FAQ.md

Frequently Asked Questions

When will my PR or fix get released?

Telegraf has four minor releases a year in March, June, September, and December. In between each of those minor releases, there are 2-4 bug fix releases that happen every 3 weeks.

PRs that resolves issues are released in the next release. PRs that introduce new features are held for the next minor release.

How can I filter or select specific metrics?

Telegraf has options to select certain metrics or tags as well as filter out specific tags or fields:

• Selectors allow a user to include or exclude entire metrics based on the metric name or tag key/pair values.
• Modifiers allow a user to remove tags and fields based on specific keys, with glob support.

For more details and examples, see the Metric Filtering section in the docs.

Could not find a usable config.yml, you may have revoked the CircleCI OAuth app

This is an error from CircleCI during test runs.

To resolve the error, you need to log back into CircleCI with your username/password if that is how you log in or if you use GitHub log, re-create your oauth/re-login with github.

That should regenerate your token and then allow you to push a commit or close and reopen this PR and tests should run.

What does "Context Deadline exceeded (Client.Timeout while awaiting headers)" mean?

This is a generic error received from Go's HTTP client. It is generally the result of a network blip or hiccup as a result of a DNS, proxy, firewall, and/or other network issue.

The error should be temporary and Telegraf will recover shortly after without the loss of data.

How do I set the timestamp format for parsing data?

Telegraf's timestamp_format config option requires the use Go's reference time to correctly translate the timestamp. For example, if you have the time:

2023-03-01T00:00:42.586+0800

A user needs the timestamp format:

2006-01-02T15:04:05.000-0700

User's can try this out in the Go playground.

Q: How can I monitor the Docker Engine Host from within a container?

You will need to setup several volume mounts as well as some environment variables:

docker run --name telegraf \
    -v /:/hostfs:ro \
    -e HOST_ETC=/hostfs/etc \
    -e HOST_PROC=/hostfs/proc \
    -e HOST_SYS=/hostfs/sys \
    -e HOST_VAR=/hostfs/var \
    -e HOST_RUN=/hostfs/run \
    -e HOST_MOUNT_PREFIX=/hostfs \
    telegraf

Q: Why do I get a "no such host" error resolving hostnames that other programs can resolve?

Go uses a pure Go resolver by default for name resolution. This resolver behaves differently than the C library functions but is more efficient when used with the Go runtime.

If you encounter problems or want to use more advanced name resolution methods that are unsupported by the pure Go resolver, you can switch to the cgo resolver.

If running manually set:

export GODEBUG=netdns=cgo

If running as a service add the environment variable to /etc/default/telegraf:

GODEBUG=netdns=cgo

Q: How can I manage series cardinality?

High series cardinality, when not properly managed, can cause high load on your database. Telegraf attempts to avoid creating series with high cardinality, but some monitoring workloads such as tracking containers are are inherently high cardinality. These workloads can still be monitored, but care must be taken to manage cardinality growth.

You can use the following techniques to avoid cardinality issues:

• Use metric filtering options to exclude unneeded measurements and tags.
• Write to a database with an appropriate retention policy.
• Consider using the Time Series Index.
• Monitor your databases using the show cardinality commands.
• Consult the InfluxDB documentation for the most up-to-date techniques.