upgrading-the-teleport-binary.mdx

title	description
Upgrading the Teleport Binary	How to upgrade a teleport binary without sacrificing availability.

In this guide, we will show you how to upgrade the teleport binary on a Linux host without sacrificing availability.

If you are running teleport as a container, see How to Run Teleport Using Docker for information on specifying a version.

Prerequisites

This guide requires a host where the teleport binary is running. The version of the binary must be behind the latest.

For Teleport major version (=teleport.major_version=) the latest version is (=teleport.version=). Compare this to the version of Teleport you have installed on the host:

$ teleport version
Teleport v8.3.7 git:v8.3.7-0-ga8d066935 go1.17.3

Step 1/3. Download a new Teleport binary

Preserve the old binary, just in case the upgrade goes wrong.

$ DIR=$(which teleport | xargs dirname)
$ sudo mv ${DIR}/teleport ${DIR}/teleport.bak

Install the newest version of Teleport on the host:

(!/docs/pages/includes/install-linux.mdx!)

Step 2/3. Fork the teleport process

Fork a new teleport process by sending it the USR2 signal:

$ sudo kill -USR2 $(pidof teleport)

The original teleport process forked a new child process and passed existing file descriptors to the child. You now have two processes handling requests on the same socket:

$ pidof teleport
# 235276 235119

In our example, 235276 is a PID of the child process, and 235119 is a PID of the parent.

You can use the following command, which prints the parent for each PID returned by pidof:

$ ps -o ppid= -p $(pidof teleport)
   1494
   1495

In the logs you will see that the parent process reports that it has forked a new child process, and the child accepts file descriptors from its parent.

2021-08-19T10:16:51-07:00 [PROC:1]  INFO Forked new child process. path:/usr/local/teleport service/signals.go:457
2021-08-19T10:16:51-07:00 [PROC:1]  INFO Using file descriptor diag 127.0.0.1:3434 passed by the parent process. service/signals.go:207

Step 3/3. Return to a single teleport process

After forking the new teleport process, check the logs to ensure that the process is running as expected. After that, you should either roll back or complete the upgrade:

If the new binary behaves with errors, shut down the child process: ```code $ sudo kill -TERM 235276 2022-04-20T15:33:58Z INFO [PROC:1] Got signal "terminated", exiting immediately. service/signals.go:86 2022-04-20T15:33:58Z WARN [PROC:1] Forked teleport process 235276 has exited with status: 0. service/signals.go:506 ```

<Admonition type="danger" title="WARNING"

Do not forget to restore the original binary
```code
$ sudo mv ${DIR}/teleport.bak ${DIR}/teleport
```

You can retry the process again later.

<Admonition type="danger" title="WARNING"

If you are upgrading a `teleport` daemon using an SSH connection established
via Teleport, make sure to connect to the newly upgraded `teleport` process
and shut down the previous `teleport` process from it.

You can see which `teleport` process handles the connection by using
`pstree`:

```code
$ pstree -aps $$
# systemd,1 splash
#  └─systemd,6247 --user
#      └─teleport-,235276
#          └─bash,190718
#              └─pstree,242371 -aps 190718
```

Shut down the parent process gracefully using `SIGQUIT`:

```code
$ sudo kill -QUIT 235119
```

The parent process will log a graceful shutdown:

```txt
2021-08-19T10:32:10-07:00 INFO [PROXY:SER] Shutting down gracefully. service/service.go:2952
```

In a couple of minutes, all existing connections drain off and the parent will exit:

```code
$ pidof teleport
# 235276
```

If for some reason, the parent process gets stuck (e.g., waiting for
existing connections to finish), you can shut it down non-gracefully:

```code
$ sudo kill -TERM 235119
```

You are all set.

Further reading

In this guide, we explained how to upgrade the teleport binary on a single host. If you would like to learn how to upgrade all of the components in a Teleport cluster while preserving compatibility, read Upgrading a Teleport Cluster.

See the full list of supported signals in the Teleport Signals Reference.