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Rollouts

How rollouts work

When you run wrangler deploy, the Worker code is updated immediately and Container instances are updated using a rolling deploy strategy. The default rollout configuration is two steps, where the first step updates 10% of the instances, and the second step updates the remaining 90%. This can be configured in your Wrangler config file using the rollout_step_percentage property.

When deploying a change, you can also configure a rollout_active_grace_period, which is the minimum number of seconds to wait before an active container instance becomes eligible for updating during a rollout. At that point, the container will be sent at SIGTERM, and still has 15 minutes to shut down gracefully. If the instance does not stop within 15 minutes, it is forcefully stopped with a SIGKILL signal. If you have cleanup that must occur before a Container instance is stopped, you should do it during this 15 minute period.

Once stopped, the instance is replaced with a new instance running the updated code. Requests may hang while the container is starting up again.

Here is an example configuration that sets a 5 minute grace period and a two step rollout where the first step updates 10% of instances and the second step updates 100% of instances:

{
  "containers": [
    {
      "max_instances": 10,
      "class_name": "MyContainer",
      "image": "./Dockerfile",
      "rollout_active_grace_period": 300,
      "rollout_step_percentage": [
        10,
        100
      ]
    }
  ],
  "durable_objects": {
    "bindings": [
      {
        "name": "MY_CONTAINER",
        "class_name": "MyContainer"
      }
    ]
  },
  "migrations": [
    {
      "tag": "v1",
      "new_sqlite_classes": [
        "MyContainer"
      ]
    }
  ]
}