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Version: 1.37

SSH Known Hosts

The SSH Known Hosts feature enables Okteto administrators to centrally manage trusted SSH hosts for SSH-based Git operations across the organization. This does not affect HTTPS-based Git clones, which rely on certificate authorities for security. By maintaining a single source of truth for the known_hosts file, you can ensure secure and reliable repository cloning without requiring custom runner images.

Key Benefits​

  • Centralized trust management - Manage SSH host keys in one place for all teams
  • Enhanced security - Prevent man-in-the-middle attacks by verifying host keys
  • Simplified operations - No need for custom images or per-job SSH configuration

Getting Started​

Enabling Known Hosts​

  • Navigate to Admin → Settings → Known Hosts
  • Toggle Enable Known Hosts to activate the feature (disabled by default)
  • Once enabled:
    • Okteto uses this centralized list for all SSH operations
    • Automatic ssh-keyscan is disabled unless explicitly called in commands
    • All Git clones and submodules honor this trust store

Configure Trusted Hosts​

  • Add entries directly in the OpenSSH known_hosts format
  • Well-known providers (GitHub, GitLab, Bitbucket, Azure DevOps) are included as commented placeholders

Clone Fallback Behavior​

When a Git clone operation fails using one protocol, Okteto automatically attempts to fallback to the other protocol:

  • If SSH clone fails (e.g., due to missing known host), Okteto attempts HTTPS
  • If HTTPS clone fails (e.g., due to missing credentials), Okteto attempts SSH

Note: This fallback only applies to the main repository clone. Submodules use the protocol specified in the .gitmodules file without fallback.

This fallback ensures public repositories remain accessible and doesn't compromise security, as HTTPS clones are secured through certificate authorities (CA) rather than known hosts.

Important: For private repositories, authentication is required through at least one protocol. Configure either:

The fallback mechanism ensures deployment succeeds if either protocol is properly configured.

How It Works​

Scope and Application​

The centralized known_hosts applies to:

  • Installer jobs - UI-triggered deploys, previews, and destroy operations
  • Remote executor commands - Commands run from the Okteto Manifest
  • CLI operations - When using okteto deploy --remote

Runtime Behavior​

  • The known_hosts file is mounted read-write in jobs (allowing runtime additions for dynamic hosts)
  • When using okteto deploy --remote, the server-level configuration always overrides local known_hosts
  • Changes made during job execution are ephemeral and don't modify the global configuration

How This Affects the Okteto CLI​

  • Remote executions automatically fetch the centralized list
  • CLI honors the centralized known_hosts when okteto deploy --remote is used

Understanding Deploy Warnings​

When SSH clone fails due to missing known hosts, you may see a warning in the deployment UI even if the deployment ultimately succeeds. This occurs because:

  • The initial SSH clone attempt failed and triggered the warning
  • The automatic HTTPS fallback succeeded
  • The warning indicates the known hosts configuration should be updated to avoid relying on the fallback mechanism

Example Configuration​

When cloning repositories, the system automatically configures Git to use the centralized hosts file:

GIT_SSH_COMMAND="ssh -o UserKnownHostsFile=/okteto/known_hosts -o StrictHostKeyChecking=yes"

Advanced Scenarios​

Working with Dynamic Hosts​

  • Pipelines that clone additional repositories succeed as long as each host appears in the centralized known_hosts
  • Users can still run ssh-keyscan explicitly in their commands to add hosts at runtime
  • Dynamic endpoints created during deploy can append entries to the mounted known_hosts within the job. These changes are ephemeral to the job and do not modify the admin-configured global template

Submodules with SSH​

Even if your main repository clones via HTTPS, submodules may be configured to use SSH URLs. In these cases:

  • The main repository clone via HTTPS succeeds normally
  • Submodule clones require the SSH host to be in the known hosts list
  • Ensure all submodule hosts are added to the known hosts configuration
  • Submodule clone failures do not fallback to HTTPS

Error Handling​

If a host is missing from the list:

  • SSH clone will fail with Host key verification failed
  • Okteto will automatically attempt to clone via HTTPS as a fallback
  • For public repositories, the HTTPS fallback typically succeeds
  • For private repositories, the HTTPS fallback requires appropriate credentials (GitHub App integration, personal access tokens, etc.)
  • Check deploy logs for details on which protocol succeeded