Using %n in agent names is deprecated and will soon be removed 👋

The default name for a Buildkite Agent used to be agent-%n, resulting in agent-1, agent-2, etc. Pretty quickly, though, this gets tricky to keep unique, especially with a big database full of agent names. So to keep our database humming, we're removing support for %n.

We began this process with Buildkite Agent v3.27.0 released on 8th February, 2021, removing %n from the default agent name. Elastic CI Stack for AWS v5.2.0 was also updated to replace usage of %n with %spawn on the same day.

If you're using Elastic CI Stack for AWS, please make sure you're running v5.2.0 or newer. The version you're using should be visible on your agents page:

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If you're running your agents another way, please review your agent configuration and confirm you're not using %n.

If you are using %n, there are a few alternatives:

• If you're running a single agent on each host, use %hostname.
• If you're running multiple agents, use the spawn option and %hostname-%spawn.
• If neither of the previous options work, use %random which will turn into a few random characters.

Check out our docs for a complete reference: https://buildkite.com/docs/agent/v3/configuration#name

We'll begin brownouts of %n on Monday, 8th August 2022. Finally, we'll remove support for %n on Monday, 5th September 2022. Agents which still use %n in their name after this date will fail to connect and accept work.

If you need some more time, or have a problem completing this migration, please drop us an email to support@buildkite.com.