will perform an upgrade if needed.`,
   flux bootstrap git --url=ssh://<SSH-Key-ID>@git-codecommit.<region>.amazonaws.com/v1/repos/<repository> --private-key-file=<path/to/private.key> --password=<SSH-passphrase> --path=clusters/my-cluster
 
   # Run bootstrap for a Git repository on Azure Devops
-  flux bootstrap git --url=ssh://git@ssh.dev.azure.com/v3/<org>/<project>/<repository> --ssh-key-algorithm=rsa --ssh-rsa-bits=4096 --path=clusters/my-cluster
+  flux bootstrap git --url=ssh://git@ssh.dev.azure.com/v3/<org>/<project>/<repository> --private-key-file=<path/to/rsa-sha2-private.key> --ssh-hostkey-algos=rsa-sha2-512,rsa-sha2-256 --path=clusters/my-cluster
 
   # Run bootstrap for a Git repository on Oracle VBS
   flux bootstrap git --url=https://repository_url.git --with-bearer-token=true --password=<PAT> --path=clusters/my-cluster