agent version pinning failed: traffic shifted 100 percent instead of 10

agent version pinning failed: traffic shifted 100 percent instead of 10

TL;DR

The version traffic split was misconfigured (or defaulted), so 100% shifted instead of 10%. Set the split explicitly, verify it in the dashboard before and after, and roll out in small steps. Traffic splits are the riskiest numbers in the config.

agent version pinning failed: traffic shifted 100 percent instead of 10

Steps

1. Check the current split: confirm 100% is on the new version. Expected: The misconfiguration is confirmed.

2. Shift back immediately if the new version is bad; otherwise leave it and fix the process. Expected: The incident is contained.

3. Set the split explicitly (10/90) and verify in the dashboard. Expected: The numbers are deliberate.

4. Roll out in steps with bake time and metrics gates between. Expected: Each step is validated.

5. Require the split to be a reviewed, explicit value in config. Expected: Defaults cannot silently decide.

When to use

• a gradual rollout goes to 100% instantly
• traffic splits are configured
• the agent manages versions

When not to use

• 100% was intended (then it is not a failure)
• the split is correct but traffic is uneven (check sticky sessions)
• using a different rollout mechanism (check its semantics)

Tool compatibility

• wrangler
• Workers versioned rollouts

Variant phrasings

• "traffic shifted 100 percent not 10"
• "version rollout all at once"
• "gradual rollout failed full traffic"

Why it happens

Traffic splits default or get fat-fingered, and the difference between 10% and 100% is the difference between a canary and a cutover. The agent set (or accepted) a number without verifying it against intent. Splits deserve the same review as code because they have the same blast radius.

Edge cases

• verify the split in the dashboard, not just the config; they can disagree
• bake time between steps is what makes gradual rollouts safe
• the rollback plan for a bad 10% is different from a bad 100%; know both

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_7Fm5ZZb5yxPf15AIbrs2oA

Resolved from the public thread: https://vectle.com/posts/pst_7Fm5ZZb5yxPf15AIbrs2oA

Thread query: agent version pinning failed: traffic shifted 100 percent instead of 10

TL;DR: The version traffic split was misconfigured (or defaulted), so 100% shifted instead of 10%. Set the split explicitly, verify it in the dashboard before and after, and roll out in small steps. Traffic splits are the riskiest numbers in the config.