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Teleport

Troubleshooting

Version 16.x

In this guide, we will explain how to address issues or unexpected behavior in your Teleport cluster.

You can use these steps to get more visibility into the teleport process so you can troubleshoot the Auth Service, Proxy Service, and Teleport agent services such as the Application Service and Database Service.

Prerequisites

  • A running Teleport cluster version 16.4.8 or above. If you want to get started with Teleport, sign up for a free trial or set up a demo environment.

  • The tctl admin tool and tsh client tool.

    Visit Installation for instructions on downloading tctl and tsh.

  • To check that you can connect to your Teleport cluster, sign in with tsh login, then verify that you can run tctl commands using your current credentials. For example: 
    tsh login --proxy=teleport.example.com --user=[email protected]
    tctl status
    Cluster  teleport.example.com
    Version  16.4.8
    CA pin   sha256:abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678
    If you can connect to the cluster and run the tctl status command, you can use your current credentials to run subsequent tctl commands from your workstation. If you host your own Teleport cluster, you can also run tctl commands on the computer that hosts the Teleport Auth Service for full permissions.

Step 1/3. Enable verbose logging

To change log levels in Teleport, you can use either of the following methods:

  • Debug Service: Allows on-the-fly log level adjustments without restarting the instance, which is ideal for troubleshooting sessions.
  • Updating configuration: Involves updating the Teleport configuration file and restarting the instance.

The Teleport Debug Service allows administrators to dynamically manage log levels without restarting the instance. The service, enabled by default, ensures local-only access and must be consumed from inside the same instance.

To change the instance log level use the teleport debug set-log-level command:

teleport debug set-log-level DEBUG
Changed log level from "INFO" to "DEBUG".
kubectl -n teleport exec my-pod -- teleport set-log-level DEBUG
Changed log level from "INFO" to "DEBUG".

If you're unsure what is the current level you can retrieve it using teleport debug get-log-level.

After troubleshooting, remember to turn the log level back to avoid generating unnecessary logs.

Specify your Teleport configuration path

If your Teleport configuration is not placed on the default path (/etc/teleport.yaml), you must specify its location to the CLI command using the -c/--config flag.

To diagnose problems, you can configure the teleport process to run with verbose logging enabled by passing it the -d flag. teleport will write logs to stderr.

Alternatively, you can set the log level from the Teleport configuration file:

teleport:
  log:
    severity: DEBUG

Restart the teleport process to apply the modified log level. Logs will resemble the following (these logs were printed while joining a server to a cluster, then terminating the teleport process on the server):

Debug logs include the file and line number of the code that emitted the log, so you can investigate (or report) what a teleport process was doing before it ran into problems. Here's an example:

DEBU [NODE:PROX] Agent connected to proxy: [aee1241f-0f6f-460e-8149-23c38709e46d.tele.example.com aee1241f-0f6f-460e-8149-23c38709e46d teleport-proxy-us-west-2-6db8db844c-ftmg9.tele.example.com teleport-proxy-us-west-2-6db8db844c-ftmg9 localhost 127.0.0.1 ::1 tele.example.com 100.92.90.42 remote.kube.proxy.teleport.cluster.local]. leaseID:4 target:tele.example.com:11106 reversetunnel/agent.go:414
DEBU [NODE:PROX] Changing state connecting -> connected. leaseID:4 target:tele.example.com:11106 reversetunnel/agent.go:210
DEBU [NODE:PROX] Discovery request channel opened: teleport-discovery. leaseID:4 target:tele.example.com:11106 reversetunnel/agent.go:526
DEBU [NODE:PROX] handleDiscovery requests channel. leaseID:4 target:tele.example.com:11106 reversetunnel/agent.go:544
DEBU [NODE:PROX] Pool is closing agent. leaseID:2 target:tele.example.com:11106 reversetunnel/agentpool.go:238
DEBU [NODE:PROX] Pool is closing agent. leaseID:3 target:tele.example.com:11106 reversetunnel/agentpool.go:238

It is not recommended to run Teleport in production with verbose logging as it generates a substantial amount of data.

Step 2/3. Generate a debug dump

The teleport binary is a Go program. Go programs assign work to CPU threads using an abstraction called a goroutine. You can get a goroutine dump of a running teleport process by sending it a USR1 signal.

This is especially useful for troubleshooting a teleport process that appears stuck, since you can see which a goroutine is blocked and and why. For example, goroutines often communicate using channels, and a goroutine dump indicates whether a goroutine is waiting to send or receive on a channel.

To generate a goroutine dump, send a USR1 signal to a teleport process:

kill -USR1 $(pidof teleport)

Teleport will print the debug information to stderr. Here what you will see in the logs:

INFO [PROC:1]    Got signal "user defined signal 1", logging diagnostic info to stderr. service/signals.go:99
Runtime stats
goroutines: 64
OS threads: 10
GOMAXPROCS: 2
num CPU: 2
...
goroutines: 84
...
Goroutines
goroutine 1 [running]:
runtime/pprof.writeGoroutineStacks(0x3c2ffc0, 0xc0001a8010, 0xc001011a38, 0x4bcfb3)
	/usr/local/go/src/runtime/pprof/pprof.go:693 +0x9f
...

You can print a goroutine dump without enabling verbose logging.

Step 3/3. Ask for help

Once you have collected verbose logs and a goroutine dump from your teleport binary, you can use this information to get help from the Teleport community and Support team.

Collect your Teleport version

Determine the version of the teleport process you are investigating.

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

You can also collect the versions of the Teleport Auth Service, Proxy Service, and client tools to rule out version compatibility issues.

To see the version of the Auth Service and Proxy Service, run the following command:

tctl status
Cluster  mytenant.teleport.shVersion  16.4.7Host CA  never updatedUser CA  never updatedJwt CA   never updatedCA pin   sha256:abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678

Get the versions of your client tools:

tctl version
Teleport v9.0.4 git: go1.18
tsh version
Teleport v9.0.4 git: go1.18

Pose your question

If you have a question or need assistance please submit a request through the Teleport support portal.

If you need help, please ask on our community forum. You can also open an issue on GitHub.

For more information about Enterprise features reach out to the Teleport sales team. You can also sign up for a free trial of Teleport Enterprise.

Further reading

This guide showed how to investigate issues with the teleport process. To see how you can monitor more general health and performance data from your Teleport cluster, read our Teleport Diagnostics guides.

For additional sources of Teleport support, please see the Teleport Support and Education Center.

Common Issues

teleport.cluster.local

It is common to see references to teleport.cluster.local within logs and errors in Teleport. This is a special value that is used within Teleport for two purposes and seeing it within your logs is not necessarily an indication that anything is incorrect.

Firstly, Teleport uses this value within certificates (as a DNS Subject Alternative Name) issued to the Auth and Proxy Service. Teleport clients can then use this value to validate the service's certificates during the TLS handshake regardless of the service address as long as the client already has a copy of the cluster's certificate authorities. This is important as there are often multiple different ways that a client can connect to the Auth Service and these are not always via the same address.

Secondly, this value is used by clients as part of the URL when making gRPC or HTTP requests to the Teleport API. This is because the Teleport API client uses special logic to open the connection to the Auth Service to make the request, rather than connecting to a single address as a typical client may do. This special logic is necessary for the client to be able to support connecting to a list of Auth Services or to be able to connect to the Auth Service through a tunnel via the Proxy Service. This means that teleport.cluster.local appears in log messages that show the URL of a request made to the Auth Service, and does not explicitly indicate that something is misconfigured.

ssh: overflow reading version string and/or 502: Bad Gateway errors

You must ensure that your reverse proxy is communicating with Teleport using HTTPS. When running Teleport in Kubernetes and using nginx as an ingress, this requires adding an annotation to the chart values:

annotations:
  ingress:
    nginx.ingress.kubernetes.io/backend-protocol: "HTTPS"

Deploying Teleport behind Cloudflare, whether using its proxy ("orange-clouding") or tunnels (cloudflared) should work with Teleport version 15.1 or higher. See the TLS Routing FAQ for more details.