User Manual

This User Manual covers usage of the Teleport client tool tsh. In this document you will learn how to:

  • Log into interactive shell on remote cluster nodes.
  • Copy files to and from cluster nodes.
  • Connect to SSH clusters behind firewalls without any open ports using SSH reverse tunnels.
  • Explore a cluster and execute commands on those nodes in a cluster that match your criteria.
  • Share interactive shell sessions with colleagues or join someone else's session.
  • Replay recorded interactive sessions.

In addition to this document, you can always simply type tsh into your terminal for the CLI reference.

$ tsh
usage: tsh [<flags>] <command> [<command-args> ...]

Gravitational Teleport SSH tool

Commands:
  help         Show help.
  version      Print the version
  ssh          Run shell or execute a command on a remote SSH node
  join         Join the active SSH session
  play         Replay the recorded SSH session
  scp          Secure file copy
  ls           List remote SSH nodes
  clusters     List available Teleport clusters
  login        Log in to the cluster and store the session certificate to avoid login prompts
  logout       Delete a cluster certificate

# Run `tsh help <command>` to get help for <command> like `tsh help ssh`

User Identities

A user identity in Teleport exists in the scope of a cluster. The member nodes of a cluster may have multiple OS users on them. A Teleport administrator assigns allowed logins to every Teleport user account.

When logging into a remote node, you will have to specify both logins. Teleport identity will have to be passed as --user flag, while the node login will be passed as [email protected], using syntax compatible with traditional ssh.

These examples assume your localhost username is 'joe':

# Authenticate against cluster 'work' as 'joe' and then login into 'node'
# as root:
$ tsh ssh --proxy=work.example.com --user=joe [email protected]

# Authenticate against cluster 'work' as 'joe' and then login into 'node'
# as joe (by default tsh uses $USER for both):
$ tsh ssh --proxy=work.example.com node

tsh login log a user into a cluster and stores the user certificate in ~/.tsh directory as well as in the ssh agent, if there is one running:

$ tsh login --proxy=work.example.com

This allows you authenticate just once, maybe at the beginning of the day. Subsequent tsh ssh commands will run without asking for credentials until the temporary certificate expires. By default Teleport issues user certificates with a TTL (time to live) of 23 hours.

Tip

It is recommended to always use tsh login before using any other tsh commands. This allows users to omit --proxy flag in subsequent tsh commands. For example tsh ssh [email protected] will work.

SSH Agent Support

If there is an ssh agent running, tsh login will store the user certificate in the agent.

This can be verified via:

$ ssh-add -L

SSH agent can be used to feed the certificate to other SSH clients, for example to OpenSSH ssh.

Identity Files

tsh login can also save the user certificate into a file:

# Authenticate user against proxy.example.com and save the user 
# certificate into joe.pem file
$ tsh login --proxy=proxy.example.com --out=joe

# Use joe.pem to login into a server 'db'
$ tsh ssh --proxy=proxy.example.com -i joe [email protected]

By default --out flag will create an identity file suitable for tsh -i but if compatibility with OpenSSH is needed, --format=openssh must be specified. In this case the identity will be saved into two files: joe and joe-cert.pub:

$ tsh login --proxy=proxy.example.com --out=joe --format=openssh
$ ls -lh
total 8.0K
-rw------- 1 joe staff 1.7K Aug 10 16:16 joe
-rw------- 1 joe staff 1.5K Aug 10 16:16 joe-cert.pub

SSH Certificates for Automation

Regular users of Teleport must request an auto-expiring SSH certificate, usually every day. This doesn't work for non-intractive scripts, like cron jobs or CI/CD pipeline.

For such automation, it is recommended to create a separate Teleport user for bots and request a certificate for them with a long time to live (TTL).

In this example we're creating a certificate with a TTL of 10 years for the jenkins user and storing it in jenkins.pem file, which can be later used with -i (identity) flag for tsh.

# to be executed on a Teleport auth server
$ tctl auth sign --ttl=87600h --user=jenkins --out=jenkins.pem

Now jenkins.pem can be copied to the jenkins server and passed to -i (identity file) flag of tsh. Essentially tctl auth sign is an admin's equivalent of tsh login --out and allows for unrestricted certificate TTL values.

Exploring the Cluster

In a Teleport cluster all nodes periodically ping the cluster's auth server and update their status. This allows Teleport users to see which nodes are online with the tsh ls command:

# This command lists all nodes in the cluster which you previously logged in via "tsh login":
$ tsh ls

# Output:
Node Name     Node ID                Address            Labels
---------     -------                -------            ------
turing        11111111-dddd-4132     10.1.0.5:3022     os:linux
turing        22222222-cccc-8274     10.1.0.6:3022     os:linux
graviton      33333333-aaaa-1284     10.1.0.7:3022     os:osx

tsh ls can apply a filter based on the node labels.

# only show nodes with os label set to 'osx':
$ tsh ls os=osx

Node Name     Node ID                Address            Labels
---------     -------                -------            ------
graviton      33333333-aaaa-1284     10.1.0.7:3022     os:osx

Interactive Shell

To launch an interactive shell on a remote node or to execute a command, use tsh ssh command:

$ tsh ssh --help

usage: t ssh [<flags>] <[[email protected]]host> [<command>...]
Run shell or execute a command on a remote SSH node.

Flags:
      --user      SSH proxy user [alice]
      --proxy     SSH proxy host or IP address, for example --proxy=host:ssh_port,https_port
      --ttl       Minutes to live for a SSH session 
      --insecure  Do not verify server certificate and host name. Use only in test environments
  -d, --debug     Verbose logging to stdout
  -p, --port      SSH port on a remote host
  -l, --login     Remote host login
  -L, --forward   Forward localhost connections to remote server
      --local     Execute command on localhost after connecting to SSH node

Args:
  <[[email protected]]host>  Remote hostname and the login to use
  [<command>]    Command to execute on a remote host

tsh tries to mimic the ssh experience as much as possible, so it supports the most popular ssh flags like -p, -l or -L. For example if you have the following alias defined in your ~/.bashrc: alias ssh="tsh --proxy=work.example.com --user=myname" then you can continue using familiar SSH syntax:

$ ssh [email protected]
$ ssh -p 6122 [email protected] ls

Proxy Ports

A Teleport proxy uses two ports: 3080 for HTTPS and 3023 for proxying SSH connections. The HTTPS port is used to serve Web UI and also to implement 2nd factor auth for tsh client.

If a Teleport proxy is configured to listen on non-default ports, they must be specified via --proxy flag as shown:

tsh --proxy=proxy.example.com:5000,5001

This means use port 5000 for HTTPS and 5001 for SSH

Port Forwarding

tsh ssh supports OpenSSH -L flag which allows forwarding incoming connections from localhost to the specified remote host:port. The syntax of -L flag is:

-L [bind_ip]:listen_port:remote_host:remote_port

where "bind_ip" defaults to 127.0.0.1.

Example:

$ tsh ssh -L 5000:web.remote:80 node

Will connect to remote server node via proxy.example.com, then it will open a listening socket on localhost:5000 and will forward all incoming connections to web.remote:80 via this SSH tunnel.

It is often convenient to establish port forwarding, execute a local command which uses such connection and disconnect. You can do this via --local flag.

Example:

$ tsh ssh -L 5000:google.com:80 --local node curl http://localhost:5000

This command:

  1. Connects to node
  2. Binds the local port 5000 to port 80 on google.com
  3. Executes curl command locally, which results in curl hitting google.com:80 via node

Resolving Node Names

tsh supports multiple methods to resolve remote node names.

  1. Traditional: by IP address or via DNS.
  2. Nodename setting: teleport daemon supports nodename flag, which allows Teleport administrators to assign alternative node names.
  3. Labels: you can address a node by name=value pair.

In the example above, we have two nodes with os:linux label and one node with os:osx. Lets login into the OSX node:

$ tsh ssh os=osx

This only works if there is only one remote node with os:osx label, but you can still execute commands via SSH on multiple nodes using labels as a selector. This command will update all system packages on machines that run Linux:

$ tsh ssh os=ubuntu apt-get update -y

Short-lived Sessions

Suppose you are borrowing someone else's computer to login into a cluster. You probably don't want to stay authenticated on this computer for 23 hours (Teleport default). This is where the --ttl flag can help.

This command logs you into the cluster with a very short-lived (1 minute) temporary certificate:

$ tsh --ttl=1 login

You will be logged out after one minute, but if you want to log out immediately, you can always do:

$ tsh logout

Copying Files

To securely copy files to and from cluster nodes use tsh scp command. It is designed to mimic traditional scp as much as possible:

$ tsh scp --help

usage: tsh scp [<flags>] <from, to>...
Secure file copy

Flags:
      --user       SSH proxy user [alice]
      --proxy      SSH proxy host or IP address
      --ttl        Minutes to live for a SSH session
      --insecure   Do not verify server certificate and host name. Use only in test environments
  -P, --debug      Verbose logging to stdout
  -d, --debug      Verbose logging to stdout
  -r, --recursive  Recursive copy of subdirectories

Args:
  <from, to>       Source and the destination

Examples:

$ tsh scp example.txt [email protected]:/path/to/dest

Again, you may want to create a bash alias like alias scp="tsh --proxy=work scp" and use the familiar sytanx:

$ scp -P 61122 -r files [email protected]:/path/to/dest

Sharing Sessions

Suppose you are trying to troubleshoot a problem on a remote server. Sometimes it makes sense to ask another team member for help. Traditionally this could be done by letting them know which node you're on, having them SSH in, start a terminal multiplexer like screen and join a session there.

Teleport makes this a bit more convenient. Let's log into "luna" and ask Teleport for your current session status:

$ tsh ssh luna
>luna $ teleport status

User ID    : joe, logged in as joe from 10.0.10.1 43026 3022
Session ID : 7645d523-60cb-436d-b732-99c5df14b7c4
Session URL: https://work:3080/web/sessions/7645d523-60cb-436d-b732-99c5df14b7c4

Now you can invite another user account in the "work" cluster. You can share the URL for access through a web browser. Or you can share the session ID and she can join you through her terminal by typing:

$ tsh join 7645d523-60cb-436d-b732-99c5df14b7c4

Connecting to SSH Clusters behind Firewalls

Teleport supports creating clusters of servers located behind firewalls without any open listening TCP ports. This works by creating reverse SSH tunnels from behind-firewall environments into a Teleport proxy you have access to. This feature is called "Trusted Clusters".

This chapter explains how to a user may connect to a trusted cluster. Refer to the admin manual to learn how a trusted cluster can be configured.

Assuming the "work" Teleport proxy server is configured with a few trusted clusters, a user may use tsh clusters command to see a list of them:

$ tsh --proxy=work clusters

Cluster Name     Status
------------     ------
staging          online
production       offline

Now you can use --cluster flag with any tsh command. For example, to list SSH nodes that are members of "production" cluster, simply do:

$ tsh --proxy=work --cluster=production ls
Node Name     Node ID       Address            Labels
---------     -------       -------            ------
db-1          xxxxxxxxx     10.0.20.31:3022    kernel:4.4
db-2          xxxxxxxxx     10.0.20.41:3022    kernel:4.2

Similarly, if you want to SSH into db-1 inside "production" cluster:

$ tsh --proxy=work --cluster=production ssh db-1

This is possible even if nodes of the "production" cluster are located behind a firewall without open ports. This works because "production" cluster establishes a reverse SSH tunnel back into "work" proxy, and this tunnels is used to establish inbound SSH connections.

Web UI

Teleport proxy serves the web UI on https://proxyhost:3080. The UI allows you to see the list of online nodes in a cluster, open web-based Terminal to them, see recorded sessions and replay them. You can also join other users via active sessions.

You can copy & paste using the mouse. For working with a keyboard, Teleport employs tmux-like "prefix" mode. To enter prefix mode, press Ctrl+A.

While in prefix mode, you can press Ctrl+V to paste, or enter text selection mode by pressing [. When in text selection mode, move around using hjkl, select text by toggling space and copy it via Ctrl+C.

Using OpenSSH Client

There are a few differences between Teleport's tsh and OpenSSH's ssh but most of them can be made completely invisible.

  1. tsh always requires --proxy flag because tsh needs to know which cluster you are connecting to. But if you execute tsh --proxy=xxx login, the current proxy will be saved in your ~/.tsh profile and won't be needed for other tsh commands.

  2. tsh ssh operates two usernames: one for the cluster and another for the node you are trying to login into. See User Identities section below. For convenience, tsh assumes $USER for both by default. But again, if you use tsh login before tsh ssh, your Teleport username will be stored in ~/.tsh

Tip

To avoid typing tsh ssh [email protected] when loggin inton servers, you can create a symlink ssh -> tsh and execute the symlink. It will behave exactly like a standard ssh command, i.e. ssh [email protected]. This is helpful with other tools that expect ssh to just work.

Teleport is built using standard SSH constructs: keys, certificates, protocols. This means that a Teleport system is 100% compatible with both OpenSSH clients and servers.

For OpenSSH client (ssh) to work with a Teleport proxy, two conditions must be met:

  1. ssh must be configured to connect via a Teleport proxy.
  2. ssh needs to be given the SSH certificate issued by tsh login command.

SSH Proxy Configuration

To configure ssh to use a Teleport proxy on proxy.example.com, a user must update the /etc/ssh/ssh_config or ~/.ssh/config. A few examples are shown below:

# When "ssh db" is executed, OpenSSH will connect to proxy.example.com on port 3023
# and will request a proxied connection to "db" on port 3022 (default Teleport SSH port)
Host db
    Port 3022
    ProxyCommand ssh -p 3023 %[email protected] -s proxy:%h:%p

# When connecting to a node behind a trusted cluster named "remote-cluster",
# the name of the trusted cluster must be appended to the proxy subsystem 
# after '@':
Host *.trusted-cluster.example.com
   Port 3022
   ProxyCommand ssh -p 3023 %[email protected] -s proxy:%h:%[email protected]

The configuration above is all one will need to ssh [email protected] if there's an SSH agent running on a client computer. You can verify it by executing ssh-add -L right after tsh login. If the SSH agent is running the cluster certificates will be printed to stdout.

If there is no ssh-agent available, the certificate must be passed to the OpenSSH client explicitly.

Passing Teleport SSH Certificate to OpenSSH Client

If a user does not want to use an SSH agent or if the agent is not available, the certificate must be passed to ssh via IdentityFile option (see man ssh_config). Consider this example: the Teleport user "joe" wants to login into the proxy named "lab.example.com". He executes tsh login command:

$ tsh --proxy=lab.example.com login --user=joe

His identity is now stored in ~/.tsh/keys/lab.example.com, so his ~/.ssh/config needs to look like this:

# ~/.ssh/config file:
Host *.lab.example.com
    Port 3022
    IdentityFile ~/.tsh/keys/lab.example.com/joe
    ProxyCommand ssh -i ~/.tsh/keys/lab.example.com/joe -p 3023 %[email protected] -s proxy:%h:%p

Now he can SSH into any machine behind lab.example.com using the OpenSSH client:

$ ssh jenkins.lab.example.com

Troubleshooting

If you encounter strange behaviour, you may want to try to solve it by enabling the verbose logging by specifying -d flag when launching tsh.

Also you may want to reset it to a clean state by deleting temporary keys and other data from ~/.tsh

Getting Help

Please open an issue on Github. Alternatively, you can reach through the contact form on our website.

For commercial support, custom features or to try our Enterprise edition of Teleport, please reach out to us: [email protected].