Signals
You can send signals to a Teleport daemon to get diagnostic or gracefully shut it down:
| Signal | Teleport Daemon Behavior |
|---|---|
USR1 | Dumps diagnostics/debugging information into syslog. |
QUIT | Graceful shutdown. The daemon will wait until connections are dropped. |
TERM , INT or KILL | Immediate non-graceful shutdown. All existing connections will be dropped. |
USR2 | Forks a new Teleport daemon to serve new connections. |
HUP | Forks a new Teleport daemon to serve new connections and initiates the graceful shutdown of the existing process when there are no more clients connected to it. |
Graceful upgrades
In this guide we will try a manual graceful upgrade of a binary and a rollback using signals.
Locate a running teleport daemon PID:
Locate teleport process PID
pidof teleport235119
Unpack a new binary and replace a binary without stopping a server. Preserve the old binary, just in case if the upgrade goes wrong.
mv /usr/bin/teleport /usr/bin/teleport.bakcp /new/binary/teleport /usr/bin/teleport
Fork a new teleport process:
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 teleport235276 235119
In our example, 235276 is a PID of the child process, and 235119 is a PID of the parent.
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 it's 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
Examine the logs and use the system. You have two options:
If the new binary behaves with errors, shut down the child process:
kill -TERM 235276
Do not forget to restore the original binary
mv /usr/bin/teleport.bak /usr/bin/teleport
You can retry the process again later.