---
title: "Update and restart applications"
description: "Distinguish saving configuration, restarting tasks, and rolling back a previous application change."
---

> Documentation Index
> Fetch the complete documentation index at: https://cdelivery.dev/llms.txt
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# Update and restart applications

Use a configuration update to change desired behavior. Use restart to replace running tasks without inventing a configuration change.

## Update

Open application settings, make the intended change, and save. Changes to images, environment, resources, networking, or supported configuration files may cause task replacement. Review the [update strategy](/docs/guides/release-safety/update-strategy/) and any [Guardian](/docs/guides/release-safety/guardian/) validation before a release.

Saving identical settings is a no-op and does not force new containers. A registry tag changing outside CDelivery also does not automatically schedule an update.

## Restart

Use the application's restart action when tasks need replacement. Restart follows the application's update strategy; it does not guarantee uninterrupted service. The default stop-first, all-at-once strategy can interrupt all replicas.

Restarting does not delete a correctly mounted volume, reset database contents, or solve an invalid command. If the process immediately fails again, inspect logs and fix its cause.

## Verify

Compare desired and actual replicas, inspect the image and startup logs, check relevant events, and issue a business request. For a stateful application, verify data as well.

An accepted request may precede completed replacement. Do not submit repeated updates just because the first replacement is still progressing.

## Rollback and removal

When a previous configuration is available, [rollback](/docs/guides/release-safety/rollback/) can restore it. It does not undo migrations or restore files. [Deleting an application](/docs/guides/apps/delete/) is separate and retains its data volumes.

Source: https://cdelivery.dev/docs/guides/apps/lifecycle/index.mdx