Every time a service is deployed, Hangar records a deployment with its build log, its status and the commit or image it came from. The service's Deployments tab lists them, newest first.
What starts a deploy
- A push, when the repository is connected through a Git provider and Deploy on push is on. You can also choose to deploy only when you publish a tag.
- The Deploy button, for a manual release.
- The deploy hook, a URL you can call from anywhere.
A build that is still running can be cancelled from the same tab.
Deploy hook
The Deployments tab shows the service's deploy hook URL. Calling it starts a deploy, which is how you release from a CI pipeline after your tests pass, or from a registry when a new image is pushed.
- For a service that runs a Docker image, a plain
POSTto the URL deploys the image again. If the request comes from a registry webhook that names the image and tag, Hangar checks that they match the service's before deploying. - For a service built from Git, add the URL as a push webhook on your Git host. Hangar reads the branch from the push event and deploys only when it is the service's branch.
Deploy hooks only work while Deploy on push is on. Treat the URL as a secret: anyone who has it can start a deploy.
Rollbacks
Rollbacks are off by default. Turn them on from the rollback settings in the service's Deployments tab; from then on, each successful deployment keeps the image it built in the platform registry.
To roll back, open Deployments and choose Roll back on an earlier deployment. The service goes back to that image and to the environment variables it was deployed with. Nothing is rebuilt, so it takes only the few seconds needed to pull the image.
Hangar keeps the last 10 deployments of each service, and with them their rollback images. For a service that runs a Docker image, deploy a tag per version so that rolling back returns to the same build. Databases have backups and point-in-time recovery instead.